茚基钠/甲苯体系引发丙烯腈聚合的研究

本文采用茚基钠作为引发剂,对丙烯腈在甲苯中的聚合进行了研究,考察了引发剂用量、单体浓度、反应时间及反应温度对丙烯腈聚合的影响。发现茚基钠/甲苯体系对丙烯腈聚合反应具有一定的引发活性,且随着引发剂用量增加聚合反应转化率增大,聚合产物的分子量下降;延长聚合反应时间,转化率和分子量都增大;温度对聚合反应转化率影响不大,但对聚合产物分子量有明显影响。用粘度法对聚合产物的粘均分子量进行了表征。     

电荷转移聚合—酚噻嗪及其衍生物引发丙烯腈光聚合

电荷转移引发的聚合近年来受到人们的广泛注意,许多电子给体,如芳香族的胺、醚、硫醚以及含氮芳杂环化合物,都可引发丙烯腈、甲基丙烯酸甲酯等负性单体光聚合,研究表明,其聚合都是通过电荷转移机制引发的。     

双光子光聚合技术及其研究进展

本对双光子光聚合技术进行了比较全面系统的综述，主要介绍了双光子光聚合的基本原理，国内外双光子光聚合光敏引发体系和具有大的双光子吸收截面有机分子的研究现状以及双光子光聚合技术的潜在应用领域．     

茚基钠/四氢呋喃体系引发丙烯腈聚合的研究

以茚基钠为引发剂,对丙烯腈在四氢呋喃中的聚合反应进行了研究,考察了引发剂用量、单体与溶剂配比、反应时间及反应温度对丙烯腈聚合的影响,并用粘度法对聚合产物的粘均分子量进行了表征.结果发现茚基钠/四氢呋喃体系对丙烯腈聚合反应具有一定的引发活性,且随着引发剂用量增加聚合反应转化率增大,聚合产物的粘均分子量下降;当单体用量一定时,溶剂的量越多,聚合反应的转化率越低,而聚合产物的粘均分子量却越大;反应时间在1 h之内,延长反应时间,转化率和粘均分子量都增大;反应温度对聚合反应转化率影响不大,但对聚合产物粘均分子量有明显影响.     

光聚合现状与展望

本文叙述了自由基和阳离子聚合光引发剂体系的最新进展,并且提供了不同引发模式下在所有光引发体系中有关引发效率、波长限制和环境安全问题的解决办法。在过去10年里,通过光聚合制备了复杂或纳米结构的大分子,因此本文也介绍了光聚合在生物材料、表面改性和纳米复合材料领域的新兴应用。     

甲基丙烯酸甲酯的光引发聚合研究

本文探讨了光引发剂的种类与浓度、光照强度、光聚合组合物体系粘度及光聚合体系氛围对甲基丙烯酸甲酯(MMA)光引发聚合硬化时间、产率、重均分子量及分子量分布的影响。结果表明,体系初始粘度或引发剂含量的增加均有利于加快光聚合速度以及提高产率,产物具有良好的实用价值。PMMA的重均分子量Mw随着光引发剂浓度的增加而降低,但对紫外(UV)光强不敏感。     

环氧丙烯酸酯／乙烯基醚光聚合反动力学研究

以二缩乙醇二乙烯基醚为活性稀释剂,研究其氧丙烯酯所组成的光滞体 自由基上发剂下引发的光聚合反应动力学其影响因素,ＤＶＥ－３含量越大,ＥＯＡ／ＤＶＥ－３体系的转化率越低。体系粘度的提高有利于提高其反应速率。若在环氧丙烯酸 酯中引入马来酸酯结构,则马来酸酯的含量越大,体系的转化率越高,马来酸酯结构的引进,可以降低体系滞后残余的双键含量。     

