Cyanoacetylurea as a Thermal Stabilizer for Poly(vinyl chloride)

Poly(vinyl chloride) (PVC) has been widely used in many fields due to its excellent comprehensive properties, although its thermal stability is poor. In the article, a urea derivative, cyanoacetylurea, is prepared and its structure is characterized by means of FTIR and 1H-NMR. The stabilization effect of cyanoacetylurea on PVC thermal stabilization is evaluated by thermogravimetric analysis (TGA), thermal aging test and Congo red test. Meanwhile, the processability of PVC stabilized by cyanoacetylurea is investigated through dynamic performance test. Compared with calcium stearate (CaSt2) and zinc stearate (ZnSt2), cyanoacetylurea shows higher stabilization effect on PVC thermal stabilization than CaSt2 and ZnSt2. Also, the synergistic effect of mixtures of cyanoacetylurea, CaSt2 and ZnSt2 on PVC thermal stabilization is investigated. At last, the stabilization mechanism is discussed and cyanoacetylurea is able to absorb hydrogen chloride and to add hydrogen chloride on the carbonyl group, as well as postpone “zinc burning.” The results show that cyanoacetylurea presents a good thermal stabilization efficiency and can be a potential organic thermal stabilizer for PVC.