Preparation and melt-spun applications of PA6-based Poly(Amide-Ether) copolymers phase change fibers with passive temperature management

Phase change fiber, as an intelligent fiber material used in passive thermal management, can balance the temperature of the microenvironment near human skin. However, the traditional blending method makes phase change material prone to leakage during the processing and applications. Herein, this work introduces the phase change material PTMEG into the polyamide 6 (PA6) chain through melt polymerization to prepare a series of PA6-based poly(amide-ether) copolymers. Copolymers exhibit an obvious microphase separation structure, with the PA6 segments and the PTMEG segments can form independent crystalline and amorphous regions. PTMEG in copolymers through polymerization method exhibits better thermal stability compared with the blended way, which effectively solves the leakage problem of phase change materials. The copolymers can be directly melt-spun (1500 m/min) to prepare PA6-based phase change fibers. The fiber can maintain excellent mechanical properties (breaking strength of 2.12 cN/dtex). Meanwhile, the crystallization enthalpy and melting enthalpy of the PTMEG in the fiber are 10.59 J/g and 12.44 J/g, respectively. The thermal management time of the fiber in the hot environment is 349 s, and the maximum temperature difference is lower 5.6 ℃ from the PA6 fiber. In addition, the exothermic duration in a cold environment is 536 s, and the maximum temperature difference is higher 1.1 °C from the PA6 fiber. Meanwhile, the thermal enthalpy of the fiber remained stable (fluctuation within 2 %) after 20th thermal cycles, and the loss rate is less than 2 % after washing at 25 ℃, 50 ℃ and 90 ℃. The fiber exhibits good thermal stability, water washability and cyclic stability. Preparation of high enthalpy polymers directly by copolymerization will provide new ideas for phase change fibers for apparel.