基于UV-LED茂铁盐体系对脂环族环氧单体的阳离子光聚合动力学研究

本文利用实时傅里叶变换红外光谱(real-time FTIR)研究了脂环族环氧单体(CE)在405 nm UV-LED光源下的光聚合动力学。以η6-异丙苯茂铁六氟磷酸盐(I-261)作为阳离子光引发剂,2-异丙基硫杂蒽酮(ITX)、姜黄素(CC)和1-[4-(苯基偶氮)苯基偶氮]-2-萘酚(SudanⅢ)作为光敏剂,探究该茂铁盐体系对CE单体环氧基团转化率及聚合速率的影响。结果表明,尽管所有光敏剂都能有效地引发光聚合,但是ITX和CC体系在405 nm光源的辐照下表现出更高的聚合效率。在8.0%(质量分数)I-261和0.5%ITX条件下,CE的单体转化率从74.4%提高至89%以上,最大聚合速率提高了1.9倍。在8.0%(质量分数)I-261和1.0%CC条件下,CE的单体转化率从74.4%提高至88%以上,最大聚合速率提高了1.7倍。     

生物医用材料表面光引发活性接枝聚合研究新进展

表面接枝聚合改性已经成为提升生物医用材料性能的最重要方法之一.参比其他活性接枝聚合方法,光引发活性接枝聚合因其独特的优势已被越来越广泛地应用于生物医用材料表面改性.根据光引发剂的类型,目前应用最多的光引发活性接枝聚合的引发体系主要有3种:光引发-转移-终止剂介导的聚合引发体系、二苯甲酮及其衍生物引发体系、硫杂蒽酮类引发体系.本文首先简要介绍了上述3种光引发活性接枝聚合体系的发展历程、接枝机理以及特点.同时结合本课题组相关研究工作,重点论述了光引发接枝聚合技术在3个不同生物医用领域的主要应用:(1)抗菌表面,利用光活性接枝的特点构建层状功能高分子刷,实现表面抗菌功能的阶段性需求.(2)免疫检测表面,使用光活性接枝方法构建层状功能高分子刷,解决检测灵敏度低以及蛋白干扰问题.(3)生物活性分子表面固定,利用可见光活性接枝聚合体系,实现酶在表面的固定化使用以及细胞表面修饰以提高细胞稳定性.最后展望了生物医用材料表面光引发活性接枝聚合研究的发展趋势.     

用于全息存储的新型感绿光敏剂的制备及其性能研究

针对目前广泛使用的532nm半导体激光器,本文制备了一种新型感绿光敏剂PRZA。以文献报道的2种感绿光敏剂(BDEA和BTCP)作为参比,研究了3种光敏剂的分子结构对其紫外-可见吸收光谱、在自由基聚合体系中的光敏引发聚合效率、在双固化型全息记录样片中的灵敏度与成像性能的影响。研究结果表明,噻吩环取代苯环使光敏剂的吸收光谱明显红移,与BDEA和BTCP相比,PRZA与532nm光源的匹配性能最好,在532nm处摩尔消光系数达到6.35×10~4 L·mol~(-1)·cm~(-1);对同一个预聚物体系,当光敏剂质量分数为0.01%时,3种光敏剂均表现出最佳的敏化引发聚合效率,其中含BTCP和PRZA体系的聚合速率与双键转化率都明显优于含BDEA的体系;以PRZA为光敏剂的全息记录样片衍射效率高达85%,且具有最高的灵敏度(297×10~(-3) cm·mJ~(-1)),同时具有良好的图像存储和再现性能。以上结果表明,PRZA样片在全息记录领域具有很好的应用前景。     

含氧光敏引发体系的研究——Ⅵ.二苯酮/三乙胺体系引发光聚合过程中的再次引发效应

过去,作者曾发表了多种光敏引发体系引发烯类单体光聚合的工作,在研究2,2-二甲氧基苯乙酮在氧存在下引发甲基丙烯酸甲酯光聚合时,结合在聚合物链端的引发剂碎片具有光化学活性,在光聚合反应中产生高分子自由基,发生再次聚合,出现高分子量     

AM/AMPS共聚物光化学改性

水溶性高分子AM/AMPS系由丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)组成.本文应用光化学方法对AM/AMPS共聚物进行改性,得到活性可聚合产物.应用这种方法,在高分子链上生成的过氧化物含量随UV光照时间有明显变化,照射5-10 min过氧化物含量最高.值得指出,较高的过氧化物生成量仅在采用二苯酮作为光敏剂和保持低温的条件下才能得到.这种活性改性AM/AMPS共聚物,可用光聚合或热聚合方法引发不同烯类单体共聚合,得到不同用途的接枝/交联共聚物产品.     

