Development And Application Of Novel Polypropylene Nucleator

Polypropylene (PP) has been used extensively as a raw material of composite because of its simple synthetic technology, low price and excellent comprehensive property, however, the low impact resistance and stiffness at high temperature and high shrinkage limites its application. Nucleator has an effect on the crystalline morphology of PP and the improvement of performance and processability of PP, which would widen the field of application of PP. Therefore, nucleators have been employed to modify PP as a significant means.The main objective of this study is to select high-performance nucleator of PP. The effect of following several kinds of nucleators on crystallization performance, heat resistance and mechanical property was investigated by X-ray diffraction (XRD), differential sanning calorimeter (DSC), Vicat softening point test and tensile strength, impact strength and flexural strength tests: a layered material synthesized by hydrolyzing and condensing ethoxy (stearoyl) silane; organic phosphate treated by surface active agents; zeolite 5A treated by organic compound.The results showed that, a layered material, marked NL1, synthesized by hydrolyzing and condensing triethoxy (stearoyl) silane induced PP to crystallize intoβform, and itsβ-nucleating ability was equivalent to that of TMB-5 with the same content in PP with the brand of PPH-XD-045, namely, NL1 was an effectiveβ-nucleator; NL1 improved the Vicat softening point of PP slightly; the tensile strength and impact strength of PP increased with the admixture of NL1, but the flexural strength did not.Another layered material, marked NL2, synthesized by hydrolyzing and condensing diethoxy (stearoyl) silane induced PP to crystallize into a form, and raised the crystallization temperature and the degree of crystallinity; the Vicat softening point of PP increased 6.3℃with NL2; there was an increase in the tensile strength of PP, the impact strength decreased with the content of NL2, and the flexural strength changed little with the admixture of NL2.The organic phosphate treated by diethoxy (stearoyl) silane, marked NAL2, induced PP crystal to grow along the normal direction of (040) crystal plane, the crystallization temperature increased 8.5℃and the degree of crystallinity increased slightly; the Vicat softening point of PP increased about 10℃with NAL2; the tensile strength of PP/NAL2 changed little, the impact strength increased, and the flexural strength decreased.The organic phosphate treated by lauryl sodium sulfate, marked NA12, induced a small amount of PP to crystallize intoβform, and there was a decrease in the crystallization temperature and the degree of crystallinity; the Vicat softening point of PP increased 7.2℃with NA12; the tensile property and the flexural property of PP/NA12 system improved, and compared to that of pure PP, the impact strength of PP/NA12 system enhenced by 1.42kJ/m~2 .XRD analysis indicated that zeolite 5A treated by organic compound makes PP crystal grain smaller; with 0.2% zeolite 5A treated by organic compound mixed, the tensile strength and impact strength of PP/zeolite 5A system increased, and the flexural strength decreased little.