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  • Electronic Resource  (101)
  • Polymer and Materials Science  (101)
  • Physics  (12)
  • 11
    Electronic Resource
    Electronic Resource
    Dielectric studies of the cure of epoxy matrix systems (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 1155-1167 
    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: Dielectric spectroscopy was used to monitor the curing process of two epoxy resin systems. The basic system (system I) consisted of DGEBA (a difunctional epoxy) and a polyamide in a 50-phr mixture. In addition, a comparative analysis was performed on a high-performance resin system (system II) used primarily in unidirectional composite applications. This system contained TGDDM (a tetrafunctional epoxy) and DDS (a tetrafunctional amine) in a 25-phr mixture. The dielectric data were obtained using a simple yet functional sample cell electrode designed and constructed in the laboratory. For system I, isothermal dielectric data were used to determine apparent activation energies for the temperature range from 22 to 70°C. The data showed that the activation energy was a function of temperature and increased as the temperature of the cure increased. This indicated that the reaction mechanism was also a function of temperature. For system II, data were collected between 140 and 190°C and an overall activation energy for that temperature range was determined. The overall activation energies for both systems, calculated using dielectric spectroscopy, compared favorably to those obtained using differential scanning calorimetry. Also, using a wider frequency range (240 Hz to 2 MHz), Argand diagrams were constructed and modeled with the Cole-Cole empirical equation for systems with a distribution of relaxation times. This justified the calculation of average relaxation times, which could then be related to the bulk physical properties of the polymer, such as viscosity. Modified Argand diagrams, where ε″ is plotted against ε′ at one frequency as a function of time, were also constructed, which aided in the understanding of the curing processes for these thermosetting systems.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070310501
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  • 12
    Electronic Resource
    Electronic Resource
    Polyamides incorporating phosphine oxide groups. III. Polymerisation of bis[4-(2-aminoethyl)aminophenyl]-phenylphosphine oxide with dicarboxylic acids (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2865-2870 
    Details
    ISSN: 0887-624X
    Keywords: phosphine oxide ; aromatic-aliphatic polyamides ; polycondensation ; thermal properties ; fire retardant materials ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new polymerisation monomer bis[4-(2-aminoethyl)aminophenyl]-phenylphosphine oxide (p-BAPPO) was prepared in good yield by the nucleophilic substitution reaction between bis(4-fluorophenyl)phenylphosphine oxide and a large excess of 1,2-diaminoethane. Five novel polyamides, incorporating phosphine oxide groups within the polymer backbone were synthesised by the condensation reaction of p-BAPPO with a series of aromatic and aliphatic dicarboxylic acids. The thermal properties of these polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. Glass transition temperatures in the 180-215°C range were recorded. Although we observed their thermooxidative stabilities (5% weight loss 〉 345°C) to be lower by 40-70°C than those previously found for wholly aromatic polyamides with phosphine oxide groups within the parent chain, char yields upon prolonged heating at 650°C were still excellent (26-38%). Also, good solubility in aprotic polar solvents was observed for all polyamides synthesised. The new polyamides clearly represent significant progress in the quest for processible fire retardant materials. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2865-2870, 1997
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    The modification of polysulfone by metalation (1988)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 26 (1988), S. 123-127 
    Details
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1988.140260211
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  • 14
    Electronic Resource
    Electronic Resource
    Miniemulsion copolymerization of vinyl acetate and butyl acrylate. III. Experimental evidence for the role of the cosurfactant (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 193-202 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The role of the cosurfactant (hexadecane) in the miniemulsion copolymerization of 50 : 50 molar ratio vinyl acetate-butyl acrylate monomer mixture is analyzed from an experimental point of view. The main factor responsible for the different kinetic behavior between the miniemulsion and conventional emulsion copolymerization processes was found to be the different particle nucleation mechanism operating in each process. Experimental evidence is presented indicating that in the miniemulsion copolymerization particle nucleation takes place in the preformed stable submicron monomer droplets.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080270117
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  • 15
    Electronic Resource
    Electronic Resource
