Cold-Resistance Plasticizers Derived from Bio-Based Trans-Aconitic Acid with High Performance on Solvent Extraction Resistance and Volatility Resistance

Dioctyl adipate (DOA) and dioctyl sebacate (DOS) are widely used cold-resistance plasticizers; however, their low molecular weight and weak polarity result in poor thermal stability and migration resistance. Here, we report the synthesis and performance of bio-based cold-resistance plasticizers derived from trans-aconitic acid with enhanced migration resistance. Tri-n-butyl trans-aconitate (TBTA), tri-n-hexyl trans-aconitate (THTA), and tri-n-octyl trans-aconitate (TOTA) were synthesized via one-step esterification with aliphatic alcohols and applied in poly(vinyl chloride) (PVC). Compared with commercial plasticizers di-(2-ethylhexyl) phthalate (DEHP), tributyl citrate (TBC) and DOA, the synthesized plasticizers demonstrated excellent thermal stability and cold-resistance. After freezing treatment, the Tg values of TBTA/PVC (18.99 °C) and THTA/PVC (20.88 °C) were lower than those of DEHP/PVC (22.74 °C). The branched architecture was supposed to strengthen interactions between plasticizers and PVC, improving volatility resistance and solvent extraction resistance. Compared with DOA/PVC at 48 h, TBTA/PVC, THTA/PVC and TOTA/PVC displayed volatility mass loss reduction of ~1.5%, 4% and 7%, respectively. Their extraction mass loss in ethanol decreased by 5–6%, while in petroleum ether, TBTA/PVC and TOTA/PVC dropped by 11.95% and 2.63%, respectively. These bio-based plasticizers are promising alternatives to the poor migration resistance of conventional low-temperature plasticizers.