【作者】 邹恩广；

【导师】 王鉴；

【作者基本信息】 东北石油大学 ， 油气田化学工程， 2011， 博士

【摘要】 聚丙烯(Polypropylene, PP)作为一种通用高分子材料,已成为继聚乙烯、聚氯乙烯之后的第三大通用塑料,是塑料中产量增长最快的品种,被广泛应用于工业生产的各个领域。但普通聚丙烯韧性差、低温易脆裂,且其非极性的线性链结构和较高的结晶性降低了与其它高分子材料和无机填料的相容性。因此对聚丙烯改性制备性能优良的聚丙烯合金及复合材料一直是学术界和企业界关注的焦点。本文介绍了聚丙烯合金的制备工艺技术和研究进展,回顾了聚丙烯合金的发展历程；分别采用原位固相法接枝丙烯酸和超临界二氧化碳协固相法接枝多单体制备出性能优异的聚丙烯合金；以该聚丙烯合金GPP作为相容剂,PP(T30S)为基质,与用自主研发的牵引剂Q以及活化剂H共同活化蒙脱土和碳酸钙微粒,制成壳核结构的纳米蒙脱土和壳核结构的碳酸钙,通过共混法制成PP/纳米蒙脱土、PP/纳米蒙脱土/碳酸钙复合材料。用原位固相法接枝丙烯酸制备聚丙烯合金,工艺简短易行,放大性良好,能有效地增加PP的极性和亲水性,PP原有的优良性能损失不大。结果表明：其接枝率受聚合温度、时间及引发剂浓度、自由基捕捉剂用量等因素的影响较大；接枝聚合过程中没有产生明显的降解副反应,产物分子量变化不大；接枝后的产物球晶得到细化；合金性能与聚丙烯基体大致相仿,表面电阻明显降低,拉伸强度和冲击强度得到提高,接枝率1.6%时,产品的水润湿角为80°。应用超临界二氧化碳(SC CO2)溶胀插嵌法协固相接枝多单体制备聚丙烯合金,接枝率高,单体分布均匀,PP的极性和亲水性明显增强,PP原有的优良性能损失很少,拉伸强度还略有增加。实验结果表明：采用以软、硬单体复配、SC CO2溶胀、常压接枝的方法对聚丙烯颗粒进行接枝改性制备PP合金的方法可行。PP与引发剂以及AA、MMA、MAH在SC CO2中溶胀4h,卸压后于80℃下反应2h,接枝率达4.29%,接枝效率达71.5%。超临界CO2对聚丙烯起到有限溶胀作用,接枝率随反应时间、反应温度、引发剂用量、单体用量的增加均出现先上升后下降的趋势；SC CO2协助PP固相接枝所需的反应时间比普通固相接枝要短2h,表明通过SC CO2溶胀插嵌使整个接枝反应的动力学由扩散控制转换为反应控制。接枝产品的熔点降低,结晶温度升高,热稳定性增加。接枝改性后聚丙烯的极性增强,水接触角由原料的980降低到72°。产品的内外表面微观形貌均发生明显改变,实现了内部均匀接枝。软、硬单体复配使用抵消了由于支链引入造成的产品力学性能下降,PP主链断裂倾向降低,产品韧性得到提高。用自主研发的牵引剂Q和活化剂H共同活化处理纳米蒙脱土制得具有壳核结构的有机纳米蒙脱土。以前面制得的极性PP合金GPP作相容剂,用具有壳核结构的有机纳米蒙脱土填充改性聚丙烯(T30S),通过熔融挤出制成PP/纳米蒙脱土复合材料,研究了各种因素对复合材料结构和性能的影响。实验结果表明：纳米蒙脱土改性产品很多性能得到提高；GPP作为相容剂一方面可以与壳-核结构聚异丁烯-纳米蒙脱土粒子结合另一方面还可以与PP结合在一起,从而促进纳米蒙脱土在PP中均匀分散,提高了共混材料的力学性能；使用复合牵引剂FQ比用单一牵引剂处理蒙脱土的效果更好。活化剂H与牵引剂FQ配合使用,可提高蒙脱土的分散性；当活化剂H/牵引剂Q/相容剂GPP三种物质复配使用时,可以能够使纳米蒙脱土在复合材料中分散的更加均匀,显著降低复合材料的挤出压力,提高复合材料的性能；复合材料产品模量高达2100MPa,冲击强度达到53 J/m,回缩率为0.52%；复合材料的加工温度为180～190℃C,产品中的蒙脱土呈2-3个单片重叠结构的片状分散,片层厚度3～4nm,分散稳定性好,没有明显的无团聚倾向。GPP的引入使纳米蒙脱土/PP基体的界面结合良好,加入量为5%左右时材料性能最好。偏光显微镜的结果显示复合带来的固体晶串珠生长方式提高了冲击性能；复合材料的热稳定高,具有较好的应用价值。拉伸强度和模量的实验值比用Halpin-Tsai方程计算值小很多,说明蒙脱土片剥离层还不充分。为了进一步提高复合材料的性能,研究使用两种无机填料的可行性,用同样的方法活化碳酸钙微粒,制成壳核结构的碳酸钙刚韧粒子；使用SC CO2协助固相接枝三单体制备聚丙烯GPP-4.3做相容剂制备PP/刚韧粒子复合材料。通过筛网实验和性能测试,研究了表面剂、活化剂和相容剂的种类、用量对挤出压力和产品性能的影响。结果表明,通过发挥表面剂、活化剂和相容剂的协同作用,可使碳酸钙粒子在复合材料中有效分散。将碳酸钙粒子与纳米蒙脱土复合使用制成无机刚韧粒子,之后再与PP共混制成PP/无机刚韧粒子复合材料,使材料的性能进一步提高。产品模量高达2300MPa,冲击强度达到60 J/m,回缩率为0.5%。更多还原

