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Cristofor Simionescu Severian Dumitriu Marcel Popa Cristina Coman Vlad Artenie 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):677-686
Pepsin was immobilized on BIOZAN R (Hercules) with dicyclohexylcarbodiimide as activator. The reaction product obtained has a protein content of 35–110 mg/g of polymer and a proteolytic activity between 20.85–28.75 μmol tyrosine/L·min·g of polymer). The coupling reaction rate is maximum under the following conditions: pepsin/BIOZAN R ratio = 0.52 g/g, DCCI/BIOZAN R ratio = 0.2 g/g, pH = 3.4, reaction time = 4 h. 相似文献
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Non-extractable photoinitiators based on thiol-functionalized benzophenones and thioxanthones 总被引:1,自引:0,他引:1
Hironori Matsushima Qin Li Masamitsu Shirai Charles E. Hoyle 《European Polymer Journal》2010,46(6):1278-1287
Non-extractable photoinitiators could be advantageous for use in biological, electronic, and food packaging applications. Therefore, thioxanthone and benzophenone derivatives were synthesized from 1,6-hexane dithiol and chlorinated benzophenone or thioxanthone. The efficiency of thiol-functionalized photoinitiators in combination with amine co-initiators was compared to benzophenone and isopropylthioxanthone with amine co-initiators, and the cleavage of photoinitiator 2,2-dimethoxy-1,2-diphenylethan-1-one in acrylic resins. The reaction kinetics were analyzed using photo-differential scanning calorimetry and real-time FTIR. Coating physical properties were evaluated by pendulum and pencil hardness, steel-wool scratch and mandrel bend tests. The non-extractable photoinitiators had higher absorbance than their benzophenone or isopropylthioxanthone counterparts due to the sulfide substitution on the phenyl ring, and the free thiol groups reacted with the acrylate by either an amine catalyzed Michael addition or a free-radical chain process. The combination of thiol-functionalized photoinitiators with secondary amines provides an efficient photoinitiator system that is locked into the photopolymerized network and cannot be extracted with typical solvents. 相似文献
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本工作对几种新型硫杂蒽酮化合物敏化光解重氮盐问题进行了研究。工作表明:敏化反应是通过电子转移过程实现的,重氮盐所带取代基以及溶剂对重氮盐的光解有较大影响。十分有趣的是该体系对甲基丙烯酸甲酯进行光敏自由基引发聚合的速率和其光解反应速率有很大的不同,本文对此现象进行了讨论。 相似文献
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本文用紫外吸收光谱、荧光光谱、磷光光谱、电子自旋共振光谱对九种水溶性硫杂蒽酮类光引发剂的光学行为进行了研究,计算了摩尔消光系数、荧光量子产率、磷光量子产率,同时测定了溶剂效应对紫外、荧光光谱的影响,并对引发剂结构与光学化学性能之间的关系做了一定的探讨。 相似文献
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利用激光闪光光解方法研究了一系列胺类、酚类、醇类在脱氧乙腈中猝灭噻吨酮(TX)三重态的反应,得到了相应的瞬态吸收光谱和猝灭速率常数(kq).通过对光谱演变特性的分析,推断出三重态噻吨酮与不含有活泼氢的胺发生了电子转移反应,与含有活泼氢的胺发生了电子-质子转移反应.三重态噻吨酮与酚类、醇类反应中观察到噻吨酮加氢自由基的生成,据此推断出三重态噻吨酮与酚类、醇类发生了氢转移反应.胺类的猝灭速率常数随着反应自由能变(ΔG)的增大而减小,说明电子转移影响了噻吨酮三重态的猝灭.酚类的猝灭速率常数先随ΔG增大而减小,后随酚阳离子的酸性增强逐渐增大,可能是猝灭过程中电子转移影响减弱的同时氢转移影响逐渐增强.醇类的猝灭速率常数随着醇的α-C—H键能的增大而减小,说明α-C—H键能是影响噻吨酮三重态猝灭的关键因素.比较以前研究的胺类、酚类、醇类与三重态呫吨酮(XT)、芴酮(FL)反应的结果可知,由于分子结构差异性的影响,相关的猝灭速率常数按照呫吨酮、噻吨酮、芴酮的顺序逐渐减小. 相似文献
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T. Daniel Thangadurai Suhee Jeong Sunghak Yun Sangsu Kim Changdae Kim Yong-Ill Lee 《Microchemical Journal》2010,95(2):235-239
The known compounds N-(2,4-dinitrophenyl)-4,4′-bipyridinium (2,4-DNPhQ+), N-phenyl-4,4′-bipyridinium (PhQ+) and N-(4-acetylphenyl)-4,4′-bipyridinium (4-AcPhQ+) have been used to prepare a series of ruthenium complexes of the type [RuCl(CO)(PPh3)2(L)] (where, L = 2,4-DNPhQ+ or PhQ+ or 4-AcPhQ+). The latter complexes reacted with sulphur derivative to give [RuCl(CO)(PPh3)2(L)(L′)] (where, L′ = thio-9-xanthone). These new ruthenium complexes display intense, visible metal-to-ligand charge-transfer (MLCT) absorptions, due to dπ(Ru) → π*(pyridinium) excitations. The MLCT energy decreases as the acceptor strength increases in the order PhQ+ < 4-AcPhQ+ < 2,4-DNPhQ+. The new ruthenium complexes have been characterized by using standard analytical and spectroscopic techniques. Fluorescence and antibacterial activity of the ligands and appropriate complexes has also been carried out. 相似文献
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Two novel thioxanthone-based compounds 1a and 1b which possess thiosemicarbazone as binding site were developed for the dual-channel detection of Hg2+ and F−. Upon treatment with Hg2+ and F− separately, the probes’ fluorescence is effectively quenched, meanwhile 1a and 1b show evident naked-eye color variations after addition of F−: colorless to yellow. They both exhibit specific sensitivity and selectivity for Hg2+ or F− over other examined ions in tetrahydrofuran (THF) solution. 相似文献
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Demet Karaca Balta 《European Polymer Journal》2010,46(6):1374-1379
The two water-soluble thioxanthone-based 2-(carboxymethoxy) thioxanthone, 1A and 2-thioxanthone-thioacetic acid sodium salts, 2A were synthesized and characterized by spectroscopic methods. The quantum yield for fluorescence emission (φf) in water was found to be 0.50 for 1A and 0.05 for 2A. The long phosphorescence lifetime, that is 201 and 114 ms in a matrix at 77 K for 1A and 2A, respectively, indicates a π-π∗ nature of the lowest triplet state. The triplet lifetimes were determined by laser flash photolysis as 12 and 12.6 μs for 1A and 2A. Polymerization of acrylamide (AAm) was initiated by both initiators in water. Decarboxylation of initiators was achieved during 20 min of irradiation. It was found that 2A initiated polymerization of AAm in water more efficiently than 1A. 相似文献
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