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1.
Comparison of MMA polymerization results with samarocene chloride, titanocene chloride and the title heterodinuclear (Sm−Ti)
catalyst, respectively, showed synergism in the Sm-Ligand-Ti system, which obviously influenced the polymerization behaviors,
for example, of yeilding higher activity and higher molecular weight polymer. Kinetic studies on polymerization of MMA with
ethylene bridged samarocene and titanocene chloride/Al(i-Bu)3 showed that the polymerization rate was first-order on the catalyst concentration, and 1.9-order on the monomer. The overall
activation energy measured was 52.8 kJ/mol.
Project supported by NSFC (No. 20074028), and SINOPEC(X598037). 相似文献
2.
POLYMERIZATION OF METHYL METHACRYLATE WITH IRON-YTTERBIUM DINUCLEAR METALLOCENE CATALYST 总被引：1，自引：0，他引：1
ＩＮＴＲＯＤＵＣＴＩＯＮＨｅｔｅｒｏｄｉｎｕｃｌｅａｒｃｏｍｐｌｅｘｅｓａｒｅｏｆｇｒｅａｔｉｎｔｅｒ ｅｓｔｆｏｒｔｈｅｓｔｕｄｙｏｆｓｙｎｅｒｇｉｓｔｉｃｅｆｆｅｃｔｓｆｏｕｎｄｉｎｂｉｍｅｔａｌｌｉｃｃａｔａｌｙｓｉｓ(Ｄｏｍｂｅｋ ,1 985;ＪｎＬｉｎｇｅｔａｌ.,1 993 ;Ｍｃｃｏｌｌｕｍｅｔａｌ.,1 996) .Ｍｏｒｅａｎｄｍｏｒｅｓｙｎｔｈｅｔｉｃｒｏｕｔｅｓｈａｖｅｂｅｅｎｒｅｐｏｒｔｅｄｉｎｔｈｅｌａｓｔｄｅｃａｄｅ(Ｈａｒｔｅｒｅｔａｌ.,1 989;Ｓｃｏｔｔｅｔａｌ.,1 993 ;Ｄｉａｍｏｎｄｅｔａｌ.… 相似文献
3.
A novel iron-ytterbium dinuclear catalyst, FcB(MeCp) Yb (MeCp) Cl (Fc: ferrocenyl, B: diethylene ether), was synthesized for
the polymerization of methyl methacrylate (MMA). Synergistic effects between the ferrocenyl group and the lanthanocene part
were investigated regarding their catalytic behaviors. UV, IR, GPC and NMR were used to characterize the structures of the
catalyst and polymer. Kinetic study showed that polymerization is first order in monomer concentration and fractional order
(0.78) in the catalyst. The bimetallic complex is a good catalyst for the polymerization of MMA, giving high molecular weight
PMMA with 78% syndiotactivity.
Project (29774021) supported by NSFC and Laboratory of Rare-Earth Chemistry and Physics, Changchun Institute of Applied Chemistry,
Chinese Academy of Sciences 相似文献
4.
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
5.
A new catalyst composed of Tin-bridged yttrocene Ph2Sn(MeCp)2YCI (MeCp=methylcyclopentadienyl) and Al (i-Bu)3 was successfully developed for the polymerization of methyl methacrylate (MMA). Detailed study of factors (such as the molar
ratio of Al/Cat., catalyst concentration, various solvents, temperature and time) influencing polymerization reaction indicated
that the catalytic active species may be still somewhat stable at high temperature and still have a long catalytic lifetime.1H NMR spectrum showed about 65% syndiotactic content in the polymethyl methacrylate (PMMA) prepared. From kinetic studies,
the polymerization rate equation may be expressed as Rp=Kp[Cat.]2.4. The overall activation energy of polymerization is 20.9±3.1 kJ/mol.
Project(29774021) supported by the Natural Science Foundation of China and National Laboratory of Element-Organic Chemistry,
Nakai, University. 相似文献
6.
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
7.
Novel homo-dinuclear silicon bridged cyanoethyl cyclopentadienyl complexes of titanium and zirconium (CH3)2Si((η5-C5H3CH2CH2CN)(C5H5)MCl2)2 (M=Ti(1), Zr(2)) were synthesized and developed for the polymerization of ethylene. Compared with their corresponding mononuclear complexes (η5-C5H4CH2CH2CN)(C5H5)MCl2 (M=Ti(3), Zr(4)), the dinuclear complexes had higher catalytic activity. And the polyethylene produced had a higher molecular weight than that obtained with mononuclear catalysts. Effects of conditions on the ethylene polymerization catalyzed by (2)/MAO (methylaluminoxane) were studied in detail. The catalyst showed a very high activity ( >106g PE/mol Zr*h) under low catalyst concentration and high molar ratio of Al/Zr. 相似文献
8.
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
9.
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
10.
Room temperature ionic liquids as solvents for palladium-catalyzed copolymerization of carbon monoxide and styrene were prepared by reaction of aqueous lead tetrafluoroborate with correspond-ing chloride or bromide salts. The recyclability of palladium composite catalyst in various ionic liquids was investigated.[Pd(bipy)2][BF4]2 showed a lower catalytic activity than [Pd(bipy)2][PF6]2 in similar conditions, although the catalytic activity of each composite catalyst in ionic liquids still existed after 4 successive recycles. It was shown the catalytic activity of palladium composite catalyst was higher than that of the catalyst formed in situ from palladium acetate, 2,2'-bipyridyl, and HA (A=PF6-, BF4-) in ionic liquids. The effects of volume of ionic liquids, reaction time, and the dosage of benzoquinone on the copolymerization were also studied. 相似文献
11.