【Abstract】 Polypropylene(PP) as a common polymer materials has been widely applicated in many fields. It developed so rapidly that makes it be the third largest general plastics next to polyethylene and polyvinyl chloride. As usual, polypropylene has the characteristics of poor toughness and easy embrittlement under low temperature, the compatibility to inorganic materials and other porlar polymers is poor due to the contribution of its nonpolar linear chains and high crystallinity. Modification of polypropylene to prepare alloys and composites is a promosing way to improve its performance.In this paper, the preparation, application and research progress of PP alloy and composites were summarized. The research progress of PP alloy catalyst has also been reviewed. PP alloys with excellent properties have been prepared through in-situ solid-phase graft acrylic acid (AA) and supercritical carbon dioxide (SC CO2) assisted grafting of multi-monomer onto PP backbone in solid-phase. The PP/nano-montmorillonite and PP/nano-montmorillonite/calcium carbonate composites were prepared in blending process with core-shell structure of nano-montmorillonite and calcium carbonate, using the GPP as the compatilizer and PP (T30S) as the raw material.The results showed that the process to make polypropylene alloys via in-situ solid-phase graft AA onto PP can effectively increase the polarity and hydrophilicity of PP, and is easy to carry out. The original properties of polypropylene were reserved. The grafting percentage was a function of polymerization temperature, time and initiator concentration, amount of free radical tapping agent and other factors. There was no significant degradation in the process of polymerization. No obviously change in molecular weight can be detected. Spherulite was refined. The most properties of alloys were almost the same as original polypropylene, but surface resistance decreased evidently, tensile and impact strength was improved. The contact angle of water drop to 80°for the product with grafting percentage of 1.6%.PP alloy were prepared by modification of PP with multi-monomer in solid-phase assisted with supercritical CO2 (SC CO2). The results indicated that monomers distribute on the surface equalitily and the polarity and hydrophilicity of PP increased effectively. The method of grafting soft-hard monomers onto PP, via solid-phase grafting with assistance of SC CO2, is practicable. Maximum grafting efficiency was more than 70%, grafting percentage was about 4.29%, in the condition that swelling time is 4h, reacting time is 2h and temperature is 80℃. PP was swelled in this process. With the increase of reacting time, temperature, initiator concentration and monomer concentration, the grafting percentage increase firstly and then drop. The reacting time for solid-phase grafting assisted with SC CO2 was shorter than normal solid-phase grafting. Melting point of the grafting product decreaseed, crystalline temperature, thermal stability and the polarity increased, the contact angle of water droped from 98°to 72°. After grafting, morphology of inner and surface of PP had been changed notable, and grafted molecules had been uniformly distributed in the PP substrate. Combination of soft monomer and hard monomer can counteract decreasing of mechanical properties caused by introducing side-chains. The tendency of main chain breaking decrease and toughness of product has been improved obviously.Based on the preparation and evaluation of PP composite, the montmorillonite was treated with a self-made organic tractive agent (Q) and activator (H) to form organic non-montmorillonite with core-shell structure. Using the GPP as the compatilizer, the PP/nano-montmorillonite composite was prepared by melt extrusion through blending process with core-shell structure nano-montmorillonite and PP. The results showed that the mechanical properties of the composite have been improved greatly for the addition of GPP. GPP can help nano-montmorillonite disperse in the composite, that is for GPP can combine with organic non-montmorillonite, and also combine with PP. the composite tractive agent (FQ) worked better than single tractive agent. When the H/FQ/GPP were used together, the nano-montmorillonite were dispersed beter that makes extrusion pressure decreased obviously. The modulus of product reached 2100MPa, the impact strength was 53J/m, the head shrinkage was 0.52% and the proper processing temperature was 180-190℃。The dispersion of montmorillonite in PP showed a laminated structure which was formed by 2-3 sheets overlapping with lamellar spacing of 3-4nm. The agglomeration tendency montmorillonite was neglectable. The adition of e GPP can promote the combination between montmorillonite and PP, the best properties of composite were achieved at the content of GPP was 5%. The polarizing microscope images indicated that the growth pattern of the composite’s crystal increased the impact property. The composite is thermal stable and can meet theneeds in many application fields.The experimental data was lower than the value of the Halpin-Tsai equation, which suggested that the stripping layer of montmorillonite was insufficient.The feasibility of two kinds of inorganic filler was investigated as to further improve the performance of the composite. In the same way, calcium carbonate particles were actived, and the core-shell construction of calcium carbonate rigid particles was formed. GPP-4.3 was used as compatilizer, then PP/rigid particles composite were prepared. The kind of surface agent, activator and compatibilizer and concentration that effect extrusion pressure and product of performance were studied by screen experiment and performance test. The result indicated that dispersion of calcium carbonate particles highly disperse in composite and the property of composite further improve through synergistic effect of surface agent, activator and compatibilizer. Inorganic rigid particles using as grafting PP have been prepared through compound use of calcium carbonate particles and nano-montmorillonite. Then PP/Inorganic rigid particles composite have been prepared through they mixed with PP. The modulus of product reached 2300MPa, the impact strength was 60J/m, the head shrinkage was 0.5%.更多还原