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  • 101. George, Gejo
    et al.
    Joseph, Kuruvilla
    Nagarajan, E R
    Jose, E Tomlal
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Thermal, calorimetric and crystallisation behaviour of polypropylene/jute yarn bio-composites fabricated by commingling technique2013In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 48, p. 110-120Article in journal (Refereed)
    Abstract [en]

    Commingled biocomposites based on polypropylene/jute yarns were prepared using commingling technique. The thermal and calorimetric behaviour of these commingled composites were studied with respect to fibre content and various chemical treatments. The thermal stability of the composites was found to be in between that of jute fibre and neat polypropylene (PP). Different chemical treatments increased the thermal stability of the composites due to increased interfacial adhesion between the matrix and reinforcement. Jute yarn acts as nucleating agents and favours the process of crystallisation thereby increasing the crystallisation temperature. Chemical treatments further increased the crystallisation temperature as a result of better interfacial adhesion between jute yarn and PP matrix. The close proximity of jute yarns weakens the mechanical bonds between PP molecules resulting in marginal lowering of melting temperatures. Polarized optical microscopic studies revealed the formation of transcrystalline layer around the jute fibre after 6 h.

  • 102. George, Gejo
    et al.
    Tomlal Jose, E.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Nagarajan, E.R.
    Kuruvilla, Joseph
    Viscoelastic behaviour of novel commingled biocomposites based on polypropylene/jute yarns2012In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 43, no 6, p. 893-902Article in journal (Refereed)
    Abstract [en]

    Jute yarn reinforced polypropylene commingled composites were prepared by an environmentally benign technique called commingling method in which the matrix fibres and reinforcing fibres are intermingled together with good alignment. The dynamic mechanical properties or viscoelastic behaviour of these commingled composites were studied with reference to fibre content and various chemical treatments. The storage and loss modulus increased with fibre content where as tan δ decreased. KMnO4 and MAPP treated composites showed much higher storage and loss modulus values at all temperatures compared to untreated one. The glass transition temperature showed a marginal increasing tendency with fibre content and chemical treatments. The surface treatment mechanisms were supported by FT-IR spectra and the increase in interfacial adhesion after chemical treatments were supported by SEM images. Theoretical modelling was used to predict the values of storage modulus and tan δ and was found to be comparable with that of experimentally obtained results.

  • 103. Goutianos, S.
    et al.
    Peijs, T.
    Nyström, B.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Development of flax fibre based textile reinforcements for composite applications.2006In: Applied Composite Materials, ISSN 0929-189X, E-ISSN 1573-4897, Vol. 13, no 4, p. 199-Article in journal (Refereed)
  • 104.
    Guo, L
    et al.
    University of Borås, Swedish School of Textiles.
    Soroudi, A.
    University of Borås, Swedish School of Textiles.
    Berglin, L.
    University of Borås, Swedish School of Textiles.
    Mattila, H.
    University of Borås, Swedish School of Textiles.
    Skrifvars, M.
    University of Borås, School of Engineering.
    Torstensson, H.
    University of Borås, School of Engineering.
    Fibre-based single-wire keyboard: the integration of a flexible tactile sensor into e-textiles2011In: AUTEX Research Journal, ISSN 1470-9589, E-ISSN 2300-0929, Vol. 11, no 4Article in journal (Refereed)
  • 105.
    Guo, Li
    et al.
    University of Borås, Swedish School of Textiles.
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Mattila, Heikki
    University of Borås, Swedish School of Textiles.
    Mehrjerdi, Adib
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Disappearing Sensors. Textile Based Sensors for Monitoring Breathing2011Conference paper (Refereed)
    Abstract [en]

    Textile based sensors were developed and used for remote monitoring of breathing. The breathing is simulated by using a new cyclic tester device. In the simulated a cyclic force is applied along the length of the textile sensor. However due to the morphology of human body, in real situation the sensor is not only under stretching but also under a certain degree of bending. A prototype garment with the sensor situated on the chest area was made. The prototype was worn by 10 persons, and breathing was recorded as the persons were sitting still, walking and jogging. Deep breathing in the supine position and breathing with a method called athletic breathing were used to evaluate the sensor. A testing circuit and a Labview program were made for preliminary test. The sensor is wearable, washable and comfortable. Sensor construction is totally ‘disappearing’ and visualize as printed pattern onto the surface of garment.

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  • 106.
    Guo, Li
    et al.
    University of Borås, Swedish School of Textiles.
    Peterson, Joel
    University of Borås, Swedish School of Textiles.
    Qureshi, Waqas
    Kalantar Mehrjerdi, Adib
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Knitted Wearable Stretch Sensor for Breathing Monitoring Application2011Conference paper (Refereed)
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  • 107.
    Guo, Li
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sandsjö, Leif
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare.
    Ortiz-Catalan, Max
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Systematic review of textile-based electrodes for long-term and continuous surface electromyography recording2020In: Textile research journal, ISSN 0040-5175, E-ISSN 1746-7748, Vol. 90, no 2, p. 227-244, article id 0040517519858768Article in journal (Refereed)
    Abstract [en]

    This systematic review concerns the use of smart textiles enabled applications based on myoelectric activity. Electromyography (EMG) is the technique for recording and evaluating electric signals related to muscle activity (myoelectric). EMG is a well-established technique that provides a wealth of information for clinical diagnosis, monitoring, and treatment. Introducing sensor systems that allow for ubiquitous monitoring of health conditions using textile integrated solutions not only opens possibilities for ambulatory, long-term, and continuous health monitoring outside the hospital, but also for autonomous self-administration. Textile-based electrodes have demonstrated potential as a fully operational alternative to ‘standard’ Ag/AgCl electrodes for recording surface electromyography (sEMG) signals. As a substitute for Ag/AgCl electrodes fastened to the skin by taping or pre-gluing adhesive, textile-based electrodes have the advantages of being soft, flexible, and air permeable; thus, they have advantages in medicine and health monitoring, especially when selfadministration, real-time, and long-term monitoring is required. Such advances have been achieved through various smart textile techniques; for instance, adding functions in textiles, including fibers, yarns, and fabrics, and various methods for incorporating functionality into textiles, such as knitting, weaving, embroidery, and coating. In this work, we reviewed articles from a textile perspective to provide an overview of sEMG applications enabled by smart textile strategies. The overview is based on a literature evaluation of 41 articles published in both peer-reviewed journals and conference proceedings focusing on electrode materials, fabrication methods, construction, and sEMG applications. We introduce four textile integration levels to further describe the various textile electrode sEMG applications reported in the reviewed literature. We conclude with suggestions for future work along with recommendations for the reporting of essential benchmarking information in current and future textile electrode applications.

