乙二硫醇/乙烯基硅氮烷体系光聚合反应动力学的研究

采用傅立叶变换红外光谱法跟踪巯基和乙烯基吸光度的变化,跟踪测定了光聚合反应过程中巯基和乙烯基的转化率,研究了乙二硫醇/乙烯基硅氮烷体系的光聚合反应动力学.结果发现,巯基与乙烯基以化学计量比1∶1反应;在巯基和乙烯基的量之比相等和乙烯基过量的情况下,按照一级反应处理的动力学数据呈现较好的线性关系,且反应速率与巯基浓度的一次方成正比,与乙烯基浓度无关.     

巯基／乙烯基硅氮烷体系的紫外光聚合机理及动力学研究

乙烯基硅氮烷(VL20)是一种液态陶瓷前驱体,在光引发剂存在下与巯基化合物快速发生光聚合反应。文中利用先进的紫外光差示扫描量热(UV-DSC)实时跟踪和博里叶变换红外光谱(FTIR)原位跟踪等方法,研究了巯基-乙烯基硅氮烷VL20体系的光聚合反应机理和动力学特征。     

巯基/乙烯基硅氮烷紫外光固化的研究

利用原位红外跟踪技术和光-示差扫描量热技术研究了不同类型多官能巯基化合物与乙烯基硅氮烷的紫外光聚合动力学过程.结果表明,巯基化合物官能度越高,聚合反应速率越高,但最终转化率越低.巯基丙酸酯类化合物比烷基硫醇类化合物更易与乙烯基硅氮烷反应.在较低温度下,反应温度对聚合反应的影响较弱,反应活化能约为2.3kJ/mol,而较高反应温度下反应速率偏离Arrhenius方程.     

樟脑醌／乙二醇-3-吗啡啉基丙酸酯甲基丙烯酸酯引发牙科复合树脂的光聚合动力学研究

采用Photo-DSC研究了樟脑醌（CQ）／乙二醇-3-吗啡啉基丙酸酯甲基丙烯酸酯（EGMPM）可见光引发牙科复合树脂聚合的动力学过程．考察了CQ浓度、EGMPM浓度以及光强对牙科修复复合树脂光聚合动力学的影响．结果表明：增加引发体系的浓度和增加光强都可以增加反应速率和转化率；同时实验结果验证了Rp∝（I0[CQ][EGMPM]）^1／2的动力学关系．     

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.     

红外光谱法测定巯基丙酸-溶聚丁苯橡胶接枝量

利用红外光谱法建立了巯基丙酸接枝改性溶聚丁苯橡胶(SSBR)中巯基丙酸接枝量的快速测定方法。结果表明,以700 cm~(-1)处吸收峰为内标峰、1 712 cm~(-1)处吸收峰为定量特征峰时,吸光度比值与接枝量的线性曲线相关因数为0.984 5,方法的精密度较好。     

红外光谱法测定巯基丙酸-溶聚丁苯橡胶接枝量

利用红外光谱法建立了巯基丙酸接枝改性溶聚丁苯橡胶（SSBR）中巯基丙酸接枝量的快速测定方法。结果表明,以700 cm-1处吸收峰为内标峰、1 712 cm-1处吸收峰为定量特征峰时,吸光度比值与接枝量的线性曲线相关因数为0.984 5,方法的精密度较好。     

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.     

环氧丙烯酸酯/乙烯基醚光聚合反应动力学研究

以二缩乙二醇二乙烯基醚 (DVE -3 )为活性稀释剂 ,研究其与环氧丙烯酸酯 (EOA)所组成的光聚合体系在自由基型光引发剂下引发的光聚合反应动力学及其影响因素。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 ,可以降低体系聚合后残余的双键含量。     

巯基化合物／乙烯基聚硅氮烷光固化体系的研究

采用三种巯基化合物作为含乙烯基聚硅氮烷(PSN-1)的光固化剂,研究了三种巯基化合物与PSN-1的反应动力学,并对光固化产物进行了热重分析.结果表明:巯基化合物/ PSN-1体系的反应速率与巯基浓度的一次方成正比,与乙烯基浓度无关,均为一级反应;四元巯基化合物比二元巯基化合物的初始反应速率快,而转化率偏低;四巯基季戊烷/PSN-1体系的陶瓷产率高达89%,更适合作先驱体转化法制备陶瓷材料的陶瓷先驱体.     

