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Excellent Thermal Stability (excellent + thermal_stability)
Selected AbstractsSolution, thermal and optical properties of novel poly(pyridinium salt)s derived from conjugated pyridine diamines,JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2010Alexi K. Nedeltchev Abstract Several novel poly(pyridinium salt)s with heterocyclic pyridine moieties in their backbones with tosylate and triflimide counterions were prepared by either ring-transmutation polymerization reaction of phenylated-bis(pyrylium tosylate) with isomeric pyridine diamines of 4-phenyl-2,6-bis(4-aminophenyl)pyridine in dimethyl sulfoxide (DMSO) for 48 h at 130,140 °C or by metathesis reaction of the respective tosylate polymers with lithium triflimide in DMSO at about 60 °C. Their chemical structures were characterized by FTIR, 1H, 13C NMR spectroscopy, and elemental analysis. Their number-average molecular weights (Mn) were in the range of 8,000,51,000 and their polydispersities in the range of 1.18,2.13 as determined by gel permeation chromatography. They had excellent thermal stabilities of 340,458 °C and high glass transition temperatures >200 °C. As they showed good solubilities in common organic solvents, their solution properties were also characterized for their lyotropic liquid-crystalline properties with polarizing optical microscopy (POM) studies. Their photoluminescent properties were examined by using a spectrofluorometer in both solution and solid states. Their quantum yields were rather low, which were in the range of 1.3,2.0%. Additionally, hand-drawn fibers from the melts were examined to determine their morphologies with a number of microscopic techniques including POM, scanning electron microscopy, and transmission electron microscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [source] Synthesis and characterization of novel aromatic poly(amide-imide)s derived from 2,2,-bis(4-trimellitimidophenoxy)biphenyl or 2,2,-bis(4-trimellitimidophenoxy)-1,1,-binaphthyl and various aromatic diaminesPOLYMER INTERNATIONAL, Issue 7 2003Ahmad Banihashemi Abstract New aromatic diimide-dicarboxylic acids having kinked and cranked structures, 2,2,-bis(4-trimellitimidophenoxy)biphenyl (2a) and 2,2,-bis(4-trimellitimidophenoxy)-1,1,-binaphthyl (2b), were synthesized by the reaction of trimellitic anhydride with 2,2,-bis(4-aminophenoxy)biphenyl (1a) and 2,2,-bis(4-aminophenoxy)-1,1,-binaphthyl (1b), respectively. Compounds 2a and 2b were characterized by FT-IR and NMR spectroscopy and elemental analyses. Then, a series of novel aromatic poly(amide-imide)s were prepared by the phosphorylation polycondensation of the synthesized monomers with various aromatic diamines. Owing to structural similarity, and a comparison of the characterization data, a model compound was synthesized by the reaction of 2b with aniline. The resulting polymers with inherent viscosities of 0.58,0.97 dl g,1 were obtained in high yield. The polymers were fully characterized by FT-IR and NMR spectroscopy. The ultraviolet ,max values of the poly(amide-imide)s were also determined. The polymers were readily soluble in polar aprotic solvents. They exhibited excellent thermal stabilities and had 10% weight loss at temperatures above 500 °C under a nitrogen atmosphere. Copyright © 2003 Society of Chemical Industry [source] Molecular Origins of the Mechanical Behavior of Hybrid GlassesADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Mark S. Oliver Abstract Hybrid organic-inorganic glasses exhibit unique electro-optical properties along with excellent thermal stability. Their inherently mechanically fragile nature, however, which derives from the oxide component of the hybrid glass network together with the presence of terminal groups that reduce network connectivity, remains a fundamental challenge for their integration in nanoscience and energy technologies. We report on a combined synthesis and computational strategy to elucidate the effect of molecular structure on mechanical properties of hybrid glass films. We first demonstrate the importance of rigidity percolation to elastic behavior. Secondly, using a novel application of graph theory, we reveal the complex 3-D fracture path at the molecular scale and show that fracture energy in brittle hybrid glasses is fundamentally governed by the bond percolation properties of the network. The computational tools and scaling laws presented provide a robust predictive capability for guiding precursor selection and molecular network design of advanced hybrid organic-inorganic