  • 108.
    Hatamvand, Mohammad
    et al.
    Yazd University.
    Abbas Mirjalili, Seyed
    Yazd University.
    Fattahi, Saeid
    Yazd University.
    Bashir, Tariq
    Yazd University.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Optimum Drafting Conditions of Polyester and Viscose Blend Yarns2017In: AUTEX Research Journal, ISSN 1470-9589, E-ISSN 2300-0929Article in journal (Refereed)
    Abstract [en]

    In this study, we used an experimental design to investigate the  influence of the total draft, break draft, distance between the aprons (Clips) and production roller pressure on yarn quality in order to obtain optimum drafting conditions for polyester and viscose (PES/CV) blend yarns in ring spinning frame. We used PES fibers (1.4 dtex × 38 mm long) and CV fibers (1.6 dtex × 38 mm long) to spin a 20 Tex blend yarn of PES (70%)/CV (30%) blend ratio. When the break draft, adjustment of distance between of aprons and roller pressure is not reasonable, controlling and leading of the fibers is not sufficient for proper orientation of the fibers in the yarn structure to produce a high quality yarn. Experimental results and statistical analysis show that the best yarn quality will be obtained under drafting conditions total draft of 38, 1.2 break draft, 2.8 mm distance between of aprons and maximum pressure of the production top roller (18daN).

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  • 109.
    Hatamvand, Mohammad
    et al.
    Department of Textile Engineering, Yazd University, Yazd, Iran.
    Mirjalili, Seyed Abbas
    Department of Textile Engineering, Yazd University, Yazd, Iran.
    Fattahi, Saeid
    Department of Textile Engineering, Yazd University, Yazd, Iran.
    Bashir, Tariq
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    OPTIMUM DRAFTING CONDITIONS OF POLYESTER AND VISCOSE BLEND YARNS2016In: AUTEX Research Journal, ISSN 1470-9589, E-ISSN 2300-0929Article in journal (Refereed)
    Abstract [en]

    In this study, we used an experimental design to investigate the influence of the total draft, break draft, distancebetween the aprons (Clips) and production roller pressure on yarn quality in order to obtain optimum draftingconditions for polyester and viscose (PES/CV) blend yarns in ring spinning frame. We used PES fibers (1.4 dtex ×38 mm long) and CV fibers (1.6 dtex × 38 mm long) to spin a 20 Tex blend yarn of PES (70%)/CV (30%) blend ratio.When the break draft, adjustment of distance between of aprons and roller pressure is not reasonable, controllingand leading of the fibers is not sufficient for proper orientation of the fibers in the yarn structure to produce a highquality yarn. Experimental results and statistical analysis show that the best yarn quality will be obtained underdrafting conditions total draft of 38, 1.2 break draft, 2.8 mm distance between of aprons and maximum pressure ofthe production top roller.

  • 110.
    Hatamvand, Mohammad
    et al.
    Yazd University.
    Mirjalili, Seyed Abbas
    Yazd University.
    Sharzehee, Maryam
    Yazd University.
    Behjat, Abbas
    Yazd University.
    Jabbari, Mostafa
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Fabrication parameters of low-temperature ZnO-based hole-transport-free perovskite solar cells2017In: Optik (Stuttgart), ISSN 0030-4026, E-ISSN 1618-1336, Vol. 40, p. 443-450Article in journal (Refereed)
    Abstract [en]

    Perovskite solar cells (PSCs) are a new generation solar cells. Low-Temperature techniques are used for fabrication PSCs on a flexible substrate that has a low thermal tolerance. In this paper, low-temperature PSCs with ZnO nanoparticles were prepared as electron transport material (ETM) without hole transport material (HTM). Effects of some of the fabrication parameters of low-temperature ZnO based PSCs without HTM, on their principal characteristics and performance, were investigated. Parameters such as the concentration of ZnO nanoparticles (NPs) dispersion, spin coating speed of ZnO NPs, and concentration of CH3NH3I on characteristics and performance of fabricated low-temperature PSCs were studied. The study shows that by changing these parameters, the performance of the fabricated PSCs changes considerably.

  • 111. Hooshmand, S.
    et al.
    Cho, S-W.
    University of Borås, School of Engineering.
    Skrifvars, M.
    University of Borås, School of Engineering.
    Mathew, A.P.
    Oksdamn, K.
    Preparation of bio-nanocomposite fibers by melt spinning of cellulose acetate butyrate (CAB) and cellulose nanowhiskers (CNW)2012Conference paper (Other academic)
  • 112. Hooshmand, Saleh
    et al.
    Aitomäki, Yvonne
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Mathew, Ali
    Oksman, Kristiina
    All-cellulose nanocomposite fibers produced by melt spinning cellulose acetate butyrate and cellulose nanocrystals2014In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, no 4, p. 2665-2678Article in journal (Refereed)
    Abstract [en]

    Bio-based continuous fibers were prepared by melt spinning cellulose acetate butyrate (CAB), cellulose nanocrystals (CNC) and triethyl citrate. A CNC organo-gel dispersion technique was used and the prepared materials (2 and 10 wt% CNC) were melt spun using a twin-screw micro-compounder and drawn to a ratio of 1.5. The microscopy studies showed that the addition of CNC in CAB resulted in defect-free and smooth fiber surfaces. An addition of 10 wt% CNC enhanced the storage modulus and increased the tensile strength and Young’s modulus. Fiber drawing improved the mechanical properties further. In addition, a micromechanical model of the composite material was used to estimate the stiffness and showed that theoretical values were exceeded for the lower concentration of CNC but not reached for the higher concentration. In conclusion, this dispersion technique combined with melt spinning can be used to produce all-cellulose nanocomposites fibers and that both the increase in CNC volume fraction and the fiber drawing increased the mechanical performance.

  • 113. Hooshmand, Saleh
    et al.
    Cho, Sung-Woo
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Mathew, Ali
    Oksman, Kristiina
    Melt spun cellulose nanocomposite fibres: Comparison of two dispersion techniques2014In: Plastics, rubber and composites, ISSN 1465-8011, E-ISSN 1743-2898, Vol. 43, no 1, p. 15-24Article in journal (Refereed)
    Abstract [en]

    Biobased fibres of cellulose acetate butyrate (CAB) and cellulose nanocrystals (CNC) and triethyl citrate (TEC) as plasticiser were prepared by melt spinning. To obtain homogeneous dispersion of CNC, two different dispersion techniques were studied. In the first, the water content of the CNC suspension was reduced and exchanged to ethanol using centrifugation. In the second, the water in the CNC suspension was completely exchanged to ethanol by sol–gel process. Results showed that tensile modulus and tensile strength of the nanocomposite fibres produced with the first technique were lower than CAB–TEC fibres, but the fibres produced by the sol–gel process showed an increase in the tensile modulus and had no decrease in the strength. Optical microscopy of the fibres indicated a few aggregations on the sol–gel prepared materials. The results indicate that the sol–gel process is enhancing the dispersion of CNC and can be a suitable way to prepare nanocomposite fibres.

  • 114. Hooshmand, Saleh
    et al.
    Soroudi, Azadeh
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Electroconductive composite fibers by melt spinning of polypropylene/polyamide/carbon nanotubes2011In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 161, no 15-16, p. 1731-1737Article in journal (Refereed)
    Abstract [en]

    In this study, the blends of polypropylene/polyamide with carbon nanotubes (CNTs) have been prepared and melt spun to as-spun and drawn fibers. Thermal analysis showed that increasing the polyamide content, decreased the degree of crystallinity in the blends. Characterization of fibers showed that both conductivity and tensile strength have been improved by increasing the amount of polyamide in the blends as well as the melt blending temperature; furthermore, the morphology, electrical and mechanical properties of the blends were significantly influenced by adding 1 phr compatibilizer to the blend. The comparison between as-spun fibers and drawn fibers proved that although mechanical properties were improved after drawing, the electrical conductivity was decreased from the order of E−02 to E−06 (S/cm), due to applied draw-ratio of three.

