Increased rubber content in high impact polypropylene via a sirius ziegler‐natta catalyst containing nanoparticles
Increased rubber content in high impact polypropylene via a sirius ziegler‐natta catalyst containing nanoparticles
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DOI：
10.1002/pola.26592
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发表时间：
2013-05
期刊：
影响因子：
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通讯作者：
Torvald Vestberg;Peter Denifl;Carl-Eric Wilén
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文献类型：
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作者：
Torvald Vestberg;Peter Denifl;Carl-Eric Wilén
采用两种不同的Ziegler-Natta催化剂（分别称为催化剂a和催化剂B），在不含SiO2纳米颗粒和存在SiO2纳米颗粒的情况下，采用Sirius乳液技术制备了两种不同的Ziegler-Natta催化剂，在双反应器串联聚合工艺中制备了高冲击聚丙烯。在工业条件下液相制备了同质聚丙烯基体，气相制备了乙烯/丙烯橡胶。催化剂B采用与催化剂A相同的乳化工艺制备，只是在制备过程中加入了SiO2纳米颗粒（平均粒径为80 nm）。扫描电镜研究表明，纳米颗粒在催化剂B颗粒内分布均匀，但存在一定的团聚现象。结果表明，B催化剂中的纳米颗粒增加了聚丙烯基颗粒的内部孔隙率，从而使橡胶含量显著增加。在没有纳米颗粒的情况下，催化剂A的最大橡胶含量约为25 wt %，而催化剂B的最大橡胶含量几乎翻了一番，达到45 wt %，这是由于纳米颗粒对催化剂内部形态的有益改变。此外，还发现在乙烯/丙烯橡胶聚合阶段，即使在橡胶含量非常高的情况下，所有的孔和腔都被橡胶填充，反应也不受传质限制。©2013 Wiley期刊公司高分子材料学报，2013
High impact polypropylene was produced in a two-reactor polymerization process operating in series using two different Ziegler-Natta catalysts (referred to as catalysts A and B) that had been prepared by Sirius emulsion technology in the absence and presence of SiO2 nanoparticles, respectively. The homo polypropylene matrix was produced in liquid bulk and the ethylene/propylene rubber in gas phase under industrial conditions. Catalyst B was prepared with the same emulsion technology as catalyst A, except that SiO2 nanoparticles (average particles size 80 nm) were added during catalyst preparation. Scanning electron microscopy studies showed that the nanoparticles were fairly evenly distributed within catalyst B particles, although there was some agglomeration. It was shown that the nanoparticles in catalyst B increased the internal porosity in the homo polypropylene matrix particles and this enabled a significant increase in the rubber content. Maximum rubber content, before running into stickiness problems, was approximately 25 wt % for catalyst A without nanoparticles, whereas the maximum rubber content for catalyst B was almost doubled to 45 wt % due to the beneficial transformation of the internal catalyst morphology by the nanoparticles. In addition, it was also found that the reaction was not mass transfer limited during the ethylene/propylene rubber polymerization stage, even at very high rubber contents where all pores and cavities were filled with rubber. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013