铈离子与乙酰苯胺及其衍生物引发丙烯酰胺聚合动力学的研究

以铈离子和酰苯胺引发体系进行丙烯酰胺的聚合,研究了不同结构酰苯胺对聚合的影响。在H_2O-CH_3CN(3∶1)介质中聚合时,乙酰对甲苯胺对聚合的促进作用最为明显,聚合速度可提高一个数量级。测定了聚合反应的表观活化能和聚合动力学方程、由聚合物的原子发射光谱,UV光谱和端基测定,提出了聚合反应机理。     

铈离子氧化还原引发体系与铈离子引发接枝或嵌段共聚合研究的新进展

本文介绍Ce⁴⁺/酰胺引发体系;Ce⁴⁺/聚酰胺、带酰苯胺侧基的聚合物引发接枝共聚合;Ce⁴⁺/氨基甲酸酯引发体系;Ce⁴⁺/聚醚氨酯引发接枝共聚合;Ce⁴⁺/羰基化合物引发体系;Ce⁴⁺引发嵌段共聚合6个方面的研究新进展.     

铈离子与乙酰乙酸乙酯体系引发烯类聚合的研究

<正> 铈离子与醇、醛、酮、α-羟基酸等组成的体系能引发烯类单体进行自由基聚合。关于铈离子与酯类化合物体系文献报道甚少。孙燕慧发现脂肪酸酯或芳香酸酯对铈离子引发丙烯酰胺(AAM)聚合能起促进作用,提高聚合速度只R_(p)但活性较小,相对聚合速度只,为1.3左右。本文研究了二元酸酯、乙酰乙酸乙酯(EACAC)分别与铈离子组成的体系引发AAM聚合,实验结果表明EACAC有很高的活性,它与铈离子组成的体系为一氧化还原引发体系。应用自由基捕捉技术和ESR波谱研究,能检测到由EACAC组分反应产生的自由基,从聚合物端基的FT-IR光谱分析,证实了该自由基能引发单体聚合而成为聚合物的端基。从而讨论了引发机理。     

等离子体引发丙烯酰胺水溶液聚合

用两种等离子体引发丙烯酰胺水溶液聚合的方法 ,制备了线性超高分子量聚丙烯酰胺 .研究了放电时间、放电功率、单体的初始浓度及溶液的pH值等对聚合产物的影响     

等离子体引发丙烯酰胺的反相悬浮聚合

通过等离子体引发技术进行了丙烯酰胺的反相悬浮聚合研究,考察了后聚合时间,放电时间,放电功率,单体浓度,分散剂浓度及溶剂极性对聚合物分子量和转化率的影响。结果发现：延长后聚合时间有利于反应的进行,而在聚合反应中存在着一个最佳的单体浓度值,增加溶剂的极性有利于反应进行,降低体系中空气残留量也有利于反应进行。     

N－（N＇，N＇－二甲氨基甲基）丙烯酰胺－过硫酸钾引发丙烯酰胺聚合的研究

The kinetic of polymerization of aeqlamide (AM ) inihated by the combination of N - (N,'N L dimethylaminomethyl ) acrylamide (DMAAM ) with potassiumpersulfate was stUdied. The rate equation was given as:R_p= K_p[DMAAM]^0.5[K₂S₂O₈]^0.5 [AM]The overall aCtivation energy was determined to be 27.86 KJ/mol. DMAAMwas shown not only joined the ndox initiahon but also incorporated intO thepolymer chains, so that the high molecular weight 107 of polyaCrylamide was obtained but the distribution of molecular weight was broad. The effect of additives on molecular weight and its distribution has been studied.     

苯甲醛及其衍生物对铈离子存在下丙烯酰胺聚合的影响

<正> 虽然Santappa等早已报道Ce~(4+)(高氯酸铈)/甲醛体系能引发丙烯腈(AN)、甲基丙烯酸甲酯(MMA)的聚合,但对醛的活性以及参与引发单体聚合的自由基都未有详细报道,近来孙燕慧等发现脂肪醛能显著促进Ce~(4+)(硝酸铈铵CAN)引发丙烯酰胺(AAM)的聚合,而且醛的活性远大于相应的醇。至于芳香醛对于Ce~(4+)引发烯类单体的聚合的影响也未见详细报道。本文扼要报道苯甲醛(BA)及其衍生物对-硝基苯甲醛(PNBA)、间-硝基苯甲醛(MNBA)、间-溴苯甲醛(MBBA)、对-氯苯甲醛(PCBA)对Ce~(4+)(CAN)存在下丙烯酰胺聚合的影响,测定了其聚合速率,以UV吸收光谱、ESR波谱测定     

