The radical-induced cationic frontal photopolymerization (RICFP) of fully biobased epoxy composites is successfully demonstrated. This curing strategy considerably reduces the curing time and improves the efficiency of the composite fabrication. Two different natural fiber fabrics made of cellulose and flax fibers are embedded in two epoxy matrices, one derived from vanillin (diglycidylether of vanillyl alcohol-DGEVA) and the other from petroleum (3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate-CE). After RICFP the composites are characterized by means of dynamic mechanical thermal analysis and tensile tests. The mechanical properties improved with increasing fiber content, confirming a strong adhesion between the matrix and the reinforcing fiber fabrics, which is further evidenced by scanning electron microscopy analyses of the fracture surfaces. Furthermore, these fully bio-based composites possess comparable or even higher mechanical strength compared with the corresponding epoxy composites fabricated with conventional CE resin. A promising facile route to high-performing natural fiber-biobased epoxy resin composites is presented. © 2022 Wiley-VCH GmbH

The poor adhesion between natural fibers and polymer matrix restricts the mechanical performance of natural fiber reinforced composites. Here, lignosulfonate was methacrylated and evaluated as a potential compatibilizer for flax fiber reinforced soybean-derived polyester thermosets. Significant improvement in both tensile and flexural properties of the fiber composites were achieved when the flax fiber mat was treated with methacrylated lignosulfonate solution. In particular, the flexural modulus and flexural strength more than doubled from 2.6 to 6.7 GPa and from 36 MPa to 76.8 MPa, respectively when the fibers were soaked in 5 wt % MLS solution. The SEM analysis revealed improved fiber-matrix interface and lower extent of fiber pull-out in the methacrylated lignosulfonate treated fiber composites, which correlates with the improved mechanical properties.

The carding of the Lyocell cellulose fiber was done with a cylindrical cross lap machine supplied by Cormatex Prato, Italy. Several mats were made by carding and needle punching in order to have a compact and well entangled mat suitable for reinforcement. The speed of the cross lap machine, the frequency of needle punching, the number of times the mat goes through needle punching, the feeding rate of the carded fiber and the depth of needle penetration determined the level of entanglement of the Lyocell fiber which ultimately increased the mechanical properties of the fiber. The good mechanical properties of the carded Lyocell fiber made it a renewable and environmentally friendly alternative as reinforcement in composite manufacturing. Compared with other jute fiber reinforced composites, the mechanical properties of the resulting Lyocell composites were found to be better. Regenerated cellulose fiber (Lyocell) composites were environmentally friendly and the mechanical properties were comparable to those of natural fibers.

In this study, impact performance of bio-composites fabricated from jute/methacrylated soybean oil (MSO) subjected to low-velocity impact loading is presented. The composite laminates were fabricated using compression moulding technique and their thickness and weave architectures effect on the impact response were investigated and the experimental observations are reported. From the results obtained, it was observed that fibre orientation and thickness variation have a significant influence on the impact resistance of jute/MSO composite material. The results show that the total absorbed energy and maximum peak load increase linearly with an increase in the thickness. Among the composite samples investigated where thickness comprised of: 1, 1.5, 2, 2.5 and 3 mm, a composite reinforced with 46 yarns per 10 cm weft and 50 warp (W2-3 mm thick) is found to have highest resistance to impact damage compared to 32 and 15 yarn per 10 cm weft samples. This was attributed to the improved fibre/matrix interface as a result of surface treatment of jute fibres and the fibre architectures effect which create the cross-over points which act as stress distributors.

Composites were developed by reinforcing available non-woven Lyocell and viscose in acrylated epoxidized soybean oil (AESO). Compression molding was used to make composites with 40–60 wt% fiber content. The fiber content comprises only Lyocell or viscose fiber, or mixture of these fibers in known ratio. Hybrid composites were made by a mixture of both the fibers in known ratio and it affects the properties. The effect of hybridization was evident in most tests which gives us an opportunity to tailor the properties according to requirement. Lyocell fiber reinforced composites with 60 wt% fiber content had a tensile strength and modulus of about 135 MPa and 17 GPa, respectively. Dynamic mechanical analysis showed that the Lyocell fiber reinforced composites had good viscoelastic properties. The viscose fiber reinforced composites had the high percentage elongation and also showed relatively good impact strength and flexural modulus. Good fiber-matrix adhesion reflected in mechanical properties. SEM images were made to see the fiber-matrix compatibility.

