A sorbitolum compound and an aryl amide compound were applied to prepare α-nucleated PP (α-PP) and β-nucleated PP (β-PP), respectively. Effects of UV irradiation on the molecular structure and tensile properties of pure PP, α-PP and β-PP were investigated. The relationship of tensile strength with carbonyl index was discussed. The change of relative content of β-modification in β-PP during photodegradation was examined by WAXD. The carbonyl index calculated from FTIR spectra arranged as α-PP > PP > β-PP, however, the tensile strength retention at the UV irradiation time of 792h arranged as PP > β-PP > α-PP. The relative content of β-crystal nearly unchanged during the photodegradation.

Pure polystyrene (PS) was subjected to natural weathering in Qionghai (QH) and Ruoqiang (RQ) of China, representing hot and humid climate and xerothermic climate respectively. The degradation profile of pure PS was studied by Fourier Transform Infrared (FTIR) Spectroscopy, Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM), X-ray Photoelectron Spectroscopy (XPS) and Spectrophotometer. Artificial accelerated weathering tests protocol A and B were carried out to simulate hot and humid climate and xerothermic climate respectively. Results show that pure PS degrade slowly at the initial stage and then become faster. Color shift could be an appropriate indicator for evaluating simulated effect of artificial accelerated weathering and protocol A simulate hot and humid climate perfectly while protocol B turns out weak for xerothermic climate.

Flame retarded ethylene-vinyl acetate copolymer (EVA) was prepared in a melt process containing melamine phosphate (MP), or MP in combination with dipentaerythritol (DPER) as flame retardants. The influence of MP and MP/DPER on flame retardant properties of EVA was investigated by limiting oxygen index (LOI) and UL 94 test. Thermal decomposition of the flame retardants and flame retarded EVA composites was studied by the thermogravimetric analysis. The results show that MP used alone in EVA does not exerts good flame retardancy, even at a loading of 50wt%. It is found that the flame retardant properties of the EVA/MP/DPER composites is greatly improved when a suitable amount of MP substituted by DPER. Moreover, mechanical properties of the EVA composites were studied.