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
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
