JournalTOCs

High Performance Polymers

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ISSN (Print) 0954-0083 - ISSN (Online) 1361-6412
Published by Sage Publications

[676 journals]

Novel, thermally stable and chiral poly(amide-imide)s derived from a new diamine containing pyridine ring and various amino acid-based diacids: Fabrication and characterization
- Authors: Mallakpour, S; Zarei, M.
  Pages: 245 - 253
  Abstract: In this investigation, several novel optically active and potentially biodegradable poly(amide-imide)s were synthesized through direct polycondensation reaction. First, a new aromatic diamine compound including pyridine ring was synthesized, which was reacted with diimide dicarboxylic acids containing different natural amino acids such as l-alanine, l-leucine, l-isoleucine and l-methionine under green condition, using molten tetrabutylammonium bromide. These new chiral macromolecules were characterized using Fourier transform infrared spectroscopy, proton and carbon nuclear magnetic resonance, field emission scanning electron microscopy (FE-SEM), x-ray diffraction (XRD) and elemental and thermogravimetric analysis techniques. They show high solubility in polar organic solvents, such as N,N'-dimethylacetamide, N-methyl-2-pyrrolidone and dimethyl sulfoxide at room temperature. XRD and FE-SEM studies show that all the obtained polymers exhibit noncrystalline and nanostructure morphology. Due to the existence of amino acids in their structures, these polymers can show a potential biodegradability and biocompatibility behavior.
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312461658|hwp:master-id:sphip;0954008312461658
  Issue No: Vol. 25, No. 3 (2013)
Shape memory effect and viscoelastic behavior of SMP epoxy filled with carbon particles
- Authors: Liang, X. Y; Yun, S. J.
  Pages: 254 - 259
  Abstract: Shape memory polymers (SMPs) are a relatively new kind of smart materials with the capability of large shape memory effect. In this study, a series of shape memory epoxy composites filled with varied carbon black (CB) contents were prepared. The shape memory effect and thermomechanical behavior of the materials were experimentally investigated. The viscoelastic properties at different temperatures were characterized by creep tests. The results show that the materials exhibit excellent shape memory effects. The CB additive has no remarkable influence on the critical shape transition temperature, but significantly improved the viscous resistance.
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312462730|hwp:master-id:sphip;0954008312462730
  Issue No: Vol. 25, No. 3 (2013)
Synthesis and characterization of poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant biphenyl and naphthyl groups
- Authors: Honkhambe, P. N; Dhamdhere, N. A, Tawade, B. V, Salunkhe, M. M, Wadgaonkar, P. P.
  Pages: 260 - 267
  Abstract: New poly(ether ether ketone)s (PEEKs) and poly(ether ether ketone ketone)s (PEEKKs) containing pendant biphenyl and naphthyl groups were synthesized by nucleophilic substitution reaction of each of the four bisphenols viz., 1-(4-biphenylyl)-1,1-bis(4-hydroxyphenyl) ethane, 1-(4-biphenylyl)-1,1-bis(3-methyl,4-hydroxyphenyl) ethane, 4,4’-[1-(2-naphthalenyl)ethylidene] bis-phenol and 4,4’-[1-(2-naphthalenyl) ethylidene] bis-3-methylphenol with 4,4’-difluorobenzophenone and 1,3-bis(4–fluorobenzoyl)benzene in a solvent mixture of N,N-dimethylacetamide and toluene in the presence of anhydrous potassium carbonate. Inherent viscosities and number-average molecular weights of polymers were in the range of 0.42–0.86 dl/g and 2.40–7.55 x 104, respectively. PEEKs and PEEKKs were amorphous in nature and were readily soluble in a wide range of organic solvents and could be cast into flexible and tough films from chloroform solution. Glass transition temperature of PEEKs and PEEKKs were in the range of 180°C –200°C. T10 values of PEEKs and PEEKKs were in the range of 424°C–512°C in nitrogen atmosphere, indicating their good thermal stability.
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312462731|hwp:master-id:sphip;0954008312462731
  Issue No: Vol. 25, No. 3 (2013)
Synthesis and characterization of highly soluble and optically transparent polyimides derived from novel fluorinated pyridine-containing aromatic diamine
- Authors: Shen, J; Li, X, Zhang, Y, Wang, W, Xu, Z, Yeung, K. W. K, Xu, M, Yi, C.
