Synthesis and application of a novel epoxidized plasticizer based on cardanol for poly(vinyl chloride)

Abstract

Cardanol, an agricultural by-product of the industrial processing of cashew, was used to synthesize epoxidized cardanol laurate (ECDL) plasticizer. The target product was characterized using FTIR, 1H NMR and 13C NMR. The plasticizing effect of ECDL substitution for petroleum-based plasticizer dioctyl phthalate (DOP) in soft poly(vinyl chloride) (PVC) was investigated using dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA) and mechanical testing, and compared to PVC incorporated with commercial epoxidized soybean oil (ESBO). When DOP was partially substituted by EDCL, there was a slight increase of 5% in glass transition temperature (Tg) and a maximum increase of 14.55% in the elongation at break. In addition, scanning electron microscopy (SEM) revealed that the morphology of blends plasticized with DOP incorporated with ECDL was finer and more homogeneous compared with blends plasticized with neat DOP or ESBO. Compared with DOP/PVC, TGA results showed that the initial degradation temperature (Ti), the 50% weight loss temperature (T50), and the first peak decomposition temperature (Tp1) for ECDL/PVC increased by 16.8, 26.5 and 7.1 °C, respectively. Moreover, plasticizing system with ECDL had longer stability time, lower volatility and exudation loss, and higher chemical resistance than that of DOP. Therefore, as an environmentally friendly and renewable biobased plasticizer, ECDL can partially replace DOP.