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1.
Lewis酸引发的1,3—戊二烯阳离子聚合   总被引:3,自引:0,他引:3  
以AlCl3,BF3.OEt2,TiCl4和AlB3等Lewis酸为引发剂,在不同溶剂中于30℃引发1,3-戊二烯阳离子聚合。实验结果表明,AlCl3和BF3.OEt2显示出较高的催化活性,AlCl3引发的聚合反应得到的聚合物具有较高的分子量,但聚合反应过程中总是伴随交联产物的生成。  相似文献   

2.
以AlCl_3、BF_3·OEt_2、TiCl_4和AlBr_3等Lewis酸为引发剂,在不同溶剂中(正己烷、二氯甲烷、甲苯)于30℃引发1,3-戊二烯阳离子聚合。实验结果表明,AlCl_3和BF_3·OEt_2显示出较高的催化活性,AlCl_3引发的聚合反应得到的聚合物具有较高的分子量,但聚合反应过程中总是伴随交联产物的生成。用甲苯作溶剂时交联反应可以被抑制。IR和 ̄1HNMR结果表明,甲苯作为聚合反应的链转移剂参与了链转移反应。  相似文献   

3.
研究了由多种Lewis酸(FeCl3、AlCl3、TiCl4、BF3·OEt2等)与SOCl2配制成的一类新型聚合引发剂,比较了它们对α-蒎烯的引发复合性能。结果表明复合引发体系的活性比之单独的Lewis酸均大幅度提高,活性大小顺序为:BF3·OEt2/SOCl2>TiCl4/SOCl2≈AlCl3/SOCl2>FeCl3/SOCl2,与它们的配位能力大小顺序一致。系统考察了TiCl4/SOCl2体系的聚合性能,研究了复合引发剂组分比、溶剂、活泼单体苯乙烯、外加Lewis碱以及聚合条件等对α-蒎烯聚合动力学、产物分子量及其分子结构的影响,据之讨论了该复合引发剂的作用机制,提出了活性种本质的看法。  相似文献   

4.
流态化CVD制备TiO2—Al2O3复合粒子   总被引:6,自引:0,他引:6  
本文探讨了流态化CVD反应器中Ti(OC4H9)4水解制备TiO2-Al2O3复合粒子新工艺,借助于SEM、TEM、BET、XRF和EPMA等现代测试手段研究了复合粒子结构和包覆过程特征。结果表明,在流态化CVD反应器中Al2O3超细颗粒以团聚体形式存在,TiO2包覆量随Ti(OC4H9)4进料浓度升高而增加,但反应温度影响不大;在包覆过程中,同时存在成核和成膜,成核包覆使复合粒子比表面积增加,成  相似文献   

5.
采用以三氟甲基磺酸铝((CF3SO3)3Al)为引发剂,二氯甲烷为溶剂的阳离子聚合方法制备了聚(1,3-戊二烯)。用IR、1HNMR和13CNMR对聚合物结构进行了表征,并基于聚合物1HNMR谱对聚合物链结构进行了定量计算,聚合物环状和线型链结构分别占54%和46%,而线型链中的5种结构单元:反-1,4、顺-1,4、反-1,2、顺-1,2和3,4结构分别为23%、10%、10%、1%和2%。  相似文献   

6.
本文探讨了流态化CVD反应器中Ti(OC4H9)4水解制备TiO2-Al2O3复合粒子新工艺,借助于SEM、TEM、BET、XRF和EPMA等现代测试手段研究了复合粒子结构和包覆过程特征.结果表明,在流态化CVD反应器中Al2O3超细颗粒以团聚体形式存在,TiO2包覆量随Ti(OC4H9)4进料浓度升高而增加,但反应温度影响不大;在包覆过程中,同时存在成核和成膜,成核包覆使复合粒子比表面积增加,成膜包覆使复合粒子比表面积减小.  相似文献   