  Pages: 268 - 277
  Abstract: A novel fluorinated pyridine-containing aromatic diamine monomer, 4-phenyl-2,6-bis[2-(4-amino-2-trifluoromethyphenoxy)phenyl]pyridine (o, p-6FPAPP), was prepared in a three-step synthetic route. This aromatic diamine was then employed to synthesize a series of fluorinated pyridine-containing polyimides (PIs) by polycondensation with various aromatic dianhydrides via the conventional two-step method. The inherent viscosities of the resulting poly(amic acid)s (PAAs) and PIs were in the range of 0.71–0.89 and 0.62–0.84 dL/g; all the PIs obtained by chemical imidization were readily soluble in common organic solvents such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF) and so on. Meanwhile, transparent, strong and flexible PI films were obtained, which had good thermal stability, with the glass transition temperature (T g) of 195.2°C–232.7°C, the temperature at 10% weight loss of 530.2°C–546.0°C in nitrogen atmosphere, and good optical transparency with the cutoff wavelengths of 354–382 nm, as well as outstanding mechanical properties with tensile strengths of 96.4–105.8 MPa, tensile modulus of 1.57–1.88 GPa and elongations at break of 9.5%–13.4%. The PI films were also found to possess low water uptake of 0.52%–0.67%.
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312462732|hwp:master-id:sphip;0954008312462732
  Issue No: Vol. 25, No. 3 (2013)
Cyanate ester resins containing pentadecyl-substituted cyclohexyl moiety: Synthesis, curing and structure-property relationship
- Authors: Kulkarni, A. D; Tawade, B. V, Wadgaonkar, P. P.
  Pages: 278 - 286
  Abstract: Cyanate ester (CE) monomers containing pentadecyl-substituted cyclohexyl moieties such as 1,1-bis(4-cyanatophenyl) 3-pentadecylcyclohexane and 1,1-bis(4-cyanatophenyl) cyclohexane were synthesized and characterized by Fourier transform infrared, proton-nuclear magnetic resonance (1H-NMR) and carbon-nuclear magnetic resonance (13C-NMR) spectroscopies as well as differential scanning calorimetry (DSC). Both 1,1-bis(4-cyanatophenyl) 3-pentadecylcyclohexane and 1,1-bis(4-cyanatophenyl) cyclohexane exhibited better processability coupled with lower melting points, lower cure onset with broad cure exotherm than the commercially available CE monomer, namely, 2,2-bis(4-cyanatophenyl) propane. Glass transition temperatures of cured 2,2-bis(4-cyanatophenyl) propane, 1,1-bis(4-cyanatophenyl) cyclohexane and 1,1-bis(4-cyanatophenyl) 3-pentadecylcyclohexane were observed to be 288°C, 302°C and 160°C, respectively. Cured 1,1-bis(4-cyanatophenyl) cyclohexane displayed higher storage modulus (1.59 x 10 9 Pa) than 1,1-bis(4-cyanatophenyl) 3-pentadecylcyclohexane (1.07 x 10 9 Pa) and 2,2-bis(4-cyanatophenyl) propane (1.39 x 10 9 Pa). The order of thermal stability of cured polycyanurates was found to be 2,2-bis(4-cyanatophenyl) propane > 1,1-bis(4-cyanatophenyl)cyclohexane > 1,1-bis(4-cyanato phenyl) 3-pentadecylcyclohexane. The moisture absorption of cured resins derived from 1,1-bis(4-cyanatophenyl) 3-pentadecyl cyclohexane and 1,1-bis(4-cynatophenyl)cyclohexane was found to be lower than that of 2,2-bis(4-cynatophenyl) propane implying the role of pentadecyl substituent and/or cyclohexyl moiety in imparting hydrophobicity to the polycyanurates.
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312463738|hwp:master-id:sphip;0954008312463738
  Issue No: Vol. 25, No. 3 (2013)
Silica-supported Ni(II) complex bearing [O^N] ligand and copolymerization to afford silica hybrid polynorbornenes nanocomposites
- Authors: He, X; Yuan, B, Chen, Y, Chen, D.
  Pages: 287 - 300
  Abstract: In situ polymerization is an ideal technique to make a perfect dispersion of nanosilica into polymer matrixes. So, in this article, a novel silica-supported β-ketoamine nickel(II) dibromide precatalyst was efficiently prepared and used in in situ slurry polymerizations of norbornene (NB) to afford a highly productive NB addition polymerization system in combination with tris(pentafluorophenyl)borane (B(C6F5)3) cocatalyst. It exhibited productivity of 176.8 kg of polynorbornene (mol Ni)–1 h–1 at a mole ratio of B/Ni = 20, and the catalyst deactivation kinetics in the early stage of polymerization fitted well by the first-order deactivation kinetics up to about 60 min. The catalyst system was also effective for the copolymerization of NB and 5-norbornene-2-carboxylic acid methyl ester to produce the addition-type copolymers with high-molecular-weights (3.28–3.45 x 105 g mol–1) and incorporation rates (8.1–49.1%) as well as narrow molecular weight distributions (polydispersity index = 1.6). The nanoparticles were confirmed to be well-dispersed in the polymer matrix with each individual nanoparticle surrounded by polymer. Transparency of nanocomposites could be kept up to about 60%. The brittleness of polymer was obviously improved, and the tensile strength of polymer film could be as high as 47.8 MPa.
