2,2′-二邻甲氧基苯基-4,4′,5,5′-四苯基-1,2′-二咪唑复合光引发体系的光聚合动力学研究

本文研究了对2,2′-二邻甲氧基苯基-4,4′,5,5′-四苯基-1,2′-二咪唑(BMOIM)复合光引发体系引发聚合动力学过程.采用紫外光谱仪对引发剂、供氢体、增感剂在紫外区的吸收谱图进行了表征.利用实时红外光谱仪对复合光引发体系引发聚合动力学过程进行实时监测,考察了不同光强、引发剂浓度以及不同官能度单体对反应速率及最终双键转化率的影响.结果表明,在引发剂浓度为0.6%(质量分数)时,20s内双键转换率达到96%,随着引发剂浓度的提高,聚合速率增大.聚合速率以及最终双键转化率随着光强增大而增大;双官能团单体的最终双键转化率比三官能团单体的最终双键转化率要高.     

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.     

二芳酮-可聚合胺紫外光引发1,6-己二醇二丙烯酸酯聚合的动力学研究

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.     

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.     

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.     

4-乙烯基-1-环己烯二环氧化物阳离子单体光聚合性能研究

本文用实时红外光谱研究了4-乙烯基-1-环己烯二环氧化物(TTA22)单体的光聚合性能。分别考察了光引发剂浓度、光源、光强及增感剂浓度对其光聚合性能的影响。选用3,4-环氧环己基甲酸-3′,4′-环氧环己基甲酯(TTA21)作为参照,比较了不同单体的光固化性能。结果表明,随着引发剂浓度以及光强的增加,环氧基转化率及转化速率随之增加。LED光源下单体的转化率和转化速率低于UV汞灯。对TTA22和TTA21光固化后材料的热稳定性进行分析,结果显示TTA21的热稳定性优于TTA22的。     

含氟光引发剂的合成及其性能研究

以2-羟基-4'-(2-羟乙氧基)-2-甲基苯丙酮(Irgacure 2959)和全氟辛酰氯(PFOC)为原料合成了光引发剂全氟辛酸-2-[4-(2-羟基-2-甲基丙酰)苯氧基]乙酯(2959-F),利用红外光谱(FT-IR)和核磁共振(¹⁹F NMR)对2959-F进行了结构表征;通过紫外吸收光谱测定了2959-F的紫外吸收谱;通过实时红外光谱(RT-IR)对合成的含氟光引发剂进行了光聚合反应动力学研究,考察了光强和引发剂浓度对单体的双键转化率和聚合速率影响,并研究了光引发剂2959-F的抗氧阻聚性能.结果表明:随着光强的增大,单体的双键转化率和聚合速率增加;在一定范围内,引发剂的浓度越高,双键转化率越高,聚合速率越快.2959-F具有较高的双键转化率和较快的聚合速率,并且具有较好的抗氧阻聚性.     

二苯酮-可聚合胺引发1,6-己二醇二丙烯酸酯的光聚合研究

以UV-Vis分光光度计法和Photo-DSC法分别研究了合成的3种可聚合胺类助引发剂DMPDA、EGDPM、EGMPM与二苯甲酮(BP)组成的引发体系的光化学初级过程及引发1,6-己二醇二丙烯酸酯(HDDA)的紫外光聚合动力学.考察了助引发剂胺的含量对BP的光化学初级过程和对引发HDDA光聚合动力学的影响,以及光强和温度对聚合动力学的影响.结果表明,随着胺含量的增加,BP的光化学初级反应速率增加,从而使体系的聚合反应速率增加.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小.     

巯基/(甲基)丙烯酸(甲基)烯丙酯光固化特性

通过对羧酸盐法改进后合成同时含有高活性的丙烯酸酯型C=C和低自由基活性的烯丙基型C=C的烯类单体(甲基)丙烯酸(甲基)烯丙酯,以实现(甲基)丙烯酸酯类紫外光固化与巯/烯光聚合结合在二元体系中;并以1173为光引发剂,利用实时红外(RT-IR)跟踪此类烯烃与三羟甲基丙烷三(3-巯基丙酸酯)(TMMP)光固化过程,探究烯烃结构、光强和引发剂用量对含有两类碳碳双键的烯类单体与巯基化合物二元体系的光固化行为的影响.研究发现,这类二元巯-烯光聚合反应中均有(甲基)丙烯酸酯双键的反应活性最大,(甲基)烯丙基次之,巯基的反应活性最小;甲基取代在烯烃的不同C=C上,对巯-烯光固化特性影响不同,甲基取代在烯丙基C=C上比甲基取代在丙烯酸基C=C上对巯-烯光固化行为影响更大;巯基最终转化率随甲基取代基数目增多而减少;丙烯酸甲基烯丙酯体系中两类双键(丙烯酸型/甲基烯丙基型)反应活性几乎相同且均具有高的转化率.     

