光致阳离子聚合引发剂的进展

光致阳离子聚合体系具有聚合速度快、不受氧干扰以及对水不敏感等优点,为了适应光致阳离子聚合体系的发展,可进行光致阳离子聚合的单体和光致阳离子引发剂的研究越来越受到人们的重视,本文就其中的一方面光致阳离子引发剂的种类、制备以及引发机理进行了综述。     

颜料、颜料制剂及填料

涉及了一种将颜料分散体胶囊化的工艺，其中在可聚合分散剂的作用下，将一种颜料在水性溶剂体系中进行分散的工艺。在体系中添加一种丙烯酸酯单体，并将所得混合体进行聚合。所用的丙烯酸酯单体也可在添加的表面活性剂或可聚合分散剂的用下在水中乳化，以及近20％的丙烯酸或其他丙烯酸类乙烯基单体可在聚合反应之前添加于丙烯酸单体中。     

阳离子型苯丙乳液聚合转化率的影响因素

采用以OP-10为主的复配乳化剂,制得了可用于木器底漆的阳离子型苯丙乳液.考查了聚合工艺、引发剂种类及用量、单体滴加速率、反应温度等因素对单体转化率的影响.研究表明:采用半连续预乳液聚合工艺、阳离子为引发体系、反应温度控制在70℃时可制得转化率高、聚合稳定性好的苯丙乳液.     

环氧化物阳离子开环聚合机理

介绍了环氧化物阳离子开环聚合的机理,主要包括活性链端机理和活性单体机理等。活性链端机理认为聚合的活性中心位于聚合增长链的链端,聚合单体与活性链端接触发生聚合反应实现链增长;活性单体机理认为聚合的活性中心位于单体分子,在活性单体向聚合链端羟基增加的过程中实现链增长。两者相结合可较成功地解释环氧化物开环聚合的实验现象。     

环硅氧烷阳离子型乳液聚合中的单体迁移

以八甲基环四硅氧烷(D4)为单体,十二烷基二甲基苄基溴化铵(DBDA)为阳离子乳化剂,KOH为催化剂,进行环硅氧烷阳离子型乳液聚合单体迁移的研究.结果表明,乳胶粒界面为聚合场所,聚合初期,由于比表面积的不同,单体液滴形成的乳胶粒与胶束形成的乳胶粒之间形成单体浓度差,导致单体发生迁移,直至平衡.在此基础上,还考察了温度、搅拌强度及DBDA用量对迁移速率的影响.结果表明,乳胶粒界面为聚合场所,在聚合初期,单体液滴形成的乳胶粒与胶束形成的乳胶粒之间在聚合过程中形成单体浓度差异,导致单体在该两类乳胶粒之间发生迁移,迁移使得聚合过程中乳胶粒之间单体浓度差逐渐缩小并达到相同的平衡值,而聚合体系中油层体积也随之减少至恒定值.温度、搅拌速度及DBDA用量增加,单体扩散速度均加快,导致聚合过程中油层体积的减少速度增加,两层单体浓度差下降.     

浅谈提高聚合生产能力的措施

世界上氯乙烯单体聚合主要有4种方法：悬浮法、本体法、乳液法和溶液法。 悬浮法聚合是氯乙烯单体以小液滴状态悬浮在水中进行聚合。单体中溶有引发剂,一个小液滴就相当于本体聚合的一个单元,从单体液滴转变成聚合物固体粒子,中间一定经过聚合物单体黏性粒子阶段,为了防止粒子相互粘结在一起,体系中需加分散剂,以便在粒子表面形成保护膜。因此,悬浮聚合体系一般由单体、引发剂、水、分散剂4个基本成分组成。     

阳离子聚合物乳液的合成研究

本文通过常规乳液聚合法合成阳离了聚合物乳液，讨论了反应引发剂、阳离子乳化剂、功能性单体、共聚单体和单体浓度等各种因素对聚合速率、乳液性能等的影响。     

辐照固化涂料进展（Ⅱ）

3 阳离子光固化体系 阳离子光固化体系的发展较自由基光固化体系为晚,因为阳离子的光固化反应是以阳离子聚合为基础的,而阳离子聚合通常要求在低温无水条件下进行,条件比自由基聚合苛刻。这种观念妨碍了阳离子光固化体系的发展。实际上光固化反应与聚合反应有很大不同,光固化反应不要求得到长链聚合物,尽管阳离子聚合在有水和高温下易于发生链终止,但链终止时仍可产生新的活性中心（质子或其它阳离子）,它们仍可和双键发生加成,引发新的反应,其链终止相当于链转移,并不影响多官能基单体、齐聚物间的交联反应,最终得到固化材料。阳离子固化体系有明显的优点如不怕氧气,固化时体积收缩问题可以得到控制。阳离子光固化体系和自由基光固化体系一样,分引发体系与树脂两部分。3.1 阳离子光引发体系     

