Preparation and Thermal Insulation of Polylactic Acid Hollow Fiber Aerogels

Facing the challenges of extreme environments (extreme cold, high temperature, etc.), the temperature fluctuations are beyond the tolerance of human beings. Aerogels, as a generation of ultralight materials, can build efficient temperature barriers to realize effective insulation and heat preservation. Herein, we use polylactic acid (PLA) hollow fibers to prepare PLA aerogels with micro- and nanoporous structures, having excellent compression properties and thermal insulation under different environmental (temperature, humidity, etc.) conditions. The results show hollow PLA (H-PLA) fiber with 56.27 ± 1.60 μm diameter has 11.82 MPa stress and 24% strain. H-PLA aerogels are fabricated through VTMS cross-linking and freeze-drying. Its compressive stress is 3.44 kPa after 100 compressive cycles, maintaining 93.47% of the original stress. Under simulating extreme environmental temperatures (cold source −60 °C, heat source 60 °C), the thermal insulation capacity of H-PLA aerogel reaches 22.64 and 37.54 °C. The lower the density of the aerogel, the greater its thermal insulation capacity. At the same time, when the environmental humidity increases from 23% to 60%, the mean temperature of the upper surface of the aerogel declines from 32.0 to 29.55 °C under a hot source and from −7.66 to −9.14 °C under a cold source, reflecting excellent thermal insulation performance. It offers an efficacious methodology for the design of insulation materials that exhibit superior thermal insulation properties under extreme environmental conditions.