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.     

Improved oxygen permeability and mechanical strength of silicone hydrogels with interpenetrating network structure

<正>The interpenetrating polymer network(IPN) silicone hydrogels with improved oxygen permeability and mechanical strength were prepared by UV-initiated polymerization of monomers including methacryloxypropyl tris(trimethylsiloxy)silane(TRIS),2-hydroxyethylmethacrylate(HEMA) and N-vinyl pyrrolidone(NVP) in the presence of free radical photoinitiator and cationic photoinitiator.The polymerization mechanism was investigated by the formation of gel network.The structure of IPN hydrogels was characterized by Fourier transform infrared spectroscopy(FTIR), differential scanning calorimetry(DSC) and transmission electron microscopy(TEM).The results showed that the IPN hydrogels exhibited a heterogeneous morphology.The mechanical properties,surface wettability and oxygen permeability were examined by using a tensile tester,a contact angle goniometer and an oxygen transmission tester,respectively.The equilibrium water content of the hydrogels was measured by the gravimetric method.The results revealed that the IPN hydrogels possessed hydrophilic surface and high water content.They exhibited improved oxygen permeability and mechanical strength because of the incorporation of TRIS.     

2,2′,5-三(2-氟苯基)-4-(3,4-二甲氧基苯基)-4′,5′-二苯基-1,1′-二咪唑复合引发体系光聚合动力学性能研究

利用实时红外对由光引发剂2,2′,5-三(2-氟苯基)-4-(3,4-二甲氧基苯基)-4′,5′-二苯基-1,1′-二咪唑(WJ-HABI)、增感剂4,4—二(N,N′—二甲基氨基)苯甲酮(EMK)及供氢体N-苯基甘氨酸(NPG)组成的复合引发体系进行光聚合动力学研究.探讨了复合引发体系的浓度、不同配比、紫外光的强度及...     

Photocurable Fluorinated Methacrylates: Synthesis and Polymerization

A series of hydroxy fluoroalkyl methacrylates were synthesized in 50% yields by the esterification reaction of the methacryloyl chloride with fluoroalkyl diol. These fluorinated methacrylates undergo rapid photopolymerization using Igacure651 as a photoinitiator. Hydrogels were prepared from various molar ratios of 2-hydroxyethylmethacrylate (HEMA), ethylene glycol dimethacrylate and fluorine containing monomers with a photoinitiator. Analyzing the water contents and contact angles of the hydrogels, we found that the content of fluorinate monomers increased, water contents decreased and contact angles increased.     

Photoinitiated copolymerization of acetonyl methacrylate

Synthesis of two methacrylate monomers derivatives of carbonyl compounds: vanillin and acetone are presented. The obtained acetonyl methacrylate was used for copolymerization with methyl methacrylate. Copolymerizations were carried out in the presence of commercially available photoinitiator Irgacure 651. Thermal and mechanical properties of the copolymers with different concentration of acetonyl methacrylate were studied.     

Photochemical synthesis of nitroxyl free radicals in the presence of vinyl monomers

The photochemical formation of an inhibitor in the presence of monomers and a photoinitiator offers the possibility of producing positive two-step photoresists. As inhibitor precursor sterically hindred amines have been used in the presence of air oxygen and Rose Bengal as oxidation photosensitizer. On irradiation with visible light (546 nm). stable nitroxyle radicals are formed, which act as strong inhibitors of free radical polymerization. Hexanediol diacrylate and 2-acryloxy-2′-propionyl oxydiethylether were used as monomers. The photoinitiator required for the second step polymerization is benzoin isopropyl ether, which photolyzes on irradiation at 340 n,. The quantum yield of nitroxyl radical formation has been determined in solution and in polymeric films. Polymerization inhibition experiments were carried out with methyl methacrylate in solution and with neat monomers. Though the quantum yield Φ_NO° is low, especially in the last case, the experiments confirm the possibilities of this two-step procedure.     

Novel photocurable monomers: The synthesis of difunctional vinyl ethers with a phosphonate group and difunctional 1‐propenyl ethers with a phosphonate group and their photoinitiated cationic polymerization

Phosphorus‐containing vinyl ether monomers and 1‐propenyl ether monomers were prepared by the regioselective addition reaction of glycidyl vinyl ether (GVE) or 1‐propenyl glycidyl ether with diaryl phosphonates with quaternary onium salts as catalysts. The reaction of GVE with bis(4‐chlorophenyl) phenylphosphonate gave bis[1‐(4‐chlorophenoxy methyl)‐2‐(vinyloxy)ethyl]phenylphosphonate in a 68% yield. The structures of the resulting phosphorus‐containing vinyl ether monomers and 1‐propenyl ether monomers were confirmed by IR and ¹H NMR spectra and elemental analysis. Photoinitiated cationic polymerizations of the resulting phosphorus‐containing vinyl ether monomers and 1‐propenyl ether monomers were investigated with photoacid generators. The polymerization of vinyl ether groups and 1‐propenyl ether groups of the obtained monomers proceeded very smoothly with a sulfonium‐type cationic photoinitiator, bis[4‐(diphenylsulfonio)phenyl]sulfide‐bis(hexafluorophosphate), upon UV irradiation. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3105–3115, 2005     