稳定高固含量阳离子丙烯酸酯乳液的合成

通过加入可聚合功能单体甲基丙烯酰氧乙基二甲基辛基溴化铵(ADMOAB),制得了具有良好稳定性的高固含量(42%)阳离子聚丙烯酸酯乳液,并考察了聚合工艺、pH、种壳中乳化剂分配、ADMOAB添加量、引发剂的类型及用量对乳液稳定性的影响。结果表明:采用种子预乳化法,使用偶氮二异丁基咪盐酸盐(AIBA)和偶氮二异丁腈(AIBN)复合引发体系,用量分别为单体总量的0.1%,当ADMOAB添加量为总单体质量的2%时,乳液各项稳定性优异。     

含异氰脲酸酯结构聚醚多元醇的合成

以1,3,5-三羟乙基异氰脲酸酯（THEIC）为引发剂、三氟化硼乙醚络合物为催化剂,环氧化合物为环单体,进行了阳离子开环聚合反应的研究。发现THEIC与环氧单体可在非均相体系中平稳地进行阳离子开环聚合反应。在THEIC体系,就链引发而言,环氧氯丙烷的大于环氧丙烷、丁基醚环氧乙烷。调整环单体加料次序就可以获得嵌段共聚醚多元醇。     

Synthesis and photo‐curing behaviors of silicon‐containing (vinyl ether)–(allyl ether) hybrid monomers

A series of silicon‐containing (vinyl ether)–(allyl ether) hybrid monomers used in nano‐imprint lithography resists were synthesized and subjected to photo‐initiated polymerization. The surface energies of the monomers and the resulting polymer films were then investigated. The surface energies of the monomers were very low at less than 15 mJ m^–2. The photo‐curing behaviors of the five hybrid monomers were investigated using real‐time Fourier transform infrared spectroscopy. The monomers were sequentially initiated with cationic (PAG201) and mixed (cationic initiator PAG201, radical initiator ITX or TPO) initiators. The vinyl ether double bond polymerized both rapidly and completely, whereas the allyl ether double bond remained when PAG201 was used as the photo‐initiator and polymerized completely with mixed initiators. The different double bonds of the silicon‐containing (vinyl ether)–(allyl ether) hybrid monomer increased the efficiency of the polymerization and overcame the intrinsic limitations of the free radical and cationic polymerization processes, including strong oxygen inhibition, large volume shrinkage and high humidity sensitivity. The five monomers with low viscosity, low surface energy, good thermal stability and good photo‐polymerization properties were suitable for nano‐imprint photoresists. © 2013 Society of Chemical Industry     

Free radical terpolymerization of three non-homopolymerizable monomers. Part IV. Terpolymerization of maleic anhydride, trans-anethole and vinyl-iso-butylether

This paper describes the free radical terpolymerization of maleic anhydride (MSA), trans-anethole (ANE) and vinyl-iso-butylether (VIBE) in chloroform, acetonitrile and tetrachloromethane at 60 °C with α,α′-azoisobutyronitrile as initiator. All these monomers are non-homopolymerizable under the used conditions, and the binary copolymerizations take place only between MSA and one of the donor-monomers but not between the two donor-monomers ANE and VIBE. Their reactivity ratios in the binary copolymerizations are all close to zero. The terpolymerizations result in polymers with always about 50 mol% donor- and 50 mol% acceptor monomer units. Against the common MSA-macroradical, VIBE is a little more reactive than ANE in acetonitrile and in chloroform; but in tetrachloromethane ANE is incorporated into the polymers 1.4 times faster than VIBE at the same concentration. The charge transfer complexes between MSA and two donor monomers have only small equilibrium constants and therefore low concentrations in the monomer feeds. But these complexes are more reactive than the free monomers. Their contribution to the total polymerization rate was kinetically determined for the two binary copolymerizations between MSA and one of the two donor monomers in chloroform. At low monomer concentrations the free monomers dominate the overall polymerization rate. At high monomer concentrations the charge transfer complex participates more to the polymerization process.     

