Facile Solvent-Free Preparation of Biobased Rigid Polyurethane Foam from Raw Citric Acid Fermentation Waste
Jixiang Liu, Zhaonan Sun, Fenghuan Wang, Daihui Zhu, Jiye Ge, Haijia Su
Abstract
To alleviate the environmental pollution caused by raw citric acid fermentation waste (CAFW) and reduce the dependence of polyurethane foam production on petroleum-based materials, a facile method of preparing raw CAFW-based rigid polyurethane foams (RPUFs) under solvent-free conditions is proposed. Glycerol and poly(ethylene glycol) (PEG) are introduced as chain extenders and their effects are discussed. Fourier transform infrared (FTIR) results confirm the successful preparation of RPUFs. Scanning electron microscopy (SEM) images show that uniform porous structures are formed. Moreover, the obtained RPUFs display excellent mechanical and thermal performance. Apparent densities of the three groups of foams (blank group, glycerol chain extender group, and PEG chain extender group) are 136.8, 74.9, and 84.0 kg/m3, respectively, and their compressive strengths are 127.4, 149.5, and 130.4 kPa, respectively. Their thermal conductivity is in the range of 0.020 and 0.027 W/(m·K). Therefore, synthesizing RPUFs is possible to alleviate the pollution problem and lower the production cost by replacing petroleum-based polyols.