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梳形聚合物侧链长度变化对增容效果的影响研究

时间:2023-08-26 08:46来源:毕业论文
梳形聚合物侧链长度变化对增容效果的影响研究,通过链转移剂巯基乙酸(Thioglycollic acid,TAC)与引发剂4, 4’-偶氮(4-氰基戊酸)(4,4’-Azobis (4-cyanovaleric acid),ACVA)调聚反应合成分子量精

摘   要近年来,支化结构(如星形、超支化、梳形)共聚物的合成及其性能研究引起学术界的广泛关注。其中,梳形聚合物因具有规整支化结构和独特的物理化学性能,在制备聚合物电解质、热塑性弹性体以及药物载体等领域得到了广泛应用。为了拓宽梳形聚合物的合成及应用范围,本文首先运用“Grafting through”法合成出具有“再反应”活性的梳形聚合物(Reactive comblike copolymer, RC),并将其作为反应性增容剂,以提高不相容共混体系的相容性,取得显著进展。较传统反应性增容剂,本文合成RC由于在加工过程中会原位形成“双梳齿”结构,能稳定地存在于界面上,更有利于实现高效增容。同时,RC的合成过程简单,增容适用范围广,有望成为一类新型高效增容剂。89724

本文主要围绕RC的合成、结构及其对不相容性共混体系的增容探究三方面来展开试验,主要研究内容及结论如下:

(1) RC的合成:本文首先通过链转移剂巯基乙酸(Thioglycollic acid,TAC)与引发剂4, 4’-偶氮(4-氰基戊酸)(4,4’-Azobis (4-cyanovaleric acid),ACVA)调聚反应合成分子量精确可控的端羧基聚甲基丙烯酸甲酯(PMMA-COOH);再利用羧基-环氧在碱性条件下的亲核开环加成反应,制得高官能化甲基丙烯酸甲酯大分子单体(MMA-macromer);随后采用“Grafting through”法利用自由基聚合共聚甲基丙烯酸甲酯(MMA)、苯乙烯(St)、GMA与MMA-macromer等单体,合成出一系列不同主链组成、主链长度、侧链长度、接枝密度及环氧含量的RC分子(MMA-co-GMA)-g-MMA或(St-co-GMA)-g-MMA)。

 (2) RC对不相容工程塑料合金的增容效果研究:利用合成的RC增容1个典型热力学不相容体系:聚乳酸/聚偏氟乙烯(PLLA/PVDF)体系,然后改变其侧链长度,研究对其影响。研究表明,RC比普通线性反应性增容剂具有更高界面稳定性,通过调节侧连长度,能够实现侧连长度的改变能影响其增容,而且会有一个增容型最好的长度。

毕业论文关键词:梳形聚合物; 大分子单体; 增容效果; 侧连长度

ABSTRACT Facile constructions of complex macromolecular architectures such as star-like, hyper-branched, dendritic and comb-like copolymers have attracted great attentions due to their branched topologies, unique physicochemical properties and widely applications。 As a subclass of graft copolymers, comb-like copolymers comprising regular side chains have captured great interests for their easiness of synthesis and their applications as polymer electrolytes, thermoplastic elastomers and smart biomaterials, etc。 Herein, we described the facile synthesis of a novel reactive comb copolymer (RC) by a “Grafting through” method; copolymerizations of methyl methacrylate (MMA), glycidyl methacrylate (GMA) and MMA macromer afforded a comblike copolymer, which had regular PMMA side chains and epoxide groups, randomly distributed along the backbone。 The RC copolymers were appplied as compatibilizers in immiscible polymer blends。 The epoxide groups of RC copolymers was able to react with the carboxyl or hydroxyl groups of a series of engineering plastics, such as poly(L-lactic acid) (PLLA), polycarbonate (PC), poly(ethylene terephthalate) (PET); thus, a “double comblike” copolymers were obtained, with the PMMA side chains interacted with one phase and the grafted chains interacted with the other phase。 It was anticipated that this novel kind of RC copolymers would have much higher compatililizing efficiency。

This thesis was pided into three main parts:

1。Synthesis of RC: Firstly, pre-macromer (PMMA-COOH) was synthesized via a telomerization of MMA with thioglycolic acid (TAC) as a chain transfer agent and 4,4’-azobis (4cyanovaleric acid) (ACVA) as an initiator。 The molecular weight of PMMA-COOH could be controlled precisely by the variations of reacting condition and feed ratios。 Then MMA macromer was obtained by a nucleophilic ring-opening addition between the terminal carboxyl groups of PMMA-COOH and epoxide groups of GMA。 By copolymerizing MMA macromer with MMA and GMA, a RC copolymer was obtained; without the using of macromer, we obtained a reactive linear (RL) copolymer。 梳形聚合物侧链长度变化对增容效果的影响研究:http://www.youerw.com/yixue/lunwen_195356.html

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