过硫酸盐和N,N,N′,N′-四甲基乙二胺体系引发烯类聚合机理的研究

<正> 过硫酸盐和N,N,N′,N′-四甲基乙二胺(TMEDA)体系用作烯类聚合的引发剂已有报道。本文报道该引发体系的反应机理。1.实验方法     

UV光引发的丙烯酰胺反相乳液聚合

报道了不透明丙烯酰胺反相乳液体系的UV光引发聚合新方法 .使用普通中压汞灯并辅以适当搅拌 ,UV光引发丙烯酰胺 水 煤油 Span80 +OP 10反相乳液聚合可在 2 0min左右完成 ,所得聚合物分子量达千万 ;聚合过程中不存在恒速期 ,扫描电镜未观察到聚合前后乳胶粒径有数量级的变化 ,表明聚合反应以单体液滴成核为主 .此外 ,考察了光引发剂类型及浓度、单体浓度、乳化剂用量、反应温度等对聚合反应的影响 ,结果表明不同光引发剂的引发活性为Irgacure 2 95 9>(ITX +EDAB) >BDK ,引发剂浓度增加 ,反应速度先增加而后降低 ,存在一最大值 ;单体浓度增加 ,反应速度加快 ,聚合物分子量提高 ;乳化剂用量增加 ,反应速度加快而分子量变化不明显 ;聚合表观活化能为 13 34kJ mol.     

二烯丙基二甲基氯化铵—丙烯酰胺反相乳液聚合的动力学特征研究

采用油酸失水山梨醇酯（ＳＰＡＮ）－壬基酚聚氧化乙烯醚（ＯＰ）复合乳化剂与Ｋ２Ｓ２Ｏ８－Ｎａ２ＳＯ３氧化还原引发剂，进行二烯丙基二甲基氯化铵－丙烯酰胺反相乳液共聚合，测得单体的竞聚率为γＤＡＤＭＡＣ＝０．１４±０．１１，γＡＭ＝５．０５±０．６６；在单体浓度为２５─４５％，引发剂浓度０．０６—０．１％，乳化剂浓度为５—９％，聚合温度３０３Ｋ条件下，得到了共聚反应动力学方程：Ｒｐ＝ｋ［Ｍ］０．６８［Ｉ］１．３１［Ｅ］０．７３，文中对上述结果做了解释．     

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     

Evaluation of the results from an inter-laboratory comparison study of the determination of acrylamide in crispbread and butter cookies

Analytical methods currently employed for determination of acrylamide (AA) in two carbohydrate-rich food samples, crispbread and butter cookies, obtained commercially, and native and spiked bread extract samples have been evaluated in a collaborative study. The objective of the study was to obtain information about the performance of the participating laboratories when analysing samples with an AA content close to the limit of quantification (LOQ) and at a higher AA level, and to investigate the influence of sample-preparation procedures on the results of the analysis. For this purpose an aqueous native extract of white bread crumb, a fortified extract, and AA standard solutions, the analyte content of which were not disclosed to the participants, were included in the study. A total of 62 laboratories, applying seven different measurement techniques and a broad spectrum of analyte extraction and sample-preparation procedures reported their analytical results. Because the measurement data were not normally distributed, they were evaluated by application of robust statistics. The relative performance of the laboratories was highlighted by calculation of z-scores. For the crispbread sample, especially, a large percentage of the calculated z-scores were outside the satisfactory range. From their distribution it became obvious that one of the analytical techniques might be biased, if not applied correctly. Consequently, the impact of the applied methods was examined in more detail. Information about the analytical technique, extraction solvent, quantity weighed, calibration method, clean-up, and the experience of the participating laboratories were extracted from the analytical protocols and transcribed into a data matrix which was evaluated by multifactor analysis of variance. The applied measurement technique seems to have a statistically significant influence on the analytical results.     

