排序方式: 共有73条查询结果,搜索用时 343 毫秒
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两亲磁性高分子微球的合成与表征 总被引:7,自引:0,他引:7
在Fe3O4磁流体存在下 ,通过苯乙烯与聚氧乙烯大分子单体 (MPEO)分散共聚制备两亲磁性高分子微球 .研究了聚氧乙烯大分子单体对微球粒径的影响 .用扫描电子显微镜 (SEM)、原子力显微镜 (AFM)表征了磁性微球的粒径、表面形貌以及表面粗糙度 ,用傅立叶红外光谱 (FTIR)鉴定了共聚物的结构 .随着聚合物中聚氧乙烯大分子单体含量的增加 ,微球表面的粗糙度增加 ,通过改变共聚物中MPEO的含量 ,可以得到含有 0 4~ 3 5mg g羟值的两亲磁性高分子微球 相似文献
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The cationic polymerizations of 1, 3-pentadiene were initiated by AlCl_3 in n-hexaneat 30℃ in the presence of alkyl halides, i.e., tert-butyl chloride, tert-butyl bromide andisobutyl chloride. The effects of these halides on the polymer yield, molecular weight,crosslinking reaction, cyclization and polymer microstructure, have been investigated. Twomain side reactions, crosslinking and cyclization, were suppressed and reduced by theaddition of the halides. The proportion of 1, 4 units of polymer chains was increasedby the presence of the halides, which reduced the polymer yield and the molecular weightof polymers. 相似文献
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活性聚合是连锁聚合反应体系中链转移和终止反应速率为零时的特殊反应类型,表现活性聚合和准活性聚合则是链转移或终止反应未被完全消除而人有活性聚合物特征两类聚合物反应,是非活性聚合活性聚合过渡和逼近时的两种聚合反应类型,本文对活性聚合,表现活性聚合和准活性聚合的基本概念及它们之间的区别作了简单的介绍。 相似文献
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使用不同阳离子引发剂和引发体系在甲苯、正己烷和二氯甲烷中引发endo-双环戊二烯(DCPD)聚合, 得到了低分子量的DCPD聚合物(PDCPD), 采用IR和1H NMR对PDCPD链结构进行了表征。结果表明, DCPD分子的降冰片烯(NB)双键和环戊烯(CP)双键均参与了聚合反应并根据不同链增长机理产生四种链结构单元: 通过NB双键的链增长反应可生成直接加成结构单元I和重排结构单元II, 通过CP双键的链增长反应生成直接加成结构单元III和跨环重排单元IV。正己烷和甲苯中所合成了PDCPD包含全部四种结构单元, 并呈现I相似文献
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选择低分子量端羟基聚二甲基硅氧烷(PDMS-OH)与聚(甲基丙烯酸甲酯-co-丙烯酸β-羟乙酯)P(MMA-co-HEA)共聚物原位复合形成氢键复合物,该复合物表现出良好的形状记忆效应.通过FTIR,SEM对材料的结构和形貌进行表征,DMA表征材料的动态力学行为,并通过弯曲实验对材料的形状记忆性能进行了表征及比较.FTIR分析证明PDMS-OH与P(MMA-co-HEA)共聚物形成氢键缔合作用;SEM分析显示,随着PDMS-OH含量的升高,氢键复合物由"海-岛"相分离结构向反转相分离结构转变;DMA分析结果表明,氢键的引入有利于复合物获得更高的模量比;形状记忆性能测试结果显示该氢键复合物具有良好的形状记忆性能,形状记忆固定率超过98%、形变恢复率超过99%,并且与聚(甲基丙烯酸甲酯-co-丙烯酸乙酯)/PDMS-OH(P(MMA-co-EA)/PDMS-OH)复合物相比,氢键复合物显示出更快的形变回复速率. 相似文献
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The cationic polymerization of 1,3-pentadiene (PD) initiated by AlCl_3 in n-hexane was carried out. Effects of arenes, alkyl halides and ethers on the gel formation resulting from crosslinking reaction were investigated. The erosslinking was reduced by various arenes through a chain transfer mechanism. Alkyl halides such as tert-butyl chloride and allyl chloride could complex with AlCl_3 to generate an initiating system giving rise to a gel-free polymerization, while benzyl chloride reduced the formation of gel by chain transfer. Ethers exerted two effects on the polymerization system: giving a complex initiating system with AlCl_3 to produce a relatively high molecular weight polymer, or reducing crosslinking by lowering activity of carbocations. 相似文献