  • 115. Hooshmand, Saleh
    et al.
    Soroudi, Azadeh
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Preparation of conductive composite fibers made from polypropylene, polyamide and multi-walled carbon nanotubes: electrical, mechanical and thermal characteristics2011Conference paper (Refereed)
  • 116.
    Jabbari, Mostafa
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lundin, Magnus
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bahadorikhalili, S
    Department of Chemistry, Ångström Laboratory, Uppsala University.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Finding solvent for polyamide 11 using a computer software2019In: Zeitschrift für Physikalische Chemie, ISSN 0942-9352Article in journal (Refereed)
    Abstract [en]

    The solvent finding step has always been a time-consuming job in chemical-involved processes. The source of difficulty mainly comes from the trial-and-errors, as a repetitive process of chosing solvents and mixing them in different proportions. Computers are good at doing repetitive processes; however, they can only deal with numerical values, rather than qulitative scales. Numerification of qualitative parameters (like solubility) has already been introduced. The most recent one is the Hansen solubility parameters (HSPs). Using the HSPs could provide a solvent or solvent-mixture. In our previous study, we introduced a computer-aided model and a software to find a solvent mixture. In this study, we have used the computer-aided solvent selection model to find some solvent mixtures for polyamide 11, a biobased polymer which has attracted enormous attention recently. Using this numerical model significantly diminished the time of solvent development experimentation by decreasing the possible/necessary trials.

  • 117.
    Jabbari, Mostafa
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lundin, Magnus
    University of Borås, Faculty of Textiles, Engineering and Business.
    Hatamvand, M
    Computer Science and Mathematics Faculty, Bielefeld University of Applied Sciences.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Computer-aided theoretical solvent selection using the simplex method based on Hansen solubility parameters2018In: Journal of Information Technology & Software Engineering, Vol. 8, no 4, article id 1000242Article in journal (Refereed)
    Abstract [en]

    Solvent selection is a crucial step in all solvent-involved processes. Using the Hansen solubility parameters (HSPs)could provide a solvent/solvent-mixture, but there are two main challenges: 1) What solvents should be selected? 2)From each solvent, how much should be added to the mixture? There is no straightforward way to answer the twochallenging questions. This contribution proposes a computer-aided method for selecting solvents (answer to thequestion 1) and finding the adequate amount of each solvent (answer to the question 2) to form a mixture of 2, 3 or4 solvents to dissolve a solute with known HSPs or to replace a solvent. To achieve this, a sophisticated computersoftware package was developed to find the optimized mixture using the mathematical Simplex algorithm based onHSPs values from a database of 234 solvents. To get a list of solvent-mixtures, polyamide66 was tested using itsHSPs. This technique reduces the laboratory effort required in selecting and screening solvent blends while allowinga large number of candidate solvents to be considered for inclusion in a blend. The outcome of this paper significantlydiminished the time of solvent development experimentation by decreasing the possible/necessary trials. Thus, themost suitable solvent/solvent-substitution can be found by the least possible effort; hence, it will save time and costof all solvent-involved processes in the fields of chemistry, polymer and coating industries, chemical engineering, etc.

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  • 118.
    Jabbari, Mostafa
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Introducing all-polyamide composite coated fabrics: A method to produce fully recyclable single-polymer composite coated fabrics2016In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 133, no 7Article in journal (Refereed)
    Abstract [en]

    Novel all-polyamide composite (APC) has been developed to replace traditional coated fabrics with good interfacial adhesionand enhanced recyclability. The composite is fully recyclable since it contains no other materials except polyamide. APC was preparedby partially dissolving a polyamide fabric by treatment with a film-forming polyamide solution. The effect of the polyamidesolution concentration and gelling time on tensile and viscoelastic properties of APCs was investigated to explore the optimum processingparameters for balancing the good interfacial adhesion. The composite properties were studied by dynamic mechanical thermalanalysis (DMTA), tensile testing and scanning electron microscopy (SEM). The results showed a good adhesion between the coatingand the fabric. A new method was introduced to convert a low value added textile waste to a high value-added product. The compositeis tunable, in terms of having a dense or a porous top-layer depending on the end-use requirements.

  • 119.
    Jabbari, Mostafa
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    New Solvent for Polyamide 66 and Its Use for Preparing a Single-Polymer Composite-Coated Fabric2018In: International Journal of Polymer Science, ISSN 1687-9422, E-ISSN 1687-9430Article in journal (Refereed)
    Abstract [en]

    Polyamides (PAs) are one of the most important engineering polymers; however, the difficulty in dissolving them hinders their applications. Formic acid (FA) is the most common solvent for PAs, but it has industrial limitations. In this contribution, we proposed a new solvent system for PAs by replacing a portion of the FA with urea and calcium chloride (FAUCa). Urea imparts the hydrogen bonding and calcium ion from the calcium chloride, as a Lewis acid was added to the system to compensate for the pH decrease due to the addition of urea. The results showed that the proposed solvent (FAUCa) could readily dissolve PAs, resulting in a less decrease in the mechanical properties during the dissolution. The composite prepared using the FAUCa has almost the same properties as the one prepared using the FA solution. The solution was applied on a polyamide 66 fabric to make an all-polyamide composite-coated fabric, which then was characterized. The FAUCa solution had a higher viscosity than the one prepared using the neat FA solvent, which can be an advantage in the applications which need higher viscosity like preparing the all-polyamide composite-coated fabric. A more viscous solution makes a denser coating which will increase the water /gas tightness. In conclusion, using the FAUCa solvent has two merits: (1) replacement of 40% of the FA with less harmful and environmentally friendly chemicals and (2) enabling for the preparation of more viscous solutions, which makes a denser coating.

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  • 120.
    Jabbari, Mostafa
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Novel lightweight and highly thermally insulative silica aerogel-doped poly (vinyl chloride)-coated fabric composite2015In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 34, no 19, p. 1581-1592Article in journal (Refereed)
    Abstract [en]

    Novel lightweight and highly thermal insulative aerogel-doped poly(vinyl chloride)-coated fabric composites wereprepared on woven fabrics made of polyester fibres using knife coating method, and their performances were comparedwith neat composite. The composites were prepared by incorporating a commercial aerogel to a ‘green’ poly(vinylchloride) (PVC) plastisol. The effect of aerogel-content, thermal insulating property, thermal degradation, surface characteristics,tensile and physical properties of the composites were investigated. Results revealed that aerogel couldreduce thermal conductivity, density and hydrophilicity of the composites dramatically without significant decrease inother properties. Experimental results showed that thermal insulation properties were enhanced by 26% (from 205 to152 mW/m-K), density decreased by 17% (from 1.132 to 0.941 g/cm3) and hydrophobicity increased by 16.4% (from76.02 to 88.671.48) with respect to the unmodified coated fabric. Analyses proved that composite with 3% aerogel isthe lightest by weight, while 4% showed the highest thermal insulation. The results showed that 4% is the criticalpercentage, and preparation of composites with aerogel content higher than 4% has limitations with the given formulationdue to high viscosity of plastisol. The prepared composite has potential applications in many fields such asdevelopment of textile bioreactors for ethanol/biogas production from waste materials, temporary houses and tents,facade coverings, container linings and tarpaulins. The prepared composite can be considered ‘green’ due to usage of anon-phthalate environment-friendly plasticiser.

