首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
本文报导采用一类崭新的乙炔室温高度顺式定向聚合催化剂—一稀土络合催化剂,在30℃使乙炔聚合,制得顺式含量在90%以上,具有金属光泽的银色薄膜。用碘、溴等电子受体对其进行液相化学掺杂,可制得高导电性稀土聚乙炔膜,其最高室温电导率达~103Ω-1·cm-1,较掺杂前增加11个数量级,而相应的掺杂剂浓度为~12.5mol%。卤素掺杂效应与聚乙炔膜的纤维填充体积大小、聚乙炔的构型以及膜的氧化程度有关。此外,用红外光谱、差动热分析、X衍射、扫描电镜分析及测定电导率、密度等对卤素掺杂稀土聚乙炔膜进行了表征。  相似文献   

2.
This article reviews the chemistry of substituted polyacetylenes developed by our research group, more specifically, development of polymerization catalyst, synthesis of new polymers, elucidation of their structure, investigation of their properties, and development of their functions. The main features are as follows: a number of catalysts based on group 5, 6, and 9 transition metals (Nb, Ta, Mo, W, and Rh) have been developed, which include living polymerization catalysts. By using these catalysts, many new substituted polyacetylenes have been synthesized, whose molecular weights are very high (Mw = 104?106). Most of the polymers are soluble in many common solvents and stable enough in the air unlike polyacetylene. Some of these polymers exhibit interesting functions including high gas permeability and photoelectronic properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 165–180, 2007  相似文献   

3.
Ring opening polymerization of propylene sulfide using rare earth coordination catalysts has been investigated for the first time. It has been found that trinary rare earth coordination catslysts composed of rare earth compounds of phosphonate, naphthenate or acetylacetonate, trialkyl sluminum and water are effective catalysts for the polymerization of propylene sulfide. The polymerization in toluene is a homogeneous reaction. High molecular weight as high as several million poly(propylene sulfide) with high yield can be prepared by these catalysts. Kinetic studies showed that the polymerization rate is of first order with respect to both monomer concentration and catalyst concentration. The activation energy of the polymerization reaction is 61.4 k fJ/mol. The structure of the polymers so obtained has also been characterized by ~(13)C NMR spectroscopy, X-ray diffraction, gel permeation chromatography and differential scanning calorimetry.  相似文献   

4.
本文综述了我国首创开拓的稀土络台催化聚合在炔烃和开环聚合方面的新进展.用稀土络合催化剂可以使乙炔、苯乙块在室温下聚合制备高顺式含量和抗氧化稳定性良好的聚炔烃膜;可以使环氧乙烷、环氧丙烷、环氧氯丙烷和环硫丙烷聚合制备高分子量聚合物;可以使丙交酯聚合制备可控分子量聚合物.  相似文献   

5.
新的铁盐体系催化合成聚乙炔   总被引:1,自引:0,他引:1  
本文发现并研究了三种乙炔定向聚合的新催化剂--环烷酸和膦酸酯铁盐与三烷基铝组成的配位络合催化剂.对所得的聚乙炔进行了IR、ESR、X-射线衍射、SEM、TEM、电阻率及元素分析等表征。结果表明,新催化剂具有聚合活性高,定向性好,可直接成膜等特点。同时发现Fe(P507)3催化所得聚乙炔有单晶衍射特征。此外,对聚乙炔膜的电化学及电池性能也进行了研究。  相似文献   