丙烯酰胺与玉米淀粉接枝共聚物的合成及其吸水性能研究

本文以硝酸铵为引发剂N，N-亚甲基双丙烯酰胺为交联剂，将丙烯酸胺与玉米淀粉接枝共聚合成了吸水剂。实验表明，当脱水葡萄糖单元与丙烯酰胺摩尔比为1：4，交联度为0．2％时，其吸水率最高可达18g／g，其对1％食盐水的吸收率为其吸水率的90％左右。然后，将以上吸水树脂以10％NaOH于60℃水解3h，制备了另一种吸水剂，吸水率约提高了16倍，但其吸1%食盐水的能力只有其吸水能力的10％左右。     

亚甲蓝-三乙酰基丙酮合锰(Ⅲ)配合物体系光敏化引发丙酰胺聚合反应研究

<正> 染料和三乙酰基丙酮合锰(Ⅲ)配合物(Mn(AA)_3)体系,作为聚合过程的引发物质而用于非银盐成像工艺中.Chaberek等在水溶液中研究了硫堇-二乙酰基丙酮合铜(Ⅱ)和铝(Ⅲ)体系,认为首先是金属配合物水解生成的配体发生酮-醇互交,而配体的烯醇式阴离子是引发聚合的活性物质.我们曾报道了硫堇-Mn(AA)_3体系在醇溶液中光敏化引发丙烯酰胺聚合的研究,发现在醇溶液中,敏化引发聚合的活性物质,显然不同于水溶液中的情况.本文研究了亚甲蓝-Mn(AA)_3体系在醇溶液中敏化引发丙烯酰胺聚合,表明它是比硫堇-Mn(AA)_3更为有效的光敏化引发体系.     

强阴离子型丙烯酰胺共聚物P(AM-co-NaAMPS)的结构与性能

在水介质中实施了丙烯酰胺 (AM)与 2 丙烯酰胺基 2 甲基丙磺酸钠 (NaAMPS)的溶液共聚合 ,制备了组成系列变化的强阴离子型共聚物P(AM co NaAMPS) ;通过红外光谱法与元素分析法对共聚物的组成进行了表征 ;稀释外推粘度法测定了共聚物的特性粘数及Huggins常数 ;测定了共聚物纯水溶液及盐水溶液的表观粘度及高温下共聚物盐水溶液的粘度保持率 ;重点考察了共聚物的结构与组成对其各种性能的影响规律 .实验结果表明 ,在聚丙烯酰胺 (PAM)分子主链上引入NaAMPS链节后 ,磺酸根的强阴离子性与庞大侧基的位阻效应 ,赋于共聚物P(AM co NaAMPS)以优良的溶解、增稠、耐温与抗盐性能 ,且这些性能随共聚物的结构与组成的改变发生规律性的变化 .     

STUDIES OF THE INITIATION MECHANISM OF VINYL POLYMERIZATION WITH THE SYSTEM PERSULFATE/N-ALKYL SUBSTITUTED ETHYLENEDIAMINE DERIVATIVES

Effects of N-alkyi substituted ethylenediamine derivatives on vinyl polymerization using persulfate as initiator were studied. The apparent kinetic equations and overall activation energies of acrylamide polymerization were determined using the above mentioned system as initiator. The promoting activities of different diamine derivatives on vinyl polymerization are in the order of tertiary diamine>secondary diamine>primary diamine. Diamines having methyl groups as the substituent on their nitrogen atom possess higher promoting activity than that of having larger alkyl groups. The initial free radicals produced through the redox reaction of persuifate and diamines were studied by spin strapping technique and ESR spectroscopy. The results obtained confirm the fact that the initial free radicals of the diamine species can initiate vinyl polymerization and become the amino end group of the resulting polymers.     

A rapid and efficient synthesis of a new pyrrolobenzodiazocines via an intramolecular Friedel-Crafts reaction

New pyrrolobenzodiazocines 3 have been prepared by an intramolecular Friedel-Crafts process from pyrrolobenzoacrylamides 2. The cyclisation process involving a 1,4-intramolecular addition of a pyrrole onto acrylamide led to the formation of an eight-membered ring.