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  • Polymer and Materials Science  (11)
  • 1995-1999  (11)
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Keywords
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Pultruded fiber-reinforced polyurethane-toughened phenolic resin, I. Reactivity and morphology (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 235 (1996), S. 35-45 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ein Phenolharz-Polyurethan-Copolymeres wurde aus einem Phenolharz, einem geschützten Polyurethan und p-Toluolsulfonsäure hergestellt. Dieses Copolymere weist trotz großer Härte eine gute Verarbeitbarkeit (einschließlich Topfzeit und Reaktivität) auf. Die Synthese des Copolymeren wurde mit IR-Spektroskopie verfolgt. Es wurde gefunden, daß die Isocyanatgruppe des Polyurethans nach Abspaltung der Schutzgruppe mit der Hydroxygruppe des Phenolharzes reagierte. Glasfaserverstärkte Verbundwerkstoffe offenbarten bei SEM-Untersuchungen eine hervorragende Verbindung zwischen Faser und Matrix. Ein Überlappungspeak im DMA-Diagram wies auf Wechselwirkungen zwischen Phenolharz und Polyurethan hin, die die Härte des Phenolharzes verbessern.
    Notes: A phenolic resin/polyurethane copolymer was synthesized by reaction of a phenolic resin, a blocked-polyurethane and p-toluene sulfonic acid. The copolymer provides a good balance between the processability (including pot life, reactivity) and toughness. The reactions that proceeded during the synthesis of the copolymer was investigated by IR spectroscopy. It was found that blocked polyurethane reacted with the hydroxy group of the phenolic resin. Glass fiber-reinforced composites showed excellent bonding between fiber and matrix as revealed by SEM photographs. An overlap peak was found from the DMA diagram; it indicated that an interaction existed between phenolic resin and polyurethane and that improved the toughness of the phenolic resin.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1996.052350104
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of hydrophilic thermotropic block copolyetheresters (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1153-1159 
    Details
    ISSN: 0887-624X
    Keywords: hydrophilic ; thermotropic ; liquid crystalline polymers ; block copolyetheresters ; melt polycondensation ; poly (ethylene oxide) segment ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The block copolyetheresters with a hard segment of poly (hexamethylene p,p′-bibenzoate) and a soft segment of poly (ethylene oxide) were prepared by melt polycondensation of dimethyl-p,p′-bibenzoate, 1,6-hexanediol, and polyethylene glycol (PEG) with molecular weights of 400, 1000, 2000, or 4000. These block copolyetheresters were characterized by intrinsic viscosity, GPC, FT-IR, 1H-NMR, and water absorption. The thermotropic liquid crystalline properties were investigated by DSC, polarized microscope, and x-ray diffraction. The block copolyetheresters exhibit smectic liquid crystallinity due to the polyester segment. The transitions are dependent on the molar content and the molecular weight of PEG used. The block copolyetheresters show high water absorption due to the hydrophilic nature of the poly (ethylene oxide) segment. The water absorption increases with increasing PEG content. As the molecular weight of PEG increases, the water absorption increases significantly. The results indicate that the water absorption of the poly (ethylene oxide) segment in the block copolymers is affected by the presence of polyester segments. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330718
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  • 3
    Electronic Resource
    Electronic Resource
    Mechanism of transesterification and cyclization of epoxy-polycarbonate blends catalyzed by quarternary ammonium salt (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 3303-3312 
    Details
    ISSN: 0887-624X
    Keywords: epoxy ; blend ; polycarbonate ; transesterification ; cyclization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of oxirane with carbonate using quarternary ammonium salts as catalyst has been studied. Curing is caused by the transesterification reaction of the oxirane cycle with the carbonate group that proceeds by an “insertion” mechanism in the stoichiometric system. The ratio of the reactants is two oxirane groups to one carbonate group. In the nonstoichiometric system, the epoxide content is more than the stoichiometric quantity required. A cyclization reaction is followed by the transesterification reaction. To identify the finished products, a model reaction was proposed using diphenyl carbonate and phenyl glycidyl ether which results in the formation of 4-phenoxymethyl-1,3-dioxolane-2-one (PMD). The mechanism of forming the cyclic structure is assumed to proceed through the chain scission of the network in which the molecular chain crosslinked with carbonate group by a transesterification reaction. © 1996 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    The epoxy-polycarbonate blends cured with aliphatic amine - II. Thermal and mechanical properties mechanisms (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 2183-2191 
    Details
    ISSN: 0887-6266
