共查询到20条相似文献,搜索用时 15 毫秒
1.
Loon-Seng Tan K. R. Srinivasan Shih Jung Bai 《Journal of polymer science. Part A, Polymer chemistry》1997,35(10):1909-1924
Thermally stable, nonrigid-rod poly(benzobisthiazoles), (R)TPA-PBZT , where R = H, Me, NMe2, and OH, and poly(benzobisoxazoles), (R)TPA-PBO , where R = Me, NMe2 containing electron-rich triarylamine groups with various para-substituents (Rs) on the pendent phenyl ring, were synthesized from either 2,5-diamino-1,4-benzenedithiol dihydrochloride or 2,4-diamino-1,5-benzenediol dihydrochloride and the respective triarylamine-based dinitrile or diacid monomer in polyphosphoric acid. Whereas (R)TPA-PBZT polymers were obtained in moderate molecular weights, analogous (R)TPA-PBO polymers were only prepared in low molecular weights. No lyotropic behaviors, characteristic of the unmodified rigid-rod benzazole polymers, as evidenced by the absence of either stir opalescence or birefringence under crosspolarizers, were observed for these homopolymers at about 10 wt % polymer concentration. Among these polymers, only (Me)TPA-PBZT and (NMe2)TPA-PBZT formed cast films with good mechanical integrity. In their pristine state, their film conductivity values were in the range of 10−10–10−9 S/cm at room temperature. Upon exposure to iodine vapor, their conductivities were increased to the maximal values of 5.0 × 10−5 S/cm ( (Me)TPA-PBZT ) and 4.1 × 10−4 S/cm ( (NMe2)TPA-PBZT ). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1909–1924, 1997 相似文献
2.
C. S. Wang J. Burkett C. Y-C Lee F. E. Arnold 《Journal of Polymer Science.Polymer Physics》1993,31(12):1799-1807
Isotropic and oriented thin films of rigid-rod, rigid-rod pseudo-ladder, and ladder polymers were ion-bombarded with 84Kr+ to a dose of 4 × 1016 ions/cm2. The bombardment was conducted at two conditions: one at 190 keV energy with 0.12 μA/cm2 current density and the other at 200 keV energy with 2.0 μA/cm2 current density. With the low current density, the polymers developed a uniform ion-bombarded layer of about 0.35 μm at the surface. This layer showed an electrical conductivity on the order of 10?3s/cm at ambient conditions, an enhancement of 6 to 9 orders of magnitude from the pristine polymers. The enhanced conductivity was found to decrease to 10?6s/cm after the implanted krypton was removed by heating under reduced pressure. It suggests that the enhanced conductivity was due to a synergistic effect of structural change of the polymers and chemical doping by the im-planted ions. With the high current density, most polymer films, except that of rigid-rod pseudo-ladder poly(p-(2,5-dihydroxy) phenylene benzobisthiazole) (DPBT), developed an additional fibrous network structure over the uniform ion-bombarded layer. The comparable conductivity, 53 to 157 s/cm, measured for the various ion-bombarded films in-dicated that neither the molecular structure, rigid-rod or ladder, nor the molecular packing order, isotropic or oriented, constituted significant effect on the conductivity of ion-bombarded polymers. Since krypton could not be detected in the polymers ion-bombarded with high current density, the enhanced conductivity was attributed to the structural change of the polymers. The DPBT films ion-bombarded with high current density showed holes of micron size, probably due to the decomposition of hydroxy pendents from the rigid-rod backbone. © 1993 John Wiley & Sons, Inc. 相似文献
3.
