Biomimetic Hollow Porous Fibers with Enhanced Mechanical Strength for Thermal Insulation

Abstract

Inspired by the hollow porous structure of polar bear fur, cellulose acetate/thermoplastic polyurethane (CT) hollow porous fibers produced via wet spinning have excellent thermal insulation properties but suffer from limited mechanical strength, hindering their broader applications. To address this issue, this study investigated the effect of CaCl2 addition on the mechanical and thermal insulation properties of cellulose acetate/thermoplastic polyurethane/CaCl2 (CTC) hollow porous fibers. The microstructure, chemical functional groups, mechanical properties, and thermal insulation were characterized using field emission scanning electron microscopy (FESEM), a Fourier-transform infrared spectrometer, a double-arm material machine, a thermal conductivity meter, an infrared thermometer, and thermocouples. SEM images confirmed the successful fabrication of CTC hollow porous fibers mimicking polar bear fur. Notably, the CTC-5% sample demonstrated several advantages, such as high porosity (94.75%), superior mechanical performance (breaking stress of 6.22 ± 0.76 MPa and breaking strain of 77.65 ± 11.15%), as well as favorable prospects for continuous large-scale production. Additionally, the woven fabric exhibited excellent thermal insulation with a thermal conductivity of 0.023 W·m–1·K–1. Collectively, these results suggest that CTC hollow porous fibers hold great promise as high-performance thermal insulation materials.