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1.
Polybenzimidazoles (PBI) with p-phenylene and/or cis-vinylene groups in the backbone were prepared from terephthalic acid (T), maleic acid (M), and 3,3′ diamino-benzidine tetrahydrochloride dihydrate (DAB) in poly(phosphoric acid) (PPA). Five polymer samples were prepared by varying the M:T molar ratios in the following order: 1:0, 1:1, 2:1, 1:2, and 1:4. The polymers were characterized by intrinsic viscosity, density, electronic fluorescence, and IR spectra. The effect of composition on the solubility of the polymers in various organic solvents was also investigated. The relative thermal stability of the polymers was evaluated by dynamic thermogravimetry in air and polybenzimidazoles (PBI) with cis-vinylene groups were found to be less stable.  相似文献   

2.
Homopolymers and copolymers containing the polybenzimidazoles ring were prepared from terephthalic acid (T), fumaric acid (F), and 3,3′-diaminobenzidine tetrachloride (DAB) in polyphosphoric acid. The polymers were characterized by viscometry, infrared spectroscopy, and nitrogen analyses. The effect of copolymer composition on the ultraviolet and visible spectra, solubility in various solvents, and density was also investigated. The relative thermal stability of the various polybenzimidazoles was investigated by using dynamic thermogravimetry in air. Polybenzimidazole derived from terephthalic acid was most stable, and the introduction of aliphatic residues resulted in a decrease in thermal stability. However, the homopolymer of fumaric acid was more stable than the copolymers of fumaric acid and terephthalic acid.  相似文献   

3.
The optical properties of poly(vinylamine) containing optically active (+)- or (?)-2-(thymin-1-yl) propionyl groups as grafted pendants (PT) and the related monomer (MT) and dimer models (DT) were investigated by UV, circular dichroism (CD), and NMR spectroscopy. Highly syndiotactic PT has a smaller hypochromicity versus MT and a larger optical rotation than the less syndiotactic PT in various solutions. These results are attributed to an interaction between the configurational arrangement of thymines, the conformation of the polymers, and base stacking between thymines. The interactions of these polymers with poly(adenylic acid) (polyA) were also studied and the results compared with other vinyl-type nucleic acid model polymers. The isomers of the optically active dimer models [prepared from meso and (dl)-2,4-diaminopentane] were separated. The CD spectra of (+)-D(?)T in CHCl3 and trifluoroethanol (TFE) displayed extremely solvent-dependent exciton coupling of the π–π* (B2u) transition of the base chromophore, which was not observed in the other models or polymers, except the meso-type dimer model (meso)-D-(?)T. This coupling decreased with increasing solvent dielectric constant, while UV hypochromicity increased. This behavior as well as the 360-MHz NMR spectra suggest that (+)-D(?)T exists in an extended form in solvents of low dielectric constant and gradually assumes a stacked conformation as the dielectric constant increases.  相似文献   

4.
Three series of polymers containing p-phenylene diacrylic group were prepared by direct polycondensation in the presence of diphenylchlorophosphate and pyridine. Series I was prepared from p-phenylene bis(acrylic acid) with various hydroquinones. Series II was prepared from p-phenylene bis (β-cyano acrylic acid) with methylhydroquinone. Series III was prepared from 3-methyl-4-aminophenol with p-phenylene bis(acrylic acid) or p-phenylene bis(β-cyano acrylic acid), respectively. The phase behavior of these polymers was studied by differential scanning calorimetry (DSC), optical polarizing microscopy equipped with a heating stage, and wide-angle x-ray diffraction (WAXD). It was found that these polymers, except IIIb , exhibit thermotropic liquid-crystalline properties and show threaded or Schlieren texture under the optical polarizing microscopic observation. Furthermore, the melting temperatures of these polymers were decreased in the range of 254–354°C by incorporating with p-phenylene diacrylic group into the main chain. © 1993 John Wiley & Sons, Inc.  相似文献   

5.
Three polymers have been prepared by the condensation of benzo[1,2-b;5,4-b ′]-dipyrrolo-2,3,4,5-tetraone (I) with 1,2,4,5-tetraaminobenzene (II), 3,3 ′-diaminobenzidine (III), and 3,3 ′,4,4 ′-tetraaminodiphenyl ether (IV) in polyphosphoric acid (PPA) solution. The polymer structures were substantiated by comparison of their infrared and ultraviolet spectra with spectra of the model compounds and elemental analysis. The polymers had inherent viscosities of 0.86-0.90 (H2SO4) and thermal stabilities of 460°C and up to 700°C in air and nitrogen atmospheres, respectively.  相似文献   