表面活性单体DMBAC光聚合动力学研究

采用偶氮二异丁脒盐酸盐(AIBA)作为光引发剂,光引发聚合并研究了阳离子表面活性单体——甲基丙烯酰氧乙基二甲基苄基氯化铵(DMBAC)的均聚及其与丙烯酰胺(AM)共聚合反应的动力学行为,聚合反应均在高于DMBAC临界胶束浓度(CMC)的条件下进行.研究结果显示DMBAC均聚合反应速率与引发剂浓度的0.29次方以及单体浓度的0.89次方成正比,均聚合反应的表观活化能约为13.74 kJ/mo1;DMBAC与AM共聚合反应速率与引发剂浓度的0.82次方以及单体总浓度的0.83次方成正比,共聚合反应的表观活化能约为10.97 kJ/mo1;同时测得DMBAC与AM共聚合反应的单体竞聚率为r₁=0.27(AM)、r₂=2.00(DMBAC),说明AM趋向于形成共聚物,而DMBAC更趋向于形成均聚物.     

1,3-Dioxine diphenyl as a novel initiator for free-radical photopolymerization

1,3-Dioxane diphenyl, a novel photoinitiator for free-radical polymerization, was synthesized and characterized. UV-Vis absorption spectroscopy was used to investigate its photochemical behavior during the photophysical process. The photopolymerization kinetics of 1,3-dioxane diphenyl was studied by realtime infrared spectroscopy. There was an optimum curing rate with the increase of 1,3-dioxane diphenyl concentration. Both the polymerization rate and final conversion increased with the increase in light intensity. 1,3-Dioxane diphenyl was the most efficient photoinitiator for tripropylene glycol diacrylate and other acrylate monomers. 1,3-Dioxane diphenyl was a more effective photoinitiator than benzophenone/ethyl-4-dimethylaminobenzoate.     

Synthesis and photopolymerizations of new phosphonated monomers for dental applications

Three novel phosphonated methacrylate monomers have been synthesized and studied for use in dental applications. Two of the monomers were synthesized from the reactions of glycidyl methacrylate (GMA) with (diethoxy‐phosphoryl)‐acetic acid (monomer 1 ) and (2‐hydroxy‐ethyl)‐phosphonic acid dimethyl ester (monomer 2 ). These monomers showed high crosslinking tendencies during thermal bulk and solution polymerizations. The third monomer (monomer 3 ) was prepared by the reaction of bisphenol A diglycidylether (DER) with (diethoxy‐phosphoryl)‐acetic acid and subsequent conversion of the resulting diol to the methacrylate with methacryloyl chloride. The homopolymerization and copolymerization behaviors of the synthesized monomers were also investigated with glycerol dimethacrylate (GDMA), triethylene glycol dimethacrylate (TEGDMA), and 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxy propyloxy) phenyl] propane (bis‐GMA) using photodifferential scanning calorimetry at 40 °C using 2,2′‐dimethoxy‐2‐phenyl acetophenone (DMPA) as photoinitiator. Monomer 1 showed polymerization rate similar or greater than dimethacrylates studied here but with higher conversion. The maximum rate of polymerizations decreased in the following order: 1 ～TEGDMA>GDMA～bis‐GMA～ 3 > 2 . A synergistic effect in the rate of polymerization was observed during copolymerizations. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2290–2299, 2008     

Synthesis and modeling of new phosphorus‐containing acrylates

New methacrylate monomers containing phosphonic acid or both phosphonic and carboxylic acids were synthesized through the reaction of t‐butyl α‐bromomethyl acrylate with triethyl phosphite followed by the selective hydrolysis of the phosphonate or t‐butyl ester groups with trimethylsilyl bromide and trifluoroacetic acid. The copolymerization of these monomers with 2‐hydroxyethylmethacrylate was investigated with photodifferential scanning calorimetry at 40 °C with 2,2′‐dimethoxy‐2‐phenyl acetophenone as a photoinitiator. Quantum mechanical tools were also used to understand the mechanistic behavior of the polymerization reactions of these synthesized monomers. The propagation and chain‐transfer reactions were considered and rationalized. A strong effect of the monomer structure on the rate of polymerization was observed. The polymerization reactivities of the monomers increased with decreasing steric hindrance and/or increasing hydrogen‐bonding capacity because of the hydrolysis of the phosphonate and the t‐butyl ester groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2574–2583, 2005