6.
New acetylene monomers, 6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-1-pheny-1-hexyne (1), 2, 5-diethynyl-thiophene (3), and 4,4'-diethynylbiphenyl(6) were synthesized. Homopolymerization of 1 and copolycyclotrimerizations of 3and 6 with 1-heptyne and 1-octyne have been achieved with WCl_6- and TaCl_5-Ph_4Sn catalysts, respectively, giving solublelinear disubstituted polyacetylene (2) and hyperbranched polyarylenes (5 and 8) with high molecular weights (up to 1.2×10~5) in high yields (up to 98%). The trictures and properties of the polymers are characterized and evaluated by IR, NMR,TGA, UV, photoluminescence (PL), and electroluminescence (EL) analyses. All the polymers possess high thermal stabilityand emit strong blue ligh upon photoexcitation. The intensity of the emitted light is greater than that of poly(1-phenyl-1-octyne), a well-known highly luminescent disubstituted polyacetylene. Little aggregation-induced red shift in the PL wasobserved in the thin films of the polymers. By constructing a multi-layer EL device, high EL quantum yield (0.18%) has beenachieved in 2, which are the best results for substituted polyacetylenes attainable so far.  相似文献   

7.
冯新德 《化学通报》1999,(10):1-6,57
简要叙述我国近20年来在高分子化学研究领域中的自由基聚合、光诱导聚合、Ziegler Natta聚合和茂金属聚烯烃、环醚、枘酯等开环聚合、缩聚反应合成PEEK和耐热性杂环高分子含氟高分子、生物医学高分子、导电高分子、液晶高分子方面的进展。  相似文献   

8.
In the last 20 years a wide variety of new types of polymers has been prepared containing metals as an integral part of the polymer backbone. This paper summarizes deveopments in the following major areas: vinylic polymers, including vinyl metal-locene derivatives and vinylic tin monomers; condensation polymers; polyorganophosphazenes; coordination polymers; mixed valence polymers with electrical conductivity such as (SN)x, polyacetylene and polyphenylene; stacked polymers such as platinum blue, polyphthalocyanines, and TTF-TCNQ. The methods of synthesis and potential applications of these materials in areas such as catalysis, elastomers with low and high temperature stability, metallic conductors, semiconductors, bacteriacides, fungicides, and cancer chemotherapeutic agents are discussed.  相似文献   

9.
设计并合成了具有较大空间位阻侧链的取代炔烃2-炔丙氧基-1,4-对苯二甲酸二甲酯单体,分别采用WCl6,WCl6-SnPh4和[Rh(nbd)Cl]2催化体系使其聚合,考察了不同催化剂对聚合的影响.采用红外光谱和核磁共振等技术对单体及聚合物结构进行了表征,并用紫外光谱和荧光光谱研究了所得聚合物的光学性能.结果表明,使用[Rh(nbd)Cl]2催化剂时得到的聚合物是高反式结构,荧光光谱中除了侧基的350 nm发射峰外,还在429 nm处存在较弱的共轭主链发射.使用WCl6-SnPh4催化体系得到的聚合物由于较高的顺式含量,主要是侧基的发射,而较大侧基位阻使主链共轭降低.尽管存在较短的间隔基,引入较大空间位阻侧基仍然迫使聚合物主链扭曲,顺式结构中侧基空间位阻的影响更大.  相似文献   

10.
芳基单取代炔合成方法   总被引:4,自引:3,他引:1  
综述了各种芳基单取代炔的制备方法;分析了各种方法的反应机制和特点,认为钯催化偶联-消去反应合成芳基单取代炔是比较好的方法。芳基取代聚炔及其衍生物呈现出光、电、磁等许多新颖的性能。芳基单取代炔的合成对芳基取代聚炔的制备起到关键作用。参考文献69篇。  相似文献   

11.
Novel polyacetylenes, poly( 1 ) and poly( 2 ) substituted with benzoxazine rings were synthesized by the polymerization of the corresponding acetylene monomers 1 and 2 using Rh catalysts, [(nbd)RhCl]2, and (nbd)Rh+BPh4 (nbd = 2,5‐norbornadiene). The polymers were heated at 250 °C under N2 to obtain the corresponding polybenzoxazine resins, poly( 1 )′ and poly( 2 )′ possessing polyacetylene main chains via the ring‐opening polymerization of the benzoxazine moieties. The polyacetylene backbones were maintained after crosslinking reaction at 250 °C, which were confirmed by Raman spectroscopy. The benzoxazine resins were thermally highly stable as evidenced by differential scanning calorimetry and thermogravimetric analysis. The surface of poly( 1 )′ film became hydrophilic compared to that of poly( 1 ), while the surfaces of poly( 2 ) and poly( 2 )′ films showed almost the same hydrophilicity judging from the water contact angle measurement. Poly( 1 )′ and poly( 2 )′ exhibited refractive indices smaller than those of poly( 1 ) and poly( 2 ). © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1884–1893  相似文献   