  • 121.
    Johansson, Matilda
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kadi, Nawar
    University of Borås, Faculty of Textiles, Engineering and Business.
    Dhakal, H. N.
    Advanced Polymers and Composites (APC) Research Group, School of Mechanical and Design Engineering, University of Portsmouth, Portsmouth, Hampshire PO1 3DJ, UK.
    Effect of lignin acetylation on the mechanical properties of lignin-poly-lactic acid biocomposites for advanced applications2023In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 202, article id 117049Article in journal (Refereed)
    Abstract [en]

    Bioplastics that possess characteristics like durability and low cost are desired for versatile applications in industries such as automotive manufacturing, marine transport manufacturing, aerospace applications, and the building industry. The automotive industry is an example of an industry that is now shifting towards a more focused approach addressing the issue concerning sustainability and the development of sustainable material. To achieve a lightweight and sustainable construction, one of the methods used by the automotive original equipment manufacturers is by substituting conventional fossil-based, non-renewable composites, and metallic materials with a bio-based alternative. One of the drawbacks with biobased polymers can be the poor interfacial adhesion, leading to poor mechanical properties when compares to conventional material. The aim of this research is to investigate if a low-cost by-product could be used as a component in a composite matrix material in the automotive industry to reduce the final weight and increase the non-petrochemical material usage of composite material without compromising the thermal and mechanicals properties demanded. In this research, lignin was chemically altered by esterification the functional groups to increase the compatibility with polylactic acid. The esterification was performed with the use of acetic acid anhydride and pyridine. To evaluate and determine the esterification, Fourier transform Infrared Spectroscopy was used. By blending the modified lignin with polylactic acid the intention was to improve the thermomechanical properties and the interfacial linkage between the components. The effects of lignin acetylation on the tensile properties, impact strength, and thermal stability and moisture repellence behaviour were investigated. According to the experimental results the modification of lignin, increased the impact strength for all the blends containing acetylated lignin compares to pristine lignin. The largest increase observed was for blends containing 20 wt% acetylated lignin and polylactic acid, which resulted in a 74% improvement compared with the blend composed of pristine lignin and polylactic acid. Similarly, the thermal stability was improved significantly with acetylation of the lignin. Moreover, the moisture repellence behaviour was also increased. The reason for the improved properties can be explained by the better interfacial compatibility between lignin and polylactic acid matrix. An increased thermal stability and a moisture repellent behaviour of the blends containing chemically modified lignin could be observed when compared with neat polylactic acid which makes the acetylation treatment of lignin a possible approach for the future of biocomposite production. 

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  • 122. Jose, T
    et al.
    Joseph, A
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Thomas, S
    Joseph, K
    Thermal and crystallization behavior of cotton: Polypropylene commingled composite systems2010In: Polymer Composites, ISSN 0272-8397, E-ISSN 1548-0569, Vol. 31, no 8, p. 1487-1494Article in journal (Refereed)
    Abstract [en]

    Techniques like thermogravimetric analysis, differential scanning calorimetry, and polarized optical microscopy were used to study the thermal and crystallization behavior of cotton-polypropylene (PP) commingled composite system. Thermal analysis was used to understand the structure-property relationship and also to quantify the amount of moisture and volatiles, which causes the deterioration of the composite performance. Thermal stability of the composite was found be intermediate between that of PP and cotton fibers. Presence of treated reinforcements had increased the crystallinity of PP. Also, fibers act as heterogeneous nucleants and favor the early crystallization of PP in the composites. The crystallization and onset crystallization temperature values were increased by the presence of cotton fibers. The theories of heterogeneous nucleation and crystal growth kinetics were used to explain the growth of transcrystalline layer (TCL) of PP on cotton fibers. The interfacial free energy difference for nucleation of PP on fiber was found to be smaller compared with that in the bulk PP. This favors the formation and growth of TCL. The thickness of TCL and radius of the spherulites increase with the increase in the crystallization temperature. Fiber surface roughness and thermal stresses facilitate the growth of transcrystallinity on cotton fiber.

  • 123.
    Kadi, Nawar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. University of Borås.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business. University of Borås.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business. University of Borås.
    Effect of Textile structure in the process parameters of thermoplastic bio-composite2019In: MATEC Web of Conferences, E-ISSN 2261-236X, Vol. 261, no 01005, p. 1-3Article in journal (Other academic)
    Abstract [en]

    Thermoplastic bio-composite have a higher potential of use based on the sustainability benefits. Natural fibres today are a popular choice for applications in biocomposite manufacturing. Hybrid yarns are a satisfactory solution to improve the fabrication of composites containing a thermoplastic matrix and plant-based fibres. Nevertheless, it is still difficult to produce bio-composites with superior mechanical properties, due to problematic impregnation and consolidation results during the production process. This paper investigates the processing parameters for the compression moulding of two different hemp/PLA textiles structure bio-composites (warp knitting and weaving structure). Finite element simulations are used to optimise the processing parameters (pressure, temperature, and time). The results demonstrated that the textile structure has a small effect on the time of production. Main while the pressure and temperature of processing parameters depend only on the type of matrix and the thickness of biocomposite has a big impact on the time of production.

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  • 124.
    Kadi, Nawar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, BehnazUniversity of Borås, Faculty of Textiles, Engineering and Business.Skrifvars, MikaelUniversity of Borås, Faculty of Textiles, Engineering and Business.
    The effect of process parameters on the mechanical properties of thermoplastic bio-composite2018Conference proceedings (editor) (Refereed)
  • 125.
    Kadi, Nawar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Using Finite Element Simulation to Optimize Thermoplastic Bio - Composites Process Parameters2018In: International Journal of Management and Applied Science, ISSN 2394-7926, Vol. 4, p. 73-75Article, book review (Refereed)
    Abstract [en]

    The use of thermoplastic composite is clearly of higher potential because of: good impact strength, easier recycling, faster processing conditions (no time for curing is required), possibility of production in longer series, lower cost, absence of toxic solvents and higher fracture toughness and elongation on the fracture. Natural fibres today are a popular choice for applications in composite manufacturing. In fact, a major challenge for natural fibre reinforced composites is to achieve high mechanical performance at competitive prices. This paper investigates the processing parameters for the compression moulding of hemp/PLA hybrid yarn bio-composites and their effect on the final mechanical properties. Finite element simulations are used to develop and assess the processing parameters pressure, temperature, and time. The application of the simulation analysis results in considerably reduced the processing times from initially 10 minutes to only 2 minutes, and improved the mechanical bio-composite

