The effect of flax and PLA fibers distribution in core-spun yarn on the properties of biomass-based composite

Natural fiber reinforced composites possess the advantages of lightweight, degradability and excellent mechanical properties. The primary objective of this work was to investigate the effect of the distribution of reinforcing fibers and the matrix within the composite on the performance of composites. The biomass-based composites were prepared by hot-pressing the fabrics woven by core-spun yarn that produced from flax noil fibers and Polylactic Acid (PLA) fibers, utilizing the thermo-plasticity of PLA fibers. The core-spun yarns were constructed with a core-sheath structure, in which the core yarn was a flax/PLA blended yarn and the sheath part was PLA staple fibers. The special structure effectively improved the hairiness, evenness and weave-ability of the yarn. The properties of the composites were improved by controlling the distribution of PLA and flax fiber in the core and sheath of the core0-spun yarn in order to improve the distribution of the reinforcing fibers and matrix. The biomass-based composites presented the excellent tensile properties (breaking strength of 32 MPa, elongation of 14.3 %), tearing properties (tearing energy of 95.71 KJ/m²) and dynamic thermo-mechanical properties (storage modulus of 1953 MPa at 35℃ temperature, loss factor of 0.285), when the blending ratio of PLA and flax fiber within the core yarn was 80:20. In addition, the composites showed superior environmental friendliness, with a biodegradability of 52.1 % within 180 days. These biomass-based composites developed in this work display admirable potential applications for automobile interiors, sporting equipment, packaging materials, etc.