稀土β成核剂对PP-R/POE共混体系力学性能的影响

Effect of Rare Earth β-nucleating Agent on Mechanical Properties of PP-R/POE Blends

研究了稀土型β成核剂WBGII对共聚聚丙烯/乙烯-辛烯共聚物(PP-R/POE)共混体系力学性能的影响,利用差示扫描量热仪及广角X射线衍射仪表征了体系结晶性能及晶态结构。结果表明,POE及WBGII在不同程度上改善了PP-R的低温抗冲性能,使得体系的脆韧转变温度降低,两者同时使用时,协同增韧效果明显;POE具有一定的异相成核作用,提高了PP-R的结晶温度;在β成核剂复合改性体系中,存在β-PP向α-PP转化的过程,在受冲击断裂的过程中,POE的存在则抑制了这一转化过程,进而使得体系的韧性增强,使得脆韧转变温度进一步降低。

The effects of rare earth β-nuleating agent （β-NA） on the mechanical properties of polypropylene random copolymer （ PP-R ）/ethylene-octene copolymer （ POE ） blends were investigated. Mechanical tests suggested that POE and β-NA improved the impact strength of PP-R, and made the brittle-ductile transition temperature （Tbd） Of the blends move to the lower temperature. In PP-R/POE/β-NA systems, β-NA and POE had an obvious synergistic effect on the toughness of the blends. Differential scanning calorimetry （DSC） and wide angle X-ray diffraction （WAXD） showed that POE played a role in the heterogeneous nucleation, and increased the crystallization temperature. On the other hand, there was a transformation of β-PP to a-PP during the impact process for the β-NA containing systems. However, POE prevented such a process, the most likely effect of POE was the improvement of fracture toughness of the system.