materials. [source] Photocrosslinkable Polythiophenes for Efficient, Thermally Stable, Organic PhotovoltaicsADVANCED FUNCTIONAL MATERIALS, Issue 14 2009Bumjoon J. Kim Abstract Photocrosslinkable bromine-functionalized poly(3-hexylthiophene) (P3HT-Br) copolymers designed for application in solution-processed organic photovoltaics are prepared by copolymerization of 2-bromo-3-(6-bromohexyl) thiophene and 2-bromo-3-hexylthiophene. The monomer ratio is carefully controlled to achieve a UV photocrosslinkable layer while retaining the ,,, stacking feature of the conjugated polymers. The new materials are used as electron donors in both bulk heterojunction (BHJ) and bilayer type photovoltaic devices. Unlike devices prepared from either P3HT:PCBM blend or P3HT-Br:PCBM blend without UV treatment, photocrosslinked P3HT-Br:PCBM devices are stable even when annealed for two days at the elevated temperature of 150,°C as the nanophase separated morphology of the bulk heterojunction is stabilized as confirmed by optical microscopy and grazing incidence wide angle X-ray scattering (GIWAXS). When applied to solution-processed bilayer devices, the photocrosslinkable materials show high power conversion efficiencies (,2%) and excellent thermal stability (3 days at 150,°C). Such performance, one of the highest obtained for a bilayer device fabricated by solution processing, is achieved as crosslinking does not disturb the ,,, stacking of the polymer as confirmed by GIWAXS measurements. These novel photocrosslinkable materials provide ready access to efficient bilayer devices thus enabling the fundamental study of photophysical characteristics, charge generation, and transport across a well-defined interface. [source] Synthesis and characterization of new unsaturated polyesters containing cyclopentapyrazoline moiety in the main chainJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Ismail A. Alkskas Abstract 3-p -Hydroxyphenyl-6- p -hydroxybenzylidene cyclopentapyrazoline (III) and 3-vanillyl-7-vanillylidene cyclopentapyrazoline (IV) were used as new starting materials for preparing new unsaturated polyesters. The polyesters were prepared by reacting (III) or (IV) with adipoyl, sebacoyl, isophthaloyl, and terephthaloyl dichlorides utilizing the interfacial polycondensation technique. The polyester samples have been characterized by elemental and spectral analyses. The polyesters have inherent viscosities of 0.55,0.97 dL/g. All the polyesters are semicrystalline and most of them are partially soluble in most common organic solvents but freely soluble in concentrated sulfuric acid. Their glass transition temperatures (Tg) range from 103.34 to 208.81°C, and the temperatures of 10% weight loss as high as 190 to 260°C in air, indicating that these aromatic polyesters have high Tg and excellent thermal stability. Doping with iodine dramatically raised the conductivity and produced dark brown colored semiconductive polymers with a maximum conductivity in the order of 3.1 × 10,7 ,,1 cm,1. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Preparation and properties of epoxy/phenol formaldehyde novolac/hexakis(methoxymethyl)melamine hybrid resins from in situ polymerizationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Xinghong Zhang Abstract Based on the self-condensation of hexakis(methoxymethyl)melamine (HMMM), the condensation between HMMM and phenol formaldehyde novolac resin (n-PF), and the addition reaction of diglycidyl ether of biphenyl A (DGEBA) and n-PF, a homogeneous, transparent hybrid thermoset was prepared via in situ polymerization of DGEBA, n-PF, and HMMM. No phase separations were observed even for the DGEBA/n-PF/HMMM hybrid thermoset containing 40 wt % HMMM. These hybrid thermosets had high glass-transition temperatures (98,127°C from differential scanning calorimetry and 111,138°C from dynamic mechanical analysis), excellent thermal stability with high 5 wt % decomposition temperatures (>322°C), high char yields (>24 wt %), and improved flame retardancy with high limited oxygen indices (>28.5). The excellent overall properties of these hybrid resins may lead to their applications in high-performance "green" electronic products. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis and properties of novel organosoluble aromatic poly(ether ketone)s containing pendant methyl groups and sulfone linkagesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Shou-Ri Sheng Abstract Several novel aromatic poly(ether ketone)s containing pendant methyl groups and sulfone linkages with inherent viscosities of 0.62,0.65 dL/g were prepared from 2-methyldiphenylether and 3-methyldiphenylether with 4,4,-bis(4-chloroformylphenoxy)diphenylsulfone and 4,4,-bis (3-chloroformylphenoxy)diphenylsulfone by electrophilic Friedel,Crafts acylation in the presence of N,N -dimethylformamide with anhydrous AlCl3 as a catalyst in 1,2-dichloroethane. These polymers, having weight-average molecular weights in the range of 57,000,71,000, were all amorphous and showed high glass-transition temperatures ranging from 160.5 to 167°C, excellent thermal stability at temperatures over 450°C in air or nitrogen, high char yields of 52,57% in nitrogen, and good solubility in CHCl3 and polar solvents such as N,N -dimethylformamide, dimethyl sulfoxide, and N -methyl-2-pyrrolidone at room temperature. All the polymers formed transparent, strong, and flexible films, with tensile strengths of 84.6,90.4 MPa, Young's moduli of 2.33,2.71 GPa, and elongations at break of 26.1,27.4%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Role of Mn of PEG in the morphology and properties of electrospun PEG/CA composite fibers for thermal energy storageAICHE JOURNAL, Issue 3 2009Changzhong Chen Abstract As an aim toward developing novel class of form-stable polymer-matrix phase change materials for thermal energy storage, ultrafine composite fibers based on cellulose acetate and polyethylene glycol (PEG) with five different molecular weight (Mn) grades were prepared by electrospinning. The effects of Mn of PEG on morphology, thermal properties and mechanical properties of the composite fibers were studied by field emission scanning electron microscopy, differential scanning calorimetry, and tensile testing, respectively. It was found that the composite fibers were smooth and cylindrical shape, with the average diameters ranging from about 1000 to 1750 nm which increased with Mn of PEG. Thermal analysis results showed that the composite fibers imparted balanced thermal storage and release properties in different temperature ranges with the variation of Mn of PEG. Thermal cycling test indicated that the prepared composites had excellent thermal stability and reliability even they were subjected to 100 heating-cooling thermal cycles. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Synthesis and properties of thermoplastic polyimides with ether and ketone moietiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2010Xiaohui Yu Abstract A series of polyimides containing ether and ketone moieties were synthesized from 1,3-bis(4-fluorobenzoyl) benzene and several commercially available dianhydrides via a conventional two-step polymerization. The inherent viscosities of Polyamide acids ranged from 0.46 to 0.73 dL/g. Thermal properties, mechanical properties, and thermalplasticity of the obtained polimide films were investigated by focusing on the chemical structures of their repeat units. These films were amorphous, flexible, and transparent. All films displayed low Tgs (184,225 °C) but also excellent thermal stability, the 5% weight loss temperature was up to 542 °C under nitrogen. The films showed outstanding mechanical properties with the modulus up to 3.0 GPa and the elongation at break in the range of 8,160%. The uniaxial stretching of PI-a at high temperature was studied owing to its excellent flexibility. The PI-a had an elongation at break up to 1600% at 245 °C and the uniaxially stretched film exhibited a much higher modulus (3.9 GPa) and strength (240 MPa) than undrawn film. The results indicated that PI-a can potentially be used to prepare materials such as fiber, ultra-thin film or ultra-high modulus film. All the obtained films also demonstrated excellent thermoplasticity (drop of E, at Tg > 103) which made the polyimides more suitable for melt processing. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2878,2884, 2010 [source] A novel thermotropic liquid crystalline copolyester containing phosphorus and aromatic ether moity toward high flame retardancy and low mesophase temperatureJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2010Xiang-Cheng Bian Abstract A series of thermotropic liquid crystalline polyesters containing phosphorus and aromatic ether groups (TLCP-AEs) were synthesized from p -acetoxybenzoic acid (p -ABA), terephthalic acid (TPA), 4,4,-oxybis(benzoic acid) (OBBA), and acetylated 2-(6-oxid-6H-dibenz(c,e) (1,2) oxaphosphorin 6-yl) 1,4-benzenediol (DOPO-AHQ). The chemical structure and the properties of TLCP-AEs were characterized by Fourier-transform spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetry analysis (TGA), scanning electronic microscopy (SEM), polarizing optical microscopy (POM), limiting oxygen index, and UL-94 tests, respectively. The results showed that TLCP-AEs had low and broad mesophase temperatures (230,400 °C). TLCP-AEs also showed excellent thermal stability; their 5%-weight-loss temperatures were above 440 °C and the char yields at 700 °C were higher than 45 wt %. All TLCP-AE polyesters exhibited high flame retardancy with a LOI value of higher than 70 and UL-94 V-0 rating. The SEM observation revealed that TLCP-AEs had good fibrillation ability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1182,1189, 2010 [source] Atom transfer radical polymerization of styrenic ionic liquid monomers and carbon dioxide absorption of the polymerized ionic liquidsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2005Huadong Tang Abstract Polymeric forms of ionic liquids have many potential applications because of their high thermal stability and ionic nature. Two ionic liquid monomers, 1-(4-vinylbenzyl)-3-butyl imidazolium tetrafluoroborate (VBIT) and 1-(4-vinylbenzyl)-3- butyl imidazolium hexafluorophosphate (VBIH), were synthesized through the quaternization of N -butylimidazole with 4-vinylbenzylchloride and a subsequent anion- exchange reaction with sodium tetrafluoroborate or potassium hexafluorophosphate. Copper-mediated atom transfer radical polymerization was used to polymerize VBIT and VBIH. The effects of various initiator/catalyst systems, monomer concentrations, solvent polarities, and reaction temperatures on the polymerization were examined. The polymerization was well controlled and exhibited living characteristics when CuBr/1,1,4,7,10,10-hexamethyltriethylenetetramine or CuBr/2,2,-bipyridine was used as the catalyst and ethyl 2-bromoisobutyrate was used as the initiator. Characterizations by thermogravimetric analysis, differential scanning calorimetry, and X-ray diffraction showed that the resulting VBIT polymer, poly[1-(4-vinylbenzyl)-3-butyl imidazolium tetrafluoroborate] (PVBIT), was amorphous and had excellent thermal stability, with a glass-transition temperature of 84 °C. The polymerized ionic liquids could absorb CO2 as ionic liquids: PVBIT absorbed 0.30% (w/w) CO2 at room temperature and 0.78 atm. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1432,1443, 2005 [source] Synthesis of autophotosensitive hyperbranched polyimides based on 3,3,,4,4,-benzophenonetetracarboxylic dianhydride and 1,3,5-tris(4-aminophenoxy)benzene via end capping of the terminal anhydride groups by ortho -alkyl anilineJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2003Huan Chen Abstract Benzophenone-containing, anhydride-terminated hyperbranched poly(amic acid)s were end-capped by ortho -alkyl aniline in situ and then chemically imidized, yielding autophotosensitive hyperbranched polyimides. The polyimides were soluble in strong polar solvents, such as N -methyl-2-pyrrolidone, N -dimethylformamide, dimethylacetamide, and dimethyl sulfoxide. Thermogravimetric analysis revealed their excellent thermal stability, with a 5 wt % thermal loss temperature in the range of 527,548 °C and a10 wt % thermal loss temperature in the range of 562,583 °C. The strong absorption of the polyimide films in ultraviolet,visible spectra at 365 nm indicated that the hyperbranched polyimides were patternable. Highly resolved images with a line width of 6 ,m were developed by ultraviolet exposure of the polymer films. A well-defined image with lines as thin as 3 ,m was also patterned, but the lines were rounded at the edges. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2026,2035, 2003 [source] Synthesis, characterization, and properties of novel ladderlike phosphorus-containing polysilsesquioxanesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2003Chin-Lung Chiang Abstract Novel ladderlike polysilsesquioxanes that contain phosphorus were successfully synthesized by the sol,gel method. The polysilsesquioxanes were characterized by Fourier transform infrared spectroscopy, 29Si NMR, and X-ray diffraction. The characterizations demonstrated that the polymer possesses a typical ladderlike structure. The thermogravimetric and differential scanning calorimetric data revealed that the polysilsesquioxanes possess excellent thermal stability. A kinetic analysis of thermal degradation showed that the activation energy of thermal degradation is 187 kJ/mol, according to Kissinger's method. The activation energy of thermal degradation normally increases with conversion (from 171 to 309 kJ/mol) according to Ozawa's method. The average activation energy, calculated by Ozawa's method, was 209 kJ/mol. The scanning electron microscopic photograph and Si and P mappings of ladderlike polysilsesquioxanes showed that the particles were uniformly dispersed at the molecular level and that the sizes of the polysilsesquioxane particles were less than 100 nm. The ultraviolet,visible spectra of the ladderlike polysilsesquioxanes revealed no absorbance in the range of 400,800 nm. Ladderlike polysilsesquioxanes possess excellent optical transparency and excellent flame retardance. This transmittance may be used as a criterion for identifying the formation of a homogeneous phase. These polymers have great potential in waveguide applications. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1371,1379, 2003 [source] Tribological performances of heterocyclic-containing ether and/or thioether as additives in the synthetic diesterLUBRICATION SCIENCE, Issue 3 2009Peipei Liang Abstract The load-carrying capacity, wear and friction properties of 2-octoxyl methylthio-benzothiazole (DEOY) and 2-dodecylthio methylthio-benzothiazole (DEMB) added to a synthetic lubricant (diester) were evaluated using a four-ball test machine. The results indicate that the two compounds added to the diester possess good load-carrying capacities and excellent anti-wear and friction reduction properties. The thermal stability of the two compounds under nitrogen atmosphere was investigated by thermogravimetric analysis (TGA). It was found that the compounds DEOY and DEMB possess excellent thermal stability. The surface topography of the rubbed surface was investigated with scanning electron microscopy, the elemental chemical nature of the anti-wear films generated on steel counterface were investigated with X-ray photoelectron spectroscopy. Copyright © 2009 John Wiley & Sons, Ltd. [source] Di-Channel Polyfluorene Containing Spiro-Bridged Oxadiazole Branches,MACROMOLECULAR RAPID COMMUNICATIONS, Issue 21 2005Rui Zhu Abstract Summary: A p,n di-channel copolymer based on polyfluorene (PF) has been designed and prepared. Branches containing oxadiazole units are attached to the PF backbone through the spiro-structure and act as channels to improve the electron affinity; these branches form a steric ,di-channel' framework with the polymer backbone. The polymer possesses excellent thermal stability. The lowest unoccupied molecular orbital energy level of the polymer is significantly altered in comparison with poly(9,9-dioctylfluorene-2,7-diyl). Schematic of the di-channel polyfluorene synthesized here and the mechanism of energy transfer through the structure. [source] Melt flow properties, mechanical properties, thermal properties and morphology of polycarbonate/highly branched polystyrene blendsPOLYMER INTERNATIONAL, Issue 5 2006Aiying Li Abstract A highly branched polystyrene (HBPS) was synthesized via the copolymerization of 4-(chloromethyl) styrene with styrene using the self-condensing atom transfer radical polymerization method. The addition of HBPS as a melt modifier for polycarbonate (PC) was attempted. Melt flow properties, mechanical properties, thermal properties and morphology of the blends were studied. The results showed that a significant drop in the blend viscosity occurs immediately on addition of HBPS. Impact strength, tensile strength and glass transition temperature (Tg) of all the blends have not been significantly reduced compared with those of pure PC. The TGA analyses showed that an initial weight loss temperature of all the blends is above 458 °C and slightly low compared with that of pure PC, but all the blends still have excellent thermal stability. Morphological studies using SEM showed that a two-phase morphology is characteristic of all the blends, with more or less spherical droplets of the minor HBPS phase dispersed in the continuous PC phase. Copyright © 2006 Society of Chemical Industry [source] Synthesis of poly(aryl ether ketone)s containing diphenyl moieties by electrophilic Friedel,Crafts solution polycondensationPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2009Mingzhong Cai Abstract A new monomer, 4,4,-bis(4-phenoxybenzoyl)diphenyl (BPOBDP), was prepared by Friedel,Crafts reaction of 4-bromobenzoyl chloride and diphenyl, followed by condensation with potassium phenoxide. Novel poly(ether ketone ketone) (PEKK)/poly(ether ketone diphenyl ketone ether ketone ketone) (PEKDKEKK) copolymers were synthesized by electrophilic Friedel,Crafts solution copolycondensation of isophthaloyl chloride (IPC) with a mixture of diphenyl ether (DPE) and BPOBDP, in the presence of anhydrous aluminum chloride and N -methyl-pyrrolidone (NMP) in 1,2-dichloroethane (DCE). The copolymers