Thiophene diester amine as a novel solid plasticizer for poly(vinyl chloride)

Polyvinyl chloride (PVC) is widely used polymer worldwide with phthalate acting as an important plasticizer material. However due to carcinogenic nature of some phthalates like dioctyl phthalate (DOP) it has become essential to replace them with safer alternatives. In order to achieve this we have used one pot synthesis of diester amine thiophene (THP) earlier suggested by K. Gewald and used it as plasticizer for PVC. The chemicals sulphur, ethyl aceto acetate and ethyl cyano acetate were heated at moderate temperature in presence of morpholine as catalyst to yield diester amino thiophene. The structure of synthesized substituted thiophene was confirmed by FT-IR, H-1 NMR, etc. We have used THP in 10 to 50 phr in PVC matrix to prepare sheets and analyzed them for mechanical, thermal, rheological studies. The glass transition temperature, elastic properties, viscosity, etc. were reduced after addition of thiophene. However the whiteness index increased on addition of THP as it imparts slight yellow colour to PVC sheets. We have used THP directly without modifying amine group present on it and though amine group of plasticizer is freely accessible to PVC chains, it does not react with PVC. The reactive amine group of THP can be modified by different acids to improve plasticization properties of THP for better applications. (C) 2017 Elsevier Ltd. All rights reserved.