The present invention discloses a PLA-PHA side-by-side composite elastic fiber and a preparation method thereof, belonging to the field of composite elastic fibers. The preparation method comprises: first, melt extruding and pelletizing PLA and polysilsesquioxane in a twin-screw extruder to obtain a master batch, then melt mixing the master batch with PLA to obtain component A; subjecting PHA to chain extension modification with double-ended epoxy siloxane, then melt mixing with PLA to obtain component B; and subjecting component A and component B to composite spinning to prepare the side-by-side composite elastic fiber. After chain extension of PHA with double-ended epoxy siloxane, its relative molecular weight can be increased and melt strength can be improved; meanwhile, the siloxane segment can play a role of internal lubrication to improve the fluidity of the melt, reduce its processing temperature, further reduce the thermal degradation of PHA, and ensure the necessary spinnability. In addition, the introduction of polysilsesquioxane in component A improves the melt fluidity of PLA, reduces the viscosity difference with component B, ensures the formation of a good interfacial structure of the composite fiber, and lays a macro structural foundation for the formation of fiber crimping. Meanwhile, polysilsesquioxane in component A can promote the nucleation and crystallization of PLA, and the blending of PLA and chain-extended modified PHA component in component B can construct a gradient distribution structure through heterogeneous flow control, which increases the difference in radial microstructure in the composite fiber and is conducive to promoting the formation of fiber crimping.
Country Code: CN
Application Number: CN202410214758.9
