Biologically degummed and chemically treated okra bast fibers-reinforced Poly(vinyl alcohol) composites

Abstract

This paper focuses on preparation of poly(vinyl alcohol) (PVA)-based composites reinforced with okra bast fibers at different percentages of 5, 10, 20% via solution casting method. Fibers obtained from different sections of okra plants were biologically degummed and scoured with Na2CO3. Selected fibers were bleached, treated with maleic anhydride or grafted with vinyl acetate. Mechanical, physical and biodegradational properties of the composites were investigated. The tensile strength of the produced composites ranges between 33.8 and 55.1 MPa, elasticity modulus from 1.8 to 2.6 GPa, elongation rate at break varies in 2.8-10%. Chemical treatments led to improved mechanical performance whereas increased fiber content reduces tensile strength, stiffness and elongation, as well as water absorption. Fiber addition significantly affected biodegradation in a complicated way: by decelerating mass loss but accelerating deterioration of mechanical properties.

A Bio-Inspired Approach to Improve the Toughness of Brittle Bast Fibre-Reinforced Composites Using Cellulose Acetate Foils

“…The Greenpoxy matrix achieved values of 2.2% and the CA foils of 20.3% (see Figure 3 A), meaning that the CA foils have significantly higher ductility than the kenaf layers, similar to the tough protein layers compared to the brittle bioglass layers in the biological role model (spicules). Due to the brittle nature of kenaf and the weakest link theory [ 52 ], the elongation at break of the composites was significantly reduced compared to the matrix, as already described in the literature for bast fibre-reinforced composites [ 57 ]. Under bending load ( Figure 3 B), the presence of the CA foils increases deformation and prevents spontaneous failure of the composite structure.…”