共查询到18条相似文献,搜索用时 54 毫秒
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用Photo-DSC(光差热扫描)研究了一种可聚合胺助引发剂乙二醇-3-吗啡啉丙酸酯甲基丙烯酸酯(EGMPM)分别与二苯甲酮(BP)、4-(4-甲苯硫基苯基)苯基甲酮(BMS)、4-氯二苯甲酮(CBP)、4-氯甲基二苯甲酮(CMBP)、4-羟甲基二苯甲酮(HMBP)等二芳酮组成的光引发体系引发以1,6-己二醇二丙烯酸酯(HDDA)为单体的紫外光聚合动力学.考察二芳酮质量分数、聚合温度、光照强度对其光聚合动力学影响,并评价其引发效果;同时计算出了EGMPM/BP引发HDDA聚合体系的活化能.结果表明,二芳酮的质量分数增加时,反应达到最大反应速率的时间减少,单体的转化率也相应增加,单体聚合速率相应增大;相同质量分数(0.1%)的不同二芳酮,BMS体系达到最大反应速率的时间最短,单体转化率也最高;随着温度和光强的增加,单体最终转化率、最大反应速率增大,达到最大反应速率所需的时间减少. 相似文献
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合成了一种可聚合双分子光引发体系——甲基丙烯酸-4-二苯酮甲酯(BPMM)光引发剂和甲基丙烯酸-3,4-亚甲基二氧基苯甲酯(MDBMM)助引发剂.采用含有水平样品支架的实时红外光谱仪(RTIR)监测光聚合动力学,动态力学分析仪(DMA)研究固化膜的机械性能.结果表明,聚合体系的聚合速率(Rp)和最终双键转化率(Pf)随MDBMM浓度的增加而增加,但是,随BPMM的浓度变化出现一最佳值(0.8%);相同的聚合条件下,与传统引发体系相比,BPMM/MDBMM虽然引发活性较差,但是其固化膜的Pf和玻璃化转变温度以及在37℃左右的储能模量与传统引发体系相近,并且MDBMM作为天然可食用植物化学成分衍生物的特点使其有可能适宜于在生物相容性要求较高的领域中应用. 相似文献
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可聚合型光引发剂4-丙烯酰氧基二苯甲酮的光聚合性能研究 总被引:1,自引:0,他引:1
以实时红外光谱(RT-IR)法研究了合成的4-丙烯酰氧基二苯甲酮(4-ABP)的光聚合动力学性质,考察了不同单体、不同引发剂和助引发剂浓度、不同光强对聚合性能的影响.以萃取法对比研究了4-ABP和二苯甲酮(BP)在固化膜中的的残留量.结果表明,4-ABP是一种非常有效的光引发剂.随着引发剂浓度和光强的增大,单体转化率、最大反应速率都增大,诱导期缩短.萃取实验表明4-ABP在固化膜中的残留量远低于BP. 相似文献
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以α-羟烷基苯酮(HAPK)、甲苯-2,4-二异氰酸酯(TDI)、聚乙二醇600(PEG600)和丙烯酸-β-羟乙酯(HEA)为原料,通过3步反应,合成了一种可聚合大分子光引发剂:HAPK-TDI-PEG600-TDI-HEA(HTPTH).用IR对反应过程进行了监测.通过Photo-DSC研究了HTPTH引发三丙二醇双丙烯酸酯(TPG-DA)光聚合动力学,考察了光强、引发剂浓度对TPGDA光聚合动力学的影响.结果表明,随着引发剂浓度和光强的增大,最大反应速率对应的转化率、单体最终转化率、最大反应速率都增大,达到最大反应速率所需的时间减小. 相似文献
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本文合成了一类新的二苯酮羧酸胺盐(BPAA),包括具有不同碳链长度的伯胺盐和叔胺盐二个系列共六种化合物。实验结果表明,BPAA和二苯酮(BP)的光物理性质相似,长碳链BPAA分子具有显著的两亲性质,在非水溶液中可发生分子缔合形成反胶束。由BPAA与叔胺(TEA)组成的体系,引发MMA光聚合反应,聚合速度(R_p)比单用BP快得多,其中BPAA叔胺盐比相应的伯胺盐活性高,长链BPAA比短链BPAA活性高。另外还对比了氧气和氮气条件下的聚合反应速度,氧存在时R_p可增加二倍以上。此外还研究了BPAA/TEA浓度对聚合反应的影响。 相似文献
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A sequential photoinitiation. phenomenon was found in the benzophenone/triethylamine/ MMA radical photopolymerization system, which leads to increase of molecular weight, amine content of polymer formed with progressive irradiation time. The results, obtained demonstrate that the sequential photoinitiation originates from the photoreaction of active amine groups at the polymer chains with excited benzophenones producing a polymer radicals, which induce sequential polymerization. The effects of benzophenone and amine concentrations,oxygen co-ntent and chain requlator were studied. Reaction mechanism was also discussed. 相似文献
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大分子量二苯甲酮光引发剂的合成及动力学研究 总被引:2,自引:0,他引:2
以4-羟基二苯甲酮(HBP)、甲苯-2,4-二异氰酸酯(TDI)、4,4′-二羟基二苯甲酮(DHBP)为原料,通过两步反应,合成了一种大分子量二苯甲酮光引发剂:HBP-TDI-DHBP-TDI-HBP(HTDTH).通过实时红外研究了HTDTH的光聚合动力学.结果表明,HTDTH是一种有效的光引发剂.采用HTDTH/胺光引发体系引发二缩三丙二醇二丙烯酸酯(TPGDA)聚合时,随着胺和引发剂浓度的增大,反应速率(Rp)和单体最终转化率(P)同时增大. 相似文献
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采用配有441.6 nm滤光片的光差示扫描量热仪研究了3,3'-羰基双(7-二乙胺香豆素)(KCD)/N-甲基二乙醇胺(MDEA)/2-(4-甲氧苯基)-4,6-双(三氯甲基)-1,3,5-三嗪(TA)三元引发剂引发丙烯酸酯/液晶复合体系光聚合动力学行为. 结果表明, 在KCD/MDEA复合引发剂中添加TA, 显著提高了丙烯酸酯/液晶复合体系的最大光聚合速率[Rp(max)]和单体转化率, 当TA质量分数为0.5%时, 体系的Rp(max)和单体转化率分别提高了100%和69%. 同时, 随着光照强度的增加, 该体系的Rp(max)和单体转化率呈增大的趋势, 当光强从1.5 mW/cm+2提高到35.2 mW/cm+2时, 其Rp(max)和最终单体转化率分别提高了2.5和2.8倍. 相似文献
