【作者】 胡彩霞；

【导师】 吕志平；

【作者基本信息】 太原理工大学 ， 应用化学， 2007， 硕士

【摘要】 聚丙烯(PP)具有合成工艺简单、价格低廉、综合性能优良等特点，被广泛应用为复合材料的重要原材料，但存在耐冲击性能差，高温刚性不足，加工成型收缩率大等缺点，使其应用受到一定限制。而成核剂可以改变PP结晶形态，进而改善PP的性能及加工性能，扩大应用范围。因此，向PP中添加成核剂已成为一种优化PP的重要手段。本文以优选成核剂为目的，采用X-射线衍射分析(XRD)、差示扫描量热分析(DSC)、维卡软化点测定及拉伸性能、冲击性能和弯曲性能测试等手段，考察了以下几种类型的成核剂对聚丙烯结晶性能、热性能和力学性能的影响：硬脂酰基硅酸酯水解、缩聚形成的层状材料；不同表面活性剂处理有机磷酸酯成核剂；以及有机物处理5A分子筛。结果表明，一硬脂酰氧基硅酸乙酯通过水解、缩聚形成的层状材料NL1诱导PP以β晶型结晶，在诱导PPH-XD-045这种牌号的聚丙烯生成β晶时与相同含量的TMB-5作用相当，是一种有效的β晶型成核剂；添加NL1使PP的维卡软化点略有提高；PP的拉伸强度随NL1含量的增加呈现先增加后保持不变的规律，冲击强度略微提高，但随含量的增加有轻微下降，对弯曲强度则影响较小。二硬脂酰氧基硅酸乙酯通过水解、缩聚形成的层状材料NL2诱导PP以α晶型结晶，同时提高了PP的结晶温度和结晶度，且添加NL2使PP的维卡软化点提高了6.3℃，PP的拉伸强度有所增加，冲击强度随NL2含量的增加降低了，弯曲强度变化较小。二硬脂酰基硅酸乙酯处理有机磷酸酯使PP结晶沿(040)晶面法线方向生长，PP的结晶温度提高了8.5℃，结晶度也略有提高；PP的维卡软化点提高了近10℃；添加该成核剂后，拉伸强度基本不变，冲击强度提高了，弯曲强度降低了。十二烷基硫酸钠处理有机磷酸酯成核剂后诱导一少部分PP以β晶型结晶，结晶温度和结晶度有所降低；PP维卡软化点提高了7.2℃；拉伸强度和弯曲强度都提高了，冲击强度与与纯PP相比提高了1.42kJ／m~2。XRD分析表明有机物处理5A分子筛后，更加细化了PP的晶粒；添加0.2％的有机物处理5A分子筛使不同含量的PP／5A分子筛体系的拉伸强度和冲击强度大幅度提高，弯曲强度略微下降。更多还原

【Abstract】 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.更多还原