N-取代N′-苯基哌嗪类化合物与硫杂蒽酮体系光诱导电子转移引发聚合体系的研究

 本工作对N-苯基-N'-乙基呱嗪作为酮/胺光引发体系中组分之一的作用机制进行了研究。发现该特殊的胺类化合物虽包括二甲基苯胺和三乙胺两个部分,但它和酮类相组合形成的光引发体系只有较低的尤引发速率。对上述现象进行了讨论,并通过加入酸类化合物使其中一个胺发生季胺盐化,用以改进光引发效率来进一步证实文中所讨论的机制。     

含硫杂蒽酮类光引发剂的聚合体系的光固化研究

首次应用N121型紫外光固化测试仪研究以硫杂蒽酮为光引发剂的光聚合体系的光固化性能。为测定以硫杂蒽酮为光引发剂的光聚合体系的光聚合速度提供了新的方法,同时讨论了光源的发射波长与光引发剂的吸收波长之间的关系。     

硫杂蒽酮光敏分解重氮盐及其用作光引发体系的研究

本工作对几种新型硫杂蒽酮化合物敏化光解重氮盐问题进行了研究。工作表明:敏化反应是通过电子转移过程实现的,重氮盐所带取代基以及溶剂对重氮盐的光解有较大影响。十分有趣的是该体系对甲基丙烯酸甲酯进行光敏自由基引发聚合的速率和其光解反应速率有很大的不同,本文对此现象进行了讨论。     

含胺基功能性单体的聚合研究——Ⅻ.N-丙烯酰-N′-苯基哌嗪类的合成、光聚合及其作为氧化还原引发体系组分的研究

我们曾报道了含芳香叔胺基功能性单体的合成及其聚合的研究,这些单体都是既参与引发反应又参与聚合的“引发剂单体”。本文报道了一种含有芳香叔胺基的新单体——N-丙烯酰-N′-苯基哌嗪(APP)和N-甲基丙烯酰-N′-苯基哌嗪(MPP)的合成及其光聚合。由于APP或MPP含有芳香叔胺基,它们和过氧化苯甲酰(BPO)配合,     

光引发剂多羟基胺连硫杂蒽酮的甲基取代效应

用¹³CNMR,UV-Vis及荧光光谱等研究甲基取代对2-[2-羟基-3-(双(2-羟乙基)氨基)]丙氧基硫杂蒽酮光引发剂分子构象及光化学性能的影响.发现当其1,3-位均有甲基取代时,2-位烷氧基受邻位两个甲基的空间排斥作用,导致其光谱性质和光化学性能异常.     

新型水溶性硫杂蒽酮类光引发剂的光引发性能研究

利用红外光谱技术对六种新型水溶性硫杂蒽酮类光引发剂在紫外光聚合反应中的引发性能进行了测试,用相对峰面积法计算了聚合反应的转化率,并据此对引发剂结构与光化学性能之间的关系做了一定的探讨。结果表明该类光引发剂具有很高的光化学活性,而引发剂的结构直接影响引发性能。研究发现硫杂蒽酮母体上甲基的引入使引发剂的引发效率增大,而引发剂侧链上羟基的引入,则由于降低了质量转移的有效性并有可能使引发剂分子缔合,致命引     

蒽醌、甲基紫精、N,N-二乙基苯胺与金丝桃蒽酮素光致电子转移的研究

金丝桃蒽酮素(HYP)是有多个羟基的醌类衍生物。在极性溶剂乙腈中,电子给体N,N-二乙基苯胺和电子受体甲基紫精、蒽醌均能有效猝灭其荧光。说明它既具有酚羟基的给电子性能,又有醌类化合物的受电子性能。HYP与平面构型的蒽醌可能形成基态复合物,以不同的方式与其发生光致相互作用。     

含胺基功能性单体的聚合研究——ⅫⅠ.丙烯腈在N-丙烯酰-N′-苯基哌嗪及其聚合物作为增感剂下的光聚合

关于含有芳香叔胺基的烯类单体,我们曾报道过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-二甲氨基苄脂(DMABMA),8-丙烯     

