Jute yarn reinforced epoxy composite

Abstract

In today's scenario, due to environmental sustainability use of natural fibre is increased as reinforcement material in polymer composites. This work is aimed to explore the potential of fibrous material in yarn form as reinforcement element in the epoxy matrix. Previous studies based on textile-composites are primarily focused on the fibrous structure and interface between fibre and matrix. The reinforcement material for the composite application must be understood in the form of long filaments or yarn. Herein, unidirectional jute yarn reinforced epoxy composites (JYREC) are prepared using hand lay-up technique. The novelty of the work is to study the effect of jute yarn having different linear density varies from 4 to 12 lb/ spyndle of jute yarn on the static and dynamic properties of the epoxy composite. The importance of the current work also includes optimising the conditions under which jute yarn is chemically treated (by alkali, bleaching, or combination alkali-bleaching), in order to improve the reinforcement-resin interphase and the corresponding composite properties. The responses of the yarns to alkali treatment and bleaching are seen to differ during the optimisation phase. There isn't a single, universally applicable optimal condition for all yarns. The final property of the yarn is mainly influenced by the weight loss percentage and reduction in breaking force, as well as other changes, such as shrinkage, change in diameter causing a change in twist, cohesiveness between the yarn's fibres, etc. For the best alkali conditions, maximum tenacity is obtained at a higher alkali concentration for the highest count (12 lb/spyndle) and a lower alkali concentration for the lower count (4 lb/spyndle). While the highest strength is attained at a 10% NaOH concentration for the medium counts of 6, 8 and 10 lb/spyndle. On the other hand, the bleaching and combined treatment resulted in a drop in the jute yarn's breaking force, tenacity, and initial modulus and an increase in its elongation percentage. Additionally, after the chemical treatment, the TPI and moisture regain% both rise, which affects the final properties of composites manufactured from them as well. For all linear densities, a composite made with untreated jute yarn has the highest tensile strength in comparison to other composites made with treated jute yarn. The mechanical properties of epoxy composites show the increment with the addition of jute yarn as compared to the neat epoxy. The results show that with increase in the linear density; tensile strength (45.86 MPa), impact strength (9.41 kJ/m2) and storage modulus (5443.08 MPa) of the JYREC increases up to 8 lb/ spyndle jute yarn after that downtrend is observed. The balanced combination of number of yarns in the composite for the same mass loading fraction, twist per inch and tenacity of individual jute yarn is responsible for the resultant properties of the composites. The effectiveness of interfacial attraction between the jute yarn and epoxy resin is also conform by the DMA results which having lower COE of 0.89 and lower damping factor of 0.27. The angle or orientation and loading fraction of jute yarn also greatly influence the tensile and dynamic mechanical properties of the composites. ANOVA conforms the higher order terms of the yarn orientation followed by yarn loading are having significance, whereas linear density of yarn makes a lowest significant difference. Results shows that, maximum tensile strength (57.65 MPa) and storage modulus (5864.81 MPa) are achieved for composite of yarn. however there is no much improvement in Tg with the change in angle of orientation of yarn. The mechanical properties of epoxy composite further enhanced with the incorporation of microcrystalline cellulose (MCC). Hierarchical composites are produced through the combination of different MCC particle concentrations, jute yarn mass loading fractions, and linear densities of jute yarn using 3-level-3-varivale box behnken design. The best result of mechanical properties of hierarchical composite are obtained at 20 wt.% 8lb/spyndle jute yarn loading and 1% MCC concentration. The efficiency of MCC particles in combination with jute yarn is governed by the lowest value of COE (0.058) and damping factor (0.273). The semi circular Cole-Cole plots for the hierarchical composites show that the epoxy composites are largely maintaining their homogeneity adhering to the addition of MCC particles, and a strong peak inflection indicated a two-phase system with a high order structure. Experimental results of tensile strength are also compared with the simulated model results and it has been observed that the analytical, experimental and simulation results, all are in close agreement and follow same trend. RVE approach gives effective idea of micro level stresses and elastic constants. However, the results differ by wide margin which may be due to the assumed perfect fibre matrix bonding in model which is not practically possible to achieve. Overall, it is concluded that JYREC may be utilized in various structural applications such as parts of automobiles, aircraft wings, marine industry and sports. The hybridization approach makes it possible to balance performance and weight of material, increasing the possibility of hierarchical polymer composites to be used in greater load bearing structural applications, particularly in the design of automobile and aircraft components.