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The mechanism of photosensitized decomposition of benzoyl peroxide by several anthracene derivatives has been studied. It comfirms that the photosensitized process is carried out by electron transfer.It is discovered that benzoyl peroxide can be decomposed by sensitizer of different anthracene derivatives which are used either electron donor or acceptor and the active radical which produces in this reaction can initiate the polymerization of MMA. It is considered that the BPO with positive charge in the charge transfer complex is easier to decompose into radical than that with negative charge,so the rate (Rp) of polymerzation of MMA in-itiated by the system of DCA/BPO has higher value than others. 相似文献
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本文研究了哌嗪 (PPZ)与二氧化硫 (SO2 )电荷转移复合物 (CTC)的制备及其作为光引发剂引发甲基丙烯酸甲酯 (MMA)的聚合 ,发现PPZ/SO2 摩尔比对聚合速率影响甚大 .当PPZ/SO2 为 1∶2时 ,形成了具有潜在引发能力的复合物 (Ⅰ ) .Ⅰ引发MMA光聚合的动力学关系式为Rp =Kp [Ⅰ ] 0 .34[MMA] 1.0 6 ,表观活化能为 2 3 7kJ/mol.并对引发机理进行了探讨 相似文献
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本文以9、10-二氰基蒽(DCA)为敏化剂,测定了用胺类,单烯类及取代苯类化合物为电子给体时光敏还原甲基紫精(MV2+)的量子产率。用三乙醇胺(TEOA)为电子给体,探索了胶体铂存在下DCA光敏分解水制氩的反应条件并研究了用甲苯、对二甲苯为电子给体时DCA光解水制氢的反应。结果表明以DCA为敏化剂时许多化合物(Eox<2V)均可作为电子给体,在制氢的同时还有可能合成有用化合物等优点。 相似文献
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甲基丙烯酸甲酯的原子转移自由基悬浮聚合 总被引:3,自引:0,他引:3
以 1 苯基氯乙烷为引发剂 ,氯化亚铜为催化剂 ,2 ,2 联吡啶为配体 ,外加搅拌 ,氮气保护下进行了甲基丙烯酸甲酯 (MMA)在 80℃下的原子转移悬浮聚合 .结果表明 ,聚合反应符合对单体浓度为一级的动力学关系 .经计算聚合体系的增长自由基浓度为 5 .74× 10 - 8mol L .聚合物分子量随转化率呈线性增加 ,分子量分布较窄 ,Mw Mn 在 1.37~ 1.40之间 .还以AIBN为引发剂 ,在三氯化铁和三苯基膦存在下进行了MMA的反向原子转移本体和悬浮聚合研究 .结果证明本体聚合具有好的可控特征 ,分子量随转化率呈线性增长 ,分子量分布指数在 1.2 7~ 1.31之间 .聚合反应速率较快 ,聚合体系中的增长自由基浓度较高 ,为 1.6 4× 10 - 7mol L .而在此催化体系下的悬浮聚合则完全失去了活性特征 相似文献
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以4,4′-偶氮二[4-氰基戊酰(对-二甲氨基)苯胺](ACPMA)/过氧化二苯甲酰(BPO)为氧化还原引发体系,研究了甲基丙烯酸甲酯(MMA)在N,N-二甲基甲酰胺(DMF)中的聚合及其动力学行为.考察了聚合反应温度、单体浓度、ACPMA浓度和BPO浓度对聚合反应速率和聚合物分子量的影响,测定了反应级数和聚合反应的活化能.结果表明,在一定范围内,聚合反应速率随单体浓度增大、ACPMA浓度增大、BPO浓度增大和反应温度的升高而增大;聚合物分子量随单体浓度的增大而增大,随ACPMA浓度的增大、BPO浓度增大和反应温度的升高而降低.该体系具有氧化还原引发体系的特征,其引发MMA的聚合速率方程为Rp=K[ACPMA]0.57 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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The methyl methacrylate(MMA)/1-propylmethacrylate-polyhedral oligomeric silsesquioxane(PM-POSS) copolymers were synthesized via atom transfer radical polymerization with CuBr as catalyst.The unreacted PM-POSS monomer could be removed completely by washing the copolymerization product with n-hexane.The copolymers were characterized with ~1H-NMR,X-ray diffraction,differential scanning calorimetry,thermogravimetric analysis and gel permeation chromatography.With increasing PM-POSS feed ratio,the total conve... 相似文献
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《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1435-1450
ABSTRACT The kinetics of the free radical bulk polymerization of methyl methacrylate (MMA) was studied by DSC, using the benzoyl peroxide (BPO)/amine initiation system. N,N dimethyl-4-aminophenethyl alcohol (DMPOH), which is a newly synthesized and used amine in the preparation of acrylic dental resins and bone cements was examined, and the results compared to the most commonly used in these applications amine, the N,N dimethyl-p-toluidine (DMT). For both amines, the effect of the molar ratio of BPO/amine and of the reaction temperature, on the polymerization kinetics was investigated. The prepared polymers were characterized by determination of the average molecular weights (M¯ n and M¯ w ) and molecular weights distribution (M¯ w /M¯ n ) using Gel Permeation Chromatography. DMPOH was found to lead in slightly higher polymerization rates, lower gel times and lower molecular weights than DMT. The values of these parameters for both amines were influenced by the molar ratio of BPO to amine, when the product of the concentrations of these was kept constant. The highest polymerization rate occurred in the lowest gel time, resulting in polymers with the lowest molecular weight, and was observed when a molar ratio of about 1.5 BPO/amine was used. However, the final monomer conversion was found to be independent of the molar ratio and amine used. The activation energy of polymerization was found to be 51.8 kJ/mol K for BPO/DMPOH and 47.1 kJ/mol K for BPO/DMT. 相似文献
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荷移光度法测定双嘧达莫 总被引:1,自引:0,他引:1
用光度法研究了双嘧达莫与氯冉酸之间发生的电荷转移反应,其中双嘧达莫是电子给予体,氯冉酸是电子接受体,反应介质是乙醇丙酮混合溶剂。应用等摩尔连续变换法和摩尔比法测得荷移络合物的组成为1∶1,稳定常数为3.9×104。络合物在526nm波长处有最大吸收,双嘧达莫浓度在10~380mg·L-1范围内服从比耳定律,相关系数为0.9996,表观摩尔吸光系数为1.34×103L·mol-1·cm-1,回收率为98.4%,测定结果的相对标准偏差为1.14%。应用该法可以快速测定双嘧达莫片中有效成分的含量,结果满意。 相似文献
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琥乙红霉素与紫色素的荷移反应及其测定 总被引:6,自引:0,他引:6
建立了一种快速测定琥乙红霉素的荷移分光光度法。琥乙红霉素与紫色素在乙醇-水介质中发生电荷转移反应,荷移络合物在546 nm波长处有最大吸收,表观摩尔吸光系数为9.18×103L.mol-1.cm-1,络合物的组成为1∶1,稳定常数为1.9×105。药物质量浓度在0~90 mg.L-1范围内服从比耳定律,相关系数为0.999 7,当琥乙红霉素质量浓度为40 mg.L-1时,6次测定结果的相对标准偏差为1.24%。测定了琥乙红霉素片剂中有效成分的含量,并与药典方法进行比较,结果基本吻合。 相似文献