可见光敏引发聚合甲基丙烯酸甲酯的动力学研究

本论文用膨胀计法进行了甲基丙烯酸甲酯在氯仿溶液中可见光光敏引发聚合动力学的研究。此光敏引发体系由光敏剂1,3,3-三甲基-2-[5-(1,3,3-三甲基-2-吲哚叉)-1,3-戊二烯]吲哚碘盐(简称NK-529),引发剂邻氯代六芳基双咪唑(简称o-Cl-HABI),氢给体3-巯基-4-甲基-4氢-1,2,4-三氮唑(简称MTA)组成。研究结果表明,此光敏聚合体系的光聚合速率与各组分的动力学方程如下:R_p=K(NK-529)^0.51(HABI)^0.41(MTA)^0.36(MMA)^1.0.     

黄酮/叔胺引发三丙二醇二丙烯酸酯的光聚合反应

采用实时红外光谱(RTIR)研究了黄酮(FL)为紫外光光敏剂, 不同氢给体(如叔胺)为助引发剂时三丙二醇二丙烯酸酯(TPGDA)的光聚合反应. 结果表明, FL分子中的大π共轭体系使其UV吸收峰的摩尔消光系数(ε_max)远远高于商业化光敏剂二苯甲酮(BP). 当FL与不同助引发剂配合使用时, TPGDA光聚合动力学有较大差异, 其中叔胺体系助引发剂能够与激发态FL发生有效的电子/质子转移过程, 产生胺烷基自由基活性种引发TPGDA的光聚合反应, 所得固化膜的最终双键转化率(DC_f)为93%~97%, 接近完全固化; 而芝麻素(SM)及胡椒环(BDO)作为助引发剂时TPGDA的聚合速率则很低, 固化膜的DC_f仅为32%~38%. 当光敏剂质量分数为1.0%, 4-N,N'-二甲氨基苯甲酸乙酯(EDAB)质量分数为1.0%时, FL/EDAB引发TPGDA的聚合动力学与商业化BP/EDAB的相同, 所得固化膜的DC_f均为97%.     

双咪唑光敏体系紫外光引发聚合甲基丙烯酸甲酯动力学和应用研究

用光敏剂4,4′ 二(N,N′ 二甲基-氨基)苯甲酮(简称米氏酮,MK)、引发剂邻氯代六芳基双咪唑(o-Cl-HABI)和氢给体助引发剂十二烷基硫醇(SH)组成光敏引发体系。研究了在高压汞灯照射下,甲基丙烯酸甲酯(MMA)光聚合速率和该敏化体系每一个组分,包括MK、o-Cl-HABI、SH和MMA的关系,还研究了该体系在PS版材上的应用,并获得了很好的效果。     

N-甲基-N-(2-甲基丙烯酰氧乙基)苯胺敏化的丙烯腈光聚合

含有芳香叔胺基的烯类单体如N,N-二甲氨基苯乙烯,N-4-N',N'-二甲氨基苯基代丙烯酰胺(DMAPAA),N-4-N',N'-二甲氨基苯基代甲基丙烯酰胺(DMAPMA),甲基丙烯酸-4-N,N-二甲氨基苄酯(DMABMA),8-丙烯酰氧喹啉(AQ)等不仅与过氧化物构成氧化还原引发体系以引发其它烯类单体的光聚合还可以作为光敏剂引发烯类单体的光聚合。由于这类功能性单体在同一分子中既含有缺电子双键基团又含有供电子生     

香豆素染料与羟基苯基碘鎓盐光敏引发体系的研究

本文通过吸收光谱、荧光猝灭、光聚合方法对羟基苯基碘盐(HTIB)的光敏引发体系进行了研究,发现具有给电子性的光敏剂香豆素1可以将引发剂羟基苯基碘盐的光响应移到长波区,而引发聚合效率与溶剂的性质有很大的关系.在一般极性溶剂中如DMSO中能有效地引发甲基丙烯酸甲酯(MMA)光聚合,而在电子受体性质的极性溶剂如乙腈中,光聚合反应受阻,这归结于香豆素1与羟基苯基碘盐形成络合物,使得光反应后生成不具活性的产物.该结果对研究其它单苯基碘盐的光敏体系提供了有价值的信息.     