6.
Coordination polymers of Cu(II), Ni(II), Co(II), zinc(II), chromium(IU), iron(IU), oxovanadium(N), and dioxouranium-(VI) with p-hydroxybenzoic acid (PHB)-thiourea (T)-trioxane (T) (PHBTT) polymer were prepared. The analytical data agree with 1:1 metal-ligand stoichiometry. Magnetic susceptibility, visible and IR spectra, and thermal and electrical conductivities of the chelates have been studied and probable structures assigned to the chelates.  相似文献   

7.
本文通过七种二羟烷基嘧啶单体与N,N’一双(2-氯乙基)氯磷酰胺进行缩聚反应,制得了七种新的含核酸碱基或其类似物和氮芥的聚磷酸酯,用核磁、红外光谱及元素分析确定了单体和聚合物的结构。部分聚合物试验结果表明,既含氮芥又含5-氟尿嘧啶的聚合物具有较高的抗癌活性和较低的毒性,聚合物(Ⅲ_a)对小鼠艾氏腹水癌的抑制率可达66%。  相似文献   

8.
Small gold clusters (<1 nm), protected by monolayers of glutathione, N-(2-mercaptopropionyl)glycine, or mercaptosuccinic acid, were prepared by reducing the corresponding Au(I)-thiolate polymers and were fractionated by size using polyacrylamide gel electrophoresis (PAGE). Mass analysis of the fractionated clusters revealed that their core sizes varied with the molecular structures of the thiolates. This finding indicates that the reduction of the Au(I)-thiolate polymers yields small clusters whose growth is kinetically hindered by passivation with thiolates. Optical spectra of the clusters with identical compositions exhibited different profiles depending on the thiolate molecular structures. This observation implies that deformation of the underlying gold cores is induced by interligand interactions.  相似文献   

9.
In an attempt to synthesize soluble polymers, diphenyl 1,5-anthraquinonedicarboxylate was treated with 3,3′-dimercaptobenzidine and 3,3′-diaminobenzidine under various conditions. Although the ester reacted readily, side reactions prevented the formation of high molecular weight compounds. It was thought that at the elevated temperatures required for reaction, the quinone group was involved in a type of Schiff's base formation. The thermal stability of the polymers was evaluated. Model compounds were prepared and their absorption spectra were compared with those of the polymers. It was observed that 1,5-anthraquinonebibenzimidazole-2 formed a stable product with acetic acid. Some of the polymers could be solubilized by reduction with sodium dithionite in alkali, but no useful fibers were produced from these solutions.  相似文献   

10.
The preparation and radical-initiated polymerization of a carbazole-substituted N-acylated dehydroalanine, namely, 2-(9-carbazolyl)acetylaminopropenoic acid ( 7 ) and its methyl ester ( 6 ) is reported. The monomers 6 and 7 were prepared by dehydrochlorination of N-acylated β-chloroalanine derivatives. The monomer model compounds for the two polymers, namely, 2-(9-carbazolyl)acetylamino-2-methylpropanoic acid ( 11 ) and its methyl ester ( 10 ), were also prepared. The polymers and their monomer model compounds were characterized by elemental analysis, IR and 1H-NMR spectra. The polymers 12 and 13 of different molecular weights could be obtained by changing the monomer-to-initiator ratios used in polymerization experiments.  相似文献   

11.
分别通过一步加料和分步加料的方法,以对苯二胺(A2)、均苯三酸(B3)和对氨基苯甲酸(AB)为原料进行溶液缩聚反应,制备了具有良好溶解性的芳香聚酰胺共聚物.产物的结构通过IR、1H-NMR得到证实.采用IR和1H-NMR对一步加料共聚反应的共聚行为进行研究,并初步考察了3种不同单体对反应的影响.  相似文献   

