共查询到19条相似文献，搜索用时 140 毫秒
1.
研究了N－丙烯酰吩噻嗪（APT）敏化甲基丙烯酸甲酯（MMA）的光聚合，得到了APT敏化MMA光聚合的速度方程和表观活化能并探讨了引发机理。 相似文献
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以过氧化苯甲酰（BPO）为引发剂,甲基丙烯酸甲酯（MMA）为单体进行本体聚合制备有机玻璃。探讨了引发剂的用量、不同阶段的反应温度等因素对反应的影响。得出最佳实验条件为：m（BPO）／m（MMA）为0．3％;-N聚水浴温度为90℃,预聚时间为1．5h;烘箱中聚合前期温度为45％,24h后升温至90℃再聚合2h。 相似文献
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利用单因素实验探讨甲基丙烯酸甲酯MMA聚合改性重质碳酸钙,用正交试验进行优化,并对改性前后重质碳酸钙性能表征。结果表明,甲基丙烯酸甲酯聚合改性碳酸钙的最优化工艺条件为液固比（TBT）：（MMA）：（CaCO3）＝1：10：100,引发剂偶氮二异丁腈AIBN 的用量为液固比（AIBN）：（MMA）＝20％,活化温度75℃,活化时间4h。在此条件下,改性重质碳酸钙沉降体积为0．96mL/g ,吸油值为18．90mL/100g ,粘度为120．00mPa ．s ,pH值为8．23。电镜分析表明重质碳酸钙经M M A改性后表面包覆聚甲基丙烯酸甲酯PM M A。 相似文献
4.
综述聚丙烯酰胺类（PAM）絮凝剂的合成工艺包括水溶液聚合法、乳液聚合法、辐射聚合法、光引发聚合法、沉淀聚合、悬浮聚合、等离子体引发聚合。分析各聚合技术的优势与不足,探讨PAM絮凝剂今后的发展趋势。 相似文献
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该文研究了可聚合的４－Ｎ－二苯甲基马来酰亚胺（ＮＢＰＭＩ）与可聚合的甲基丙烯酸－Ｎ，Ｎ－二甲氨基乙酯（ＤＭＡＥＭＡ）构成的光氧化还原引发体系引发两烯腈聚合的动力学。 相似文献
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研究了以碘代乙腈退化转移剂的丙烯酸醋活性自由基聚合，实验结果表明：在碘代乙腈的存在下控制甲基丙烯酸甲酯（MMA）的聚合，得到的分子量大（1万-10万），而控制丙烯酸甲醋（MA）、丙烯酸乙醇（EA）、醋酸乙烯醋（VAc）得到的分子量较小（〈1万）．实验得出：[IAN]与EAIBN]之比对控制活性自由基聚合有很大的影响，[IAN]与[AIBN]之比为6：1是有效控制聚合的理想浓度．反应温度为60℃时，转化率随时间的增长而增高，分子量随转化率的增高而增大，成线性关系，分子量的分布较窄（〈1．5）．^1H NMR分析表明，在聚合物主链的末端连有碘，说明碘代乙腈在反应中起退化-转移聚合（IDTP）的作用，通过循环往复的碳-碘键的活化，断裂，再形成而得到最终活性的聚合物。 相似文献
8.
利用差示扫描量热仪(DSC)对MMA/纳米Si3N4体系的聚合过程进行研究,着重考察了聚合温度,纳米Si3N4粉体加入量及引发剂AIBN用量对体系聚合速率的影响.结果表明:升高聚合反应温度,增大引发剂用量,均可使体系的凝胶效应提前出现,聚合速率增大;而纳米Si3N4粉体的加入对体系的聚合起到延缓的作用,且随着加入量的增加,聚合速率逐渐降低. 相似文献
9.
夏平 《湖州师范学院学报》2001,23(3):32-35
在原子活性自由基聚合中，St可用引发剂（AIBN）通过一种新的方法成功聚合，此反应首先在60℃持续10hr，然后在100℃聚合,我们在引发体系中，使用不同摩尔比的AIBN和CuCl2对此进行试验，实验结果说明此种聚合方法引发效率高，易于控制，所得产物分子量分布窄，一般情况下Mw/Mn－＝1．36。 相似文献
10.
祝保林 《渭南师范学院学报》2012,(2):61-66
于加热熔融的氰酸酯树脂(BACDy)中加入异丁烯酸甲酯(MMA),在引发剂存在下,引发单体及预聚体MMA发生本体聚合,采用同步合成法和异步合成法分别制备互穿聚合物网络氰酸酯树脂/聚异丁烯酸甲酯(BACDy/MMA-SIPN)高分子材料,研究了几种不同配比的SIPN体系.结果表明,BACDy/MMA-SIPN网络形成的反应条件对体系的力学性能和耐热性能都有较大提高.给出了较合理的制备工艺条件. 相似文献
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研究了pH值对He-Ne激光诱导的亚甲兰增感丙烯酰胺体系光聚合的影响,测定了在不同pH值条件下亚甲兰的光褪色速率以及光聚合反应速率。还探讨了噻嗪类染料结构对其光褪色行为的影响。 相似文献
12.
Methyl methacrylate (MMA) emulsion polymerization in the presence of nanometer calcium carbonate (nano-CaCO3) surface modified with (-methacryloxypropyltrimethoxysilane (MPTMS) was carried out to prepare poly (methyl methacrylate) (PMMA)/nano-CaCO3 composite. The reaction between nano-CaCO3 and MPTMS, and the grafting of PMMA onto nano-CaCO3 were confirmed by infrared spectrum. The grafting ratio and grafting efficiency of PMMA on nano-CaCO3 modified with MPTMS were much higher than that on nano-CaCO3 modified with stearic acid. The grafting ratio of PMMA increased as the weight ratio between MMA and nano-CaCO3 increased, while the grafting efficiency of PMMA decreased. Transmission electron micrograph showed that nano-CaCO3 covered with PMMA was formed by in-situ emulsion polymerization. 相似文献
13.