含氧光敏引发体系的研究——Ⅳ.硫杂蒽酮/叔胺/氧体系的研究

本文研究了硫杂蒽酮(TX)/三乙胺(TEA)/氧体系引发甲基丙烯酸甲酯(MMA)光聚合的动力学及影响聚合速度的各种因素。结果表明,聚合速度和[TX]~0.1[TEA]~0.3及[MMA]成正此,同时,由于TX的nπ~*和ππ~*激发态能级接近,溶剂的性质对聚合速度有显著的影响。体系中的氧对聚合反应有明显的加速作用,特别在硬脂酸存在时,使量子收率增加2.3倍。     

Effect of Alkylaluminum Activators on Ethylene Trimerization Based on 2,5‐DMP/Cr(III)/TCE Catalyst System

Ethylene trimerization toward 1‐hexene catalytic system with 2,5‐dimethylpyrrole (2,5‐DMP)/Cr(III)/alkylaluminum/tetrachloroethane (TCE) was investigated. The effects of various cocatalysts on catalytic activity and product selectivity were discussed. The results showed that triethylaluminum (TEA), trimethylaluminum (TMA), tri‐n‐hexylaluminum (TNHA) and tri‐isobutylaluminum (TIBA) were all effective cocatalysts for ethylene trimerization toward 1‐hexene. 2,5‐DMP/Cr(III)/TEA/TCE catalytic system afforded the best results for ethylene trimerization, while reducing the level of by‐product formation. Some specific interaction modes of alkylaluminum with active Cr species in the catalytic cycle were proposed to explain the effect of cocatalyst on catalytic activity and 1‐hexene selectivity.     

PHOTOINITIATED POLYMERIZATION BY ARYLIODONIUM SALT/BENZOPHENONE/TERTIARY AMINE BINARY PHOTOSENSITIZATION SYSTEM

A novel binary photosensitization system composed of benzophenone (BP)/diphenyliodonium chloride (DPIOC) Ariethylamine (TEA), exhibiting a good photoresponse at near UV and visible light regions, was used as the initiator for photopolymerization of MMA. The radical photogeneration in the binary system consists mainly of two parallel reactions, i. e. , BP/TEA photohydrogen-abstraction and DPIOC/TEA complex photodecomposition, but the latter is more active than the former. The results of comparative study indicate that the rate of polymerization induced by the binary system (BDT)is remarkably higher than those by the corresponding single systems The polymerization rates are proportional to [BP]~(0.16), [DPIOC]~(0.32) [TEA]~(0.45) and [MMA]. The mechanism is also discussed.     

二乙胺导向合成SAPO-34及与其它模板剂的对比

以二乙胺 (DEA) 为模板剂, 合成了 SAPO-34 分子筛, 详细考察了磷酸用量、水用量以及硅源和铝源等因素的影响. 结果表明, 在 0.7 ≤ n(P2O5)/n(Al2O3) ≤ 1.2 及 25 ≤ n(H2O)/n(Al2O3) ≤ 100 范围内, 可以得到纯相 SAPO-34 分子筛, 铝源对所得样品的组成影响较大. 同时, 采用三乙胺 (TEA)、吗啉 (MOR) 以及二乙胺-三乙胺 (DEA-TEA) 混合模板剂合成了 SAPO-34, 通过 X 射线衍射、X 射线荧光分析、扫描电镜、热重和 29Si 固体核磁共振等手段对所得样品进行了表征. 结果显示, 不同模板剂促使硅进入 SAPO-34 骨架的能力顺序为 SAPO-34 (DEA) SAPO-34 (MOR) SAPO-34 (TEA); SAPO-34 骨架中所能容纳的最大 Si(4Al) 含量顺序为 SAPO-34 (DEA) ≈ SAPO-34 (MOR) SAPO-34 (TEA).     

Effect of catalyst aging on catalyst activity and stereospecificity for MgCl2/ethyl benzoate or dioctyl phthalate/TiCl4-triethylaluminium for propene polymerization

The aging of the MgCl₂/dioctyl phthalate (DOP) or ethyl benzoate (EB)/TiCl₄ catalyst was studied. Because of the strong complexation of DOP with the catalyst, only a small fraction of DOP was extracted by cocatalyst triethylaluminium (TEA) during aging, resulting in converting some highly isospecific sites into aspecific ones. No change of the overall number of sites was detected. EB, on the other hand, could be readily removed by TEA, resulting in a large increase in aspecific sites. Clustering of those sites facilitated catalyst deactivation.     

