新型的含葡萄糖胺的水溶性高分子型硫杂蒽酮光引发剂

将硫杂蒽酮光引发剂(TX)和共引发剂葡萄糖胺(GA)引入同一个高分子链上,合成新型水溶性高分子型硫杂蒽酮光引发剂(PTX-GA).通过改变PTX-GA中TX与GA的比例,合成了PTX-GA1、PTX-GA2、PTX-GA3,并通过光膨胀计实验研究了3种引发剂引发丙烯酰胺聚合的能力.研究表明这种水溶性高分子型硫杂蒽酮光引发剂即使在没有共引发剂胺的情况下,引发丙烯酰胺(AAM)的聚合效率也非常显著.同时由于它具有水溶性,而且含有生物分子,有利于改善光引发剂的生物相容性.     

大分子二苯甲酮光引发剂的合成及性能研究

合成了两种大分子光引发剂PPI 1和PPI 2,紫外吸收行为均与4-BP相似,摩尔消光系数比4-BP高,且光解速率快。在不加助引发剂EDAB条件下引发单体HDDA聚合效率良好,对比PPI 1和PPI 2,随着吸光基团官能度（分子量）增大,聚合速率增加、最终转化率增高。将各自诱导单体PEGDA聚合的固化膜,在二氯甲烷溶液中浸泡5天后,PPI 1的萃取量是4-BP的44.5%,PPI 2的萃取量是4-BP的40%,说明PPI 1和PPI 2都是引发效率良好的低迁移光引发剂。     

基于α-羟烷基苯酮(HAPK)可聚合大分子光引发剂的合成及其引发三丙二醇双丙烯酸酯(TPGDA)光聚合动力学的研究

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.     

吡咯烷基-N-甲酸-丙烯酸乙二醇酯光聚合动力学的研究

采用实时红外技术对所合成的活性稀释剂吡咯烷基-N-甲酸-丙烯酸乙二醇酯的聚合动力学进行了测试.研究了光强、引发剂浓度及引发剂种类对其光聚合的影响.结果表明:光强越强、引发剂浓度越大,聚合速率越高,但是反应的最终双键转化率基本不变,均能达到100%左右.引发剂种类对其光聚合的最终双键转化率的影响不是特别明显,但对聚合速率有一定的影响.     

季戊四醇四苯甲酰甲酸酯的合成及光引发性能

大分子光引发剂可以解决小分子光引发剂残留碎片带来的毒性对其在食品和医用材料领域应用的限制,为此,本文以苯甲酰甲酸(BF)和季戊四醇(PET)为原料,通过酰氯法在季戊四醇主链上引入了4个苯甲酰甲酸酯基团,制备了多官能度的季戊四醇四苯甲酰甲酸酯(PTF)大分子光引发剂。 PTF在225 ℃时失重15%,热稳定性优于2-羟基-2-甲基-1-苯基-1-丙酮(1173)光引发剂,与1173光引发剂相比,用PTF作光引发剂所制备的光固化涂料,在起始分解温度以及失去相同比例质量所需温度均提高了100 ℃以上。 PTF引发三羟甲基丙烷三丙烯酸酯(TMPTA)聚合时最大反应速率为0.037 s^-1,最终双键转化率为39.5%,PTF光引发活性大于1173光引发剂。 在同等实验条件下,PTF的相对小分子残留量仅为1173光引发剂的5%。     

新型光引发剂体系及其应用

紫外光固化技术具有环保、节能、可控等优点而广泛地应用于涂料、油墨、微电子和生物材料的领域,在紫外光固化技术光引发剂体系中起着十分关键的作用,新型高性能光引发剂的研制与开发广受科研工作者的重视,同时光引发剂因其独特的优点而不断的应用到一些新兴的科学领域中。本文介绍了作者课题组近5年来在新型高分子光引发剂方面的研究工作,这些工作主要围绕新型高分子硫杂蒽酮光引发剂、高分子二苯甲酮光引发剂和两亲性高分子光引发剂等三个方面展开,同时还介绍了这些新型的高分子光引发剂体系在微纳米粒子和聚合物刷等方面的应用。     

大分子引发剂用于合成嵌段液晶共聚物的新进展

前有多种制备嵌段液晶共聚物的方法，采用大分子引发剂合成嵌段液晶共聚物，方法简单且易于实施，越来越受到人们的青睐。综述了由大分子引发剂合成嵌段液晶共聚物方面取得的新进展。     

