The rising industrial demand for environmentally friendly and sustainable materials has shifted the attention from synthetic to natural fibers. Natural fibers provide advantages like affordability, lightweight nature, and renewability. Jute fibers’ substantial production potential and cost-efficiency have propelled current research in this field. In this study, the mechanical behavior (tensile, flexural, and interlaminar shear properties) of plasma-treated jute composite laminates and the flexural behavior of jute fabric-reinforced sandwich composites were investigated. Non-woven mat fiber (MFC), jute fiber (JFC), dried jute fiber (DJFC), and plasma-treated jute fiber (TJFC) composite laminates, as well as sandwich composites consisting of jute fabric bio-based unsaturated polyester (UPE) composite as facing material and polyethylene terephthalate (PET70 and PET100) and polyvinyl chloride (PVC) as core materials were fabricated to compare their functional properties. Plasma treatment of jute composite laminate had a positive effect on some of the mechanical properties, which led to an improvement in Young’s modulus (7.17 GPa) and tensile strength (53.61 MPa) of 14% and 8.5%, respectively, as well as, in flexural strength (93.71 MPa) and flexural modulus (5.20 GPa) of 24% and 35%, respectively, compared to those of JFC. In addition, the results demonstrated that the flexural properties of jute sandwich composites can be significantly enhanced by incorporating PET100 foams as core materials.
Fungal biomass (FB), a by-product of the fermentation processes produced in large volumes, is a promising biomaterial that can be incorporated into poly(lactic acid) (PLA) to develop enhanced biocomposites that fully comply with the biobased circular economy concept. The PLA/FB composites, with the addition of triethyl citrate (TEC) as a biobased plasticizer, were fabricated by a microcompounder at 150 °C followed by injection molding. The effects of FB (10 and 20 wt %) and TEC (5, 10, and 15 wt %) contents on the mechanical, thermal and surface properties of the biocomposites were analyzed by several techniques. The PLA/FB/TEC composites showed a rough surface in their fracture section. A progressive decrease in tensile strength and Young’s modulus was observed with increasing FB and TEC, while elongation at break and impact strength started to increase. The neat PLA and biocomposite containing 10% FB and 15% TEC exhibited the lowest (3.84%) and highest (224%) elongation at break, respectively. For all blends containing FB, the glass transition, crystallization and melting temperatures were shifted toward lower values compared to the neat PLA. The incorporation of FB to PLA thus offers the possibility to overcome one of the main drawbacks of PLA, which is brittleness.
The fungus Rhizopus delemar was grown on bread waste in a submerged cultivation process and wet-laid into films. Alkali or enzyme treatments were used to isolate the fungal cell wall. A heat treatment was also applied to deactivate biological activity of the fungus. Homogenization of fungal biomass was done by an iterative ultrafine grinding process. Finally, the biomass was cast into films by a wet-laid process. Ultrafine grinding resulted in densification of the films. Fungal films showed tensile strengths of up to 18.1 MPa, a Young's modulus of 2.3 GPa and a strain at break of 1.4%. Highest tensile strength was achieved using alkali treatment, with SEM analysis showing a dense and highly organized structure. In contrast, less organized structures were obtained using enzymatic or heat treatments. A cell viability assay and fluorescent staining confirmed the biocompatibility of the films. A promising route for food waste valorization to sustainable fungal wet-laid films was established. © 2022 The Authors
Bio-based textiles are an emerging area of cross-disciplinary research, involving material science and design and contributing to textile sustainability. An example of a bio-based textile is an orange-waste film, which is plant-based and biodegradable and possesses mechanical properties which are comparable to some commodity plastics. The research project presented in this article aimed to explore orange-waste film as a new material for textile and fashion design and highlights how experimental co-design processes and innovation involving orange waste film as a textile material adds a new layer of material understanding to both textile design and technology-driven material research. Material-development methods were used to develop the orange-waste film, as were textile design methods with a focus on surface design. The results show that material variables such as tensile strength and elongation are dependent on the grinding process and drying temperature used for the raw material, as these determined the quality and durability of the orange-waste film and its applicability to the field of textile design. The use of orange waste in the creation of textiles opens up more ways of thinking about and working with materials, and orange waste could become a desirable raw material for textile design on the basis that it introduces certain aesthetic and functional possibilities through its visual and tactile expression and material behaviour, in addition to defining methods of producing textiles.
