Semi-Interpenetrating Novolac-Epoxy Thermoset Polymer Networks Derived from Plant Biomass (original) (raw)

Bio-based phenol-formaldehyde polymer (BioNovolac) was developed by reacting molar excess of bio-oil/phenol with formaldehyde in acidic medium. Glycidyl 3,5-diglycidoxybenzoate (GDGB), was prepared by direct glycidylation of α-resorcylic acid (RA), a naturally occurring phenolic monomer. GDGB was crosslinked in the presence of BioNovolac by anionic polymerization. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of semi-interpenetrating polymer networks. The glass transition temperature and moduli of biobased crosslinked systems were observed to increase with increasing GDGB content. Active chain density and mass retention measured by dynamic mechanical analysis (DMA) and Soxhlet extraction, respectively, indicated a high crosslink density of the cured networks. Scanning electron microscopy (SEM) images depicted the homogeneity of the bulk phase. The preparation of bio-based epoxy-novolac thermoset network resulted in reduced consumption of petroleum-based chemicals.