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312463739|hwp:master-id:sphip;0954008312463739
  Issue No: Vol. 25, No. 3 (2013)
New autophotosensitive semiaromatic hyperbranched polyimides with excellent thermal stabilities and low birefringences
- Authors: Liu, C; Zhao, X, Li, Y, Yang, D, Wang, L, Jin, L, Chen, C, Zhou, H.
  Pages: 301 - 311
  Abstract: A series of autophotosensitive semiaromatic hyperbranched polyimides were prepared by (A2 + B3)-type method and endcapped with 3-aminophenylacetylene. The photosensitive-hyperbranched polyimides (PHBPIs) showed excellent solubility, excellent optical properties, and low birefringences in the range of 0.0010–0.0027, caused by their special hyperbranched structures and alicyclic chain segments reduced both intramolecular and intermolecular charge transfer complex effect. The cured films also showed high glass transition temperatures between 204°C and 220°C, excellent thermal stabilities with 10% thermal decomposing temperatures in the range of 476–495°C, and good mechanical properties. The PHBPIs had photosensitivities (D g) in the range of 80–162 mJ/cm2 and showed a clear negative image with a line width of 8 µm when exposed to an ultraviolet light of 365 nm (i-line).
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312463740|hwp:master-id:sphip;0954008312463740
  Issue No: Vol. 25, No. 3 (2013)
Comparative study on polyimides derived from isomeric diphenylsulfonetetracarboxylic dianhydrides
- Authors: Pei, X; Chen, G, Hou, Y, Fang, X.
  Pages: 312 - 323
  Abstract: In this study, three diphenylsulfonetetracarboxylic dianhydride (DSDA) isomers namely 2,2',3,3'-DSDA (3,3'-DSDA), 2,3,3',4'-DSDA (3,4'-DSDA) and 3,3',4,4'-DSDA (4,4'-DSDA) were prepared from the corresponding diphenylthioethertetracarboxylic dianhydride isomers. Based on the three DSDA isomers, a series of isomeric polyimides were prepared. The properties, such as film-forming ability, solubility, wide-angle x-ray diffraction, thermal and mechanical properties as well as rheological behavior, were compared among the isomeric polyimides. It was found that 4,4'-DSDA-based polyimides had much better film-forming ability than 3,3'-DSDA- and 3,4'-DSDA-based polyimides. 3,4'-DSDA-based polyimides had better solubility than 3,3'-DSDA- and 4,4'-DSDA-based polyimides. Furthermore, for a given diamine, the glass transition temperatures of the polyimides from the three DSDA isomers decreased in the order of 3,3'-DSDA > 3,4'-DSDA > 4,4'-DSDA, while the 5% weight loss temperatures in both air and nitrogen atmospheres of the polyimides mainly increased in the order of 3,3'-DSDA
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312463741|hwp:master-id:sphip;0954008312463741
  Issue No: Vol. 25, No. 3 (2013)
Nanoblends of novel polyesters with polyaniline: Conductivity and heat-stability studies
- Authors: Kausar, A; Hussain, S. T.
  Pages: 324 - 336
  Abstract: The present work initially deals with the fabrication of a new generation of polyesters (bearing thiophene, azomethine, thiourea and ether moieties) and subsequent blending with polyaniline (PAN) exhibiting extremely valuable nanoblend characteristics. Few poly(azomethine-thiourea-ester)s (PATEs), by the polycondensation of a new diol 4,4'-oxydiphenyl bis((E)-1-(4-hydroxobenzylidene)thiourea) with thiophene-2,5-dicarbonyl/terephtaloyl chloride, were synthesized. The polymers obtained were characterized by Fourier-transform infrared, proton-nuclear magnetic resonance, solubility, solution viscosity, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry and wide-angle x-ray diffraction. The polymers exhibited high molar mass (77–89 x 103) and thermal stability (T 10 528–531°C, glass transition temperature (T g) 265–268°C). Then the electrically conducting blends, of PAN dispersed in the PATEs matrix, were prepared by mash-blending and melt-blending techniques. Materials obtained by conventional melt-blending approach generated an efficient conductive network compared with those produced by mash blending. Field emission scanning electron microscopy images displayed nanoblend morphology of the melt-blended system, owing to increased physical interactions (hydrogen bonding and – stacking) between the two polymers. Moreover, miscible blends of thiophene-based PATE/PAN led to superior conductivity (1.5–2.1 S/cm) and heat stability (T 10 503°C) even at low PAN concentration relative to previous thiophene, azomethine or PAN-based structures.