7.
1,3-戊二烯阳离子聚合引发体系(CH3)3SiCl/EtAlCl2的研究   总被引:1,自引:0,他引:1  
研究了阳离子引发体系Me3SiCl(TMSCl)EtAlCL2在正己烷中引发的1,3-戊二烯(PD)聚合反应。研究结果表明,在EtAlCl2引发的PD聚合反应中引入TMSCl后大幅主提高了聚合物产率,同时使聚合反应速率明显提高,在「TMSCl」/「EtAlCl22」=0-1范围内,TMSCl/EtAlCl2体系制备的聚合物分子量高于EtAlCl2引发制备的聚合物,这些结果表明Me3SiCl/EtA  相似文献   

8.
研究了反应时间、反应温度对异丁基乙烯基醚(IBVE)/Cl2/TiCl4聚合反应的影响及其反应活性,在低一70℃的CH2Cl2中,呈在较高温度并添加给电子试剂,均实现了活性阳离子聚合。  相似文献   

9.
吡啶对异丁烯阳离子聚合反应活性的作用   总被引:3,自引:0,他引:3  
采用t-BuOAc/TiCl4作引发体系,研究了吡啶对异丁烯阳离子聚合反应活性的作用。实验结果表明,在本聚合体系中加入吡啶,能控制聚合物的分子量,降低分子量分布,当PY/t-BuOAc=2时,得到MWD=1.2,M=6750的聚合物,Conv=95%。  相似文献   

10.
研究了反应时间、反应温度对异丁基乙烯基醚(IBVE)/Cl2/TiCl4聚合反应的影响及其反应活性。在低于-70℃的CH2Cl2中,或在较高温度并添加给电子试剂,均实现了活性阳离子聚合。  相似文献   

11.
交联大分子的合成与表征   总被引:2,自引:1,他引:1  
设计了含有分子内反应和分子间反应的聚合体系,这是一对竞争反应,竞争的结果可达到一定的平衡,使无法控制的凝胶化过程得以控制,从而合成了具有交联结构的大分子。通过分子尺寸的测定还发现了交联大分子在溶液中的特殊行为,这种特殊行为恰好验证了所合成的大分子具有交联结构。  相似文献   

12.
合成了一系列新型的具有光引发聚合反应活性的单体;不同分子量的聚乙二醇的双甲基丙烯酸酯。单体在紫外光引发条件下进行自由基聚合,生成交联的聚合产物。用^1H-NMR对单体进行了表征。用IR对单体和聚合物进行了分析,研究了双甲基丙烯酸二乙二醇酯的聚合反应动力学,测定了聚合活化能。  相似文献   

13.
改性MgCl2负载α-二亚胺镍催化乙烯聚合   总被引:2,自引:0,他引:2  
制备了一种含有胺基官能团α-二亚胺镍配合物,并将该配合物负载在改性MgCl2载体MgCl2/AlRn(OEt)3-n上制备负载催化剂,不用昂贵的MAO(甲基铝氧烷)而用通用烷基铝作助催化剂,研究了其对乙烯的聚合性能。采用高温13C-NMR、高温GPC、差示扫描量热法(DSC)和扫描电镜(SEM)对聚合物进行了研究。结果发现,该催化剂具有很高的催化活性,得到的聚乙烯产品含有各种短支链(甲基、乙基、丙基、丁基)和长支链,分子量在0.35×106和1.08×106之间,分子量分布较窄(2.34~2.93),载体对聚合物具有较好的模板作用。  相似文献   

14.
A new series of photosensitive poly(arylene ether sulfone)s containing chalcone moiety in the main chain were synthesized from 4,4′-dihydroxychalcone (4DHC), 4,4′-difluorodiphenylsulfone (DFDPS) and bisphenol A (BPA). This series of polymers were characterized by 1H NMR, FT-IR, UV spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The polymers were stable up to 400 °C, which indicates that the polymers possess good thermal properties. The polymers were found to be soluble in polar solvents and chlorinated solvents. However, the polymers were insoluble in hydrocarbons and in hydroxyl group-containing solvents. After the irradiation of UV light, the thin polymer film was crosslinked to give an insoluble film in the absence of a photoinitiator or sensitizers. The rate of photocrosslinking was also examined and discussed.  相似文献   