Synthesis and photopolymerization kinetics of oxime ester photoinitiators

Oxime Ester (OXE) Photoinitiators were synthesized and characterized by HPLC, FTIR, UV–Vis spectra, and ¹H‐NMR. The UV–Vis spectra of these photoinitiators were similar to Benzophenone (BP) but showed large red‐shifted maximum absorption. OXE were not only soluble in many solvents and (meth) acrylate monomers but also could be dispersed easily in propylene glycol monomethyl ether acetate (PGMEA). The kinetics of polymerization of monomer using OXE as photoinitiator was studied by Real‐time infrared (RTIR) spectra. It showed that OXE were an efficient photoinitiator. The concentration of OXE, functionality of monomer, and light intensity had effect on the photopolymerization kinetics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

新型紫外光产酸剂的合成及其光聚合动力学研究

以2-硝基噻吩,甲基磺酰氯及苯乙腈为原料合成了一种紫外光产酸剂(5-甲磺酸酯亚胺-5H-噻吩-2-亚基)-苯基-乙腈(MTPA),通过傅里叶红外光谱仪、核磁共振仪和紫外吸收光谱仪及热重分析对所合成的产物的结构和性能进行了表征,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、产酸剂浓度对引发速率及单体转化率的影响。结果表明,在一定浓度范围内,随着引发剂浓度增大,聚合速率加快,最终的双键转化率也增高。     

Curing kinetics of UV‐initiated cationic photopolymerization of divinyl ether photosensitized by thioxanthone

Photodifferential scanning calorimetry was used to investigate the photocuring kinetics of UV‐initiated cationic photopolymerizations of 1,4‐cyclohexane dimethanol divinyl ether (CHVE) monomer with and without a photosensitizer, 2,4‐diethylthioxanthone (DETX), in the presence of a diaryliodonium‐salt photoinitiator. Two kinetics parameters, the rate constant (k) and the order of the initiation reaction (m), were determined for the CHVE system with different amounts of added DETX photosensitizer (0–1 wt %) and at different isothermal temperatures (25–55°C) using an autocatalytic kinetics model. The photosensitized CHVE system exhibited much higher k and m values than did the nonphotosensitized system, which was attributable to the effects of photosensitization. Furthermore, the values of k and m for both CHVE systems increased significantly with increasing isothermal temperature because of a thermal contribution toward increasing the mobility of active species. The addition of DETX lowered the activation energy for the UV‐curable vinyl ether system. The collision factor for the system with DETX was higher than that obtained for the system without DETX, indicating that the reactivity of the former was greater than that of the latter because of the photosensitization effect. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1345–1351, 2005     

The characterization of coal macerals by diffuse reflectance infrared spectroscopy

Diffuse reflectance Fourier transform infrared (DRIFT) spectroscopy was applied to study the structure of vitrinites, liptinites and fusinites isolated from different rank coals (77.0-91.5%C) using a centrifugal float-sink procedure. Among the macerals separated from a given coal, liptinites are characterized by the highest proportion of aliphatic CH groups, occurring principally as CH₂, and fusinites by the most aromatic structure. Macerals separated from the low rank coals show comparable content of hydroxyl groups that occur as free OH or form similar types of hydrogen bonds. Carbonyl groups appear not only as conjugated ketones and quinones in vitrinites, but also as carboxylic groups in liptinites and low rank fusinites. CH_ar/CH_al ratio does not vary with carbon content in liptinites, but increases in vitrinites and fusinites. In the case of liptinites and vitrinites, a linear relationship between CH_ar/CH_al and reflectance is observed up to vitrinite R₀ value of 1.80%. For all macerals, the ratio CH_ar/CC increases with reflectance, but at different rates. Structural parameters CH_ar/CH_al and CH_ar/CC calculated from DRIFT spectra are very helpful in monitoring the differences among macerals of given coal and following structural rearrangement occurring with rank.     