Rong Chen Gennadi G. Nossarev Thieo E. Hogen‐Esch 《Journal of polymer science. Part A, Polymer chemistry》2004,42(21):5488-5503
Well‐defined and narrow molecular weight distribution macrocyclic poly(2‐vinylnaphthalene) (P2VN) and poly(2‐vinyl‐9,9‐dimethylfluorene) (PDMVF) containing a single 1,4‐benzylidene or 9,10‐anthracenylidene unit have been synthesized via the potassium naphthalide initiated polymerization of the monomers followed by the end‐to‐end coupling of the resulting P2VN dianions under high‐dilution conditions with 1,4‐bis(bromomethyl)benzene or 9,10‐bis(chloromethyl)anthracene. Molecular characterization has been carried out by size exclusion chromatography, nuclear magnetic resonance, differential scanning calorimetry, ultraviolet–visible spectroscopy, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. The thermal properties show distinct differences between the cyclic and matching linear polymers, with the macrocycles showing much higher glass‐transition and decomposition temperatures. The absorption bands are both hyperchromic and hypochromic with respect to the model aromatic compounds, and this is consistent with intensity borrowing. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5488–5503, 2004 相似文献
4.
Dong‐Gyun Kim Hae‐Sung Sohn Sung‐Kon Kim Aeri Lee Jong‐Chan Lee 《Journal of polymer science. Part A, Polymer chemistry》2012,50(17):3618-3627
A series of organic/inorganic hybrid star‐shaped polymers were synthesized by atom transfer radical polymerization using 3‐(3,5,7,9,11,13,15‐heptacyclohexyl‐pentacyclo[9.5.1.13,9.15,15.17,13]‐octasiloxane‐1‐yl)propyl methacrylate (MA‐POSS) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) as monomers and octakis(2‐bromo‐2‐methylpropionoxypropyldimethylsiloxy)octasilsesquioxane as an initiator. Star‐shaped polymers with methyl methacrylate (MMA) and PEGMA moieties were also prepared for comparison purposes. Dimensionally stable freestanding film could be obtained from the hybrid star‐shaped polymer containing 26 wt % of MA‐POSS moieties although its glass transition temperature is very low, ?60.9 °C. As a result, the hybrid star‐shaped polymer electrolyte containing lithium bis(trifluoromethanesulfonyl)imide showed ionic conductivities (1.75 × 10?5 S/cm at 30 °C), which were two orders of magnitude higher than those of the star‐shaped polymer electrolyte with MMA moieties. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
5.
Danming Chao Xiaoteng Jia Hongtao Liu Libing He Lili Cui Ce Wang Erik B. Berda 《Journal of polymer science. Part A, Polymer chemistry》2011,49(7):1605-1614
We present a series of novel poly(arylene ether sulfone) copolymers containing pendant oligoaniline groups. A novel monomer containing oligoaniline, 2,6‐difluorobenzoyl aniline tetramer (DFAT), was synthesized by reaction of 2,6‐difluorobenzoyl chloride and parent aniline tetramer and incorporated into the aforementioned copolymers via direct copolymerization with 4,4′‐dichlorodiphenyl sulfone (DCDPS), and 4,4′‐isopropylidene diphenol (BPA) using N,N′‐dimethylacetamide as solvent. The structures of these copolymers were confirmed by FTIR, 1H NMR, and GPC. Spectral analysis of the copolymers in different oxidation states was investigated via UV‐visible spectra. The copolymers exhibited outstanding thermal stability and good solubility in various organic solvents. Their electroactivity, explored with cyclic voltammetry, was found to increase as the content of oligoaniline in the polymer increased. The electric and dielectric properties of the copolymers were also studied in detail. The electrochromic performance of the copolymers was investigated by electrochromic photographs and transmittance spectra; the color of the copolymer thin films changes from grey (at 0.0 V), to green (at 0.4 V), to blue (at 0.6 V) and to pearl blue (at 1.0 V) and the maximum transmittance change (ΔT) at 700 nm is 42.6% (90.7% ? 48.1%). © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
6.
合成了一种新型感光性单体丙烯酸(4 N,N 二甲氨基肉桂酰氧乙基)酯(DMACEA)及其与丙烯酸的共聚物P(DMACEA co AA).用紫外吸收和荧光光谱研究了聚合物溶液的光敏感性,用傅立叶红外光谱研究了聚合物成膜后的光交联性及其过程.结果表明:DMACEA具有较好的光敏性,P(DMACEA co AA)具有较好光交联性,交联膜水溶胀和透光性也较好. 相似文献
7.