Luminescent textiles are being increasingly used in apparel and sportswear aswell as in buildings, agriculture and automotives, for safety alert or forillumination or as a design feature[1]. Till now these luminescent textiles havebeen based on technologies such as LED, luminescent particles (rare earthmetals and metal oxides), which are not so eco‐friendly[2].Bio‐inspired strategies can provide efficient methods to achieve eco friendlybioluminescent textiles. Research projects have explored ways which aremainly based on culture of bioluminescent algae[3] or bacteria on textiles.Here we present another approach to achieve bioluminesence using biobasedproducts from various living organisms such as fireflies, fungi, earthwormsthat are found in land and in jelly fishes, shrimps, dinoflagellates, corals inmarine environment [4]. In order to mimic the luminescence effect seen innature, reaction mechanisms in various bioluminescent living organisms arestudied and the components or molecules responsible for luminescence areidentified [5‐10]. Most of the time, these involve enzymatic reactions.However the main challenge is to reproduce the bioluminescent mechanismand to adapt it to new materials which can yield some eco efficient bioinspired luminescent textiles.
Nature is the most exquisite thing around us with the existence of living organisms exhibiting different phenomena such as water repel/ency, touch sensitive plant and chameleon skin. Some of these phenomena inspired scientists to explore and design smart fabrics biomimicking the behaviour or pattern in living organisms. Bioluminescence is one such phenomenon where-in different living organisms such as firefly, jelly fish and crustaceans have the ability to impart visible light of specific wavelength, by enzyme catalysed reactions. Existence and study of such light emitting living organisms have been carried out, and harnessing these reactions has already transformed significant areas of medical field and clinical diagnosis, but research work on transforming this into living light is limited. In the present study, luminous bacterial system was investigated to assess and detect the bioluminescence behaviour onto the textile material. In the Luminous bacterial system, in vivo biochemical mechanism involves two different enzymes as well as different substrate components. Emission of light due to in vivo luminous bacterial reaction mechanism is seen in visible region. For in vitro reaction mechanism study, physical adsorption technique was used to graft both enzymes on plasma activated PET nonwoven textile and when substrates were introduced manually during the analysis, the biochemical reaction leading to light production occured. A Luminometer equipment was used to determine the light intensity in terms of Relative light units (RLU). The measurement results were obtained for nonwoven plasma treated PET with enzyme and substrate addition at different concentration and RLU value was obtained. The analysis data revealed that light intensity in RLU could be recorded by introducing both the enzymes and substrates on textile material, however intensive research is required in order to observe emitted light through the naked eye. The research study will help to attain
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.
Citrus waste has been used as a source of bioplastics for research in different ways. Because the juice industry produces significant amounts of residue each year, it would be advantageous to use the byproducts in the creation of new materials. Researchers have long explored eco-friendly methods to convert citrus and other organic waste into polymers for producing biodegradable films. The goal of this study is to create biofilms from orange waste (OW) and ginger waste (GW) using an ultrafine grinder and study the films’ properties. Since pectin has the ability to gel, and because cellulosic fibers are strong, citrus waste has been studied for its potential to produce biofilms. After being washed, dried, and milled, orange and ginger waste was shaped into films using a casting process. Tensile testing was used to determine the mechanical properties of biofilms, while dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) were used to determine their thermal properties. As the number of grinding cycles increased, the suspension’s viscosity increased from 29 mPa.s to 57 mPa.s for OW and from 217 mPa.s to 376 mPa.s for GW, while the particle size in the suspension significantly decreased. For OW and GW films, the highest tensile strength was 17 MPa and 15 MPa, respectively. The maximum strain obtained among all films was 4.8%. All the tested films were stable up to 150 °C, and maximum degradation occured after 300 °C.
