Cross-Linked Acrylic Polymers from the Aqueous Phase of Biomass Pyrolysis Oil and Acrylated Epoxidized Soybean Oil

Development of cross-linked, soft polymeric materials from biomass has been a focus of research. The aqueous phase of biomass pyrolysis oil (bio-oil) has been used as a precursor for monomer synthesis. Pine wood was ground and pyrolyzed to produce liquid bio-oil which was further separated into organic and aqueous phases. Gas chromatography–mass spectroscopy (GC-MS), 31P-nuclear magnetic resonance (31P NMR), 1H NMR, and Fourier transform-infrared (FTIR) spectroscopy were used for the characterization of bio-oil and its derivatives. Methacrylation reaction was carried out on the concentrated aqueous phase to yield methacrylated aqueous bio-oil. Acrylated epoxidized soybean oil (AESO) and methacrylated aqueous bio-oil were blended in different proportions and were polymerized by free radical polymerization. The polymer samples were evaluated by FTIR, dynamic mechanical analysis (DMA), Soxhlet extraction, and scanning electron microscopy (SEM). Tensile modulus, storage modulus, active chains density, and mass retention increased with higher AESO content. The polymers displayed sub-ambient glass transition temperatures (−30 to −21 °C). The impact of plasticizing and cross-linking effects of polymer chains on the glass transition temperature was studied with the theoretical Fox and Loshaek models. Utilization of the low-valued aqueous bio-oil and soybean oil renders the cross-linked polymers potential replacement of conventional polymers and helps to improve the overall sustainability.