关键词: 生物柴油, 二聚化, 环氧二聚酸甲酯, 辅助增塑剂

Abstract: With biodiesel as raw material,synthesis of dimers and their epoxidation product using the double bonds existing in biodiesel was obtained. Under the reaction conditions of 240℃/6h,the effects of different catalysts and the content of unsaturated bonds on dimerization were investigated. Moreover,the combustion performance of biodiesel after dimerization was explored. The yield of dimeric acid methyl esters(DAME) reached up to 28%(catalyzed by aluminum silicate). Comparing cetane numbers(CN) of biodiesel before and after the reaction,the CN of unreacted biodiesel was essentially unchanged,which indicated that dimerization had no effect on combustion performance.The application of epoxy dimeric acid methyl ester(EDAME) in polyvinyl chloride(PVC) blending with bis(2-ethylhexyl) benzene-1,4-dicarboxylate(DOTP) was further studied. The mechanical properties thermogravimetric analysis(TGA) and processing rheology of PVC were measured. Results showed that the elongation at break of sample F2 increased by 2.62% when EDAME content increased from 0 to 20%. The initial decomposition temperature(T_i),the 10% weight loss temperature(T₁₀) and the 50% weight loss temperature(T₅₀) increased 6.5℃,9.9℃ and 26.8℃,respectively,when EDAME substituted DOTP totally,and the char yield increased from 8.7% to 11.7%. The dynamic stability time increased,and the equilibrium torque of F2 decreased from 3.8N·m to 3.2N·m compared to that of F0. All of these improved the processability of PVC blends. Therefore,it can be considered that EDAME can be treated as an environmentally-friendly and renewable secondary plasticizer to replace DOTP. Meanwhile,the new technology of the production of biodiesel combined with EDAME can improve the comprehensive economic benefit in the process of biodiesel production which has broad market prospects.

Key words: biodiesel, dimerization, epoxy dimeric acid methyl ester, secondary plasiticizer