The idea of using man-made cellulosic fibres as reinforcement for casein films in this study was inspired by their well defined fibre diameter and availability in large quantity, eventually leading to a homogeneous high quality composite at low cost. The casein biofilms were fabricated by solution casting from an aqueous alkaline solution of the bovine milk protein casein in the presence of glycerol as a plasticizer, and the fibre-reinforced biocomposites were prepared by the addition of regenerated cellulose fibre to the casein casting solution with various amounts of glycerol. The effects of glycerol content and cellulose fibre reinforcements on the mechanical, thermal and physiological properties were characterized. The results showed that increasing glycerol content decreased the film strength, Young’s modulus and thermal stability with a gradual increase in the elongation. However, the tensile properties were noticeably improved when reinforced with cellulose fibre. The composite with 20 wt% glycerol and 20 wt% cellulose fibre showed the maximum tensile strength of 23.5 MPa and Young’s modulus of 1.5 GPa. The corresponding values for the composite with 30 wt% glycerol and the same fibre content were 15.1 MPa and 0.9 GPa, which were 2.3- and 3.2-fold higher compared to 30 wt% glycerol plasticized film. The thermal analysis revealed that the glass transition temperature and the thermal stability were decreased when the glycerol content was increased. Addition of cellulose fibres increased the glass transition temperature as well as the thermal stability. The gel electrophoresis (SDS-PAGE) analysis indicated that there was no significant decrease in the molecular weight of the casein protein during sample preparation. Scanning electron microscopy showed that the obtained composites with low glycerol content had adequate interfacial bonding, and Fourier transform IR spectroscopy confirmed the formation of molecular interactions between the cellulose fibres and the casein.

Biocomposites were produced from regenerated cellulose fiber reinforcement and soybean based bio-matrix. Mechanical, thermal, viscoelastic and morphological results show the good potential of these composites to be used as structural materials in automotive industries. This article focuses on manufacturing and testing of these composites for engineering materials. Regenerated cellulose fibers such as Lyocell and viscose were reinforced in soybean based thermoset matrix to produce composites by compression molding. Hybrid composites were produced by mixing both these fibers at known ratio and the total fiber content in composite was between 40 and 60 weight %. In general, Lyocell based composites showed better tensile properties than viscose based composites. Composites consisting 60 weight % Lyocell and rest with matrix had tensile strength of 135 MPa and tensile modulus of 17 GPa. These composites also showed good flexural properties; flexural strength of 127 Mpa and flexural modulus of 7 GPa. Dynamic mechanical thermal analysis showed that these composites had good viscoelastic properties. Viscose based composites had better percentage elongation during tensile test. These composites also showed relatively good impact and viscoelastic properties. Scanning electron microscope images showed that the composites had good fiber-matrix adhesion. Several efforts are made to produce sustainable biomaterials to replace synthetic materials due to inherent properties like renewable, biodegradable and low density. Biocomposites play significant role in sustainable materials which has already found applications in automotive and construction industries. Many researchers produced biocomposites from natural fiber and bio-based/synthetic matrix and it had found several applications. There are several disadvantages of using natural fiber in composites; quality variation, place dependent, plant maturity, harvesting method, high water absorption etc. These composites also give odor which has to be avoided in indoor automotive applications. These natural fibers can be replaced with lignocelluloses, agro mass and biomass to develop biocomposites as they are from natural origin. Lyocell and viscose are manmade regenerated cellulose fibers which is from natural origin has excellent properties. These fibers can be used as reinforcements to produce biocomposites which can overcome most of the above listed disadvantages of natural fibers. Many composites were made from natural fiber reinforcement and petroleum based synthetic matrix. Researchers have been finding ways to get matrix out of natural resources like soybean and linseed on chemical modifications. This article is focused on producing and testing sustainable material with regenerated cellulose and soybean based bio-matrix for automotive applications.

