Macro-RAFT试剂调介下的异相RAFT聚合及应用研究

发布时间：2018-05-02 07:48

  本文选题：异相聚合 + RAFT聚合　； 参考：《湘潭大学》2016年硕士论文

【摘要】：异相体系下的自由基聚合如乳液聚合、分散聚合、悬浮聚合、沉淀聚合等是制备功能性聚合物微球的重要方法。近年来,将可逆加成断裂链转移(RAFT)自由基聚合技术引入到异相体系中,特别是在大分子RAFT(Macro-RAFT)试剂调介下的异相RAFT聚合引起了广泛关注。这种方法在原位生成嵌段共聚物,并通过聚合诱导自组装形成聚合物粒子方面显示了优势。本论文致力于研究异相体系下的RAFT聚合反应及其在功能性聚合物粒子制备中的应用,先后开展了如下研究工作:(1)无皂乳液RAFT共聚合制备阳离子PS/PMMA胶乳设计合成一种两亲性聚N-(4-乙烯苯基)-N,N-二正丁基胺盐酸盐(PVBAH)Macro-RAFT试剂。以PVBAH作为Macro-RAFT试剂和表面活性剂,研究其调介苯乙烯与甲基丙烯酸甲酯的无皂乳液RAFT共聚合。分别研究共聚单体组成、乳液固含量、乳化剂浓度及Macro-RAFT试剂分子量对无皂乳液RAFT共聚合的影响。结果表明,在苯乙烯含量超过30%,乳液固含量低于40%,单体与Macro-RAFT试剂PVBAH的比例小于_(60)0/1及Macro-RAFT试剂PVBAH的分子量在4.7 kg/mol到10.5 kg/mol的条件下,该无皂乳液RAFT共聚合具有较快的聚合反应速率和良好的可控性。聚合导致原位生成PVBAH-b-P(St-coMMA)-b-PVBAH嵌段共聚物,并通过聚合诱导组装形成具有“核-壳”结构的聚合物纳米粒子,其中亲水链段PVBAH形成壳层,疏水链段P(St-co-MMA)形成核。合成的嵌段共聚物的分子量与单体转化率呈现线性关系,且与理论值相近,嵌段共聚物的分子量分布小于1.3。形成的阳离子PS/PMMA胶乳具有较好的稳定性,而且聚合物纳米粒子的尺寸在24 nm~53 nm可调控。(2)分散RAFT聚合制备“核-壳-冠”聚合物纳米粒子采用“两步”溶液RAFT聚合方法,分别制备两种两嵌段Macro-RAFT试剂,聚(N,N-二甲基丙烯酰胺)-b-聚(3-丙烯酰胺基苯硼酸)(PDMA_(60)-b-PAPBA21-TTC)和聚(N,N-二甲基丙烯酰胺)-b-聚(2,2-二甲基-5-乙基-1,3-二氧六环)丙烯酸甲酯(PDMA_(60)-b-PEDMA25-TTC)。研究PDMA_(60)-b-PAPBA21-TTC和PDMA_(60)-bPEDMA25-TTC两种Macro-RAFT试剂同时调介下的苯乙烯分散RAFT聚合。该聚合反应具有较好的可控性,并且聚合诱导自组装形成PDMA_(60)-b-PEDMA25-b-PS/PDMA_(60)-b-PAPBA21-b-PS多组分“核-壳-冠”聚合物纳米粒子。其中,疏水性链段PS形成“核”,PAPBA和PEDMA链段形成“壳”,亲水性链段PDMA形成“冠”。由于“壳”层中PEDMA链段上的缩酮基团在酸性条件下能够水解成双羟基基团,并且双羟基基团与PAPBA链段上的苯硼酸基团在p H调控下能够发生动态交联,从而制备出动态壳交联多组分“核-壳-冠”聚合物纳米粒子。该聚合物纳米粒子在生物传感以及纳米载药系统的设计中具有广阔的应用前景。
[Abstract]:Radical polymerization in heterogeneous systems such as emulsion polymerization dispersion polymerization suspension polymerization and precipitation polymerization are important methods for preparing functional polymer microspheres. In recent years, the technology of reversible addition chain transfer radical polymerization (RAFT) has been introduced into heterogeneous systems, especially the heterogeneous RAFT polymerization with macromolecular RAFTN Macro-RAFT reagent. This method has shown advantages in in situ formation of block copolymers and in the formation of polymer particles by polymerization induced self-assembly. This thesis is devoted to the study of RAFT polymerization in heterogeneous systems and its application in the preparation of functional polymer particles. The following studies have been carried out in this paper: 1) RAFT copolymerization of soap-free emulsion to cationic PS/PMMA latex has been carried out. An amphiphilic polyN-4 ethylphenylethyl-N- (N-)-di- Ding Ji amine hydrochloride (PVBAHN) Macro-RAFT reagent has been designed and synthesized. The soap-free emulsion RAFT copolymerization of styrene with methyl methacrylate was studied using PVBAH as Macro-RAFT reagent and surfactant. The effects of monomer composition, emulsion solid