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312464254|hwp:master-id:sphip;0954008312464254
  Issue No: Vol. 25, No. 3 (2013)
Physical and thermal properties of thermoplastic poly(azo-urethane)s: Effect of novel chain extender and hard segment content
- Authors: Kausar, A; Hussain, S. T.
  Pages: 337 - 347
  Abstract: New thermoplastic segmented poly(azo-urethane)s (PAUs) have been synthesized by one-step polycondensation from aromatic diazo-diol, (E)-1-(4-(4-(3-hydroxypyridyl-azo)thiocarbamoylaminobenzyl)-phenyl)-3-(3-hydroxypyridylazo)thiourea, as chain extenders, phenylene diisocyanate and 20–60 mol % polyethylene glycol (PEG) with the molecular weight of 2000 g/mol. The effect of diazo-diol used in the structure and some physicochemical, thermal and mechanical properties of the segmented polyurethanes were studied. The structure was examined by proton nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FTIR) analyses. Polyazos were the products with good processability and high molar mass in the range 120 103–135 103 g/mol. Thermal properties, investigated by thermogravimetric analysis and differential scanning calorimetry indicated that PAUs up to 40 mol % polyol were fairly stable above 530°C, having initial weight loss of around 528–539°C, 10% gravimetric loss in the range 553–567°C and own high glass transition temperature 259–264°C. The polymers also demonstrated higher tensile strength (56.53–63.83 MPa) and elongation at break (1.58–1.63). However, compared with typical polyurethanes, PAUs with lower polyol content displayed higher Tg s, heat and mechanical stability owing to warily designed rigid hard segment structure.
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312464255|hwp:master-id:sphip;0954008312464255
  Issue No: Vol. 25, No. 3 (2013)
Synthesis, characterization, and properties of aniline-p-phenylenediamine copolymers
- Authors: Li, T; Yuan, C, Zhao, Y, Chen, Q, Wei, M, Wang, Y.
  Pages: 348 - 353
  Abstract: Polyaniline (PANI), poly(aniline-co-p-phenylenediamine) (P(Ani-co-pPD)), and poly(p-phenylenediamine) (PpPD) have been synthesized by oxidative polymerization using ammonium persulphate as an oxidant in hydrochloric acid medium. Several important properties such as solubility, electrical conductivity, and crystallinity of these polymers were comprehensively compared. The polymers were characterized by infrared spectroscopy, x-ray diffraction, thermogravimetry, scanning electron microscopy, and a four-point probe conductivity method. The results reveal that PANI shows the maximum conductivity and thermal stability among the polymers; P(Ani-co-pPD) exhibits the best solubility, PpPD presents the highest crystallinity, and all the polymers exist in granular morphology.
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312465451|hwp:master-id:sphip;0954008312465451
  Issue No: Vol. 25, No. 3 (2013)
Synthesis and properties of polyimides-containing benzoxazole units in the main chain
- Authors: Song, G; Wang, D, Zhao, X, Dang, G, Zhou, H, Chen, C.
  Pages: 354 - 360
  Abstract: A series of polyimide (PI) films were prepared from a diamine-containing benzoxazole unit (5,4'-diamino-2-phenyl benzoxazole) and five dianhydrides via two-step polymerization process. The PI films showed outstanding mechanical properties with tensile modulus up to 7.3 GPa without preorientation process. According to the results of thermal analysis, the glass transition temperature of the films was up to 412°C, and the films showed good thermodimensional stability. Thermal analysis and wide-angle x-ray diffraction analysis revealed that the PIs were semicrystalline. Excellent properties of these PIs were attributed to the benzoxazole group in the main chain and accordingly to the rigid-rod structure and high level of linearity of the polymer backbones. These results correlate with each other and contribute to our overall understanding of the effects of benzoxazole moiety on the properties of the PI films.
  PubDate: 2013-04-17T23:37:14-07:00
  DOI: 10.1177/0954008312466278|hwp:master-id:sphip;0954008312466278
  Issue No: Vol. 25, No. 3 (2013)