The aim of this project was to address the food waste problem, particularly bread waste, to some extent by producing monofilaments obtained from wet spinning of fungal hydrogel through the cultivation of Rhizopus delemar on bread waste. The project had two phases. Firstly, the possibility of production of chitosan fiber with wet spinning (using different acids) was evaluated, the process was optimized, and then applied to the production of fungal fiber. Regarding first stage of the project, adipic acid, a non-toxic solvent with two carboxyl groups, was used as acting physical crosslinker between the chitosan chains, resulting in improving properties of the monofilaments. Adipic acid performance was compared with conventional solvents, such as citric, lactic, and acetic acids. By injecting chitosan solutions into a coagulation bath (EtOH or NaOH 1M or EtOH-NaOH or H2SO4-EtOH), monofilaments were formed. Scanning electron microscopy showed that uniform chitosan monofilaments with smooth surface were formed using adipic and lactic acids. In general, fibers obtained from adipic acid displayed higher mechanical strength (Young’s modulus of 4.45 GPa and tensile strength of 147.9 MPa) than that of monofilaments produced using conventional solvents. Fiber dewatering with EtOH before drying led to greater fiber diameter and lower mechanical strength. As the second stage of this study, Rhizopus delemar was cultivated on bread waste in shake flasks and 1.3 M3 bioreactor. While different combinations of ground bread and K2HPO4 was used as the substrate for shake flask cultivations, white bread waste without K2HPO4 was utilized for scaling up the process, mostly due to the Glucosamine (GlcN) and N-acetyl-glucosamine (GlcNAc) content in the fungal cell wall. GlcN and GlcNA content obtained from ground bread was remarkably higher than that of obtained from combinations of ground bread and K2HPO4 as the substrate. Cultivation in 1.3 M3 bioreactor resulted in about 36 kg wet biomass with a mean of 14.88% dry weight, indicating 5.95 g biomass/L. The biomass yield of 0.15 g dry biomass/g dry bread was achieved. Alkali insoluble material (AIM) was obtained by alkali treatment of biomass. Fungal hydrogel was prepared by adding adipic and lactic acid to AIM, followed by grinding treatment. While hydrogels treated with lactic acid showed better spinnability and gelling ability, the one from adipic acid was not uniform to be wet spun. Considering hydrogels treated with lactic acid, the optimum grinding cycle for more spinnable hydrogel was 6 negative cycles, contributing to the fibers with the tensile strength of around 82 MPa. Such fibers showed antibacterial property against Escherichia coli, making them as a good option for suture applications. However, further in vitro and in vivo trials are essential to test the fungal fiber for such applications.
Adipic acid was evaluated as a novel solvent for wet spinning of chitosan fibers. A solvent with two carboxyl groups could act as a physical crosslinker between the chitosan chains, resulting in improved properties of the fibers. The performance of adipic acid was compared with conventional solvents, i.e., lactic, citric, and acetic acids. Chitosan solutions were injected into a coagulation bath to form monofilaments. Sodium hydroxide (NaOH) and its mixture with ethanol (EtOH) were used as coagulation agents. Scanning electron microscopy confirmed the formation of uniform chitosan monofilaments with an even surface when using adipic acid as solvent. These monofilaments generally showed higher mechanical strength compared to that of monofilaments produced using conventional solvents. The highest Young’s modulus, 4.45 GPa, was recorded for adipic acid monofilaments coagulated in NaOH-EtOH. This monofilament also had a high tensile strength of 147.9 MPa. Furthermore, taking advantage of chitosan insolubility in sulfuric acid (H2SO4) at room temperature, chitosan fibers were successfully formed upon coagulation in H2SO4-EtOH. The dewatering of fibers using EtOH before drying resulted in a larger fiber diameter and lower mechanical strength. Adipic acid fibers made without dehydration illustrated 18% (for NaOH), 46% (for NaOH-EtOH), and 91% (for H2SO4-EtOH) higher tensile strength compared to those made with dehydration.