Synthesis of novel highly reactive silicone-epoxy monomers for cationic photopolymerizations

A series of novel cationically photopolymerizable silicone-epoxide monomers bearing substituted benzyl ether groups were prepared. Monomers with methoxy groups on the aromatic ring of the benzyl ether group were synthesized by sequential hydrosylation reactions of 1,1,3,3-tetramethyl disiloxane. Kinetic studies using real-time infrared spectroscopy of the cationic photopolymerizations of these novel monomers showed that those monomers with methoxy groups exhibited elevated rates of photopolymerization. The acceleration effect was explained on the basis of synergistic effects of two mechanisms, namely, the normal ring opening polymerization catalyzed by a Brönstead acid, and the cationic photopolymerization induced by the redox interaction between the free radicals formed in the backbone of the monomer and the onium salt used as photoinitiator. The methoxy groups on the aromatic ring of the benzyl ether enhance the stabilization of the carbocation formed in the structure of the monomer. Silicone-epoxy monomer with 2,5-dimethoxybenzyl ether group exhibited the higher photopolymerization rate. The latter compound can also be used as accelerator of the cationic photopolymerization of commercial silicone-epoxy monomer when used in low concentrations.     

Study on water resistance of paper treated with polyacrylate microlatex

Polyacrylate microlatexes were synthesized by microemulsion polymerization of acrylic monomers in the presence of cationic emulsifiers using a modified process. Paper treated with some of the polyacrylate microlatexes showed good water resistance. Paper's water resistance and its relation to the glass transition temperature (Tg) of the copolymer, the particle size of the microlatex, and the emulsifier were studied. It was found that paper fiber can be uniformly coated by cationic microlatexes with polymers of lower Tg, resulting in higher resistance to water penetration. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 962–966, 2005     

丙烯酸-环氧阳离子树脂的合成研究

研究了以环氧树脂为母体与丙烯酸酯类单体接枝聚,生成阳离子树脂的反应机理和合成工艺;通过IR和GPC对树脂物性的表征,证实了树脂合成配方和工艺的可靠性。     

Effect of water‐soluble monomers on emulsifier‐minor emulsion polymerization of butylacrylate–methacrylic acid–styrene and properties of the latices

The stability of emulsifier‐minor emulsion polymerization and the final latices depends on whether water‐soluble monomers can be bound to the particle after polymerization, which relies on the hydrophilicity of the water‐soluble monomers. Less hydrophilic monomers are apt to be buried in the latex particle, but extremely hydrophilic monomers tend to homopolymerize in the water phase. The suitable hydrophilic index I/O of water‐soluble monomers is preferably 3–5. The adhesion power and water resistance of emulsifier‐minor latex films are better than that of conventional latex film, but the impact resistance and gloss of the former are poorer. The gloss and water resistance of the emulsifier‐minor latex films are relevant to the type of water‐soluble monomers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 796–801, 2006     

UP树脂光增稠研究

本文介绍了光引发剂、光敏化剂、光源距离和光照时间等对ＵＰ树脂光引发聚合增粘的影响，以及各种单体与ＵＰ树脂的光引发聚合的比较，说明利用光引发聚合可以达到ＵＰ树脂增稠的目的。     

Novel piperidinium salts as latent initiators for cationic polymerization of epoxide and vinyl ether

Novel dibenzylpiperidinium salts with nonnucleophilic anions (DBPi‐SbF₆, DBPi‐PF₆) have been prepared as latent cationic initiators. Utility of these salts in the photo and thermal‐induced cationic polymerizations of epoxide and vinyl ether monomer systems has been studied. The new initiator, DBPi‐SbF₆ showed good solubility, high reactivity, and high thermal latency for polymerizations of epoxide and vinyl ether monomers with only 1 wt % of concentration. Cationic polymerization of vinyl ether monomer was significantly faster than epoxide monomer by the synthesized initiators. This article describes the synthesis, characterization, and activity of novel initiators. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Ring opening polymerization initiated by methylaluminoxane/AlMe3 complexes

The ROP of cyclic ethers, carbonates and esters in the presence of commercially available methylaluminoxane/trimethylaluminum system has been studied. MALDI-ToF end groups analysis indicates that in a majority of systems considered, the polymerization process is initiated by insertion of a monomer into the Al-O-Al bond, generating alkoxide species, which are active sites in coordination polymerization. The polymerization of six-membered carbonates proceeds selectively, forming linear polydiols with high yields at moderate temperatures. The polymerization of oxiranes and lactones is, however, accompanied by back-biting reactions leading to cyclic oligomers. The interaction of oxirane with aluminoxane electrophilic sites causes also the formation of cationic species, which initiate the polymerization of THF. The cationic species formed in those systems were trapped by triphenylphosphine and identified by ³¹P NMR spectra.