【作者】 周思凯；

【导师】 方少明； 陈志军；

【作者基本信息】 郑州轻工业学院 ， 材料学， 2006， 硕士

【摘要】 可控/“活性”聚合是一种较新的合成方法,目前在高分子科学领域是一个研究的热点之一,主要的合成方法有:“活性”开环聚合、“活性”阴离子聚合、“活性”阳离子聚合、可逆加成一断裂链转移自由基聚合、原子转移自由基聚合和氮氧调控自由基聚合等。 本文采用氮氧稳定自由基聚合方法制备了聚苯乙烯(PS)、聚4-乙烯吡啶(P4-VP)和聚苯乙烯与聚4-乙烯吡啶嵌段共聚物(PS-b-P4-VP),聚合物的分子量、分子量分布以及结构分别用凝胶渗透色谱(GPC)和红外(IR)进行了表征。并用原子力显微镜(AFM)研究了PS-b-P4-VP对PS与P4-VP共混体系的增容性。结果表明:在氮氧稳定自由基(HTEMPO·)存在下,用过氧化苯甲酰(BPO)引发苯乙烯聚合,所制备聚苯乙烯的分子量分布在1.15-1.25范围;将该聚苯乙烯溶于4-乙烯吡啶,在135±2℃时可以继续引发4-乙烯吡啶进行聚合反应,且4-乙烯吡啶的聚合反应具有“活性”聚合的特征,共聚物的分子量分布在1.12-1.3范围,分子量在14000 g/mol～20000 g/mol范围内。IR谱图说明共聚物为嵌段共聚物。AFM结果说明所合成的嵌段共聚物PS-b-P4-VP是PS与P4-VP的良好增溶剂。 另外,本文采用氮氧稳定自由基聚合方法在单晶硅表面制备了聚苯乙烯、聚苯乙烯与4-乙烯吡啶无规共聚物以及聚苯乙烯与4-乙烯吡啶嵌段共聚物“刷子”,此方法分以下几步进行:(ⅰ)将3-甲基丙烯酰氧基丙基三甲氧基硅烷接枝到单晶硅表面,(ⅱ)以过氧化二苯甲酰(BPO)为催化剂,将2,2,6,6-四甲基哌啶N-氧基-1-羟基(HTEMPO·)引入3-甲基丙烯酰氧基丙基三甲氧基硅烷的末端,(ⅲ)在HTEMPO·存在下,苯乙烯和4-乙烯吡啶在单晶硅的表面进行“活性”自由基聚合反应,从而在单晶硅表面制备出聚苯乙烯与4-乙烯吡啶无规共聚物以及聚苯乙烯与4-乙烯吡啶嵌段共聚物“刷子”。可控/“活性”自由基聚合反应可以精确控制聚合物的分子量及其分布。光电子能谱(XPS)的测试结果表明,带有引发剂的烷氧基链已接枝到单晶硅表面。XPS和椭偏仪的测试结果表明,聚苯乙烯、聚苯乙烯与4-乙烯吡啶共聚物以及聚苯乙烯与4-乙烯吡啶共聚物以化学键的方式被锚接到了单晶硅上。接枝聚合物层的厚度可由反应时间控制。随着接枝时间的增加,表面趋于平坦。更多还原

【Abstract】 Controlled / living free radical polymerization have recently attracted considerable attention and there have been numerous studies in the field of macromolecules. There are many methods to synthesis polymer, such as living ring opening polymerization , living anionic polymerization, living cationic polymerization, nitroxide-mediated polymerization, reversible addition-fragmentation chain transfer polymerization and atom transfer radical polymerization and so on.In this paper, a series of polystyrene, poly(4-vinylpyridine), polystyrene-block-poly(4-vi-nylpyridine) (PS-b-P4-VP) were synthesized by using living free radical polymerization initiated by benzoyl peroxide (BPO) in the presence of 4-hydroxyl-2, 2, 6, 6-tetramethylpiperridine-oxyl-l(HTEMPO.). The polystyrene and diblock copolymers were characterized by gel permeation chromatography (GPC) and fourier transform infrared spectroscopy (FTIR). The morphologies of PS/P4-VP/P(St-b-4-VP) was imaged by atomic force microscope(AFM). Experimental results have showed that the polymerization of styrene has "living" nature, the molecular polydispersities of synthesized polystyrene is in the range of 1.15 to 1.25. The polystyrene with "living" ends can initiate the living free radical polymerization of 4-vinylpyridine in the presence of 4-hydroxyl-2, 2, 6, 6-tetramethylpiperridine-oxyl-1 to sequentially form the polystyrene-block-poly- (4-vinylpyridine) with molecular polydispersities in the range of 1.12 to 1.35 and molecular weight in the range of 14000 g/mol to 20000g/mol. The structure of diblock was determined by FTIR. The diblock polymerization (PS-b-P4-VP) is good compatibiliers for PS and P4-VP.On the other hand, a new method of fabricating a brush-like polystyrene layer anchored on the surface of the silicon substrate was described, which involves three steps, namely (i) the attachment of 3-methacryloxypropyltrimethoxysilane onto the silicon surface;(ii) the reaction of vinyl moiety at another extremity of the anchored 3-methacryloxypropyltri-methoxysilane to 4-Hydroxyl-2, 2, 6, 6-tetramethyl-1-piperidinyloxy (HTEMPO.) catalyzed by Benzoyl Peroxide (BPO);(iii) living free radical graftingpolymerization in the presence of HTEMPO. The controllable living free radical polymerization permits accurate control of both the molecular weight and the polydispersity. X-photoelectron spectroscopy measurement proved that the alkoxyamine initiator layer was formed on the silicon surface. XPS and Ellipsometry measurements showed that the polymers’ chains were covalently anchored onto the silicon surfaces. The thickness of the grafted polymer layer can be accurately manipulated by altering the polymerization time. The new method allows synthesizing random copolymer and block copolymers by the sequential growth of monomers from the substrate surface.更多还原