  • 126.
    Kadi, Nawar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Muhandes, HasanKalácska, GáborSkrifvars, MikaelUniversity of Borås, Faculty of Textiles, Engineering and Business.
    Pin-on-Plate Abrasive Wear Test For Several Composite Materials2018Conference proceedings (editor) (Refereed)
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  • 127.
    Kadi, Nawar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Muhandes, Hasan
    Kalácska, Gábor
    Thermoplastic biocomposite based on cellulose fibers2017Conference paper (Refereed)
  • 128.
    Kadi, Nawar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Peterson, Joel
    University of Borås, Faculty of Textiles, Engineering and Business.
    Holmudd, Olle
    University of Borås, Faculty of Textiles, Engineering and Business.
    Karnoub, Amer
    University of Aleppo.
    The Effect of Warp Tension on the Colour of Jacquard Fabric2017In: IOP Conference Series: Materials Science and Engineering, 2017, Vol. 254, article id 082014Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    The aims of this paper is to demonstrate the effect of warp tension on fabric colour for several types of weaves structures, and found a relationship between them. The image analyse technique used to determine the proportion of yarns colour appearance, the advantage of this techniques is the rapidity and reliability. The woven fabric samples are consisting of a polyester warp yarn with continuous filaments and density of 33 end/cm, a polypropylene weft yarn with a density of 24 pick/cm, and the warp tension ranged between 12-22 cN/tex. The experimental results demonstrated the effect of the warp tension on the colour of fabric, and this effect is related to several factors, where the large proportion of warp appearance leads to larger effect on fabric colour. The difference in the value of colour differences ΔEcmc is larger is in the range 16 to 20 cN/tex of warp tension. Using statistical methods, a mathematical model to calculate the amount of the colour difference ΔEcmc caused by the change in warp tension had been proposed.

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  • 129. Kalantar Mehrjerdi, Adib
    et al.
    Abebe Mengistu, Bemnet
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Effects of a titanate coupling agent on the mechanical and thermo-physical properties of talc-reinforced polyethylene compounds2014In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 131, no 13, p. 40449-40449Article in journal (Refereed)
    Abstract [en]

    An experimental study was carried out to investigate the effects of a titanate coupling agent on the mechanical properties, moisture absorption, and thermal conductivity of talc-filled high-density polyethylene (HDPE). Talc (0–35 wt %) was used as reinforcement particulate filler in an HDPE matrix and samples were prepared in a micro-compounder and an injection molding machine. Isopropyl tri(dioctyl)phosphate titanate (0.5 wt %) was used as coupling agent. Composites with and without coupling agent were evaluated for changes in mechanical and thermo-physical properties, morphology, and void content. Addition of the titanate coupling agent most often resulted in an increase in stiffness and tensile strength. Furthermore, both the void content and the elongation at break of composites were reduced. Results also showed that the coupling agent had no effects on the thermal conductivity, thermal diffusivity, and specific heat capacity of the composites. In addition, it was observed that the coupling agent was more effective at low concentrations of filler. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40449.

  • 130. Kalantar Mehrjerdi, Adib
    et al.
    Adl-Zarrabi, Bijan
    Cho, Sung-Woo
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Mechanical and thermo-physical properties of high-density polyethylene modified with talc2013In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 129, no 4, p. 2128-2138Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to examine the physical, mechanical, and thermo-physical properties of high-density polyethylene (HDPE) modified with talc. Different weight fractions of talc (up to 35 wt %) were compounded with an HDPE matrix containing 2.5 wt % of carbon black (CB) in a twin-screw compounder. The composites were then processed by injection moulding to obtain specimens for testing. The results indicate that CB causes a significant decrease in the toughness, while talc not only enhances the thermal conductivity and thermo-physical properties of the composites but can also play a role in compensating for the negative effects of CB on impact resistance. The experimental data show that the presence of CB reduces the impact resistance of HDPE by up to 34%, while addition of up to 8 wt % talc can return this value to close to that of pure HDPE. No significant effect on the composite tensile yield and fracture strength was observed for either component at all concentrations. The thermal conductivity, thermal diffusivity, and specific density values of the composites increased almost linearly, but the increase in moisture absorption in the long term showed nonlinear behavior in the concentration range of the experiment.

  • 131.
    Kalantar Mehrjerdi, Adib
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bashir, Tariq
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Melt rheology and extrudate swell properties of talc filled polyethylene compounds2020In: Heliyon, E-ISSN 2405-8440Article in journal (Refereed)
    Abstract [en]

    An experimental study of high-density polyethylene (HDPE) composites filled with talc (0–15 wt.%) was carried out to investigate the rheological properties. The apparent melt viscosity, melt density, and die-swell ratio (B) of the composites were measured at constant shear stress and constant shear rate by using a melt flow indexer and capillary rheometer. The experimental conditions were set to a temperature range from 190 to 220 C for both apparatuses whereas a load range from 5 to 12.16 kg was selected for melt flow indexer and shear rate range from 1 to 10000 s1 for capillary rheometer. The initial study showed that the talc particulates did not influence the melt viscosity compared with the neat HDPE but decreased the elasticity of the polymer system. The HDPE/talc systems obeyed power-law model in shear stress–shear rate variations and were shear thinning, meanwhile, the die-swell increased with an increased wall shear rate and shear stress. The melt density of the composites increased linearly with an increase of the filler weight fraction and decreased with the increase of the testing temperature. The talc-HDPE composites showed compressible in the molten state.

  • 132.
    Kalantar Mehrjerdi, Adib
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Naudin, Sébastien
    Eco-Design in Polymers and Composites, University of South Brittany.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Development of Polyolefin Compound and Post-Polymerization Treatments for Ground Heat Exchangers2017Conference paper (Refereed)
    Abstract [en]

    A ground source heat pump (GSHP) system can be used for both cooling and heating modes simultaneously for commercial, industrial and residential buildings virtually at any location with great flexibility to cover a wide range of demands all around the world. Polyethylene (PE) has been used as the main raw material in production of the Ground Heat Exchangers (GHE). This paper briefly reviews the history of polyethylene and development in polymerization process with emphasis on the third-generation bimodal structure. The characteristics of PE pipes used in GSHP systems are discussed. This paper is devoted to a critical review on the attempts in post-polymerization treatments of the PE, and GHEs to improve the performance of the systems. The experimental and simulated comparisons show that the enhancement of the thermal conductivity of the material can reduce significantly the overall borehole thermal resistance.

  • 133. Kalantar Mehrjerdi, Adib
    et al.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Geothermal pipe collector2014Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A geothermal pipe collector is provided. The geothermal pipe collector is made from a polymer composition comprising: more than 50wt% polyethylene, 0.1wt% -35wt% talc and 0.5wt% -10wt% carbon black.