Direct photoreduction and ketone-sensitized reduction of nitrospirobenzopyranindolines by aliphatic amines

The photoreduction of 6-nitrospiro[2H-1-benzopyran-2,2'-indoline] (N1) and two derivatives (N2 and N3) by diethylamine or triethylamine (TEA) in solution was studied by pulsed and steady-state photolysis. The quantum yield of coloration of the ring-closed Sp form, due to photoinduced ring opening, decreases in acetonitrile with increasing the TEA concentration. The main reason is reaction of TEA with the triplet-excited open merocyanine form. Quenching of this triplet state by amines is rather inefficient for N1-N3; the rate constant for triplet quenching by TEA is k(6) = (2-3) × 10(6) M(-1) s(-1). The secondary transient with an absorption maximum at 420 nm is ascribed to the radical anion. This and the corresponding α-aminoethyl radical subsequently undergo slow termination reactions, yielding a relatively stable product with a maximum at 420-450 nm, which is attributed to a ring-opened dihydromerocyanine (MH(-)). The mechanisms of the two subsequent reduction reactions are discussed. Using acetone as sensitizer the same dihydroproduct was obtained with the Sp form as acceptor, indicating a reaction sequence from photogenerated radicals via a ring-opened radical to MH(-)/MH(2). The effect of TEA concentration on the direct and ketone-sensitized reduction mechanisms was analyzed. Photoreduction by amines, due to competing triplet quenching, is strongly decreased on admission of oxygen.     

RADICAL PHOTOPOLYMERIZATION USING ARYLIODONIUM SALT/TERTIARY AMINE COMPLEX SYSTEM AS THE PHOTOINITIATOR

The diphenyliodonium salt (DPIOC)/triethylamine (TEA) is used as photoinitiator for radical photopolymerization. It was found that a ground state CT complex formed between DPIOC as electron acceptor and TEA as electron donor, which results in extending the photosensitivity range of DPIOC/TEA system up to above 500nm compared with DPIOC alone. The kinetic studies on photopolymerization of methyl methacrylate (MMA) were carried out in CH_3CN: H_2O (14: 1, v/v) mixture solution at 30℃by dilatometer. The results obtained show that the polymerization rate (R_p) increases with increasing concentrations of DPIOC and TEA with exponent 0. 65 and 0. 62 respectively. The activation energy E_a and k_p/k_~(1/2) value were determined to be 4.1 Kcal mol~(-1) and 0.045 respectively. The other influence factors and reaction mechanism were also discussed.     

胶束体系中光敏聚合的研究 Ⅶ．微泡水溶液体系中光聚合的研究

研究了在双十六烷基二甲基溴化铵（ＤＣＤＡＢ）形成的微泡溶液中，二苯酮（ＢＰ）／三乙胺（ＴＥＡ）体系的光化学初级反应和引发ＭＭＡ光聚合反应．动力学实验结果表明，ＤＣＤＡＢ微泡对聚合反应有显著的催化作用，使聚合速度提高近４倍左右，其效果和离子型胶束的催化作用结果相近．由ＤＣＤＡＢ微泡中光聚合得到的产物ＰＭＭＡ，具有较高的结构规整性，它的间同和全同结构可达７０％左右．     

Novel Aluminoxanes Prepared from AlEt_3/Al(i-Bu)_3 Mixture as Cocatalyst for Metallocene Catalyzed Ethylene Polymerization

Methylalundnoxane(MAO)isthemostimportantcocatalystformetallocenecatalyzedolefinpolymerization.Intheearlyyearsofthefieldithadbeentheonlycocatalystwhichcanactivatemetallocenecatalyststoveryhighactivity.MAOispreparedbypartialhydrolysisofAl(CHs)s(TMA)undercontrolledconditions1.TMAisanextremelyreactiveanddangerousreagent,andthismakesMAOapreciouschendcalreagent.MAOaccountsforalargepercentageinthecostofthemetallocenecatalystsystem,becauseahighMAO/metalloceneratioisneededforpoIymerization'.I…     

三苯基烷基硼盐作引发剂的染料光敏聚合

三苯基烷基硼盐作引发剂的染料光敏聚合陈汉清，李妙贞，汪秀智，常志英，王尔鉴（中国科学院感光化学研究所北京１００１０１）关键词染料光敏作用，三苯基烷基硼盐，高分子光聚合近年来，光诱导电子转移光解反应已在光敏聚合方面得到重要应用’‘’，作者过去已报道了采...