Scalable Preparation of Complete Stereo-Complexation Polylactic Acid Fiber and Its Hydrolysis Resistance

Area of Science:

• Polymer Science
• Materials Science
• Textile Engineering

Background:

• Polylactic acid (PLA) applications are limited by poor thermal and hydrolysis resistance.
• Stereo-complexation (SC) between poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) can enhance PLA properties.

Purpose of the Study:

• To investigate the effects of high-temperature tension heat-setting on PLA fiber with SC structure.
• To evaluate improvements in crystalline structure, thermal, mechanical, and hydrolysis resistance of SC PLA fibers.

Main Methods:

• Blended melt-spinning of PLLA/PDLA to create PLA fiber with SC structure.
• High-temperature tension heat-setting process applied to the spun fibers.
• Analysis of crystalline structure, thermal properties (melting point), mechanical properties (strength retention), and hydrolysis resistance.

Main Results:

• A tension heat-setting temperature of 190 °C yielded an almost complete SC structure in PLA fibers.
• The SC PLA fiber exhibited a high melting point of 222.5 °C.
• SC crystallites demonstrated superior hydrolysis resistance compared to homocrystallization (HC), with SC-190 fiber retaining 78.5% strength after 24h hydrolysis.

Conclusions:

• High-temperature tension heat-setting is effective in forming a complete SC structure in PLLA/PDLA fibers.
• The SC structure significantly enhances the thermal and hydrolysis resistance of PLA fibers.
• SC PLA fibers offer improved durability for applications requiring resistance to heat and moisture.