12.
A dicarboxylic acid ( I ) was prepared from the condensation of 9,9-bis[4-(4-aminophenoxy) phenyl] fluorene and trimellitic anhydride. A new family of poly(amide-imide)s having inherent viscosities of 0.75-1.04 dL/g was prepared by the triphenyl phosphite activated polycondensation from the diimide-diacid I with various aromatic diamines in a medium consisting of N-methyl-2-pyrrolidone (NMP), pyridine, and calcium chloride. Most of the resulting polymers showed an amorphous nature and were readily soluble in polar solvents such as NMP and N,N-dimethylacetamide. All the soluble poly(amide-imide)s afforded transparent, flexible, and tough films. The glass transition temperatures of these polymers were in the range of 262–325°C and the 10% weight loss temperatures were above 525°C in air. © 1994 John Wiley & Sons, Inc.  相似文献   

13.
李鸣芳  王兵 《化学学报》2012,70(7):921-928
以槲皮素-钴(Ⅱ)的配合物为模板分子,在强极性甲醇溶剂中分别采用低温光引发和高温热引发聚合制备槲皮素-钴(Ⅱ)配位印迹聚合物.紫外-可见光谱分析确定了槲皮素与钴(Ⅱ)形成配合物的最佳配位比.根据印迹聚合物的平衡结合量优化功能单体丙烯酰胺用量.利用红外光谱、透射电镜和平衡结合实验,考察不同引发方式对聚合物的结构、微观形貌及结合性能的影响.进一步通过特异吸附容量和印迹指数确定,低温光引发聚合更适于配位分子印迹聚合物的制备.同时研究了不同阳、阴离子对印迹聚合物选择识别性的影响.结果表明光引发的金属配位分子印迹聚合物具有良好的吸附选择性,印迹指数可达3.919.  相似文献   

14.
Four series of copoly(amide-ester)s containing conjugated double bonds were prepared by using direct polycondensation in the presence of diphenylchlorophosphate (DPCP) and pyridine. Series I–III were prepared from para, meta-aminophenol, or their mixture with p-phenylene bis(acrylic acid) (PPBA), p-carboxylic cinnamic acid (PCCA), and stilbenedicarboxylic acid (SDBA), respectively. Series IV was prepared from a mixture of aminophenols [2-methyl 4-aminophenol (MePAP) and m-aminophenol (MAP)] with a mixture of diacids (PPBA and SDBA). Thermotropic liquid-crystalline behavior of these polymers was studied by differential scanning calorimetry (DSC), and optical polarizing microscopy equipped with a heating stage. Series I , series II , and P40–P100 of series IV could undergo crosslinking reaction by heating. However, series III could undergo crosslinking reaction only by photoirradiation upon heating. After crosslinking reaction occurred, the properties of these polymers were also examined by DSC, TGA, WAXD, and IR. The synthesized polymers could be crosslinked in the liquid-crystalline phase with retention of the order in the final crosslinked solid. © 1993 John Wiley & Sons, Inc.  相似文献   

15.
Head-to-head (H–H) poly(allyl alcohol) (PAA) was prepared by the LiAlH4 reduction of H–H poly(methyl acrylate) obtained from the methylation of alternating copolymer of ethylene with maleic anhydride. H–H poly(allyl acetate) (PAAc) and H–H poly(allyl benzoate) (PABz) were further derived by means of its acylations. All of these three H–H polymers were characterized by IR, NMR, TGA, and PGC measurements. The corresponding head-to-tail (H–T) polymers were also prepared by a similar method from the conventional H–T polymer of methyl acrylate, and characterized to allow comparison with the H–H polymers. The softening temperatures of all H–H polymers were somewhat higher than those of the respective H–T polymers, probably suggesting that the H–H placements increased the stiffness of the polymers. Unlike poly(acrylic esters) reported previously, these H–H allyl polymers were found to degrade at temperatures slightly lower than the H–T polymers. On pyrolysis at 430°C, both PAAc and PABz were also observed to release predominantly acetic acid and benzoic acid, respectively, and small quantities of the corresponding allyl ester monomers. The molar ratios of acid to ester were substantially larger for H–H polymers.  相似文献   

16.
新型功能性超支化聚酯的合成及表征   总被引:11,自引:0,他引:11  
近年来 ,树枝状和超支化聚合物的研究受到了广泛重视 ,被视为 2 1世纪聚合物科学发展的重要方向[1] .这两种聚合物都有大量的端基 ,与相同分子量的线型聚合物相比 ,它们具有更低的粘度和更好的溶解性 .树枝状聚合物具有规整的结构 ,但合成困难 ;超支化聚合物的支化结构不完整 ,可以通过简单的一步聚合获得 ,因此 ,后者受到更广泛的重视 ,也最有可能实现工业化 [2 ,3] .通常 ,超支化聚合物是通过 ABx(x≥ 2 )型单体的缩聚合成的 ,通过改变超支化聚合物的组成、结构及对其端基进行功能修饰 ,可以制备多种具有特殊用途的新材料 ,在粘度改性剂…  相似文献   