  • 134.
    Kalantar Mehrjerdi, Adib
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Mechanical and morphological properties of talc filled high density polyethylene2013Conference paper (Other academic)
  • 135.
    Kalantar Mehrjerdi, Adib
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Tariq, Bashir
    University of Borås, Faculty of Textiles, Engineering and Business.
    Melt Flow and Rheological Properties of Talc-Polyethylene Compounds2015Conference paper (Refereed)
  • 136.
    Kalantar Mehrjerdi, Adib
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Influence of talc fillers on bimodal polyethylene composites for ground heat exchangers2020In: Journal of applied polymer scienceArticle in journal (Refereed)
  • 137.
    Karimi-Avargani, Mina
    et al.
    Department of Biotechnology, University of Isfahan, Isfahan, Iran.
    Bazooyar, Faranak
    University of Borås, Faculty of Textiles, Engineering and Business.
    Biria, D.
    Department of Biotechnology, University of Isfahan, Isfahan, Iran.
    Zamani, Akram
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    The promiscuous potential of cellulase in degradation of polylactic acid and its jute composite2021In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 278, article id 130443Article in journal (Refereed)
    Abstract [en]

    It has been suggested that cellulolytic enzymes can be effective on the degradation of PLA samples. The idea was investigated by examining the impact of cellulase on degradation of PLA and PLA-jute (64/36) composite in an aqueous medium. The obtained results demonstrated 55% and 61% thickness reduction in PLA and PLA-jute specimens after four months of treatment, respectively. Gel permeation chromatography (GPC) showed significant decline in the number average molecular weight (Mn) approximately equal to 85% and 80% for PLA and PLA-jute in comparison with their control. The poly dispersity index (PDI) of PLA and PLA-jute declined 41% and 49% that disclosed more homogenous distribution in molecular weight of the polymer after treatment with cellulase. The cellulase promiscuity effect on PLA degradation was further revealed by Fourier-transform infrared spectroscopy (FT-IR) analysis where substantial decrease in the peak intensities of the polymer related functional groups were observed. In addition, PLA biodegradation was studied in more detail by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) of control and cellulase treated specimens. The obtained results confirmed the promiscuous function of cellulase in the presence or the absence of jute as the specific substrate of cellulase. This can be considered as a major breakthrough to develop effective biodegradation processes for PLA products at the end of their life cycle.

  • 138.
    Karimi-Avargani, Mina
    et al.
    Department of Biotechnology, University of Isfahan, Isfahan, Iran.
    Bazooyar, Faranak
    University of Borås, Faculty of Textiles, Engineering and Business.
    Biria, Davoud
    Department of Biotechnology, University of Isfahan, Isfahan, Iran.
    Zamani, Akram
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    The special effect of the Aspergillus flavus and its enzymes on biological degradation of the intact polylactic acid (PLA) and PLA-Jute composite2020In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 179Article in journal (Refereed)
    Abstract [en]

    The biodegradation of PLA and PLA-Jute (64/36) in an aqueous media with Aspergillus flavus CCUG 28296, as well as its cell-free enzyme extract, was investigated through their physical, molecular, and thermal characterization. Results indicated that the thicknesses of the fungal treated PLA and PLA-jute samples during seven months have reduced by 52% and 63%, respectively while for the enzyme-treated samples, 45% and 49% reduction in the thickness has occurred. Moreover, the gel permeation chromatography (GPC) revealed a substantial decrease (about 75%) in the weight average molecular weight (Mw) of PLA and PLA-Jute treated with fungus, which confirmed the effective performance of A. flavus on the biological degradation of PLA. The obtained results were further supported by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) of the treated and control samples as well. Interestingly, the observed reduction in the Mw of PLA in PLA-Jute was 64% after the enzymatic treatment, while for the unblended PLA, it was just about 32%. These results pointed to the synergistic effect of jute on PLA degradation because of the promiscuous activity of the effective enzymes on jute degradation, which could accelerate the PLA decomposition.

  • 139.
    Karnoub, Amer
    et al.
    Faculty of Mechanical Engineering, University of Aleppo.
    Kadi, Nawar
    University of Borås, Faculty of Textiles, Engineering and Business.
    Holmudd, Olle
    University of Borås, Faculty of Textiles, Engineering and Business.
    Peterson, Joel
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    The Effect of Warp Tension on the Colour of Jacquard Fabric Made with Different Weaves Structures2017In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 254Article in journal (Refereed)
    Abstract [en]

    The aims of this paper is to demonstrate the effect of warp tension on fabric colour for several types of weaves structures, and found a relationship between them. The image analyse technique used to determine the proportion of yarns colour appearance, the advantage of this techniques is the rapidity and reliability. The woven fabric samples are consisting of a polyester warp yarn with continuous filaments and density of 33 end/cm, a polypropylene weft yarn with a density of 24 pick/cm, and the warp tension ranged between 12-22 cN/tex. The experimental results demonstrated the effect of the warp tension on the colour of fabric, and this effect is related to several factors, where the large proportion of warp appearance leads to larger effect on fabric colour. The difference in the value of colour differences ΔEcmc is larger is in the range 16 to 20 cN/tex of warp tension. Using statistical methods, a mathematical model to calculate the amount of the colour difference ΔEcmc caused by the change in warp tension had been proposed.

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  • 140.
    Khalili, Pooria
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kádár, R.
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Blinzler, B.
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg.
    Impregnation behaviour of regenerated cellulose fabric Elium® composite: Experiment, simulation and analytical solution2021In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 10, p. 66-73Article in journal (Refereed)
    Abstract [en]

    Filling time and volume fill prediction of long and complex parts produced using the method of resin infusion is of prominent importance. Fibre volume fraction, reinforcement type and composite laminate thickness significantly affect the manufacturing behaviour. It is crucial to have an estimate of fabrication parameters such as filling time. The PAM-RTM (resin transfer moulding) commercial software package makes it possible to characterize the production parameters in connection with lab scale experiments. In this work, simulation tools demonstrate an accurate prediction of the resin infusion process of pulp-based fabrics and characterization of the dynamic phenomena are verified using the analytical solution for a simple part. The accurate prediction for fabrication of pulp-based fabric Elium® composite demonstrated here can be beneficial for scaling up the composite part size and production speed. The filling time was accurately predicted until 270 s for the volume fill of 10-100% using the software tool and analytical solution. This proves the rayon fabric processing capabilities as a reinforcement for industry related projects and opens for the possibility of infusion process optimization.

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  • 141.
    Khalili, Pooria
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. Swedish Centre for Resource Recovery, Faculty of Textiles, Engineering and Business, University of Borås, 510 90 Borås, Sweden.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business. Swedish Centre for Resource Recovery, Faculty of Textiles, Engineering and Business, University of Borås, 510 90 Borås, Sweden.
    Dhakal, Hom Nath
    Advanced Polymers and Composites (APC), School of Mechanical Design and Engineering, University of Portsmouth, Portsmouth PO1 3DJ, UK.
    Dashatan, Saeid Hosseinpour
    Brunel Composite Centre, Brunel University London, London UB8 3PH, UK.
    Danielsson, Mikael
    Albany International AB, 302 41 Halmstad, Sweden.
    Gràcia, Alèxia Feiner
    Department of Textile Technology and Design, Universitat Politècnica de Catalunya-Barcelona Tech—UPC, 08034 Barcelona, Spain.
    Mechanical Properties of Bio-Based Sandwich Composites Containing Recycled Polymer Textiles2023In: Polymers, E-ISSN 2073-4360, Vol. 15, no 18, p. 1-14, article id 3815Article in journal (Refereed)
    Abstract [en]

    In this paper, sandwich composites were produced by compression moulding techniques, and they consisted of regenerated cellulose fabric (rayon) and bio-based polypropylene (PP) to form facings, while virgin and recycled polyamide (PA) textiles were used as core materials. To compare the mechanical performance between sandwich composites and typical composite designs, a control composite was produced to deliver the same weight and fiber mass fraction from rayon and PP. To evaluate the influence of recycled textile on the mechanical properties of the composites, a series of flexural, low velocity impact (LVI) and tensile tests were performed. It was found that the incorporation of thicker PA textile enhanced the bending stiffness by two times and the peak flexural force by 70% as compared to those of control. Substitution of a layer of recycled textile for two layers of rayon provided a good level of impact energy absorption capacity (~28 J) and maximum force (~4893–5229 N). The tensile strength of the four sandwich composites was reported to be in the range of 34.20 MPa and 46.80 MPa. This value was 91.90 for the control composite. The 2D cross-section slices of the composite specimens did not show any evidence of fiber tow debonding, fiber bundle splitting, or delamination.

