聚丙烯高支化聚乙烯合金的制备与性能

化工论文编号:HG218  论文字数:19170,页数:36

目  录
中文摘要   I
英文摘要  Ⅲ
目录  Ⅴ
1 绪论 1
1.1前言 1
1.2 丙烯聚合的催化剂 2
1.2.1前过渡金属催化剂 3
1.2.2 茂金属催化剂 3
1.2.3 后过渡金属催化剂 4
1.3 丙烯聚合工艺 5
1.3.1 聚丙烯气相法 7
1.3.2 聚丙烯淤浆法 7
1.3.3 聚丙烯本体法 8
1.3.4 聚丙烯本体法-气相组合法 9
1.4 聚丙烯低温抗冲性能的改进 10
1.4.1 物理共混 11
1.4.2 原位合金 12
1.5  研究目的与方法 12
2  实验部分 13
2.1 原料及预处理 13
2.1.1 原料 13
2.1.2 原料的预处理 14
2.2. 载体制备 15
2.2.1 制备方法 15
2.2.2 制备工艺 15
2.3 聚丙烯球负载催化剂制备 16
2.3.1 催化剂前体制备 16
2.3.2 负载催化剂制备 17
2.4负载催化剂表征 17
2.5 聚合物表征 18
3 聚合反应 18
4 实验结果与讨论 19
4.1 乙烯聚合 19
4.2 聚合物性质 21
4.2.1 聚乙烯的DSC 21
4.2.2 聚乙烯的结构 23
4.2.3 聚乙烯的分子量和分子量分布 25
4.2.4 聚合反应动力学 27
4.2.5 合金形态 27
5 结论 29
致  谢 30
参考文献 30

摘要：聚丙烯是一种极有价值的化工材料，有很多良好性能，但还缺乏固有的韧性，特别是在低于其玻璃化温度的条件下,所以可以通过添加冲击改性剂，提高其抗冲击性能。本实验通过在聚丙烯极性球体内负载后过渡金属催化剂，使其只需要通入单一原料乙烯，形成高支化聚乙烯，在合适的操作条件下形成高支化聚乙烯/聚丙烯合金。本文采用在聚丙烯极性球体内负载后过渡金属催化剂制备合金的方法，首先将后过渡金属催化剂二－（2,6-二甲基苯基）戊二亚胺溴化镍负载到聚丙烯极性球体内，再使乙烯在PP球中聚合，改变反应温度得到含不同支化度的聚乙烯与聚丙烯的反应器内合金，测定了不同样品的基本性能，
研究发现，引入少量极性官能团的聚丙烯可以作为后过渡金属催化剂的良好载体。通过调节操作参数，如温度，可以制备得到不同支化度聚乙烯与聚丙烯的合金。当反应温度从20℃升高到50℃，聚乙烯的支化度从20.0增加到130.4。聚乙烯的主要支链是甲基，随着反应温度升高，尽管支链主要由甲基组成，但戊基以及长支链含量迅速增大。
关键词：聚丙烯；高支化聚乙烯； 二亚胺镍催化剂；二氢月桂烯三甲基硅醚

Abstract：Polypropylene is a valuable chemical material with a lot of good performance, but it has an inherent lack of tenacity, especially below its glass transition temperature. Its impact-resistance can be modified by adding elastomers.
In this paper, brPE/iPP alloy was obtained under appropriate operating conditions by ethylene polymerization in iPP particles, which was catalyzed by late transition metal catalyst supported in the functionalized iPP particles. First, functionalized polypropylene was prepared with Z-N catalyst in a 2-liters reactor at 70℃ and 2atm. Then the late transition metal catalyst bi-(2,6-dimethylphenyl) pentane diimine nickel dibromide was supported on the fuctionalized iPP particles. When ethylene was input in the reactor, ethylene diffused into iPP particles and polyethylene formed in iPP particles. The obtained product is an alloy of polypropylene and branched polyethylene. By varying the polymerization temperature, the branching degree of polyethylene can be tuned and different brPE/iPP in-reactor alloy could be obtained. Besides the process, we investigated the basic properties of these products.
Experiments showed that the functionalized polypropylene is a good support material for late transition metal catalyst. By adjusting the operating parameters such as temperature, brPE/iPP in-reactor alloy can be prepared When the polymerization temperature increased from 20 ℃ to 50 ℃, the branch of polyethylene varied from 20.0 to 130.4. The branch chain mainly consist of methyl branch, but with the temperature increasing, the long branches, especially amyl , hexyl and longer than hexyl, increase rapidly and the content of long branches are comparable to that of methyl branch.
Keywords: Polypropylene; high-Polyethylene; diimine nickel catalyst; dihydro Myrcene three-silicon ether