Abstract:

Polyactic acid (PLA) filamens sized with conventional alkaline sizing solution at temperature (T>60℃) have poor structure and mechanical properties. The changes of the microstructure of PLA filaments before and after sizing process under various conditions are examined using scanning electron microscope (SEM), and the effects of temperature and pH value on the physical properties were analyzed. Significant changes in the microstructure of the PLA filaments are evident and markedly decreases in their tensile strength are found when the PLA filaments are sized under alkaline solutions at higher temperature (T>600C). In contrast, when the PLA filaments are sized in a neutral sizing solution under relatively lower temperature (e.g., T<600C for the sizing solution and T<700C for the drying temperature), tensile strength of the sized filaments increases up to 59.74% and the reduction of elongation rate is as low as 7.10%, which meets the weaving requirements.

Key words: sizing, polylactic acid filament, tensile strength, sizing temperature, pH value of sizing liquor