Fabrication and mechanical properties of completely biodegradable hemp fiber reinforced polylactic acid composites

Biodegradable composite materials can be produced by the combination of biodegradable polymers and natural fibers. In this study, a new biodegradable composite of hemp fiber reinforced polylactic acid (PLA) was fabricated using the hot press method. Mechanical properties of composites with different fiber volume fractions were tested. The optimum fiber content was determined according to the test results. Effects of alkali treatment on the fiber surface morphology and the mechanical properties of the composites were investigated. Test results show that the composite with 40% volume fraction of alkali treated fiber has the best mechanical properties. The tensile strength, elastic modulus. and flexural strength of the composite with 40% treated fiber are 54.6 MPa, 8.5 Gpa, and 112.7 MPa respectively, which are much higher than those of PLA alone. The composites have lower densities, which were measured to be from 1.19g/cm(2) to 1.25g/cm(3). Specific strengths were also calculated. Surface morphologies of fiber and fracture surfaces of the composites were observed using the SEM method.