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  • 142.
    Khalili, Pooria
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Dhakal, Hom Nath
    Advanced Polymers and Composites (APC), School of Mechanical Design and Engineering, University of Portsmouth, Portsmouth, PO1 3DJ, United Kingdom.
    Jiang, Chulin
    Advanced Polymers and Composites (APC), School of Mechanical Design and Engineering, University of Portsmouth, Portsmouth, PO1 3DJ, United Kingdom.
    Regenerated cellulose fabric reinforced bio-based polypropylene sandwich composites: fabrication, mechanical performance and analytical modelling2023In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 22, p. 3423-3435Article in journal (Refereed)
    Abstract [en]

    Sandwich composites were fabricated successfully with the balsa wood as core material and regenerated cellulose fabric bio-based polypropylene (PP) composite skins. The regenerated cellulose fabric PP composites were produced using two different methods: the conventional stacking lay-up and directly using PP pellets. Sandwich composites were made using the hot press equipment with the customized mold. The sandwich composite system and bio-composite laminate were designed to achieve very close weight to compare the key mechanical properties that each design can bear. It was evidenced from the experimental results that 416% increase in the bending load bearing property of the part can be obtained when sandwich structure was used. These experimental results were in close agreement with one of the analytical modelling utilised. The drop weight impact test results demonstrated that the sandwich specimen is capable of withstanding more than 6 kN load and absorbing the impact energy of 28.37 J.

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  • 143.
    Khalili, Pooria
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Erturk, Semih Ertürk
    Department of Industrial and Materials Science, Chalmers University of Technology, 412 96 Gothenburg, Sweden.
    Fabrication: Mechanical Testing and Structural Simulation of Regenerated Cellulose Fabric Elium(R) Thermoplastic Composite System2021In: Polymers, E-ISSN 2073-4360, Vol. 13, no 17Article in journal (Refereed)
    Abstract [en]

    Regenerated cellulose fibres are an important part of the forest industry, and they can be used in the form of fabrics as reinforcement materials. Similar to the natural fibres (NFs), such as flax, hemp and jute, that are widely used in the automotive industry, these fibres possess good potential to be used for semi-structural applications. In this work, the mechanical properties of regenerated cellulose fabric-reinforced poly methyl methacrylate (PMMA) (Elium(R)) composite were investigated and compared with those of its natural fibre composite counterparts. The developed composite demonstrated higher tensile strength and ductility, as well as comparable flexural properties with those of NF-reinforced epoxy and Elium(R) composite systems, whereas the Young's modulus was lower. The glass transition temperature demonstrated a value competitive (107.7 degrees C) with that of other NF composites. Then, the behavior of the bio-composite under bending and loading was simulated, and a materials model was used to simulate the behavior of a car door panel in a flexural scenario. Modelling can contribute to predicting the structural behavior of the bio-based thermoplastic composite for secondary applications, which is the aim of this work. Finite element simulations were performed to assess the deflection and force transfer mechanism for the car door interior.

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  • 144.
    Kopf, Sabrina
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Hakkarainen, Minna
    School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Stockholm, Sweden.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Effect of hydroxyapatite particle morphology on as-spun poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/hydroxyapatite composite fibers2023In: Results in Materials, ISSN 2590-048X, Vol. 20, article id 100465Article in journal (Refereed)
    Abstract [en]

    Hydroxyapatite (HA) has shown very promising results in hard tissue engineering because of its similarity to bone and hence the capability to promote osteogenic differentiation. While the bioactivity of HA is uncontested, there are still uncertainties about the most suitable hydroxyapatite particle shapes and sizes for textile scaffolds. This study investigates the influence of the shape and size of HA particles on as spun fibers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and HA, their mechanical and thermal properties as well as their influence on the fiber degradation in simulated blood matrix and their capability to mineralize in simulated body fluid. The key findings were that the different HA particles’ size does not affect the melting temperature and still maintains a thermal stability suitable for fiber production. Tensile testing revealed decreased mechanical properties for PHBV/HA as spun fibers, independently of the particle morphology. However, HA particles with 30 nm in width and 100 nm in length at 1 wt% HA loading achieved the highest tenacity and elongation at break amongst all composite fibers with HA. Besides, the Ca/P ratio of their mineralization in simulated body fluid is the closest to the one of mineralized human bone, indicating the most promising bioactivity results of all HA particles studied.

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  • 145.
    Kopf, Sabrina
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Textile Fiber Production of Biopolymers - A Review of Spinning Techniques for Polyhydroxyalkanoates in Biomedical Applications2023In: Polymer reviews, ISSN 1558-3724, p. 200-245Article, review/survey (Refereed)
    Abstract [en]

    The superior biocompatibility and biodegradability of polyhydroxyalkanoates (PHAs) compared to man-made biopolymers such as polylactic acid promise huge potential in biomedical applications, especially tissue engineering (TE). Textile fiber-based TE scaffolds offer unique opportunities to imitate the anisotropic, hierarchical, or strain-stiffening properties of native tissues. A combination of PHAs' enhanced biocompatibility and fiber-based TE scaffolds could improve the performance of TE scaffolds. However, the PHAs' complex crystallization behavior and the resulting intricate spinning procedures remain a challenge. This review focuses on discussing the developments in PHA melt and wet spinning, their challenges, process parameters, and fiber characteristics while revealing the lack of an in-depth fiber characterization of wet-spun fibers compared to melt-spun filaments, leading to squandered potential in scaffold development. Additionally, the biomedical application of PHAs other than poly-4-hydroxybutyrate is hampered by a failure of polymer purity to meet the requirements for biomedical applications.

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  • 146. Krishnaprasad, R
    et al.
    Veena, N.R.
    Maria, H.J.
    Rajan, R
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Joseph, K
    Mechanical and thermal properties of bamboo microfibril reinforced polyhydroxybutyrate biocomposites2009In: Journal of Polymers and the Environment, ISSN 1566-2543, E-ISSN 1572-8919, Vol. 17, no 2, p. 109-114Article in journal (Refereed)
    Abstract [en]

    In the present investigation, microfibrils were extracted from raw bamboo and characterized using scanning electron microscope. Composites based on polyhydroxybutyrate (PHB) and bamboo microfibril were prepared with various microfibril loading. The mechanical and thermal properties of the resulting composites were measured. Tensile strength and impact strength of the composites were found to be increasing with increase in the loading of bamboo microfibrils, reached an optimum and thereafter decreased with further increase in microfibril loading. Percentage crystallinity was found to be increasing with increase in fibril loading. Thermal stability of the composite was higher than that of pure PHB. The composite could be developed further for various structural applications.