Paula Carretero Serena Molina Ricardo Sandín Juan Rodríguez‐Hernández Angel E. Lozano Javier de Abajo 《Journal of polymer science. Part A, Polymer chemistry》2013,51(4):963-976
Novel polyisophthalamides containing pendent poly(ethylene oxide) (PEO) sequences were prepared by grafting PEO onto poly(5‐hydroxy‐isophthalamide)s (HO‐PIPAs). First, an optimized method of synthesis was applied to prepare HO‐PIPAs, following the rules of the direct polyamidation reaction promoted by triphenyl phosphite and catalyzed by pyridine. Next, the modification of HO‐PIPAs was performed by a nucleophilic substitution reaction with chlorine‐terminated PEO monomethyl ether of average molecular weight 100, 550, and 1000 g/mol. The modification (grafting) reaction was optimized to assure virtually 100% yield. Polymers behaved as graft or brush‐like copolymers of polyisophthalamide (PIPA) and PEO, covering a wide range of ratios of PIPA/PEO. Physical properties, such as solubility, glass transition temperature, and thermal resistance were determined. Special attention was paid to the affinity of the novel copolymers for water. It was realized that with a high content of PEO, the materials could absorb water in amounts exceeding their own weight. Gravimetric methods and water contact angle measurements were used to quantify the hydrophilicity of the current PIPA‐g‐PEO copolymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
8.
Gangfeng Cai Morton H. Litt 《Journal of polymer science. Part A, Polymer chemistry》1992,30(4):649-657
10-(Pentamethyl disiloxanyl) decyl oxazoline ( Si ) was synthesized. It was copolymerized with either undecyl ( U ) or nonyl ( N ) oxazolines using methyl 4-nitrobenzenesulfonate as initiator. Two series of random poly(N-acylethylenimine) copolymers, U/Si and N/Si , were synthesized over the whole composition range of Si monomer with a total degree of polymerization of about 100. Narrow molecular weight distributions were obtained. At a monomer to initator ratio of about 1060, the final degree of polymerization was 374 with a polydispersity index of 1.93. This shows the effect of chain transfer in this system. 相似文献
9.
Kumaranand Palaniappan Nadia Hundt Prakash Sista Hien Nguyen Jing Hao Mahesh P. Bhatt Yun‐Yue Han Elizabeth A. Schmiedel Elena E. Sheina Michael C. Biewer Mihaela C. Stefan 《Journal of polymer science. Part A, Polymer chemistry》2011,49(8):1802-1808
Poly(3‐hexylthiophene)‐b‐poly(4‐vinylpyridine) diblock copolymer was synthesized by RAFT polymerization of 4‐vinyl pyridine using a trithiocarbonate‐terminated poly(3‐hexylthiophene) macro‐RAFT agent. The optoelectronic properties and the morphology of the block copolymer blends with CdSe quantum dots were investigated. UV‐vis and fluorescence experiments were performed to prove the charge transfer between CdSe and poly(3‐hexylthiophene)‐b‐poly(4‐vinylpyridine) diblock copolymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
10.
J. Cardoso R. Manrique M. Albores-Velasco A. Huanosta 《Journal of Polymer Science.Polymer Physics》1997,35(3):479-488
The synthesis, characterization, thermal, and dielectric properties of three different zwitterionic methacrylates of the sulfobetaine type are presented. Diethylamine-ethyl-, 2-(diethylaminoethoxy)-ethyl-, and 2-(2-diethylaminoethoxy) ethoxy-ethyl-methacrylates were made to react with butanosultone to prepare monomers with variable flexibility. The flexibility of the lateral chain of the polymethacrylates decreased the glass transition temperature (Tg down to 300 K) of the polymers. A linear relationship between Tg and the number of carbon atoms was shown for these materials. X-ray diffraction and DSC experiments showed the formation of new ordered phases in these polymers, which inhibited their dipole conductivity. On heating, these phases were destroyed and values of conductivity of 10−7–10−3 S cm−1 were obtained in the studied range of temperature. Variation of conductivity with temperature was established according to the Arrhenius equation. Dielectric properties exhibited a small deviation of the Debye type behavior, and β parameters of the Cole–Cole equations were calculated for the synthesized polymers. © 1997 John Wiley & Sons, Inc. 相似文献
11.