水溶性光引发剂二苯甲酮氯化铵引发三丙二醇双丙烯酸酯光聚合动力学的研究

以4-羟基二苯甲酮、环氧氯丙烷和三甲胺盐酸盐为原料,通过2步反应,合成了一种水溶性光引发剂——氯化[2-羟基-3-(4-苯甲酰基苯氧基)-N,N,N-三甲基-1-丙铵](HBPCl)。其结构通过核磁共振氢谱(1H-NMR)和傅里叶红外光谱(FT-IR)得到了证实。研究了水溶性光引发剂HBPCl的紫外吸收和降解特性,并通过实时红外(RT-IR)研究了氢助剂含量、HBPCl浓度和光强对HBPCl引发的TPGDA光聚合动力学的影响。结果表明,HBPCl在285 nm处有最大紫外吸收峰,能够有效地引发单体聚合;另外,随着氢助剂含量、引发剂浓度和光强的增大,光聚合速率和单体最终转化率随之增大,诱导期被缩短。     

二苯甲酮环缩醛单组分光引发剂的合成与光聚合性能的研究

本文合成了一种新型二苯甲酮基复合光引发剂5-(4'-苯甲酰基苯甲氧基)-1,3-二氧苯并环戊烷(BPCH2BDO),利用FIR、1HNMR对其结构进行表征。并采用实时红外光谱研究了BPCH2BDO光引发剂引发丙烯酸酯类单体的光聚合行为。结果表明,该引发剂的最大吸收光谱在258 nm,随着紫外光照的进行,BPCH2BDO的最大吸收峰258 nm逐渐减少。当引发剂的浓度不断增大时,单体的反应速率和该体系的反应程度先增大后减小;随着光照强度增大,单体转化率和最大聚合速率都增大。BPCH2BDO与传统的光引发剂二苯甲酮/4-二甲基氨基苯甲酸乙酯(BP/EDAB)引发效率相当。     

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

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．     

Photopolymerization synthesis of poly(N-isopropylacrylamide) hydrogels

Poly(N-isopropylacrylamide) (NIPAAm) gels were formed by photopolymerization of NIPAAm in the absence of a crosslinker using a water solvent at 25°C. Factors affecting formation were the wavelength region of irradiated light, the type of photoinitiators, and the concentrations of the photoinitiator and monomer. A high-pressure mercury lamp (400 W) was used as a light source. An NIPAAm concentration of 10 wt % and irradiation time of 15 h was used for the photopolymerization. The gel (68% yield) was formed when the quartz glass system was used, but no gelation was observed for the Pyrex glass system that transmits light with π > 290 nm. The gel (100% yield) was easily formed, even in the latter system, when 30 mmol/L of hydrogen peroxide and potassium persulfate were used as the photoinitiator. Water soluble photoinitiators such as ferric chloride and sodium anthraquinone-2,7-disulfonate were not effective for the gel formation. Yield of the gel increased with increasing the potassium persulfate concentration (1–30 mmol/L), but it decreased when a high concentration of hydrogen peroxide (60 mmol/L) was used. The gel yield increased with the NIPAAm concentration (5–20 wt %). The degree of swelling of the resultant poly(NIPAAm) gels, which was measured by immersing the gels in water at various temperatures (0–50°C) for 24 h, steeply decreased at about 30°C with increasing temperature, exhibiting a temperature-responsive character. The gels swelled and shrank in water below and above the temperature, respectively. The extent of the character depended on the concentrations of hydrogen peroxide and monomer. The formation mechanism of the gel in the photopolymerization of NIPAAm using hydrogen peroxide photoinitiator was discussed. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1313–1318, 1997     

2,4-双(三氯甲基)-6-(4-甲氧基-1-苯乙烯基)-s-三嗪光引发剂的合成与聚合动力学研究

本研究以4-甲氧基苯甲醛和2,4-双(三氯甲基)-6-甲-基1,3,5-三嗪为原料合成了一种引发剂2,4-双(三氯甲基)-6-(4-甲氧基-1-苯乙烯基)-s-三嗪(BMT),并利用红外光谱、紫外光谱、核磁共振等手段对其结构进行表征.利用实时红外光谱研究其光聚合动力学性能,结果表明,不同引发剂浓度,不同单体和不同光强对单体双键转化率都有一定的影响.     