Synthesis of novel macrophotoinitiator for the photopolymerization of acrylate

A new kind of macrophotoinitiator (MPI) was synthesized through the copolymerization of acrylic monomers and the polymerizable photoinitiator monomer 2959‐AA. Monomer 2959‐AA was obtained by an esterification reaction between acrylic acid (AA) and the water‐soluble photoinitiator Irgacure 2959 [2‐hydroxy‐4‐(2‐hydroxyethoxy)‐2‐methylpropiophenone]. By adjusting the monomer proportions in the MPIs, two series of MPIs with different 2959‐AA contents and different glass transition temperatures were obtained. The molecular structure of 2959‐AA was characterized by Fourier‐transform infrared spectroscopy, nuclear magnetic spectrometry, and mass spectrometry. Polymerization of 1, 6‐hexanediol diacrylate was initiated using Irgacure 2959 and 2959‐AA, and two series of MPIs to be polymerized were studied with a photo‐DSC test. Results showed that 2959‐AA had higher chemical reactivity than Irgacure 2959 because of the higher solubility of the former. It was evident from the experiments that 2959‐AA content in the MPI progressively increased the polymerization rate and monomer conversion when the glass transition temperatures of MPIs were similar. At the same 2959‐AA content, the polymerization rate slightly slowed down with increased glass transition temperature. However, the radical lifetime and polymerization time were prolonged. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40352.     

Kinetic investigations on the UV‐induced photopolymerization of nanocomposites by FTIR spectroscopy

The kinetics of the photopolymerization for nanocomposites containing nanosilica with 2,2‐dimethoxy‐1,2‐diphenylethan‐1‐one or benzophenone/n‐methyl diethanolamine (BP/MDEA)as photoinitiators were studied by FTIR spectroscopy. It was found that nanocomposites containing nanosilica had higher conversion in comparison with pristine EA. The presence of MPS and ethanol accelerated the photopolymerization of nanocomposites, while the presence of water decelerated it. The photopolymerization of nanocomposites was more sensitive to oxygen than that of pristine EA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99:1429–1436, 2006     

The effect of solvent on postcuring in free radical photopolymerization

During free radical photopolymerization, with an increasing degree of conversion, the viscosity increased and vitrification occurred. The unreacted double bonds had difficulty diffusing to the reactive site in the vitrifying polymer. However, the free radicals generated in the vitrifying matrix could survive for a long time. Thus, the postcuring process occurred. In this study, free radical photopolymerization kinetics of methacrylate with or without solvent was investigated by real‐time FTIR, which was combined with a heating device. Results showed that without solvent, postcuring occurred only by heating at a higher temperature than the glass transition temperature of the polymer. However, with solvent, the postcuring occurred even at room temperature, where only a small amount of solvent was enough to cause postcuring. The lifespan of the free radicals inside the polymer was over 10 h. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44223.     

阿莫西林的反应机理及反应进程的监测

阐明了阿莫西林的反应机理并使用在线傅立叶变换红外系统对阿莫西林的反应进程进行了监测,对于实际生产具有指导意义.     

用FTIR研究聚氨酯弹性体的固化动力学

使用傅里叶变换红外光谱仪 ,原位跟踪了催化及未催化聚氨酯弹性体(PU)的固化反应动力学行为。结果表明 ,—NCO和—OH的本体聚合在反应初期遵循二级反应和催化动力学规律 ;未催化和催化的PU固化反应的活化能分别为48.0kJ/mol和38.86kJ/mol,频率因子分别为3.01×108 L/(mol·s)和1.14×108L/(mol·s)。