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     

一步法制备聚二甲基硅氧烷大分子偶氮引发剂及其用于嵌段共聚物的合成

提出了一种简单易行的合成聚二甲基硅氧烷大分子偶氮引发剂的方法.通过羟基封端的聚二甲基硅氧烷(HO-PDMS-OH)与4,4′-偶氮-二(4-氰基戊酸)(ACPA)在十分温和的条件下直接进行一步缩聚反应,合成了含有PDMS链段的大分子偶氮引发剂.用这种大分子引发剂来引发聚(乙二醇)甲醚甲基丙烯酸酯大分子单体(PEGMA)进行自由基溶液聚合,得到了一系列两亲性梳状嵌段共聚物(PDMS-PEG).     

功能超支化聚合物的制备及应用

超支化聚四氮唑表现出良好的导电性；半结晶超支化聚（酯-酰胺）具有合适的T_g和T_m，可以用于光固化粉末涂料中；含叔胺和硫醚的超支化大分子光引发剂有着良好的光引发活性。本文将主要从这3个方面综述超支化聚合物在新材料领域的应用。     

Synthesis and characterization of hyperbranched‐poly(siloxysilane)‐based polymeric photoinitiators

Three UV‐sensitive, hyperbranched‐poly(siloxysilane)‐based polymeric photoinitiators, bearing an alkyl phenone moiety linked to the surface of the hyperbranched polymer, were synthesized via the hydrosilylation of hyperbranched poly(siloxysilane) and modified UV‐sensitive compounds. Hyperbranched poly(siloxysilane) was prepared via the polyhydrosilylation of the AB₂‐type monomer methylvinyldichlorosilane. The chemical structures of the polymeric photoinitiators were characterized with ¹H, ¹³C, and ²⁹Si NMR, elemental analysis, Fourier transform infrared, differential scanning calorimetry, UV spectrophotometry, and thermogravimetric analysis. The UV‐curing behaviors of the blends of the hyperbranched polymeric photoinitiators with UV‐curable epoxy acrylate (EA) resin were determined by Fourier transform infrared, and the results showed that the initiation efficiency of the polymeric photoinitiators was excellent and that the thermostability of the EA/polymeric photoinitiator curing systems was higher than that of the EA/photoinitiators. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3261–3270, 2006     

Hyperbranched poly(ether amine)(hPEA)as novel backbone for amphiphilic one-component type-Ⅱ polymeric photoinitiators

A series of amphiphilic polymeric photoinitiators with hyperbranched poly(ether amine) (hPEA) as novel backbone were developed, which can initiate photopolymerization of water-soluble and hydrophobic monomers very efficiency and might have great potential applications in the field of photo-curing.     

Novel polymeric photoinitiators comprising of side-chain benzophenone and coinitiator amine: Photochemical and photopolymerization behaviors

Three kinds of macrophotoinitiators, PBP-P, PBP-E and PBP-B, were synthesized by step-polymerization of benzophenone and different coinitiator amino monomers. The low molecular weight analogue, 2,4-di(3-(diethyl amino)-2-hydroxypropoxy)-benzophenone (DAHBP), was also synthesized as a low molecular weight model compound. The UV-vis spectra of PBP-P, PBP-E, PBP-B and DAHBP are similar with large red-shifted maximum absorption comparing with BP. ESR spectra of PBP-P and DAHBP possess the same initiation mechanism with DEBP/TEA systems. The photopolymerization of two monomers with different functionality poly(propylene glycol)diacrylate (PPGDA) and trimethylolpropane triacrylate (TMPTA), initiated by macrophotoinitiators and low molecular weight analogs, was studied through photo-DSC. The results show that different efficiency of photoinitiators towards monomers: first, polymeric photoinitiators are more efficient than low molecular weight analogs; then PBP-E is the most efficient for PPGDA; lastly, PBP-B is the most efficient for TMPTA. The efficiency of the photopolymerization is mainly affected by structure of amine in macrophotoinitiator.     

Comparative reactivity of water soluble photoinitiators as viewed in terms of excited states processes

The activity of 10 water soluble photoinitiators derived from thioxanthone, benzophenone, and benzil were studied comparatively. The mechanisms of initiation were determined by time resolved laser spectroscopy and steady state polymerization. The characteristic features of each series of compounds are pointed out. The possible contribution of biphotonic processes to the initiation step is considered.     

