Synthesis and Evaluation of Bio-Based Plasticizers from 5-Hydroxymethyl-2-Furancarboxylic Acid for Poly(vinyl chloride)

5-Hydroxymethyl-2-furancarboxylic acid (HFCA), a promising biomonomer from renewable resources, was used to synthesize two bio-based plasticizers, namely, hexyl 5-((hexanoyloxy)methyl)-2-furancarboxylate (HHMFC) and dihexyl 5,5'-(oxybis(methylene))bis(furan-2-carboxylate) (DHOBFC). The chemical structures of these prepared plasticizers were confirmed using Fourier transform infrared and nuclear magnetic resonance, and then, their plasticization effects on poly(vinyl chloride) (PVC) were also studied. As a result, HFCA-based plasticizers were miscible with PVC and exhibited excellent plasticization performances, compared with commercial dioctyl phthalate. It was noted that HHMFC had a much better plasticizing effect on the PVC film than DHOBFC; however, it displayed a poorer volatility resistance and exudation resistance, which could be attributed to its smaller molecular weight. Besides, because each rigid furan ring of the synthesized plasticizers contained one oxygen atom, the polarity of HFCA-based plasticizers was improved, which inhibited them from migrating from the PVC matrix into nonpolar solvents. Therefore, the HFCA-based plasticizers have good potential as primary plasticizers for PVC.