Modification And Application Of Transparent Polypropylene

The effects of extrusion temperature and speed on the performance of transparent polypropylene were study. Best polypropylene process temperature is:the first section 185℃, the second section 210℃, the third section 210℃, the forth section 220℃, the nose 195℃. Best extruder speed:21 Hz.Various transparent polypropylenes were processed by adding sorbitol nucleating agent NA-S25, NA-S20, Millad3988 and organic phosphate nucleating agent such as NA-21, NA-45. It was found that the transparent polypropylene haze is minimum when the concentration of nucleating agent from 0.3% to 0.4%. Compare to the organic phosphate nucleating agent, sorbitol nucleating agent is more effective. Especially, adding 0.4%NA-S20, the haze of F401 is 28.74%, and the PPR is 25.87%. Nucleating agent can improve the tensile strength and bending strength of polypropylene, but the impact strength is decreased. Organic phosphates are better to improve mechanical properties of polypropylene.It is showed that the nucleation density and the number of polypropylene crystal significantly increase, and crystal size significantly reduced after adding nucleating agent. Nucleating agent also can increase crystallinity and the crystallization temperature increases, and crystallization rate is accelerated.Nucleating agent mix with NA-S20:NA-21 can get polypropylene has low haze and high mechanical properties when the ratio is 3:1. Tinuvin-770 reduces moren than 70% impact of y-irradiation on transparent polypropylene when the concentration is 0.1%.