content, emulsifier concentration and molecular weight of Macro-RAFT reagent on soap-free emulsion RAFT copolymerization were studied. The results show that when the content of styrene is more than 30%, the solid content of emulsion is lower than 40%, the ratio of monomer to PVBAH of Macro-RAFT reagent is less than 60% of the PVBAH and the molecular weight of PVBAH of Macro-RAFT reagent is 4.7 kg/mol to 10.5 kg/mol. The soap-free emulsion RAFT copolymerization has fast polymerization rate and good controllability. Polymerization results in the in-situ formation of PVBAH-b-P(St-coMMA)-b-PVBAH block copolymers and the formation of polymer nanoparticles with "core-shell" structure by polymerization induction, in which the hydrophilic segment PVBAH forms a shell layer and the hydrophobic segment PPVBAH-b-P(St-coMMA)-b-PVBAH St-co-MMA forms the nucleus. The molecular weight of the block copolymers was linearly related to the monomer conversion and was close to the theoretical value. The molecular weight distribution of the block copolymers was less than 1.3. The formed cationic PS/PMMA latex has good stability, and the size of polymer nanoparticles can be controlled at 24 nm~53 nm. (2) dispersed RAFT polymerization is used to prepare "core-shell crown" polymer nanoparticles by "two-step" solution RAFT polymerization. Two kinds of diblock Macro-RAFT reagents were prepared, poly (N- (N-) N-dimethylacrylamide) -b-, poly (3-acrylamido-phenylboric acid), PDMA-60- b-PAPBA21-TTC) and poly (N- (N-N-dimethylacrylamide) -2-dimethyl-2-dimethyl-5-ethyl-1-3-dioxane) methyl acrylate) methyl ester PDMA60- b-PEDMA25-TTCn. The polymerization of styrene dispersive RAFT with PDMA_(60)-b-PAPBA21-TTC and PDMA_(60)-bPEDMA25-TTC Macro-RAFT reagents simultaneously was studied. The polymerization has good controllability, and the polymerization induces self-assembly to form PDMA_(60)-b-PEDMA25-b-PS/PDMA_(60)-b-PAPBA21-b-PS multi-component "core-shell-crown" polymer nanoparticles. The PS of hydrophobic segment formed "nucleus" PAPBA and PEDMA segment to form "shell", and hydrophilic segment PDMA formed "crown". In the "shell" layer, the Ketal group on the PEDMA segment can be hydrolyzed into a dihydroxyl group under acidic conditions, and the dihydroxyl group can be dynamically crosslinked with the phenylboric acid group on the PAPBA segment under the control of pH. Thus, dynamic shell crosslinked multi-component "core-shell-crown" polymer nanoparticles were prepared. The polymer nanoparticles have broad application prospects in biosensor and drug delivery system design.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O631.5
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本文编号：1833006