N-甲基丙烯酰-N′-嘧啶基哌嗪及其聚合物敏化的丙烯腈光聚合

我们曾报道过同一分子中含有给电子生色基团和电子受体基团的一类功能性单体,如甲基丙烯酸-4-N,N-二甲氨基苄酯(DMABMA),N-(4-N′,N′-二甲氨基苯基代丙烯酰胺,N-(4-N′、N′)-二甲氨基苯基代甲基丙烯酰胺(DMAPMA),8-丙烯酰氧喹啉(AQ),N-丙烯酰-N′-苯基哌嗪(APP)的合成、聚合以及单独或与过氧化二酰构成氧化还原体系以引发烯类单体的聚合研究。N-甲基丙烯酰-N′-嘧啶基哌嗪(MPMP)     

硫杂蒽酮类光引发剂的紫外光谱特性及量子化学研究

本文研究了十四种烷基、烷氧基取代的硫杂蒽酮类光引发剂的紫外光谱特性，利用量子化学的分子轨道理论圆满地解释了硫杂蒽酮类化合物的紫外吸收波长与其结构的关系。利用具有分子结构逻辑识别功能和分子结构编辑功能的ＣＡＭＴＣ软件，及ＰＰＰ计算程序对十四种硫杂蒽酮类化合物的吸收波长进行了计算，计算的结果和实测值能够很好的吻合。计算得到的线性回归方程对于预测硫杂蒽酮类化合物的最大吸收波长是十分有用的。     

PHOTOINDUCED CHARGE TRANSFER POLYMERIZATION OF STYRENE INITIATED BY ELECTRON ACCEPTOR

Photoinduced charge transfer polymerization of styrene (St) with electron acceptor asinitiator was investigated. In case of fumaronitrile (FN) or maleic anhydride (MA) asinitiator the polymerization takes place regularly, whereas the tetrachloro-1, 4-benzenequinone (TCQ), 2, 3-dichloro-5, 6-dicyano-1, 4-benzenequinone (DDQ). ortetracyano ethylene (TCNE) as initiator the polymerization proceeds reluctantly only afterthe photoaddition reaction. A mechanism was proposed that free radicals would be formedfollowing the charge and proton transfer in the exciplex formed between St and electronacceptors.     

2-芳基苯并噁唑的荧光猝灭和光诱导电子转移研究

本工作对两种不同的2-芳基苯并 唑化合物溶液荧光被四氯化碳所猝灭的机理进行了详细研究,通过多种途径研究表明该猝灭过程具有光诱导电子转移性质,工作还利用此电子转移所形成的活泼自由基来引发烯类单体的聚合,得到了有一定聚合度的聚甲基丙烯酸甲酯。     

N－甲基丙烯酰－N＇－嘧啶哌嗪与过硫酸钾引发体系引发的丙烯酰胺聚合

Ｎ－甲基丙烯酰－Ｎ＇－嘧啶哌嗪与过硫酸钾引发体系引发的丙烯酰胺聚合高青雨，张福莲，杨更须，张举贤（河南大学化学化工系，开封，４７５００１）李福绵（北京大学化学系，北京，１０００８７１）关键词Ｎ－甲基丙烯酰－Ｎ＇－嘧啶哌嗪，可聚合芳香叔胺，氧化还原引发...     

STUDY ON THE POLYMERIZATION KINETICS AND STABILITY OF P(UA)/MMA MICROEMULSION*

 Urethane acrylate anionomer (APUA) as a kind of new type polymerizable emulsifier was synthesized using 2,4-toluene diisocyanate (TDI), polypropylene glycol (PPG), 2-hydroxyethyl methacrylate (HEMA) and dimethylolpropionic acid (DMPA). The critical micelle concentration (CMC) of APUA was measured by the methods of conductance and surface tension. The comparative studies between polymerizable emulsifier AUPA and conventional emulsifier sodium dodecyl sulfate (SDS) were carried out in the emulsion polymerization of methyl methacrylate (MMA). Polymerization kinetics,stability, size and morphology of the latex particles were investigated. It was found that in APUA both water soluble initiator potassium persulfate (KPS) and oil soluble initiator 2,2'-azobisisobutyronitrile (AIBN) can start the reaction of MMA, and the polymerization rate and yield were very high. On using AIBN as an initiator, the conversion-time behavior of MMA with APUA as emulsifier was different to that of SDS as emulsifier, signifying a different nucleation mechanism of the polymer latex particle. The average size of the two kinds of particles is about 50 nm. The particle size decreases with increasing emulsifier concentration. On using KPS as the initiator, APUA as emulsifier, cross-linking hydrogel of PMMA would be formed, but SDS was used as emulsifier and the hydrogel of PMMA was not present.     

