RAFT聚合方法合成响应性聚合物和功能性聚烯烃

发布时间：2018-07-03 20:23

  本文选题：可逆加成-断裂链转移聚合 + 刺激响应　； 参考：《中国科学技术大学》2017年博士论文

【摘要】：响应性聚合物和功能性聚烯烃是目前国内外高分子界异常活跃的领域。近年来,可控/活性聚合的发展,使得单体以可控的方式进行聚合成为可能。本文通过设计具有功能性的单体,利用可逆加成-断裂链转移(RAFT)聚合,制备了具有不同环境响应的聚合物及功能化的聚烯烃。论文主要研究内容包括以下四个部分:1、利用RAFT聚合反应一锅法制备刺激响应的超支化聚合物,将其加入水中制备了多刺激响应的凝胶粒子。研究表明,聚合物具有温度敏感性,当温度升至低临界溶液温度(LCST)以上时,其溶解能力大大降低,形成纳米粒子,随后,分子间发生二硫键的交换反应交联纳米粒子而形成了纳米凝胶。这种纳米凝胶具有温度、光和还原响应性。2、通过RAFT聚合制备了含有二硫键的PEG超支化聚合物,考察了其温度响应性和自交联的反应条件。然后将超声分散于水中的SiO2纳米粒子作为模板,通过控制pH、温度和聚合物浓度等手段,利用微量进样器来连续滴加,获得了 PEG/SiO2核壳结构的纳米粒子。并在此基础上,通过HF腐蚀内核SiO2,得到了可生物降解的PEG纳米空心胶囊。3、联合阴离子开环反应和RAFT聚合,一锅法制备了环硫丙烷和异丙基甲基丙烯酰胺、环硫丙烷和N,N-二甲基丙烯酰胺的共聚物。S-1-十二烷基-S'-(α,α'-二甲基-α"-乙酸)三硫代碳酸酯为丙烯酰胺类单体RAFT聚合的链转移剂和环硫丙烷开环聚合(ROP)的引发剂。实验结果表明,制备的环硫丙烷与异丙基甲基丙烯酰胺共聚物由于含有亲水和疏水段,在室温下自组装成胶束。当暴露在活性氧的环境中时,聚环硫丙烷(PPS)转变成亲水的聚丙烯砜(PPP),此时胶束解聚成溶液。再次升高温度至聚异丙基甲基丙烯酰胺(PNIPMAM)的LCST以上时,新的胶束再次形成。使用活性氧和温度作为刺激方式在药物释放方面具有潜在的应用前景。4、温和条件下(T=70℃,P≤30bars)利用RAFT聚合成功合成了一系列功能性的聚乙烯材料。该方法制备的共聚物具有较高的分子量、窄分布(Mn10000 g/mol,PDI1.3)和可调控的极性单体的插入比,拓展了功能性聚烯烃的合成思路。
[Abstract]:Reactive polymers and functional polyolefin are very active in the field of polymer industry at home and abroad. In recent years, the development of controllable / active polymerization has made it possible to polymerize monomers in a controllable manner. In this paper, functional monomers were designed and polymerized by reversible addition-break chain transfer (raft) to prepare polymers and functionalized polyolefin with different environmental responses. The main contents of this paper are as follows: 1. The hyperbranched polymers with stimulus response were prepared by the one-pot method of raft polymerization, and the multi-stimuli responsive gel particles were prepared by adding them into water. The results show that the polymer is temperature-sensitive, and when the temperature rises above the low critical solution temperature (LCST), the solubility of the polymer decreases greatly, forming nanoparticles, and then, Exchange reaction of disulfide bond between molecules and crosslinking of nanoparticles to form nanogels. The nanogel was characterized by temperature, light and reductive responsiveness. PEG hyperbranched polymers containing disulfide bonds were prepared by raft polymerization. The temperature response and the reaction conditions of self-crosslinking were investigated. Then the Sio _ 2 nanoparticles dispersed in water by ultrasonic were used as templates. By controlling pH, temperature and polymer concentration, the PEG / Sio _ 2 core-shell nanoparticles were obtained by using a micro sampler. On this basis, biodegradable PEG nano-hollow capsules. 3 were prepared by HF corrosion core SiO2, combined with anionic ring-opening reaction and raft polymerization. Cyclothiopropane and isopropylmethacrylamide were prepared by one-pot method. The copolymers of cyclothiopropane and N-dimethylacrylamide. S-1- dodecyl (伪, 伪 -dimethyl- 伪 "-acetic acid) trithiocarbonate is the chain transfer agent and initiator of cyclic thiopropane ring-opening polymerization (ROP) for acrylamide monomer raft polymerization. The experimental results show that the prepared copolymers of cyclothiopropane and isopropylmethacrylamide are self-assembled into micelles at room temperature due to their hydrophilic and hydrophobic segments. When exposed to reactive oxygen species, polycyclic thiopropane (PPS) is transformed into hydrophilic polypropylene sulfone (PPP), and the micelle is decomposed into solution. When the temperature is raised again above the LCST of PNIPMAM, the new micelles are formed again. A series of functional polyethylene materials were successfully synthesized by raft polymerization under mild conditions (T _ (70 鈩，

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