Bis-uracil based high efficient heat stabilizers used in super transparent soft poly (vinyl chloride)

Two novel kinds of bis-uracil derivative based organic stabilizer with different length of alkyl chains to provide outstanding compatibility with poly (vinyl chloride) (PVC) were designed and synthesized in this paper, which exhibited high efficient thermal stability and could get super transparency PVC composites. After confirming the structures of 6,6′-diamino-1,1′,3,3′- tetramethyl-5,5´-(octylidene)bis[pyrimidine-2,4(1H,3H)-dione] (OSU) and 6,6′-diamino-1,1′,3,3′-tetramethyl −5,5´-(hendecylidene)bis[pyrimidine-2,4(1H,3H)-dione] (USU) by Fourier infrared spectrum (FT-IR) and Mass spectra, 2 phr of each was introduced into PVC respectively to verify that bis-uracil derivatives could absorb HCl released by PVC to enhance the thermal stability, confirmed through discoloration and Congo red tests, but the initial whiteness was not satisfied. In addition, epoxy soybean oil (ESBO) and phosphite ester showed excellent synergistic effects with OSU and USU that could effectively further improve the initial whiteness, thermal stability and transparency of PVC samples, proved by discoloration tests, UV vis spectrophotometer and transmittance/haze tests. We believe that such complex stabilizers without any metallic elements may widen the applications of the resultant soft transparent PVC in artificial leather, wire and cable, packing materials and so on.