铈盐－过硫酸盐复合引发体系的研究

铈盐－过硫酸盐复合引发体系的研究李朝阳，丘坤元（北京大学化学系，北京，１００８７１）关键词复合引发体系，铈盐，过硫酸盐，氧化还原引发本文研究了一种新的复合引发体系，即在传统的单独钟盐引发体系中引人过硫酸盐这一本身具有强氧化性的新组分，提高原体系的引发...     

铈离子/4-甲氧基丁二酰-对-甲苯胺或4-甲氧基马来酰-对-甲苯胺体系引发烯类聚合

研究了铈离子与四种不同结构的酰苯胺类化合物,如4-甲氧基丁二酰苯胺(MSA)-4-甲氧基丁二酰-对-甲苯胺(MST)、丁二酸单酰-对-甲苯胺(SAMT)和4-甲氧基马来酰-对-甲苯胺(MMT),组成的引发体系对丙烯酰胺聚合的影响,测定了聚合表现活化能和聚合反应动力学方程。由聚丙烯腈的红外光谱端基分析证实了MST组分与铈离子反应产生的自由基能引发烯类聚合。     

PHOTOSENSITIVITY OF CERIC ION INITIATED ACRYLAMIDE POLYMERIZATION

Polymerization of acrylamide initiated by ceric ammonium nitrate alone has been studied in aqueous medium. The effects of UV light irradiation on the initial rates of polymerization, the activation energy and on the polymer molecular weights have been investigated. Compared with that in the dark, the rate of polymerization under UV light was accelerated to eleven times higher, and the overall activation energy was lowered markedly.     

铈离子与4,4′-二乙酰氨基二苯基甲烷体系引发烯类聚合

四价铈离子可与多种有机还原剂组成氧化还原引发体系用于烯类聚合。Samal等报道酰胺化合物如硫代乙酰胺、丁二酰胺、乙酰胺能与铈离子匹配进行丙烯腈(AN)水溶液聚合。我们研究室发现铈离子与乙酰苯胺及其衍生物组成的体系,能顺利引发丙烯酰胺AAM聚合。本工作考察了二酰胺化合物,4,4′-二乙酰氨基二苯基甲烷     

STUDIES ON THE INITIATION MECHANISM OF CERIC ION AND ACETYLACETONE REDOX SYSTEM IN VINYL POLYMERIZATION

The initiation mechanism of acrylamide (AAM)polymerization using ceric ion/acetylacetone system as an initiator has been studied. The redox polymerization was revealed by the low value of overall activation energy of AAm polymerization. The structure of free radicals formed from above-mentioned initiation sytem were detected by radical trapping and ESR spectra techniques and the end groups of polymers obtained were determined by FT-IR spectra analysis method. Based on these results the initiation mechanism is proposed.     

VINYL RADICAL POLYMERIZATION INITIATED WITH CERIC ION AND N-(SUBSTITUTED PHENYL) ACETAMIDE SYSTEMS

The polymerization of acrylamide (AAM)in H_2O/DMF or in H_2O/CH_3CN mixed solvent initiated with ceric ion (Ce~(4+) )/N-(substituted phenyl)-acetamide systems have been studied. The redox polymerization was revealed by the low value of overall activation energy (E_α) of AAM polymerization using ceric ion/N-(substituted phenyl) acetamide system as an initiator. The end group of polymer formed was detected by IR spectrum analysis method, it revealed the presence of N-(m-acetoxy-methylphenyl) acetamide (m-AAe) moiety end group in the polymer obtained with ceric ion/m-AAe initiation system.     

锰(Ⅲ)离子与羧酸或α-羟基羧酸体系引发丙烯酰胺聚合

锰(Ⅲ)离子可以引发烯类单体自由基聚合。羧酸,α-羟基羧酸对丙烯酰胺聚合有促进作用,其活性顺序为羟基多元羧酸(柠檬酸)>羟基羧酸(乳酸)>羧酸(正丁酸)。测定了在较高酸性([H~+]=3.0M)的硫酸水溶液中,单独Mn~(3+),Nn~(3+)-乙醇酸,Mn~(3+)-乳酸引发丙烯酰胺聚合的活化能与动力学方程。