Preparation and performance evaluation of bio-based wood-plastic composites from ricinoleic acid ring-openning epoxidized soybean oil

With the enhancement of sustainable development concepts and environmental protection awareness, replacing fossil resources with biomass to prepare unsaturated polyester resins is an essential approach to achieve green chemistry. In this study, a bio-based unsaturated polyester (ERM) was synthesized using epoxidized soybean oil and castor oil acid as raw materials. The reinforced modification of two fast-growing woods, Cunninghamia lanceolata (Chinese fir) and Pinus sylvestris var. mongolica (Pine), was investigated. The structure and molecular weight of the polyester at various stages were detected through infrared spectroscopy, proton nuclear magnetic resonance, and size exclusion chromatography. It was found that compared to the original wood, the density of the modified Cunninghamia lanceolata (Chinese fir) and Pinus sylvestris var. mongolica (Pine) increased from 0.36 g/cm³ and 0.45 g/cm³ to 0.9 g/cm³ and 0.78 g/cm³, respectively. Their compressive strength increased from 30.1 MPa and 32.1 MPa to 73.9 MPa and 73.8 MPa, respectively. The water absorption rate decreased from 167.3% and 103.8% to 16.86% and 16.59%, respectively, and thermal stability also showed a significant improvement.