    Keywords: epoxy ; blend ; polycarbonate ; transesterification ; transamidation carbamate ; urea ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The transamidation reaction converts the carbonate and amine into N-aliphatic aromatic carbamate and urea, causing the equivalent of oxirane and amine nonstoichiometric in the primary cure stage. After postcure, the substitution reaction takes place and results in a more tightly crosslinked structure. Such a higher crosslinking density is responsible for higher Tg, tensile strength, and tensile modulus in the postcure stage than that in the primary and secondary cure stages. This trend is more pronounced in those PC-epoxy blends containing higher molecular weight aliphatic amine or a higher content of PC. This phenomenon is due to the difference in the fraction of amino group of aliphatic amine consumed in the transamidation. PC-epoxy/aliphatic amine blends show minor improvement in the high strain rate Izod impact tests, while toughness improvement for some blends is substantial at low strain rate tensile tests. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2183-2191, 1997
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Strength of hydrogen bonding in the novolak-type phenolic resin blends (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 1721-1729 
    Details
    ISSN: 0887-6266
    Keywords: phenolic ; miscibility ; hydrogen bonding ; PEO ; PEG ; PVA ; glass transition temperature ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The specific interaction strength of novolak-type phenolic resin blended with three similar polymers [i.e., poly(ethylene oxide) (PEO), poly(ethylene glycol) (PEG), and poly(vinyl alcohol) (PVA)] were characterized by means of glass transition temperature behavior and Fourier transform infrared (FTIR) spectroscopy. The interassociation formed within phenolic blends with the addition of a modifier not only overcomes the effect of self-association of the phenolic upon blending, but also increases the strength of phenolic blend. The strength of interassociation within the phenolic blend is the function of the hydrogen bonding group of a modifier, in increasing order, is phenolic/PVA, phenolic/PEG, and phenolic/PEO blend, corresponding to the result of “q” value in the Kwei equation. The FTIR result is in agreement with the inference of Tg behavior. In addition, the fact that the specific strength of hydrogen bonding of hydroxyl-hydroxyl is stronger than that of hydroxyl-ether can also be concluded. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1721-1729, 1998
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    The epoxy-polycarbonate blends cured with aliphatic amine - I. Mechanism and kinetics (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 2169-2181 
    Details
    ISSN: 0887-6266
    Keywords: epoxy ; blend ; polycarbonate ; transesterification ; transamidation ; carbamate ; urea ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Reaction mechanism of the PC-epoxy blends cured by aliphatic amine has been investigated by varying PC contents in the blends. The transamidation reaction tends to convert nearly all the carbonates into N-aliphatic aromatic carbamates even at ambient temperature before normal curing. The remaining amine proceeds the normal curing with epoxy at a higher temperature (80°C). For the PC-epoxy/aliphatic amine blend containing 6 wt % PC, the yielded N-aliphatic aromatic carbamate further reacts with amine to produce the urea structure. The urea undergoes substitution reaction with the hydroxyl formed from the normal curing to give the N-aliphatic aliphatic carbamate. For the blend containing 12 wt % PC, the N-aliphatic aromatic carbamate converts into the N-aliphatic aliphatic carbamate via two different routes. For the blend containing lower molecular weight of the aliphatic amine, the N-aliphatic aromatic carbamate reacts with hydroxyl to form the N-aliphatic aliphatic carbamate directly. For the blend containing higher molecular weight of aliphatic amine, the N-aliphatic aromatic carbamate decomposes into the aliphatic isocyanate accelerated by the presence of the residual oxirane. The isocyanate formed then reacts with hydroxyl to yield the N-aliphatic aliphatic carbamate. The activation energy (Ea) and preexponential factor (A) of the PC-epoxy/POPDA blends decrease with the increase of the PC content. Kinetic study by thermal analysis by the method of autocatalyzed model is able to correctly predict oxirane conversion vs. time relationship for the neat epoxy/aliphatic amine and the PC-epoxy/aromatic amine systems because the dominant reaction is the normal curing reaction between amine and oxirane. The model fails to predict the PC-epoxy/aliphatic amine system because the system is complicated by several other reactions besides the normal curing reaction. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2169-2181, 1997