Tao Zhang Hongliang Fan Jianguang Zhou Qinhan Jin 《Journal of polymer science. Part A, Polymer chemistry》2009,47(12):3056-3065
This article reports the synthesis, optical properties, and pH responses of a water‐soluble poly(phenylene ethynylene) with pendant carboxylate groups. This conjugated polyelectrolyte, PPE‐OBS, was prepared via a facile synthetic route, using 1,4‐di(ethyl 4‐oxy‐butyrate)‐2,5‐diiodo‐benzene as polymeric monomer and followed by the alkali induced saponification. PPE‐OBS absorbs strongly in the blue region and emits a moderately intense fluorescence. However, it subjects to unstable emission in neutral aqueous media, which is believed to arise because the polymer tends to become more hydrophobic via protonation and to form much heavier aggregates (clusters). Subsequent studies on the interaction and stabilization of PPE‐OBS with various surfactants indicate that its fluorescence stability can be largely improved in the presence of a small amount of surfactant. More interestingly, even at low pH, the surfactant‐stabilized polyelectrolyte with its pendant groups being ? COOH rather than ? COO? remains water‐soluble and emits efficiently, which is expected of great significance for the covalent linkage to bio‐molecules. In addition, the sensitive pH response in emission spectrum of PPE‐OBS/surfactant complex over a relatively wide range suggests surely a potential access to the fluorescent sensing of pH variation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3056–3065, 2009 相似文献
12.
Takefumi Mikami Kenji Miyatake Masahiro Watanabe 《Journal of polymer science. Part A, Polymer chemistry》2011,49(2):452-464
A series of block copoly(arylene ether)s containing pendant superacid groups were synthesized, and their properties were investigated for fuel cell applications. Two series of telechelic oligomers, iodo‐substituted oligo(arylene ether ketone)s and oligo(arylene ether sulfone)s, were synthesized. The degree of oligomerization and the end groups were controlled by changing the feed ratio of the monomers. The nucleophilic substitution polymerization of the two oligomers provided iodo‐substituted precursor block copolymers. The iodo groups were converted to perfluorosulfonic acid groups via the Ullmann coupling reaction. The high degree of perfluorosulfonation (up to 83%) was achieved by optimizing the reaction conditions. Tough and bendable membranes were prepared by solution casting. The ionomer membranes exhibited characteristic hydrophilic/hydrophobic phase separation with large hydrophilic clusters (ca. 10 nm), which were different from that of our previous random copolymers with similar molecular structure. The block copolymer structure was found to be effective in improving the proton‐conducting behavior of the superacid‐modified poly(arylene ether) ionomer membranes without increasing the ion exchange capacity (IEC). The highest proton conductivity was 0.13 S/cm at 80 °C, 90% relative humidity, for the block copolymer ionomer membrane with IEC = 1.29 mequiv/g. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
13.