12.
本文研究了不同钕化合物Nd(P_204)_3,Nd(P_507)_3,Nd(NO_3)_3·3P_350,Nd(BA)_3·3H_2O,Nd(acac)_3·3H_2O与三烷基铝,给电子化合物组成络合催化剂使乙炔聚合的规律。酸性膦酸酯钕盐Nd(P_507)_3体系具有最高的催化活性,所制得的聚乙炔膜的顺式结构含量可达97%以上。  相似文献   

13.
Summary: The applications of calixarenes in polymer synthesis have been reviewed. Calixarenes have been used as ligands to prepare rare earth calixarene complexes. A series of rare earth calixarene complexes have been synthesized and employed as efficient catalysts for the polymerization of ethylene, styrene, butadiene, propylene oxide, styrene oxide, trimethylene carbonate, and 5,5-dimethyl trimethylene carbonate. On the other hand, the synthesis and characterization of star-shaped polymers with calixarene as core molecules are also described.  相似文献   

14.
Acetylenic and diacetylenic liquid crystalline monomers have been prepared in order to obtain conjugated polymers with an orientational character. Unlike the polydiacetylene derivatives obtained and which do not exhibit any mesomorphic behaviour, a smectic phase, stable over a large temperature range, occurs in the case of all the polyacetylenes. This mesophase appears to be stabilized by an in situ polymerization of the monomers oriented in the nematic state. After iodine doping, a nematic phase appears in the polymer in addition to the smectic phase. AC complex conductivity measurements, realized over a large frequency range. are reported for some doped and undoped polyacetylenes. Preliminary results concern both non-oriented polymers and an undoped polymer in which the mesogenic groups have been oriented after polymerization.  相似文献   

15.
Highly stereospecific polymerization of monosubstituted acetylenes was carried out using the Rh complex, [Rh(norbornadiene)Cl]2 catalysts. The resulting polyacetylenes were characterized in detail by 1HNMR, ESR, laser Raman, diffuse reflective UV, and wide angle X-ray diffraction methods. The data showed that the Rh complex were the preferred catalyst to selectively yield the corresponding cis-transoid polymers even at room temperature when alcohol, triethylamine or water was used as the polymerization solvent. Additionally, the resulting cis polyacetylenes were found to have a helical form whose polymer is amorphous or composed of pseudohexagonal structures called π-conjugated columnar as self-assembly or super structure. Further compression of the amorphous cis polymers resulted in cis to trans isomerization at room temperature under vacuum, breaking rotationally the cis C=C bonds giving π-radicals called solitons as the origin of a polymer magnet. On the other hand, the π-conjugated columnar was also found to show an extremely longer wavelength absorption compared with that of the amorphous one, although the absorption maximum was shifted to a shorter wavelength when the columnar was destroyed by the compression. Therefore, the formation of the π-conjugated columnar can be considered as a new and quite useful control method concerning color of such conjugated polymers, i.e., a new concept concerning the color of conjugated polymers.  相似文献   

