Allyl chloride/AlCl_3/ether cationic initiating systems for polymerization of 1,3-pentadiene

Various ethers were used to mediate the polymerizations of 1,3-pentadiene (PD) initiated by AlCl3 and by allyl chloride (AllyCl)/AlCl3. The introduction of the ethers exert considerable effects on polymer yield and molecular weight due to its interaction with the propagating carbocation. The carbocation reactivity is reduced by this interaction which is subject to the ether's nucleophilicity determined by the steric hindrance of groups adjacent to oxygen. The reduction of carbocation reactivity gives rise to a decrease of polymer yield owing to inhibition of propagation but results in an augmentation of molecular weight due to suppression of various side reactions such as terminations. By using suitably nucleophilic ethers such as diphenyl ether, the polymerization can be mediated to give an high molecular weight polymer in high yield.     

Dielectric Analysis of Dynamic Fouling Behavior on Surface of Polyethersulfone Composite Ultrafiltration Membrane

基于界面极化与静电场理论建立了聚醚砜复合超滤膜表面污染层与溶液体系的介电解析模型. 应用参数敏感性分析和介电测量研究了体系中浓差极化层与滤饼层的厚度与电导率对超滤体系介电弛豫的影响机制. 结果表明超滤过程中浓差极化层能快速建立,而滤饼层的形成是一个增长与剥蚀的动态过程;并且浓差极化层与滤饼层的电学性质是影响超滤体系介电谱的关键因素. 比较介电测量与模拟结果证实了建立的超滤体系介电解析模型能够有效可靠地描述与解释超滤体系产生介电驰豫的机制.     

endo-双环戊二烯阳离子聚合及聚合物链结构

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   

环戊烯阳离子聚合反应

使用不同阳离子引发剂聚合环戊烯，得到了低聚合度的ＣＰ齐聚物。ＩＲ和＾１ＨＮＭＲ研究发现齐聚物链端碳阳离子通过质子消去反应生成了相应的不饱和端基，这种通过质子消去机现发生的链转移反应和生成稳定叔碳阳离子的１，２－Ｈ转移反应导致了聚合反应的氏聚合度。ＣＰ在甲苯中不发生聚合反应而是通过链转移反应与甲苯生成偶合产物。     

STUDY ON THE CATIONIC POLYMERIZATION OF 1, 3-PENTADIENE INITIATED BY AlCl_3/ALKYL HALIDE SYSTEMS

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.     

CATIONIC POLYMERIZATION OF 1, 3—PENTADIENE INITIATED BY ORGANIC AZIDE/Et2AlCl

The cationic polymerization of 1, 3-pentadiene was initiated by the organic azide/Et_2 AlClinitiating system in CH_2Cl_2 and n-hexane. The polymerizations were also carried out in parallelwith organic chloride/Et_2AlCl and Et_2 AlCl alone for comparison. The Et_2 AlCl- induced polymer-ization gives a low yield while the polymerization initiated by organic chloride/Et_2 AlCl producesmainly insoluble product. In contrast, the polymerization with azide/Et,AlCl has a high conver-sion and the resulting polymer having a high molecular weight is totally soluble. The SEC spectraof the polymers have clearly shown the differences between these initiating systems.     

Crosslinking reaction in the cationic polymerization of 1, 3-pentadiene

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.     

聚合物太阳能电池的降解与稳定性研究

近几年,聚合物太阳能电池的光电转化效率进展迅速,由5%提升至目前的11%以上,应用前景及商业化生产备受关注,但其稳定性问题一直是一个重要的限制因素。无机太阳能电池,如硅电池使用寿命长达25年,而聚合物太阳能电池因其易受氧气、水甚至光的作用而发生降解,使用寿命仅几千小时,且由于其复杂的多层结构、各层不同的降解机制以及加工方法多样,所以仍无法弄清其降解机理。本文概述了对聚合物太阳能电池的稳定性和降解过程的认识,分析讨论了活性层材料的光稳定性、本体异质结器件的反型结构、相分离的影响以及卷对卷加工(R2R)方法所产生的特殊稳定性等问题。     

1,3-戊二烯阳离子聚合过程中环化反应的研究

以ＡｌＣｌ３和（ＣＦ３ＳＯ３）３Ａｌ为引发剂，ＣＨ２Ｃｌ２为溶剂，在２０℃聚合了１，３ 戊二烯（ＰＤ）．对聚合物（ＰＰＤ）的结构分析表明，（ＣＦ３ＳＯ３）３Ａｌ生成的聚合物具有较高的环化度．聚合物的环化过程是通过两种机理，分子内链转移机理和阳离子引发机理，后者可以通过加入ＤｔＢＰ得到抑制．ＡｌＣｌ３引发的聚合反应中环化过程以前一种机理为主，而（ＣＦ３ＳＯ３）３Ａｌ则以后一种机理为主．通过阳离子引发的环化反应主要发生在ＰＰＤ１，２单元侧基双键上