To increase the solubility and film forming ability of polybenzimidazole (PBI), poly(N‐methylbenzimidazole) (PNMBI) with different degrees of methylation was synthesized. Chemical structure, degree of substitution, and solubility of PNMBI was studied. PNMBI is easier to be doped with acid than PBI. The basicity of PNMBI was improved with the introduction of methyl groups on the imidazole moiety. Effects of methylation degree, H3PO4 content and temperature on proton conductivity of PNMBI doped H3PO4 was studied. Proton conductivity of H3PO4 doped PNMBI‐1.2 membranes increases with increasing doping level. Temperature dependence of proton conductivity of H3PO4 doped PNMBI‐1.2 membranes follows the Arrhenius law. With an increase in the degree of substitution, proton conductivity of H3PO4 doped PNMBI decreases dramatically. The proton transport mechanism was also discussed. The proton conductivity of PNMBI/H3PO4 is mainly contributed by proton hopping or Grotthuss mechanism. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
14.
Ziyue Ma Cui Zheng Zhihao Shen Dehai Liang Xinghe Fan 《Journal of polymer science. Part A, Polymer chemistry》2012,50(5):918-926
A series of novel comb polymers, poly{2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene}‐g‐polystyrene (PMPCS‐g‐PS), with mesogen‐jacketed rigid side chains were synthesized by the “grafting onto” method from α‐yne‐terminated PMPCS (side chain) and poly(vinylbenzyl azide) (backbone) by Cu(I)‐catalyzed 1,3‐dipolar cycloaddition click reaction. The α‐yne‐terminated PMPCS was synthesized by Cu(I)‐catalyzed atom transfer radical polymerization initiated by a yne‐functional initiator. Poly(vinylbenzyl azide) was prepared by polymerizing vinylbenzyl chloride using nitroxide mediated radical polymerization to obtain poly(vinylbenzyl chloride) as the precursor which was then converted to the azide derivative. The chemical structure and architectures of PMPCS comb polymers were confirmed by 1H NMR, gel permeation chromatography, and multiangle laser light scattering. Both surface morphologies and solution behaviors were investigated. Surface morphologies of PMPCS combs on different surfaces were investigated by scanning probe microscopy. PMPCS combs showed different aggregation morphologies when depositing on silicon wafers with/without chemical modification. The PMPCS comb polymers transferred to polymer‐modified silicon wafers using the Langmuir‐Blodgett technique showed a worm‐like chain conformation. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
15.
丁基噻吩在硝基苯溶液中以六氟磷酸四丁基季铵盐为支持电解质,在恒电流条件下进行电化学氧化聚合,通过电导率的测量及可见──紫外光谱分析,讨论了单体浓度、电解质浓度、电流密度、聚合温度对聚合物膜的导电性能的影响。扫描电镜图表明,随着聚合的进行.膜的表面呈“菜花”状结构。循环伏安图表明聚了基噻吩与聚噻吩具有相近的氧化峰位。 相似文献
16.
Thieo E. Hogen‐Esch 《Journal of polymer science. Part A, Polymer chemistry》2006,44(7):2139-2155
The synthesis and characterization by size exclusion chromatography, liquid chromatography, NMR, matrix‐assisted laser desorption/ionization, thermal analysis, and other techniques of well‐defined and narrow molecular weight distribution macrocyclic polystyrene (PS), poly(2‐vinylpyridine), poly(α‐methylstyrene), poly (2‐vinyl‐naphthalene) (P2VN), and poly(9,9‐dimethyl‐2‐vinylfluorene) (PDMVF) containing a single 1,4‐benzylidene, methylidene, or 9,10‐anthracenylidene unit are reviewed. The absorption and emission spectroscopy of PS, P2VN, and PDMVF is also discussed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2139–2155, 2006 相似文献
17.