以高分子微球聚苯乙烯（PST）和聚甲基丙烯酸甲酯（PMMA）作为组装体,采用自组装方法在PST和PMMA微球表面自组装制备纳米α-Fe2O3电池负极材料,组装温度为PST（T=70℃）和PMMA（T=60℃）聚合温度.结果显示,采用PST作为组装体获得的α-Fe2O3纳米粒子颗粒更细,约70nm,粒径更均匀,分散性更好;而PMMA组装体获得的纳米粒径约80nm,分散性相对较差,主要原因是PMMA微球质地较软,易发生变形,而使α-Fe2O3纳米粒子吸附在PMMA表面不均匀,在热处理过程中受热不均导致α-Fe2O3纳米粒子尺寸不均,且有团聚趋势.XRD显示,两种组装体获得的均为纯相α-Fe2O3结构.电化学性能显示,采用PST作为组装体制备的纳米α-Fe2O3作为电池负极电化学性能明显优于PMMA组装体. 相似文献
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In order to improve the present aviation ejection escape system, the application of explosion cutting technique to aviation escape system is proposed to weaken the strength of canopy before ejecting it. A series of mini cutting explosives are designed to investigate the process of splitting PMMA plate. The phenomenon of spallation in PMMA is observed. The effects of different parameters of mini cutting explosives on the cutting depth are obtained. Consequently the appropriate material of half-circular metal covers, explosive types and the ranges of charge quantities are determined. On the other hand, the cutting process of aviation PMMA plate by mini cutting explosives is simulated by means of nonlinear dynamic analysis code LS-DYNA. In finite element analysis,Arbitrary Lagrangian Euler (ALE) algorithm is used to depict the fluid property of high energy explosives. Continuous damage material model is used to simulate the complicate dynamic damage behavior of PMMA due to explosion shock waves. Only sliding contact option is defined to fulfill the fluid-structure interaction between explosives and PMMA plate by distributed parameter methods. Phenomenon of spallation observed in the experiment is presented in the simulation. The relationship between the penetration depth of PMMA plate and charge linear density obtained by numerical simulation agrees well with experimental result. 相似文献
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将抽象因子分析法用于解析配合物体系的吸光度数据以确定体系中的吸光物种数，为研究表面活性剂对金属离子与显色剂反应体系增敏作用机理提供一种新方法。用该法对Fe（Ⅲ）-SCN和Fe（Ⅲ）-SCN-Tween-80两显色体系的吸光度数据进行处理，结果表明，新的多元配合物的生成是表面活性剂对Fe（Ⅲ）-SCN显色反应增敏的主要原因。 相似文献
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We proposed a novel method of fabricating polydimethylsiloxane （PDMS） microfluidic chip polymer master molds in this paper. The method mainly includes two steps. First, a stainless steel slice was laser etched to form a metal model. Then, the organic solution of poly（methyl methacrylate） （PMMA） was casted onto the metal model to fabricate the PMMA master which subsequently would be used to fabricate PDMS chips. We systematically researched different laser parameters influencing the surface status of microchannels and obtained optimized etching parameters. We investigated and optimized the organic solution composition of PMMA while casting chip masters, and developed a method to form fine polymer masters using two different viscosity solutions to cast the model in turn, and studied the repeatable replication. Then, we investigated physical performance of this chip and evaluated the practicability by analyzing Rhodamine B. Compared with present methods, the proposed method does not need photolithography on photoresistant and chemical etching. The entire fabricating progress is simple, fast, low-cost and can be controlled easily. Only several minutes are required to make a metal model, 3 hours for a PMMA master, and one day for PDMS chips. 相似文献
18.
ZHANG Zhao yang GAO Lei ZHANG Ying CHEN Hao 《上海大学学报(英文版)》1999,3(3):208-213
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19.
Potential immunomodulation effect of the extract of Nigella sativa on ovalbumin sensitized guinea pigs 总被引：1，自引：0，他引：1
Boskabady MH Keyhanmanesh R Khameneh S Doostdar Y Khakzad MR 《Journal of Zhejiang University. Science. B》2011,12(3):201-209
Several different pharmacological effects have been described for Nigella sativa (Siah-Daneh), including an anti-inflammatory effect. In the present study, the effect of the extract of N. sativa on lung pathology and blood interleukin-4 (IL-4) and interferon-γ (IFN-γ) of sensitized guinea pigs was examined. Three groups
(n=8 for each group) of guinea pigs sensitized to ovalbumin (OA) were given drinking water alone, and drinking water containing
low and high concentrations of the plant extract, respectively. The animals of the control group (n=8) were treated with saline instead of OA and were given drinking water. The pathological changes of the lung, including
infiltration of eosinophils and lymphocytes, local epithelial necrosis, the presence of oedema, thickening of the basement
membrane, smooth muscle layer hypertrophy, mucosal secretion, and the presence of mucosal plug, and blood IL-4 and IFN-γ of
sensitized guinea pigs were evaluated. The lungs of the sensitized group showed significant pathological changes (P<0.001). Blood IL-4 and IFN-γ were increased in sensitized animals compared to the controls (P<0.01 and P<0.001, respectively). Treatment of sensitized animals with the extract led to a significant decrease in pathological changes
of the lung (P<0.01 to P<0.001), except for the oedema in the sensitized group treated with low concentration of the extract, but an increased IFN-γ.
These results confirm a preventive effect of N. sativa extract on lung inflammation of sensitized guinea pigs. 相似文献