Construction and Synthesis of High-Stability Biobased Oligomeric Lactate Plasticizer: Applicable to PVC and PLA Polymers

A novel green plasticizer, cyclohexyl ester-capped glutaric acid oligomeric lactate (CGOL) with many poly(lactic acid) (PLA) matrix repeating units, applicable for plasticizing both poly(vinyl chloride) (PVC) and PLA, was designed and developed through a two-step esterification reaction route. Due to the growing concerns about the environment and health, we used biobased raw materials to synthesize the biobased plasticizer with the hope of potentially replacing petroleum-based plasticizers that are already widely used. The molecular structure of CGOL was confirmed, and then CGOL was blended with PVC or PLA for performance testing. Compared with commercial plasticizers, it had better comprehensive plasticization performance, showing high thermal stability, mechanical stability, and migration stability in both PVC and PLA polymers, which could be demonstrated by thermogravimetric analysis, tensile tests, and migration resistance test results. Among all PVC blends containing 50 phr plasticizer, CGOL plasticized PVC films exhibited the highest elongation at break (736.3%) and initial degradation temperature (Ti, CGOL-50 = 273.5 °C), the lowest glass transition temperature (Tg = 24.8 °C), and minimal migration in various environments, better than that of commercial ATBC, DOTP, and DOP. As for PLA blends, CGOL plasticized PLA films outperformed PLA/ATBC films in terms of comprehensive performance. Overall, CGOL demonstrated potential as a novel green substitute plasticizer for preparing flexible products of PVC and PLA.