Thermomechanical characteristics of flax-woven-fabric-reinforced poly(lactic acid) and polypropylene biocomposites

Flax is a prominent natural fiber used in biodegradable and sustainable polymeric biocomposites as reinforcement material. The prime objective of this research was to fabricate, characterize and compare flax-woven-fabric-reinforced poly(lactic acid) (PLA) and polypropylene (PP) with different directions (lengthwise and cross-wise) by using hot-press technology. Tensile strength, elastic modulus, flexural strength, flexural modulus, thickness swelling and water absorbency tests were carried out to assess the physical and mechanical performance of the composites. The flax/PLA composites exhibited the highest tensile strength (128.6 MPa) in the lengthwise direction, whereas flax/PP showed the lowest tensile strength in the cross-wise direction (90.69 MPa). Flax/PP had the highest flexural strength (53.80 MPa) in the lengthwise direction, although flax/PLA (lengthwise) provided the maximum bending modulus (40.809 MPa). Moreover, scanning electron micrographs were also investigated to observe the appearance of the matrix for flax/PLA and flax/PP composites before and after applying tensile loads. Fourier transform infrared spectroscopy analysis indicated successful lamination of flax woven fabrics with the thermoplastic polymers (PLA and PP). Thermogravimetric investigation showed enhanced thermal stability of the produced biocomposites.