Natural fiber composites have got more focus in recent times due to their intrinsic properties such as lightweight, biodegradable, low cost etc. Several researchers have made bio-composites out of many natural fibers such as jute, flax, sisal. These composites have large market in Europe and North America where it is used in automobile and construction industry. A lot of research has been done to improve the properties such as surface modification of fiber, manufacturing hybrid composites. However, the natural fibers are dissimilar and vary largely due to many factors such as variety, harvest, maturity, climate etc. Apart from technical drawbacks, these fibers grow only in certain countries such as India and China. High demand raised the price of these fibers which increases the product price as well. Wood-based fibers such as Lyocell and Viscose was used to make composites in order to make less variation in products, decrease the dependency of natural fibers, promoting locally available fibers and encourage forest products as value-added products. Lyocell and viscose fibers have relatively less variation and high quality. Bio-composites were made by reinforcing wood-based fibers in soybean based thermoset matrix. Hybrid composites were prepared by mixing two different wood-based fibers in known ratio. The fiber content in the composites was between 40 and 60 weight%. Mechanical properties were characterized by tensile, flexural and impact tests. Lyocell and viscose based composites had better mechanical properties than jute fiber composites. Alkali treatment of Lyocell fibers improved the mechanical properties of the composites. The behaviour of wood-based fiber composites were studied under wet environment as well. In wet environment, the mechanical properties of wood-based fiber composites were superior to jute fiber composites. Lyocell based composites had tensile strength of 135 MPa and tensile modulus of 17 GPa. The composites had flexural strength of 127 MPa and flexural modulus of 7 GPa. Better percentage elongation was obtained when viscose fiber was reinforced in matrix. Viscose composites had better impact strength and viscoelastic properties. The change in properties in two different wood-based fibers (Lyocell and viscose) lies in the morphology of the fiber itself. Hybrid composites were produced and the effect of hybridization was clear in most of the cases. The properties were able to be tailored by making hybrid composites, by changing the amount of each fiber in the composites. The results (tensile and flexural) were competitive and fulfil the requirements of these composites to be used in several applications including automotive headliners, car door panel, construction door frame etc. The forest products such as wood fibers could be used in composites to produce environmentally friendly products and promote forest industry. Wood-based fibers such as Lyocell and Viscose was used to make composites in order to make less variation in products, decrease the dependency of natural fibers, promoting locally available fibers and encourage forest products. Bio-composites were made by reinforcing wood-based fibers in soybean based thermoset matrix. Hybrid composites were prepared by mixing two different wood-based fibers in known ratio. Mechanical properties were characterized by tensile, flexural and impact tests. Lyocell and viscose based composites had better mechanical properties than jute fiber composites. Alkali treatment of Lyocell fibers improved the mechanical properties of the composites. The behaviour of wood-based fiber composites were studied under wet environment as well. In wet environment, the mechanical properties of wood-based fiber composites were superior to jute fiber composites. Lyocell based composites had tensile strength of 135 MPa and tensile modulus of 17 GPa. The composites had flexural strength of 127 MPa and flexural modulus of 7 GPa. Viscose composites had better impact strength and viscoelastic properties. The result fulfils the requirements of these composites to be used in several applications including automotive headliners, car door panel etc. The forest products could be used in composites to produce environmentally friendly products and promote forest industry.

Composites were manufactured from regenerated cellulose and biobased matrix by compression molding. The reinforcing materials used were Lyocell and viscose, while the matrix used was chemically modified soybean oil. Hybrid composites were prepared by mixing both the fibers. The total fiber content in the composites was between 40-60 weight %. Lyocell based composites had better tensile properties than viscose based composites; composites consisting 60 weight % Lyocell impregnated with matrix had tensile strength of 135 MPa and tensile modulus of 17 GPa. These composites also showed better flexural properties; flexural strength of 127 MPa and flexural modulus of 7 GPa. Dynamic mechanical thermal analysis results showed that these composites had good viscoelastic properties. Viscose based composites had better percentage elongation; these composites also showed relatively good impact and viscoelastic properties. Hybrid composites showed good mechanical and viscoelastic properties. Scanning electron microscope images showed that the composites had good fiber-matrix adhesion.

Wood pulp based regenerated cellulose fibers like Lyocell and viscose which are from natural origin have high and even quality; used to develop superior composites with good properties. In this project, Lyocell and viscose fibers were reinforced in chemically modified soybean based bio-matrix, acrylated epoxidized soybean oil (AESO) by compression molding technique. The composites are characterized for mechanical performance by tensile, flexural and impact tests, viscoelastic performance by dynamical mechanical thermal analysis (DMTA) and morphological analysis by scanning electron microscopy (SEM). In general, Lyocell composites had better tensile and flexural properties than viscose based composites. The same goes with elastic and viscous response of the composites. Hybrid composites were formed by fiber blending; on addition of Lyocell to viscose based composites improved the properties. The amount of Lyocell and viscose fibers used determined the properties of hybrid composites and the possibility of tailoring properties for specific application was seen. Hybrid composites showed better impact strength. Morphological analysis showed that the viscose composites had small fiber pull out whereas Lyocell composites had few pores. Hybrid composite analysis showed that they had uneven spreading of matrix; delamination occurred on constant heating and cooling. To overcome the above mentioned issue and to reduce the water absorption, surface modification of the fiber was done by alkali treatment and silane treatment. The effect of treatment is done through swelling, water absorption and morphological analysis tests. The properties could be increased on proper modification of the fibers. The results show the good potential of these composites to be used in automotives and construction industries.