This study investigates the properties of polylactic acid (PLA) multifilament and its warp-knitted fabrics. Multifilament properties were tested and compared with PET multifilament with different diameters. The 83.3 dtex PLA multifilament was used to knit the fabric, and the fabric properties before and after dyeing were studied. Results showed that the mechanical properties of PLA multifilament were comparable to those of PET. However, PLA had a higher heat shrinkage rate. The dyed PLA warp-knitted fabric has excellent color fastness. Due to the influence of temperature and dye particles during the dyeing process, the breaking strength, air permeability and moisture permeability of the fabric were decreased. On the contrary, the elongation at break, abrasion resistance, anti-pilling properties, drape and crochet value of the fabric were increased.

The MWCNT-COOH and CTAB modified MMT were hybridized by the ultrasonic method, and the nylon 66/MMT/WMCNT composite was prepared by in-situ polymerization to study the effect of the introduction of MMT and MWCNT on the properties of nylon 66. A scanning electron micrograph of the composite cross-section shows that the CNTs were uniformly dispersed in the nylon 66 matrix. The XRD patterns show that the introduction of MMT and MWCNT-COOH caused the ratio of α1 and α2 of nanocomposites. The TGA results show that the heat resistance and residual carbon content of the composite material are improved. The mechanical properties of nanocomposites show that the mechanical properties of the material are improved relative to pure PA66.