Polylactic acid and polyhydroxybutyrate coating on hemp fiber: Its effect on hemp fiber reinforced epoxy composites performance

Abstract

The present research work investigated the influence of biodegradable polymer coatings of hemp fiber on the structural, water absorption, mechanical and tribological properties of hemp fiber and hemp fiber reinforced epoxy composites (HFREC). Hemp fibers were initially treated with sodium hydrogen carbonate and then coated with biodegradable polymers like polyhydroxybutyrate (PHB) and polylactic acid (PLA). SEM images of the coated fibers showed a visible change in fiber surface and improvement in surface roughness, while; XRD analysis indicated the improvement in crystallinity of the coated fibers resulting in enhanced interfacial adhesion between the coated fibers and the epoxy matrix. The experimental results also revealed that both PHB and PLA coatings of the fibers have resulted in improvement of water resistance and mechanical properties such as tensile strength, modulus and impact strength of coated HFREC. Tribological test results also revealed that the coated HFREC have improved wear and frictional properties in comparison to uncoated HFREC. The best tribological and mechanical properties were exhibited by PLA coated HFREC, which was also confirmed through the SEM images of worn and fractured surfaces of the uncoated and coated hemp fiber composites.

Mechanical, water absorption and tribological properties of epoxy composites filled with waste eggshell and fish scale particles

“…46,47 This may be the possible reason for better wear resistance of filler reinforced composites. 48 Among all the wear tested composite samples at different sliding speed, EFREC shown the best wear performance followed by FREC and EREC. The hybrid composite (EFREC) developed might have the proper amount of eggshell and fish scale in the epoxy matrix which may contributed to more uniform dispersion of these filler particles in the epoxy matrix than EREC and FREC.…”

Biocomposite Based on Polyhydroxybutyrate and Cellulose Acetate for the Adsorption of Methylene Blue

“…This is due to the polymeric matrix's hydrophobic nature, which decreases their hydrophilic character. Similarly, Behera et al [27] performed PHB and PLA coatings on hemp fibers, and observed greater water absorption resistance with coated fibers than uncoated fibers. In terms of specific results, cellulose showed faster water absorption, reaching 99% at 120 h, while coconut fiber reached 97%.…”

“…Samples of each material were immersed in water for different periods, recording the weight change at 24-h intervals. For the test, 0.6 g of each material was added to 5 mL of water, following the methodology proposed by Behera et al [27]. The percentage of water absorption was calculated using Equation (1):…”

“…In addition, it is observed that the biopolymer layers are thin. This inhomogeneous distribution and the thinness of the biopolymer layers may be related to a higher water resistance in the presence of PHB [27].…”

Mechanical and tribological properties of chemically modified jute/epoxy composites

“…The surface viscosity of the material decreased, mostly due to the strong bond between the treated fibre and the matrix. This led to the development of a lubricant layer that prevents material loss and reduces the friction coefficient [49][50][51]. Figure 10(B) indicates that the highest COF obtained for untreated JFREC is 0.57 at a sliding speed of 2.5 m s −1 and the lowest COF is obtained for ST JFREC is 0.41 at a sliding speed of 1 m s −1 .…”