文章以苯乙烯为原料,通过溴化和脱溴化氢生成苯乙炔。利用无水AlCl3作催化剂合成聚苯乙炔(PPA),并通过物理共混法制得聚苯乙炔/磁流体复合物薄膜。对其磁性、成膜性进行了研究,结果表明:产物磁性、成膜性均良好并且受催化剂用量影响较大。 相似文献
12.
Tan Dingsheng 《上海大学学报(英文版)》1998,2(1):67-71
ＳｔｕｄｙｏｎＳｕｒｆａｃｅＭｏｄｉｆｉｃａｔｉｏｎｏｆＴｉｔａｎｉｕｍＤｉｏｘｉｄｅＵｓｉｎｇＰｏｌｙｍｅｔｈｙｌＭｅｔｈａｃｒｙｌａｔｅＴａｎＤｉｎｇｓｈｅｎｇ（ＳｈａｎｇｈａｉＵｎｉｖｅｒｓｉｔｙ）ＹａｎＮｉａｎｘｉＸｕｅＱｉｎｇ（Ｓｏｃｈｏｗ... 相似文献
13.
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
14.
无水三氯化铝催化合成乙酸乙酯的研究 总被引：10，自引：1，他引：9
以无水乙醇和冰乙酸为原料 ,采用无水三氯化铝作催化剂合成乙酸乙酯 .考察了催化剂用量、原料配比和反应时间等因素对反应的影响 .找到了一种无污染、催化活性较高的催化剂无水三氯化铝 ,确定了无水三氯化铝作为催化剂的最佳反应条件∶无水乙醇∶冰乙酸 =2 ∶1 (摩尔比 ) ,无水三氯化铝用量占整个反应体系总质量的 7 2 % ,反应时间为 30min ,转化率 (以冰乙酸计 )达 80 6 % . 相似文献
15.
本文介绍了d-f异双核配合物的制备并探讨了d-过渡金属离子对稀土离子荧光影响。综述了含有d-过渡金属离子和三价稀土离子的异双核配合物研究的成果。 相似文献
16.
Novel homo-dinuclear silicon bridged cyanoethyl cyclopentadienyl complexes of titanium and zirconium (CH3)2Si((η5 ? C5H3CH2CH2CN)(C5H5)MCl2)2(M = Ti(1), Zr(2)) were synthesized and developed for the polymerization of ethylene. Compared with their corresponding mononuclear complexes (η5 ? C5H4CH2CH2CN)(C5H5)MCl2(M = Ti(3), Zr(4)), the dinuclear complexes had higher catalytic activity. And the polyethylene produced had a higher molecular weight than that obtained with mononuclear catalysts. Effects of conditions on the ethylene polymerization catalyzed by (2)/MAO (methylaluminoxane) were studied in detail. The catalyst showed a very high activity (> 106 g PE/mol Zr·h) under low catalyst concentration and high molar ratio of Al/Zr. 相似文献
17.
S_(3307)和PP_(333)对龙眼实生苗生长发育和抗寒力的影响 总被引：2，自引：0，他引：2
本试验研究了两种三唑类植物生长延缓剂S_(3307)和PP_(333)对龙眼实生苗生长发育和抗寒力的影响,结果表明:1mg/L的S_(3307)和10mg/L的PP_(333)浸种、浸根均能促进幼苗根系的生长,显著提高根冠比,幼苗断根移栽时,S_(3307)和PP_(333)均能促进主根断口处萌发侧根,使幼苗迅速恢复生长发育,在低浓度下,S_(3307)的“控上促下”活性明显大于PP_(333),高浓度(S_(3307)>50mg/L,PP_(333)>100mg/L)会严重抑制幼苗生长,适宜浓度的S_(3307)和PP_(333)不仅可以加快龙眼砧木育苗速度,而且能明显提高幼苗对低温的抵抗能力。 相似文献
18.
以苯酐和2-乙基己醇为原料,在自制的TiO_2/Al_2O_3复合型催化剂上合成邻苯二甲酸二异辛酯;确定了反应中催化剂的最佳配比及催化剂制备温度。考察了原料配比、催化剂用量、反应温度等工艺条件对酯化反应的影响。结果表明,该催化剂体系具有较好的催化活性,合成的DOP产品色相较好。 相似文献
19.
1 Introduction It is i mportant to study polymerization mechanisminpolymerization engineering. Obtaining kinetic data isthe key step for establishing polymerization mechanismand understanding elementary reactions . The kineticdata contains two groups of data ,i.e.,the rate andreaction order .The rate ,especially the rate constant ,is i mportant and to be esti mated assuming that the or-der of the reactionis known.Furthermore ,esti mationof rate constants for polymerization is an active anddif… 相似文献
20.
INTRODUCTION One of the main advantages of chemical groutsis easy control of gel time (Mollamahmutoglu andLittlejohn, 1996; ?nupárek and Soucek, 2000).Calcium acrylate is a chemical grout usually used ingeotechnical engineering (Zelanko and Karfakis,1997), and is a water-soluble monomer that po-lymerizes in an aqueous solution. The rate of po-lymerization is controlled by the concentration ofcatalyst and activator. The polymerization of cal-cium acrylate is free radical chain pol… 相似文献