氧化-还原低温引发甲基丙烯酸甲酯/丙烯酸丁酯超浓乳液聚合研究

以乳化剂十二烷基硫酸钠 (SDS)和共乳化剂十六烷醇 (HD)作为复合乳化体系 ,过氧化二苯甲酰(BPO)和N ,N 二甲基苯胺 (DMA)作为氧化还原引发体系 ,甲基丙烯酸甲酯 丙烯酸丁酯 (MMA BA)作为混合单体 ,制备了分散相占 83 %以上的稳定的超浓乳液 ,然后在低温下引发聚合 .探讨了引发剂浓度、氧化剂与还原剂的摩尔比、乳化剂的浓度、液膜增强剂的种类、聚合温度等因素对聚合稳定性和聚合速率的影响 ,测定并计算得到了聚合速率的公式 ;用激光散射粒度分布仪测定了聚合物乳胶粒子的大小及粒径分布 ,用透射电子显微镜观察了聚合物乳胶粒的形态 ,讨论了乳化剂浓度、聚合温度等对乳胶粒形态、大小的影响     

TERMINATION AND TRANSFER OF THE CHAIN RADICALS IN THE POLYMERIZATION OF ACRYLONITRILE INITIATED BY VANADIUM(V)-THIOUREA REDOX SYSTEM

The dependence of the molecular weights on the concentration of reactants in the polymerization of acrylonitrile initiated by vanadium (V)-thiourea redox system has been investigated. It was found that the molecular weights of the polymer change nonlinearly with increasing concentrations of nitric acid and thiourea. Probably, the composition of the complexes exert a great influence on the chain initiation and termination. The reaction of "complextermination" gives rise to the decrease of the molecular weights markedly while the concentrations of thiourea and vanadium (V)in the range from one to three molar ratios.     

STUDIES ON THE POLYMERIZATION OF ACRYLONITRILE INITIATED BY METAVANADATE-CONTAININ G ANION EXCHANGER-THIOUREA REDOX SYSTEM

The polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by metavanadate-containing anion exchange resin (PV)-thiourea (TU) redox system at 20—40℃. has been investigated. The overall rate of polymerization (R_p) is given byR_p=1.92×10~4e~(-6.860/RT) [AN]~(1.2) [PV]~(0.44) [TU]~(1.0)[HNO_3]~(1.0)The kinetic parameters differed from those of V~(5+)-TU system indicated that the generation of the primary radicals is mainly a difffusion-controlled reaction. The effect of macromolecular field arisen from the polymer matrix exerts a great influence on the polymerization process.     

STUDY OF THE EFFECT OF TWO BPO/AMINE INITIATION SYSTEMS ON THE FREE-RADICAL POLYMERIZATION OF MMA USED IN DENTAL RESINS AND BONE CEMENTS

ABSTRACT

The kinetics of the free radical bulk polymerization of methyl methacrylate (MMA) was studied by DSC, using the benzoyl peroxide (BPO)/amine initiation system. N,N dimethyl-4-aminophenethyl alcohol (DMPOH), which is a newly synthesized and used amine in the preparation of acrylic dental resins and bone cements was examined, and the results compared to the most commonly used in these applications amine, the N,N dimethyl-p-toluidine (DMT). For both amines, the effect of the molar ratio of BPO/amine and of the reaction temperature, on the polymerization kinetics was investigated. The prepared polymers were characterized by determination of the average molecular weights (M¯ _n and M¯ _w ) and molecular weights distribution (M¯ _w /M¯ _n ) using Gel Permeation Chromatography. DMPOH was found to lead in slightly higher polymerization rates, lower gel times and lower molecular weights than DMT. The values of these parameters for both amines were influenced by the molar ratio of BPO to amine, when the product of the concentrations of these was kept constant. The highest polymerization rate occurred in the lowest gel time, resulting in polymers with the lowest molecular weight, and was observed when a molar ratio of about 1.5 BPO/amine was used. However, the final monomer conversion was found to be independent of the molar ratio and amine used. The activation energy of polymerization was found to be 51.8 kJ/mol K for BPO/DMPOH and 47.1 kJ/mol K for BPO/DMT.