obtained were characterized by various analytical techniques such as FT-IR, DSC, TGA, and wide-angle X-ray diffraction (WAXD). The results showed that the resulting copolymers exhibited excellent thermal stability due to the existence of diphenyl moieties in the main chain. The glass transition temperatures are above 152°C, the melting temperatures are above 276°C, and the temperatures at a 5% weight loss are above 548°C in nitrogen. The copolymers with 50,70,mol% BPOBDP had tensile strengths of 101.5,102.7,MPa, Young's moduli of 3.23,3.41,GPa, and elongations at break of 12,17%. All these copolymers were semicrystalline and insoluble in organic solvents. Copyright © 2008 John Wiley & Sons, Ltd. [source] Polydimethylsiloxane,cristobalite composite adhesive system for aerospace applicationsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 5 2009Seema Ansari Abstract The effect of phase-pure cristobalite (a high temperature crystalline polymorph of silica) on the adhesive characteristics of hydroxyl terminated polydimethylsiloxane (PDMS) was studied. The potential advantages of PDMS/cristobalite composite system as an adhesive for aerospace applications are also discussed. A PDMS/cristobalite composite adhesive system containing different filler contents (0,46 volume percentage, vol%) was prepared. The filler material, phase-pure cristobalite, was synthesized by the pyrolysis of fused silica at 1400°C. The mechanical, rheological, and thermal characteristics of the composites were studied. A high yield stress (0.151,Pa), shear-thinning index (1.051), and fast recovery rate were observed for ,34,vol% cristobalite loading, which indicate that PDMS retains its excellent adhesive and flow characteristics even at high filler loading with enhanced mechanical characteristics. Thermal analysis shows the onset of degradation of PDMS shifts to higher temperatures, 372,438°C and 317,417°C in nitrogen and air atmosphere respectively, which shows excellent thermal stability. The residual component yields after thermal degradation of PDMS/cristobalite composite system in nitrogen and air atmosphere show different degradation mechanisms. Copyright © 2008 John Wiley & Sons, Ltd. [source] Low loss second-order non-linear optical crosslinked polymers based on a phosphorus-containing maleimidePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 10 2004Chih-Ping Chen Abstract A series of crossslinked organic and organic/inorganic polymers based on maleimide chemistry have been investigated for second-order non-linear optical (NLO) materials with excellent thermal stability and low optical loss. Two reactive chromophores (maleimide-containing azobenzene dye and alkoxysilane-containing azobenzene dye) were incorporated into a phosphorus-containing maleimide polymer, respectively. The selection of the phosphorus-containing maleimide polymer as the polymeric matrices provides enhanced solubility and thermal stability, and excellent optical quality. Moreover, a full interpenetrating network (IPN) was formed through simultaneous addition reaction of the phosphorus-containing maleimide, and sol-gel process of alkoxysilane dye (ASD). Atomic force microscopy (AFM) results indicate that the inorganic networks are distributed uniformly throughout the polymer matrices on a nano-scale. The silica particle sizes are well under 100,nm. Using in situ contact poling, the r33 coefficients of 2.2,17.0,pm/V have been obtained for the optically clear phosphorus-containing NLO materials. Excellent temporal stability (100°C) and low optical loss (0.99,1.71,dB/cm; 830,nm) were also obtained for these phosphorus-containing materials. Copyright © 2004 John Wiley & Sons, Ltd. [source] Synthesis of thermally crosslinkable fluorine-containing poly(arylene ether ketone)s,II.POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2004Propargyl ether terminated poly(arylene ether ketone)s Abstract Novel thermally crosslinkable fluorine-containing poly(arylene ether ketone)s comprised of 2,3,5, 6-tetrafluoro-1,4-phenylene moiety were synthesized by the termination of polymer chain ends with propargyl ether groups in order to improve solvent resistance. Crosslinking reaction occurred over 250°C through the formation of both chromen ring and polyene structure. This structure change brought about not only the outstanding solvent resistance but also the increase in glass transition temperature (Tg). The cured films also exhibited excellent thermal stability, transparency and hydrophobicity derived from fluorine atoms. Copyright © 2004 John Wiley & Sons, Ltd. [source] | |||||||||||||