The plasticizers used in this study were synthesized from renewable raw materials using succinic acid, oleic acid, and propylene glycol. Four environmentally friendly plasticizer samples were obtained; their chemical structures and compositions were confirmed by gas chromatography (GC) and infrared spectroscopy (FT–IR) analyses, and their physicochemical properties and thermal stability (TGA analysis) were investigated. The obtained ester mixtures were used as poly(vinyl chloride) (PVC) plasticizers and their plasticization efficiency was determined in comparison to traditional, commercially available phthalate plasticizers, such as DEHP (di(2-ethylhexyl phthalate) and DINP (diisononyl phthalate). Mechanical properties and migration resistance were determined for soft PVC with the use of three concentrations of plasticizers (40 PHR, 50 PHR, and 60 PHR). It was observed that the obtained plasticizers exhibited the same plasticization efficiency and were characterized with good mechanical and physical properties in comparison to commercial plasticizers. The tensile strength was approx. 19 MPa, while the elongation at break was approx. 250% for all tested plasticizers at a concentration of 50 PHR. Furthermore, plasticizer migration studies showed that the synthesized plasticizers had excellent resistance to plasticizer leaching. The best migration test result obtained was 70% lower than that for DEHP or DINP. The ester mixture that was found to be the most favorable plasticizer was characterized by good thermal and thermo-oxidative stability (5% weight loss temperature: 227.8 °C in air and 261.1 °C in nitrogen). The results of the research clearly indicate that the synthesized esters can provide a green alternative to toxic phthalate plasticizers.

This study describes the synthesis of new nonmigrating PVC plasticizers based on oleic acid as the main raw material. Their structures and production routes were planned to ensure that the resulting synthesis by-products could also act as PVC plasticizers. All received Esters 1, 2, and 3 revealed plasticizing effect on PVC. Achieved results of elongation at break (260%) for PVC composites with Ester 2 (C11) and Ester 3 (C14) were comparable to those recorded for diisononyl phthalate (DINP) and dioctyl terephthalate (DOTP) (C2 and C5), and only 15% lower for Ester 1 (C8). As intended, the developed plasticizers showed high resistance to migration. The Ester 3 proved to be an extremely migration-resistant bio-based plasticizer, due to its high oxirane ring content and large molecule size. After 28 days of survey, the loss of this plasticizer from the PVC sample with 50 PHR of plasticizer was 4.7%, which is nearly 80% lower compared to DINP. Ester 2 was slightly less resistant to migration-with 14.1% mass loss observed after 28 days, which can be attributed to the smaller size of its molecules. Additionally, PVC composites containing Esters 1, 2, and 3 exhibited higher thermal stability compared to composites with DINP or DOTP. T 10% for PVC composites with 60 PHR of Esters 1, 2, and 3 was recorded at 286.2 C, 282.8 C, and 286.4 C, respectively. Thus, the developed esters can act not only as PVC plasticizers, but also as thermal stabilizers.

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