  • 147. Kumar, Hemanathan
    et al.
    Mahimaisenan, Pirabasenan
    Cho, Sung-Woo
    University of Borås, School of Engineering.
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Casein films and its composites with regenerated cellulose fibre for packaging applications2011Conference paper (Other academic)
    Abstract [en]

    A novel approach in the production of protein based films and composites were performed, using the bovine milk protein casein and regenerated cellulose fibres (lyocell). The films were prepared by first dissolving the casein protein in an aqueous alkaline solution in the presence of glycerol as a plasticizer. Further the composite films were prepared by the addition of fibres on aqueous alkaline solution with casein. The casein films and composites were thereafter prepared by casting the solution mixture on Teflon coated glass plate and drying for 48 hr. The effects of glycerol content and lyocell fibre reinforcements on the mechanical, thermal and physiological properties of the casein films were characterized. The results revealed that the increase in the addition of glycerol content decreases the tensile strength, young’s modulus, thermal stability of the film and increases the elongation percentage. Tensile property and thermal stability of the films was improved by the increase in the addition of the fibre content with a gradual decrease in the elongation percentage. The casein film made of 20% glycerol and 20% fibre content showed the maximum tensile strength of 23.5 MPa, E-modulus of 1.5 GPa and glass transition temperature (Tg) of 67.1±1.5 ºC. The sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that there was no significant change in the molecular weight of the protein during sample preparation. The inter molecular networks have taken place in the casein films and composites, when analyzed under Fourier Transform Infrared Spectroscopy (FTIR), and proper bonding between fibres and protein was observed by scanning electron microscope (SEM).

  • 148.
    Kumar Ramamoorthy, Sunil
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Alagar, Ragunathan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Akhtar, Naeem
    University of Borås, Faculty of Textiles, Engineering and Business.
    End of life textiles as reinforcements in biocomposites2017In: Journal of Polymers and the Environment, ISSN 1566-2543, E-ISSN 1572-8919, p. -12Article in journal (Refereed)
    Abstract [en]

    A number of attempts have been made to recycle cotton/polyester blend woven fabrics after use; however, most of these fabrics are disposed of in landfills. Major part of these blend fabrics are not recycled due to complexity of the fibre arrangement and cannot be separated economically. This study shows that these discarded woven fabrics could be directly used as reinforcements in composites without fibre separation. Uniform alignment in the woven fabric provided consistent properties to the composites. The fabrics were reinforced by soybean-based-bioresins to produce biocomposites. The composites were analysed for mechanical, thermal, viscoelastic and morphological properties. Porosity and wettability of the composites were also evaluated. Results demonstrate that the tensile strength and modulus of over 100 and 10 MPa, respectively, can be obtained without any fibre treatment. Furthermore, impact strength over 70 kJ/m2 was obtained without any chemical treatment on fibres. The porosity of the composites produced was less than 9 vol%. Additionally, the fabrics were treated with alkali in order to improve the fibre–matrix interface and the composite properties were studied. From the economical perspective, these composites can be produced at a low cost as the major component is available for free or low cost.

  • 149.
    Kumar Ramamoorthy, Sunil
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rajan, Rathish
    Tampere University of Technology.
    Rainosalo, Egidija
    Centria University of Applied Sciences.
    Thomas, Selvin
    Yanbu Industrial College and Advanced Materials Laboratory.
    Zavasnik, Janez
    Jožef Stefan Institute.
    Vuorinen, Jyrki
    Tampere University of Technology.
    Mechanical, thermal, and burning properties of viscose fabric composites: Influence of epoxy resin modification2018In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 135, no 36Article in journal (Refereed)
    Abstract [en]

    The influence of epoxy resin modification by 3-aminopropyltriethoxysilane (APTES) on various properties of warp knitted viscose fabric is reported in this study. Dynamic mechanical, impact resistance, flexural, thermal properties, and burning behavior of the epoxy/viscose fabric composites are studied with respect to varying content of silane coupling agent. The results obtained forAPTES-modified epoxy resin based composites reinforced with unmodified viscose fabric composites are compared to unmodified epoxy resin based composites reinforced with APTES-modified viscose fabric. The dynamic mechanical behavior of the APTES-modified resin based composites indicates improved interfacial adhesion. The composites prepared from modified epoxy resin exhibited a twofold increase in impact resistance. The improved adhesion between the fiber and modified resin was also visible from the scanning electron microscope analysis of the impact fracture surface. There was less influence of resin modification on the flexural properties of the composites. The 5% APTES modification induced early degradation of composites compared to all other compo-sites. The burning rate of all the composites under study is rated to be satisfactory for use in automotive interior applications.

  • 150.
    Kumar Ramamoorthy, Sunil
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rajan, Rathish
    Tampere University.
    Periyasamy, Aravin Prince
    Technical University of Liberec.
    Mechanical performance of biofibers and their corresponding composites2019In: Mechanical and Physical Testing of Biocomposites, Fibre-Reinforced Composites and Hybrid Composites / [ed] Mohammad Jawaid, Mohamed Thariq, Naheed Saba, Woodhead Publishing Limited, 2019Chapter in book (Refereed)
    Abstract [en]

    This chapter focuses on mechanical performance of biofibers such as flax, hemp, and sisal and their effect on mechanical performance when they are reinforced in thermoset and thermoplastic polymers. The aim of this chapter is to present an overview of the mechanical characterization of the biofibers and their corresponding composites. The mechanical characterization includes tensile, flexural, impact, compressive, shear, toughness, hardness, brittleness, ductility, creep, fatigue, and dynamic mechanical analyses. Detailed studies of each test have been widely reported and an overview is important to relate the studies. Studies pertaining to the topics are cited. The most common materials used in biocomposites are biofibers (also called natural fibers) and petroleum-based polymers such polypropylene. The use of renewable materials in biocomposites has increased in the past couple of decades owing to extensive research on cellulosic fibers and biopolymers based on starch or vegetable oil. Today, research is focused on reinforcing natural fibers in petroleum-based polymers. However, the emphasis is shifting toward the amount of renewable materials in biocomposites, which has led to the use of biopolymers instead of petroleum-based polymers in composites. The mechanical properties of some renewable resource-based composites are comparable to commercially available nonrenewable composites.

    Several plant biofibers have been reinforced in thermoplastics or thermosets to manufacture biocomposites because of their specific properties. The Young's modulus of commonly used biofibers such as hemp and flax could be over 50 GPa and therefore they could be good alternatives to glass fibers in several applications. The good mechanical properties of these biofibers influence the composites' mechanical performance when reinforced in polymers. It is important to understand the mechanical performance of these biofibers and biocomposites in a working environment. A detailed discussion about the mechanical performance of commonly used biofibers and composites is provided in this chapter.

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