Design And Synthesis Of Asymmetric Ester Plasticizers Based On HFCA And Exploration Of Their Plasticizing Properties

Due to its low cost,excellent flame retardancy andgood corrosion resistance,polyvinyl chloride(PVC)has been widely applied to all aspects of human daily life.However,there exist strong polar interactions among PVC chains,which makes PVC brittle in nature.In order to overcome this defect,it is necessary to incorporated plasticizers into PVC during processing.At present,phthalate plasticizers still dominate the plasticizer industry.These plasticizers are carcinogenic and teratogenic to humans and animals,and will pose a huge threat to the environment and humans if long-term exposure.With the enhancement of people's awareness of environmental protection and health,“green” plasticizers derived from renewable resources have received more and more attention.In this study,we designed and synthesized a series of environmentally friendly asymmetric diester plasticizers,using renewable5-hydroxymethyl-2-furancarboxylic acid(HFCA)as the raw material,and comprehensively investigated the plasticizing properties of these bio-based plasticizers in PVC blends.This paper includes two main contents as the following aspects:1.5-((Hexanoyloxy)methyl)-2-furancarboxylate(HHMFC)and dihexyl5,5'-(oxybis(methylene))bis-(furan-2-carboxylate)(DHOBFC)are designed and synthesized as bio-based plasticizers from HFCA.Besides,the effect of the HFCA-based plasticizer on the plasticization properties in PVC blends was studied by using dioctyl phthalate(DOP)as a reference.The results showed that the plasticizing efficiency of HHMFC is much higher than DHOBFC and DOP,while the volatilization resistance and exudation resistance of HHMFCwas poorer.Furthermore,because each rigid furan ring of the synthesized plasticizers contained one oxygen atom,the polarity of HFCA-based plasticizers was improved,and they show good solvent resistance in nonpolar solvents.Therefore,the HFCA-based plasticizers have good potential as primary plasticizers for PVC.2.A series of bio-based plasticizers with various alkyl chain asymmetry and the same molecular weight were synthesized,using HFCA as the raw material.The influence of alkyl chain asymmetry on plasticization properties of the HFCA-based plasticizers in PVC blends was studied in detail.It was found that increasing the alkyl chain asymmetry of the HFCA-based plasticizer and keeping the molecular weight unchanged simultaneously could further improve its plasticizing efficiency,without sacrificing its volatility and exudation resistance.The results showed that this study provided a new approach for further optimizing the comprehensive properties of asymmetric diester plasticizers.