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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(εmax)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(DCf)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DCf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DCf均为97%. 相似文献
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Azides were reduced to the corresponding amines by two new metal/Lewis acid systems in aqueous EtOH with yields ranging from 80% to 95%. The new reduction systems were Fe/AlCl3·6H2O or Fe/BiCl3 system in H2O/ethanol (2 : 1, Ⅴ :Ⅴ) at room temperature. Fifteen azides with different functional groups were well reduced to the corresponding amines in excellent yields. 相似文献
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Microcalorimetric Study on the Oscillating System of Two-phase Reaction of Aqueous Acid with Primary Amine in Chloroform 总被引:2,自引:0,他引:2
It has been found that the two-phase reactions of aqueous HCl,HOAc or H3PO4 with primary amine N1923 in chloroform are osiclating reactions.Their power-time curves were measured by the titration microcalorimetric method,and the induction period(tin).The first oscillating period(tp.1) and the second oscillating period (tp.2) were determined.The apparent activating parameters and the orders of the oscillating systems were calculated and the following relationships were established:for the oscillating system of hydrochloric acid. 相似文献
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The structure and properties of a chiral nematic phase, which reflects one hand of circularly polarized light in a narrow region of wavelength, of fully acetylated (ethyl) cellulose [(acetyl) (ethyl) cellulose, AEC] in acrylic acid (AA) were studied in comparison with (ethyl) cellulose (EC). AEC mesophase formed right-handed chiral nematic structure while EC formed left-handed one. AEC mesophase showed higher birefringence and reflection intensity. The relationship between the reflection wavelength and the polymer concentration was negatively correlated for both AEC and EC mesophases. The relationship between the reflection wavelength and the molecular weight was also negative for AEC mesophase whereas positive for EC mesophase. AEC mesophase was solidified by photopolymerization of AA moiety. It was revealed that the optical properties of AEC mesophase could be preserved by photopolymerization, since the resulting solid material reflects selectively one hand of circularly polarized light. 相似文献
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José. A. Tenorio López Juan. J. Benvenuta Tapia María del Carmen Cuevas Díaz 《大分子反应工程》2009,3(8):473-485
The copolymerization reaction of butadiene and styrene copolymers prepared by anionic living polymerization using an initiator composed of alkyl aluminum, n‐butyl lithium, and barium alkoxide is studied using a kinetic model that considers the reactivity of active sites to be different; this assumption is justified by the varying geometric configurations. With the first‐order Markov model, the expressions for the fraction of active sites and dyad distribution are obtained. The rate constants are determined by fitting to the conversion and Bernoulli dyad data using the nonlinear least squares method. The conversion and dyad sequence distribution are correctly predicted, and the experimental results indicate that the microstructure and sequence distribution do not change with the conversion and temperature.