Green composites, renowned for their biodegradable and recyclable attributes, have recently gained substantial prominence. Their sustainability, eco-friendliness, and lightweight characteristics position them as a compelling alternative to conventional plastic-based materials. This study delves into the mechanical performance, encompassing tensile, flexural, and Charpy impact test properties, of jute and flax thermoplastic composite laminates. Additionally, it explores the flexural behavior of sandwich composites reinforced with jute and flax fabrics individually. To accomplish this, we manufactured various composite laminates, including jute/PP, flax/PP (64.2 % fiber mass fraction), flax/PP (45.0 % fiber mass fraction), and plasma-treated flax/PP (PTF/PP) composite laminates using compression molding techniques. We also crafted sandwich composites by integrating flax and jute natural fabrics as reinforcements into a polypropylene (PP) matrix for the sandwich surface layer, along with recycled polyethylene terephthalate (PET) foam as the core material. This allowed for a comprehensive comparative analysis of their functional properties. In addition to mechanical testing, the differential scanning calorimetry (DSC) analysis was conducted on various composite laminates to evaluate the crystallinity levels and melting behavior of PP within these diverse formulations. Further characterizations included Fourier transform infrared (FTIR) spectroscopy and digital imaging analysis. Our experimental results unequivocally demonstrated the superior performance of Flax/PP composite laminates over Jute/PP composite laminates in terms of flexural, tensile, and impact properties. In the context of sandwich composites, Flax/PP/PET foam exhibited the highest force resistance, along with superior bending strength and modulus when compared to Jute/PP/PET foam. Notably, Jute/PP/PET foam displayed a higher incidence of delamination and breakage. Interestingly, both sandwich composites demonstrated nearly identical properties in the impact test. Furthermore, plasma treatment of flax composite laminates had a beneficial effect on specific mechanical properties, leading to an 8.6 % enhancement in flexural strength (54.09 MPa) compared to the performance of flax/PP (45.0 % fiber mass fraction) laminate.
Chitin nanofibers (ChNFs) were extracted from Mucor indicus by a purification method followed by a mechanical treatment, cultivated under obtained optimum culture medium conditions to improve fungal chitin production rate. A semi synthetic media containing 50 g/l glucose was used for cultivation of the fungus in shake flasks. The cell wall analysis showed that N-acetyl glucosamine (GlcNAc) content, which is an indication of chitin content, was maximum in presence of 2.5 g/l H3PO4, 2.5 g/l of NaOH, 1 g/l of yeast extract, 1 mg/l of plant hormones, and 1 ml/l of trace metals. The chemical characterizations demonstrated that the isolated fibers had a degree of deacetylation lower than of 10%, and were phosphate free. The FTIR results revealed successful removal of different materials during the purification step. The FE-SEM of fibrillated chitin illustrated an average diameter of 28 nm. Finally, X-ray diffraction results showed that the crystallinity index of nanofibers was 82%.
Climate change, waste disposal challenges, and emissions generated by the manufacture of non-renewable materials are driving forces behind the production of more sustainable composite materials. All-cellulose composites (ACCs) originate from renewable biomass, such as trees and other plants, and are considered fully biodegradable. Dissolving cellulose is a common part of manufacturing ACCs, and currently there is a lot of research focused on effective, but also more environmentally friendly cellulose solvents. There are several beneficial properties of ACC materials that make them competitive: light weight, recyclability, low toxicity, good optical, mechanical, and gas barrier properties, and abundance of renewable plant-based raw material. The most prominent ACC applications are currently found in the food packing, medical, technical and vehicle industries. All-cellulose nanocomposites (ACNCs) expand the current research field and can offer a variety of more specific and functional applications. This review provides an overview of the manufacture of sustainable ACCs from lignocellulose, purified cellulose, and cellulosic textiles. There is an introduction of the cellulose dissolution practices of creating ACCs that are currently researched, the structure of cellulose during complete or partial dissolution is discussed, and a brief overview of factors which influence composite properties is presented. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.