17.
Based on the special properties and advantages of β-cyclodextrin (β-CD), β-CD polymers have been widely studied and used in recent years. A lot of researches have focused on the adsorption and separation properties of β-CD polymers. In this paper, β-CD polymer modified by sulfonate groups, which was named S-β-CDP, was prepared using epichlorohydrin as crosslinker and tiron (1,2-dihydroxybenzene-3,5-disulfonic acid disodium salt) as modifier. β-CD polymer without modification, which was named β-CDP, was also prepared for comparison. Infrared spectra, elemental analysis and adsorption tests of S-β-CDP were carried out and compared with β-CDP. The content of sulfonate groups in S-β-CDP was obtained from elemental analysis. The dramatically increased adsorption capability toward methylene blue and basic magenta confirmed the existence and chemical activity of sulfonate groups in S-β-CDP. Due to the convenient preparation process and modified adsorption properties, S-β-CDP will find its applications in various fields such as water purification, drug loading, separation and analysis.  相似文献   

18.
The model chelating compounds β-[2,4-bis(dimethylamino)-s-triazin-6-yl] hydrazinoacetic acid, β-[2,4-bis(dimethylaniino)-s-triazind-yl] hydrazino-N, N-diacetic acid, 2,4-bis(dimethylamino)-s-triazin-6-yl-aminoacetic acid, and 2,4-bis(dimethylamino)-s-triazin-6-yl-iminodiacetic acid have been synthesized and characterized by composition analysis, infrared spectroscopy, and potentiometric titration data. The copper(II), nickel(II), cobalt(II), zinc(II), magnesium(II), and palladium(II) complexes of the first two model compounds, and the copper, nickel, cobalt, and zinc complexes of the third and fourth model compounds have been prepared. The infrared absorption spectra of the model compounds and their complexes were recorded for the range 3800 to 600 cm?1, and the assignment of pertinent bands was made by comparison with reported infrared correlations. In those cases where applicable, shifts in the NH stretching vibration and carboxylate stretching vibration frequencies of the metal complexes were compared to those of the proper references and used as an indication of possible chelation effects in the metal complexes.

The aldehyde-reactable β-[2,4-diarnino-s-triazin-6-y1] hydrazinoacetic acid was also prepared and characterized; its polymers were prepared by the reaction of both the free ligand and its copper(II) complex with formaldehyde. Qualitative studies on the reaction of these polymers with metal ions and on the ease of metal ion elution from the polymers indicate that t h is a promising chelating polymer system.  相似文献   

19.
A series of ferrocene-containing polyesters and polyamides were prepared by refluxing 1,1′-dichlorocarbonylferrocene with various diols and primary diamines in xylene–pyridine solvent. The polyamides were all solids, but some of the polyesters were liquids. Reported are the infrared spectra and solubility characteristics of all the polymers and, where possible, the molecular weight and molecular weight distributions. In general, these polyamides and polyesters were of relatively low molecular weight (below 4000), but the polyesters were readily chain extended and crosslinked by di- and triisocyanates. Elemental analyses are reported for all the polymers prepared.  相似文献   

20.
首先利用高真空活性负离子聚合方法制备聚异戊二烯锂(PI-Li)和(聚苯乙烯-b-聚异戊二烯)锂(PS-PI-Li)活性链,再与单羟基七乙烯基多面体齐聚倍半硅氧烷(VPOSS-OH)发生加成反应,一步法制备2种含羟基的七臂星形聚合物.用分级沉淀法去除低加成产物,即可得到纯的七臂星形聚合物7PI-POSS-OH和7(PS-PI)-POSS-OH,利用凝胶渗透色谱(GPC)、核磁共振波谱(1H-,13C-NMR)、红外光谱(FTIR)和基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)表征了聚合物的化学结构、分子量及分子量分布,并通过热失重分析(TGA)测试了聚合物的热分解温度.  相似文献   

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