16.
Different new catalysts based on transition metal compounds of groups IVb, Vb, VIb and VIIIb combined with a reducing agent such as: triethylaluminium and butyllithium in various solvents; toluene and silicone oil, were used for the polymerization of acetylene. By changing the catalyst, cocatalyst, solvent and polymerization conditions, a large variety of polyacetylenes were obtained. The polyacetylenes were characterized by SEM, FTIR and C13 NMR spectroscopies. Some of the new polymers were stretched mechanically and then doped with iodine. Thus highly conducting thick (20μm) and transparent films (0.1 μm) were obtained, with conductivities of 20000 ω−0.cm−1 and 8000 ω−1.cm−1, respectively. After modification of the standard catalyst system (Ti(OC4H9) 4-Al (C2H5) 3-silicone oil) by the introduction of some additional reducing agents, conductivities as high as 120000 ω−1.cm−1, after elongation and iodine doping of the polymers, were reached. In this paper we present also a comparative stability study of the new (CH)x films and powders.  相似文献   

17.
A series of substituted acetylenes has been polymerized with WOC14/Ph4Sn metathesis catalyst and [Rh(cod)OMe]2 insertion catalyst, and the thermal degradation of the polyacetylenes prepared has been studied using pyrolysis capillary gas chromatography (Py-GC) with flame ionization and mass spectrometric detection to obtain information on the effect of the catalyst on the head-tail (H-T) isomerism of polyacetylenes (poly(phenylacetylene), poly[(4-methylphenyl)acetylene], poly(benzylacetylene), poly((2-fluorophenyl)acetylene], poly[(3-fluorophenyl)acetylene], and poly[(4-fluoro-phenyl)acetylenel). Cyclotrimers have been found to be the main pyrolysis products in all cases. Direct Py-MS connection was used to determine the temperature profiles of the released pyrolysis products. 1,3,5-Trisubstituted benzenes were found to be the predominant pyrolysis products of the polymers prepared with the insertion catalyst, which proves the presence of long head-to-tail sequences of monomeric units in these polyacetylenes. On the other hand, both 1,2,4- and 1,3,5-trisubstituted benzenes are present in significant amounts in the pyrolysis products of polymers prepared with the metathesis catalyst, which proves the presence of a significant content of the head-to-head (HH) and tail-to-tail (TT) linkages in these isomers of polyacetylenes. Contents of the regular (HT) and inverse (HH-TT) monomer linkages (RML and IML, respectively) in polymer chains were determined from the relative amounts of di-, tri-, and tetrasubstituted benzenes found in the Py-GC products.  相似文献   

18.
<正> 聚乙炔掺入杂质后,做为高分子导电材料已引起人们的极大关注。有关聚乙炔(下称PA)的合成、结构及性能测试,以及电池研究已有很多报道,其催化剂体系已有关于Ti、V、Cr、W、Fe、Mo、Ni和Co等过渡金属化合物,稀土化合物合成PA的报道。本文进行了应用重元素钍的高配合物[Th(P_(204))_8Cl_4]与三乙基铝组合作为催化剂、使乙炔在常温下定向聚合的研究,得到具有余属光泽银白色的PA,顺式含量为80%,并对PA薄  相似文献   

19.
本工作采用三乙酰基丙酮钒及二乙酰基氧钒同烷基铝组成的催化体系,研究了乙炔聚合的规律及聚乙炔成膜的条件,并初步研究了聚乙炔膜的链节结构、形态结构及室温电导率。  相似文献   

20.
近年来文献中出现了一些以歧化催化剂用于炔烃聚合的尝试[1-4],例如以WCl6-ph4Sn、MoCl5-ph4Sn体系进行炔烃聚合反应,均有活性。我们在烯烃均相催化歧化反应的研究中,试探了将此类催化剂用于乙炔聚合,结果是:(1)试验过的7种催化体系均能使乙炔聚合,生成黑色不溶的高分子,红外光谱测定表明,得到的聚乙炔是顺式和反式结构的混合物,此外,部分乙炔尚三聚环化成苯;(2)不同催化剂作用下乙炔聚合和烯烃歧化的活性和选择性没有平行关系;(3)几种催化体系对乙炔高聚和环化三聚的选择性不同(见表1)。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号