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis and properties of thermotropic polyesters modified with a non-mesogenic rigid group (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 2155-2164 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Four series of copolyesters, namely BB6-DMT, BB5-DMT, BB6-DMI and BB5-DMI series, were prepared by melt polycondensation of dimethyl 4,4′-bibenzoate (BB) with a dimethyl phthalate (DMT: dimethyl terephthalate or DMI: dimethyl isophthalate) and an alkanediol (1,6-hexanediol or 1,5-pentanediol). The homopolyesters poly(hexamethylene 4,4′-bibenzoate) (BB6) and poly(pentamethylene 4,4′-bibenzoate) (BB5) exhibit a smectic phase. The thermotropic liquid crystalline and crystalline properties of the copolyesters are significantly influenced by the presence of the non-mesogenic rigid phthalate unit. All BB6-DMT copolyesters remain crystalline. As x, the molar fraction of the phthalate units in the diacid units, ≧ 0.7 the mesophase of the BB6-DMT copolyesters is destroyed completely. For BB5-DMT copolyesters, the mesophase disappears as x ≧ 0.4, and the copolyesters become amorphous as 0.5 ≦ x ≦ 0.8. The mesophase and the crystallinity of the BB6-DMI copolyesters are destroyed completely as x 〉 0.5. The BB5-DMI copolyesters lose the mesophase as x ≧ 0.3, and become amorphous as x ≧ 0.4. The results indicate that the non-linear isophthalate unit destroys mesophase and crystallinity of the copolyesters to a greater extent than the para-linked terephthalate unit.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1996.021970707
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  • 8
    Electronic Resource
    Electronic Resource
    Hydrophilic thermotropic block copolyetheresters with poly(pentamethylene p,p′-bibenzoate) segments (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 196 (1995), S. 3459-3468 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Block copolyetheresters 1 with poly(pentamethylene p,p′-bibenzoate) segments and poly(ethylene oxide) segments were prepared by melt polycondensation of dimethyl p,p′-bibenzoate, 1,5-pentanediol, and poly(ethylene glycol) (PEG) with molecular weights of 400, 1 000, or 2 000. The 1H NMR analysis shows that the feed mole ratio of PEG to dimethyl p,p′-bibenzoate determines the composition of the block copolyetheresters. The differential scanning calorimetry (DSC) results indicate that some block copolyetheresters exhibit a monotropic smectic liquid-crystalline phase due to the poly(pentamethylene p,p′-bibenzoate) segments. The transitions depend on the content and the molecular weight of the PEG. The block copolyetheresters 1 show high water absorption due to the hydrophilic nature of the poly(ethylene oxide) segments. The water absorption increases with increasing PEG content. As the molecular weight of PEG increases, the water absorption increases significantly.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1995.021961103
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  • 9
    Electronic Resource
    Electronic Resource
    Blocked diisocyanate-modified epoxy resin: Mechanism and mechanical properties (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 523-531 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The modification of bisphenol-A-based epoxy resin with isocyanates was investigated. To increase the crosslinking density by a urethane reaction and to conduct the normal cross-linking reaction between the epoxide and the amine during the cure cycle, blocking the isocyanates with active hydrogens is necessary, which may be deblocked and reacted at elevated temperature. The modified reactions involving diisocyanates and hydroxyl groups generated from epoxy cured with an amine system were studied. This mechanism can be identified by the variations of infrared spectra in the carbonyl group stretching region. Furthermore, the effect of the blocked isocyanate incorporation with amine on the reactivity of epoxy was also studied. The thermal and the mechanical properties were characterized. It was found that the glass transition temperature increased with an aromatic blocked-diisocyanate content. The mechanical properties were improved by blocked diisocyanate. The morphology was also investigated, which showed that a homogeneous structure existed in the modified system. © 1996 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Preparation and characterizations of thermotropic copolyesters of p-hydroxybenzoic acid, sebacic acid, and hydroquinone (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 56 (1995), S. 471-476 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A series of copolyesters of p-hydroxybenzoic acid (HBA), sebacic acid and hydroquinone were prepared by melt polycondensation of p-acetoxybenzoic acid, sebacic acid and p-phenylene diacetate. The copolyesters were characterized by IR, NMR, DSC, polarized microscopy, and X-ray diffraction. It was found that the copolyesters exhibited liquid crystallinity when the HBA content was 25-67 mol %. The copolyesters with an HBA content of 25-43 mol % showed a nematic phase and a biphasic range, and the isotropization temperature increased as the HBA content increased. The copolyesters with an HBA content of 54-67 mol % showed a nematic phase up to above 400°C. The liquid crystalline order increased as the HBA content increased due to the increased of the average length of the rigid moieties. © 1995 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070560408
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