15.
Coated beads were prepared by soaking in sodium alginate solutions spherical matrices (beads) of carboxymethylcellulose crosslinked with aluminum chloride (AlCl3) and loaded with ambroxol hydrochloride as a model drug. The residual amount of the crosslinker induced an interfacial crosslinking reaction of the sodium alginate. Therefore, an insoluble, smooth and uniform in thickness coat was formed around the beads. As the coating time increased, the coat thickness increased until1 AlCl3 was present inside the beads. The rate of drug release from the coated beads was slower than that from the uncoated beads and decreased with the increase in coating time. Moreover, a constant rate phase, subsequent a burst period for the samples obtained with the highest coating times, was achieved. The dynamic swelling analysis allowed to exclude the influence of the polymer relaxation on the release process which appeared to be controlled by the alginate coat.  相似文献   

16.
Abstract

Coated beads were prepared by soaking in sodium alginate solutions spherical matrices (beads) of carboxymethylcellulose crosslinked with aluminum chloride (AlCl3) and loaded with ambroxol hydrochloride as a model drug. The residual amount of the crosslinker induced an interfacial crosslinking reaction of the sodium alginate. Therefore, an insoluble, smooth and uniform in thickness coat was formed around the beads. As the coating time increased, the coat thickness increased until1 AlCl3 was present inside the beads. The rate of drug release from the coated beads was slower than that from the uncoated beads and decreased with the increase in coating time. Moreover, a constant rate phase, subsequent a burst period for the samples obtained with the highest coating times, was achieved. The dynamic swelling analysis allowed to exclude the influence of the polymer relaxation on the release process which appeared to be controlled by the alginate coat.  相似文献   

17.
高吸水聚合物 (SAP)是一类不溶不熔的低交联高分子聚合物 ,常规的色谱法无法进行分析鉴定。本文介绍了红外光谱 (IR)、核磁共振法、热分析及电镜法在表征SAP中的应用  相似文献   

18.
Photocross-linking behaviour of poly(ethylene-co-glycidyl methacrylate) (EGMA) initiated by benzylsulphonium slats (BSS) has been investigated in relation to negative photoresist. Unlike triarylsulphonium slats which produce Brønsted acids, following the reaction with solvents or monomers, BSS directly produces benzyl cation on photoirradiation at > 300 nm and the resulting benzyl cation attacks the epoxy residues in EGMA to initiate cationic polymerization, leading to interchain cross-linking of the polymer. In this photocross-linking reaction, the efficiency was found to be so high that only 0.15 mol% BSS (based on the epoxy content in the copolymer) was enough to produce an insoluble network of the copolymer. This fact strongly suggests the presence of domains where the epoxy moieties and BSS are concentrated, thereby once initiating species (benzyl cation) are formed photochemically, the cationic polymerization takes place effectively in these domains.  相似文献   

19.
尼龙-6膜与丙烯酸接枝共聚合的研究   总被引:2,自引:0,他引:2  
通过一系列实验选择以(NH4)2(NO)6/HSO4为引发剂,了尼龙-6膜与丙烯酸的接枝共聚合反应,通过改变单体浓度,反应温度,(NH4)2Ce(NO3)6浓度,H2SO4浓度,尼龙-6膜在甲酸中的溶胀时间等因素发现,接枝膜的接枝率与单体浓度有关,。随单体浓度的改变,接枝率有一个极大值,单体浓度高于或低于此浓度,接枝率都较低,通过改变(NH4)2Ce(NO3)6和H2SO4浓度也得到类似规律,反应温度对接枝膜的接枝率也有影响,温度过高(>70度)或过低(小于40℃)都得不到较高的接枝率;将尼龙-6膜在20%甲酸中溶胀,有利于提高产物的接枝率。  相似文献   

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