Novel Synthetic Pathways for Bis(acyl)phosphine Oxide Photoinitiators

Photoactive: A cheap, safe, and widely functional-group-tolerant synthetic protocol to an important class of photoinitiators, bis(acyl)phosphine oxides (BAPOs), has been disclosed, together with examples of application to stain-proof fabrics and photoactive polymeric films.     

Radical polymeric photoinitiators bearing side‐chain camphorquinone moieties linked to the main chain through a flexible spacer

New polymeric photoinitiators bearing the side‐chain camphorquinone moiety spaced from the backbone by a long and flexible connection have been prepared and tested in the photocuring of acrylic monomers upon irradation with visible light in the presence of tertiary amine coinitiator. The results indicate that the photoinitiating activity of the polymeric initiators may be comparable to the related combination of low molecular weight derivatives when the camphorquinone component has a polymeric structure, and depends on the chemical structure of both the components of the initiator/coinitiator pair. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5879–5888, 2005     

Quantifying Photoinitiation Efficiencies in a Multiphotoinitiated Free‐Radical Polymerization

Online size exclusion chromatography–electrospray ionization–mass spectrometry (SEC/ESI–MS) is employed for quantifying the overall initiation efficiencies of photolytically generated radical fragments. In a unique experiment, we present the first quantitative and systematic study of methyl‐substituted acetophenone‐type photoinitiators being employed in a single cocktail to initiate the free‐radical polymerization of methyl methacrylate (MMA) in bulk. The photoinitiators are constituted of a set of two known and four new molecules, which represent an increasing number of methyl substituents on their benzoyl fragment, that is, benzoin, 4‐methylbenzoin, 2,4‐dimethylbenzoin, 2,4,6‐trimethylbenzoin, 2,3,5,6‐tetramethylbenzoin, and 2,3,4,5,6‐pentamethylbenzoin. The absolute quantitative evaluation of the mass spectra shows a clear difference in the initiation ability of the differently substituted benzoyl‐type radical fragments: Increasing the number of methyl substituents leads to a decrease in incorporation of the radical fragments.     

Efficient photopolymerization of thick pigmented systems using upconversion nanoparticles‐assisted photochemistry

Photopolymerization of thick pigmented systems still remains challenging due to the light screening effect of the pigments. Here, we present a facile method based on upconversion nanoparticles (UCNPs)‐assisted photochemistry to achieve efficient photopolymerization and improved curing depth of pigmented systems. Under a 980‐nm laser irradiation, UCNPs are able to convert NIR light into UV and visible light to activate photoinitiators for the initiation of polymerization. Influencing factors on photopolymerization were systematically investigated. With optimal parameters, 25.5 mm of photopolymerization depth combined with 70% of maximal double bond conversion was obtained. The peak temperature of 120.4 °C during UCNPs‐assisted photopolymerization is comparable with or lower than that of some reported frontal photopolymerization applied to prepare functional composite polymeric materials. Both indentation hardness and reduced modulus of the photocured materials using UCNPs as internal lamps were higher than those of the reference cured under traditional blue LED light. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 994–1002     

Phenacyl onium salt photoinitiators: synthesis, photolysis, and applications

Onium salts, namely sulfonium, phosphonium, ammonium, and pyridinium salts containing phenacyl group are photoinitiators appropriate for the polymerization of monomers such as oxiranes and vinyl ethers, which are not polymerizable by a free-radical mechanism. The initiation is accomplished by direct or indirect (sensitized) photolysis of the salts. Depending on the type of the salt, the direct photoinitiation of cationic polymerization involves reversible or irreversible processes. The photolysis of phenacylsulfonium compounds proceeds by a reversible process, while the other types undergo irreversible photolysis leading to complete fragmentation of the photoinitiator. An additionally useful tool, namely photosensitized generation of initiating species enlarges the versatility of these salts as photoinitiators. Photoinitiated free-radical and zwitterionic polymerizations by using phenacyl-type salts are also addressed. Keto-enol tautomerization of phenacyl pyridinium salts is discussed. Moreover, an interesting application concerning in situ synthesis of clay-poly(methyl methacrylate) nanocomposites with the aid of the phenacyl anilinium salt-based photopolymerization technique is noted.     

Aromatic Keto Compounds as Initiators in Photopolymerizations

The present article deals with the primary photochemical reactions of carbonyl compounds commonly used as photoinitiators. It is shown that radical formation results mainly from three processes, i.e. hydrogen abstraction, β-cleavage, and α-cleavage. The difference in the suitability of the radicals for chain initiation is discussed.