熔融共混制备接枝聚合物及增容效果研究

摘要：本论文通过带端羧基的聚甲基丙酸甲酯（PMMA-COOH）低聚物与乙烯基-甲基丙烯酸缩水甘油酯（EGMA）熔融共混反应制备接枝聚合物EGMA-g-PMMA来增容PVDF/LDPE共混物。通过改变PMMA-COOH低聚物的添加量、分子量以及熔融共混时间等研究了接枝聚合物的接枝密度、侧链长度以及混炼时间对PVDF/LDPE共混物增容效果的影响。主要内容如下：

1、接枝聚合物EGMA-g-PMMA的接枝接枝密度对PVDF/LDPE共混物性能的影响。在本研究中，通过对比在PVDF/LDPE共混物中分别只加入EGMA与同时在共混物中加入EGMA、PMMA-COOH低聚物的增容效果。研究发现，PMMA-COOH低聚物的引入，与单纯地添加EGMA相比极大地提高了PVDF/LDPE共混物的相容性，并且随着PMMA-COOH低聚物添加量的增加即接枝聚合物接枝密度的提高，其增容效果进一步提高，材料表现出更加优异的力学性能。

2、接枝聚合物的侧链长度对PVDF/LDPE共混物性能的影响。在本研究中，添加分子量为2K-8k的PMMA-COOH低聚物，考察接枝聚合物侧链长度对PVDF/LDPE共混物的增容效果。当侧链长度从2k提高到4k时，增容效果有所提高。但是当侧链长度继续增大到8k时，由于空间位阻和PMMA-COOH低聚物上的端羧基活性下降，PMMA-COOH低聚物与EGMA上的环氧基团的开环反应受到影响，无法有效接枝到EGMA主链上，这使得PMMA-COOH低聚物仍然以小分子的形式，存在于PVDF基体中无法起到接枝聚合物中PMMA-COOH侧链与PVDF基体进行缠结从而起到增容的作用，因此增容效果没有增加反而有所下降。

3、熔融共混时间对PVDF/LDPE共混物性能的影响。在本研究中，PMMA-COOH和EGMA的反应时间也是影响增容效果的重要因素。

关键词：梳形聚合物；反应性增容；聚偏氟乙烯；聚甲基丙烯酸甲酯；乙烯基-甲基丙烯酸缩水甘油酯；低密度聚乙烯

ABSTRACT：In this dissertation, the graft polymer EGMA-g-PMMA was prepared by the melt-blending of carboxyl-terminated polymethylmethacrylate (PMMA-COOH) oligomer and vinyl glycidyl methacrylate (EGMA). Compatibilize PVDF/LDPE blends. The effects of grafting density, side chain length and mixing time on the compatibilization of PVDF/LDPE blends were investigated by changing the addition amount, molecular weight and melt-blending time of PMMA-COOH oligomers. The main contents are as follows:

1. Effect of Grafting Density of Graft Polymer EGMA-g-PMMA on Properties of PVDF/LDPE Blends . In this study, the compatibilization effects of adding only EGMA or PMMA-COOH oligomers to PEG and PMMA-COOH oligomers in the blends were compared in the PVDF/LDPE blends. Studies have found that the introduction of PMMA-COOH oligomers greatly improves the compatibility of PVDF/LDPE blends compared to simply adding EGMA or PMMA-COOH oligomers, and with PMMA-COOH oligomers The increase of the amount of addition means that the grafting density of the grafted polymer is increased, the compatibilization effect of the grafted polymer is further increased, and the material exhibits more excellent mechanical properties.

2. Effects of Side Chain Length of Graft Polymers on Properties of PVDF/LDPE Blends . In this study, PMMA-COOH oligomers with a molecular weight of 2K-8k were added to investigate the compatibilization effect of graft polymer side-chain length on PVDF/LDPE blends. When the length of the side chain is increased from 2k to 4k, the compatibilizing effect is improved. However, when the length of the side chain continues to increase to 8k, due to steric hindrance and the decrease in the carboxyl-terminal activity of the PMMA-COOH oligomer, the ring-opening reaction of the PMMA-COOH oligomer with the epoxy on the EGMA is affected and cannot be effected. Effective grafting to the main chain of EGMA, which makes PMMA-COOH oligomers still in the form of small molecules exist in the PVDF matrix can not play a role in the graft polymer PMMA side chain and PVDF matrix entanglement The role of content, so no increase in the capacity increase but decreased. 熔融共混制备接枝聚合物及增容效果研究:http://www.chuibin.com/cailiao/lunwen_206412.html