Photopolymerization kinetics of dimethacrylate‐based light‐cured dental resins

The influence of certain factors [structure and concentration of tertiary amines as coinitiators, monomer composition, presence of inorganic pigments, and incident light intensity (I₀)] on the polymerization rates (R_p), polymerization quantum yields, and conversions of bisphenol A–bis(glycidyl methacrylate) (Bis‐GMA)/triethylene glycol dimethacrylate based resins was studied. The initial rate of bulk polymerization increased and the final conversion decreased with the content of Bis‐GMA in the mixture. In contrast, it was established that, for all monomer compositions, the R_p grew when increasing the I₀, the R_p being directly proportional to the square root of I₀. Such behavior is in agreement with the well‐known kinetic expression for the ideal radical photoinitiated polymerization in solution of monofunctional monomers, in spite of the complexity of the dimethacrylate mixtures that were studied. Both the structure and the concentration of reducing amine affected the efficiency of the initiator system and therefore the kinetic behavior of polymerization of these formulations under irradiation. The rate of polymerization increased with the increase of coinitiator concentration over the interval of 0–1%, but later it diminished when increasing the amine content, suggesting that the excess coinitiator retards the polymerization process. The study of the photoreduction of camphorquinone in the presence of different amines showed that the efficiency of the coinitiator depends not only on its ability to photoreduce camphorquinone, forming amine‐derived radicals, but also on the reactivity of these radicals toward the initiation of acrylic monomer polymerization. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1016–1023, 2005     

Conducting Electroactive Polymers via Photopolymerization: A Review on Synthesis and Applications

Photopolymerization can be considered as an appropriate method in synthesis of conducting electroactive polymers. This paper presents a survey on the major principles of photopolymerization method, then reviews performed researches on photopolymerization leading to conducting electroactive polymer-based materials, and thereby reveals the significant information relevant to their structures and properties. The main focus of this state-of-the-art review is classification of the photoinduced synthesis of conducting electroactive polymers according to predominant mechanism in detail. Furthermore, practical applications of photopolymerization to fabrication of conducting polymeric structures such as films and nanostructures are surveyed from different publications.     

Photopolymerization of poly(melamine-co-formaldehyde) acrylate for dental restorative resins

This paper describes the investigation of photoinitiated polymerization of poly(melamine-co -formaldehyde) acrylate (PMFA) by camphorquinone (CQ) and amines (AMH) by visible light (λ>400 nm). It was shown that as the concentration of CQ and/or AMH increases, the rate of polymerization reaches a maximum and then decreases. The double bond conversion of PMFA was 20–35%, whereas monomer conversion was 90–96%, depending on the polymerization conditions. Addition of inorganic filler up to 70 wt% did not significantly influence the polymerization kinetics. The final hardness of the photocured samples (with 70 wt% filler) was about half that found in a commercial dental restorative composite. The shrinkage of a composite with 70 wt% filler was 2.12%. Dental formulations based on photocuring of PFMA can be considered for clinical applications, after biological and toxicological evaluation. © 1999 Society of Chemical Industry     

2-(4-甲氧基苯基)-4,6-双(三氯甲基)-S-三嗪光引发剂的合成及其光聚合动力学性能研究

以对甲氧基苯甲腈和三氯乙腈为原料合成了光引发剂2-(4-甲氧基苯基)-4,6-双(三氯甲基)-S-三嗪(MBTT),通过傅里叶红外光谱仪、核磁共振仪和紫外吸收光谱对所合成的产物结构进行了表征.并利用实时红外(RT-IR)对该引发剂进行了光聚合反应动力学研究,考察了单体、引发剂浓度和光强对引发速率及单体转化率的影响.结果表明,MBTT是一种高效的紫外光引发剂,在引发剂用量为0.1%时光聚合的单体转化率就能达到90%;随着光强的增大,单体的双键转化率和最大反应速率都增大,诱导期缩短;双丙烯酸酯类单体的双键转化率比三丙烯酸酯类单体的双键转化率要高.     

Photopolymerization of carbazolyloxiranes

Photopolymerizations of 1-allyloxy-3-(carbazol-9-yl)-2-propanol glycidyl ether and 1-(carbazol-9-yl)-4-oxa-2-pentanol glycidyl ether with diaryliodonium salts in solution and in bulk are reported. These reactions give oligomers of degree of polymerization 4–6. The influence of the functional groups of the monomers on the rate of polymerization, conversion limit and molecular weight is discussed. The effects of photoinitiator and reaction media on these factors have also been studied.