Preparation and characterization of ultralight glass fiber wool/phenolic resin aerogels with a spring-like structure

Abstract

Spring-like ultralight glass fiber wool enhanced phenolic resin aerogels was produced by a simple sol-gel polymerization in a slurry containing ultralight glass fiber wool (UGFW), phenolic resin (PR), hexamethylenetetramine (HMTA) as well as ethylene glycol (EG). UGFW was hierarchically structured and covered with a filmy layer of PR binder between the contact points of fibers to fabricate a stabile three-dimensional (3D) enhancement skeleton before PR aerogel attached. PR aerogels was distributed evenly and randomly on the UGFW skeleton. Compared with other fiber reinforced aerogels (FRAs), ultralight glass fiber wool enhanced phenolic resin aerogels (UGFW/PRAs) exhibited excellent resiliency, low density and structurally adaptive performances. The elastic modulus for the aerogels were ranged from 0.81 to 3.92 kPa at the densities from 7.17 to 37.1 mg/cm3, respectively. The degrees of uniformity (DU) of both samples were under 15.19%. Furthermore, the sound transmission loss (STL) of UGFW/PRAs was significantly increased by 13.16 dB at 4 kHz, 3 times of the calculated value in accordance with mass law. The thermal conductivity (λ) for the composites was ranged from 0.031 to 0.0366 W m−1 K−1 with the density decreased from 36.1 to 13.95 mg/cm3. Moreover, the basic mechanisms of the resilient and the reinforced principles of UGFW/PRAs were analyzed. Accordingly, the synthesis of ultra-lightweight flexible fiber reinforced organic aerogels is expected to involve various fabrics with stable structure, which provides a rich way to develop various new fiber reinforced functional composites.