一类新型的含4-叔丁基环己基和烯烃共轭结构的双苯并噻唑类聚合物PBTs III1,2由1,1’-双(4-氨基-3-巯基苯基)-4-叔丁基环己烷二盐酸盐(BAMPBCH?2HCl)与烯烃二元酸经过缩聚反应制备得到。聚合物的结构都经过了红外(IR)、核磁(NMR)、元素分析(EA)的表征。4-叔丁基环己基的引入提高了此类聚合物的溶解性并保持了较好的热稳定性,失重10%的温度在419 oC以上。相比聚苯撑苯并双噻唑(PBZT),PBTs III1,2的紫外吸收波长发生了蓝移,相对聚2,2’-对苯撑-6,6’-(4-叔丁基)环己基双苯并噻唑(PBT)则发生了红移,光学能带隙分别为2.56eV和2.53eV,大侧基和烯烃结构的引入扩大了苯并噻唑类聚合物光学能带隙的可调范围。PBTs III1,2的荧光发射波长较PBT发生了红移,大侧基的引入降低了固态时聚合物分子链的聚集程度。顺磁共振(EPR)的结果表明,PBTs III1,2都有明显的顺磁共振信号,顺磁中心是它们本身所固有的。 相似文献
18.
Antonio Cardone Carmela Martinelli Vita Pinto Francesco Babudri Maria Losurdo Giovanni Bruno Pinalysa Cosma Francesco Naso Gianluca M. Farinola 《Journal of polymer science. Part A, Polymer chemistry》2010,48(2):285-291
Fully fluorinated arylenevinylene polymers have been synthesized via a methodology based on the Stille cross‐coupling reaction and characterized by FTIR spectroscopy and MALDI‐TOF mass spectrometry. Investigation of thin film properties by cyclic voltammetry and ellipsometry shows that complete substitution of hydrogen atoms with fluorine atoms on the conjugated backbone of the poly(arylenevinylene)s results in a strong increase of the band gap. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 285–291, 2010 相似文献
19.
Lie Chen Yiwang Chen Kai Yao Weihua Zhou Fan Li Liping Chen Rongrong Hu Ben Zhong Tang 《Journal of polymer science. Part A, Polymer chemistry》2009,47(18):4723-4735
Series of poly(p‐phenylene)s (PPPs) containing terphenyl mesogenic pendants with cyano and methoxy terminal groups by flexible ? COO(CH2)6O? bridge [ P(CN) and P(OCH3) ] are synthesized through Yamamoto polycondensation with Ni‐based complex catalysts. The effects of the structural variation on their properties, especially their mesomorphism, ultraviolet–visible (UV), and photoluminescence behaviors, are studied. All of the polymers are stable, losing little of their weights when heated to ≥340 °C. The polymers show good solubility and can be dissolved in common solvents. P(CN) with cyano terminal group shows enantiotropic SmAd phase with bilayer packing arrangement, while P(OCH3) with methoxy terminal group readily forms nematic and SmAd phase when heated and cooled. Photoexcitation of their solutions induces strong blue light emission. Compared with P(OCH3) , the light‐emitting bands of polymer P(CN) is slightly redshifted to 428 nm and the emission intensity of P(CN) is much stronger, due to the existence of donor–acceptor pairs. More interestingly, both of the polymers exhibit obvious Cotton effect on the CD spectra, resulting from the predominant screw sense of the backbone. This indicates that the bulky mesogenic pendant orientating around the backbone will force the main chain with helical conformation in the long region due to steric crowdedness. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4723–4735, 2009 相似文献
20.
Lihua Liu Shiyan Yang Zhijie Zhang Qian Wang Zemin Xie 《Journal of polymer science. Part A, Polymer chemistry》2003,41(17):2722-2730
Poly(diethylsiloxane) and its copolymers with various kinds of R1R2SiO (R1 = R2 = methyl or phenyl, or R1 = methyl and R2 = phenyl) units have been prepared by the equilibrium polymerization of cyclosiloxanes. All the polymers have been characterized by 1H and 29Si NMR, gel permeation chromatography, differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) measurements. The results indicate that a random distribution of different units has been obtained in the structures of copolymers containing 50 mol % diethylsiloxane units content. DSC and DMA show that the presence of 2.5 mol % diphenylsiloxane units or 5.0 mol % methylphenylsiloxane units in the copolymer can disrupt the crystallinity and lead to noncrystalline copolymers with low glass‐transition temperatures (ranging from ?133 to ?137 °C according to DSC). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2722–2730, 2003 相似文献