    Semicontinuous seeded emulsion copolymerization of vinyl acetate and methyl acrylate (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 169-186 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The semicontinuous seeded emulsion copolymerization of vinyl acetate and methyl acrylate was investigated. The effect of type of process (starved process versus semi-starved process), type of feed (neat monomer addition versus monomer emulsion addition), amount of seed initially charged in the reactor, and feed rate on the time evolution of the overall conversion, copolymer composition, and polymer particle size was analyzed. It was found that, in the case of the starved process, both monomers, but mainly vinyl acetate, accumulated in the reactor. The preferential accumulation of vinyle acetate resulted in a drift of the copolymer composition. Both monomers accumulation and copolymer composition drift were reduced by increasing the amount of seed initially charged in the reactor and by decreasing the feed rate. For the semi-starved process, it was found that a vinyl aceatate rich copolymer was formed when a low methyl acrylate feed was used, whereas a methyl acrylate rich copolymer was obtained at high methyl acrylate feed rates. For both starved process and semi-starved process, the total number of polymer particles, after an initial increase, reached a plateau value which was the same in all of the experiments carried out. These results were analyzed by means of a mathematical model developed for this system.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1991.080290204
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  • 16
    Electronic Resource
    Electronic Resource
    Grafting reactions of vinyl acetate onto poly[(vinyl alcohol)-co-(vinyl acetate)] (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 2581-2594 
    Details
    ISSN: 0887-624X
    Keywords: grafting ; poly(vinyl alcohol) ; poly(vinyl acetate) ; vinyl acetate ; methine carbon ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The grafting preference of vinyl acetate onto the methine carbon of poly(vinyl alcohol) (PVOH) versus the acetate group of poly(vinyl acetate) (PVAc) was determined as part of an attempt to prepare novel branched PVOH from partially hydrolyzed PVAc. The results showed long chain grafting on the acetate groups of the PVAc units rather than the methine carbons of the PVOH or PVAc units. Decreasing the monomer or initiator concentration decreased the molecular weight of the graft copolymer formed. Of the initiators studied, ammonium persulfate gave the largest increase in copolymer molecular weight. Both hydrolysis and reacetylation combined with gel permeation chromatography (GPC) and 13C-NMR of the fully hydrolyzed material were used to estimate the number and location of grafts. © 1996 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Miniemulsion copolymerization of vinyl acetate and butyl acrylate. I. Differences between the miniemulsion copolymerization and the emulsion copolymerization processes (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 861-874 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Differences between the emulsion copolymerization and miniemulsion copolymerization processes, in terms of emulsifier adsorption, emulsion stability, polymerization kinetics, copolymer composition and dynamic mechanical properties were studied for the comonomer mixture of 50:50 molar ratio vinyl acetate (VA+) - butyl acrylate (BuA), using sodium hexadecyl sulfate (SHS) as a surfactant and hexadecane (HD) as a co-surfactant. The use of hexadecane with the appropriate SHS initial concentration led to a higher adsorption of surfactant, smaller droplet size, higher stability of the emulsions, lower polymerization rates, and larger latex particle size. The copolymer composition during the initial 70% conversion was found to be less rich in Vac monomer units for the miniemulsion process. The dynamic mechanical properties of the copolymer films showed less mixing between the BuA-rich core and the VAc-rich shell in the miniemulsion latexes compared to the conventional latex films.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080240505
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  • 18
    Electronic Resource
    Electronic Resource
    Structure-property relationships of ionene polymers (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 87-109 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of new ionenes was accomplished by the reaction of novel diamines and dihalides. A new class of crosslinkable ionenes was made possible by the synthesis of tertiary diamines with acrylate functionality, generated ultimately from diepoxides and secondary amines. Other tertiary diamines were produced by endcapping of diols with tolylene diisocyanate, followed by reaction with N,N-dimethylethanolamine and also termination of living poly(tetrahydrofuran) polymer with dimethylamine. New dihalides were produced by the opening of diepoxides with ω-bromoacids.These diamines and dihalides underwent Menschutkin reactions providing novel ionenes for structure-property relationship studies. Correlations were drawn concerning amine nucleophilicity, dihalide nucleofugascity, and molecular weight. Stress-strain and thermal data reflected the effects of ionic domains and large flexible segments in the polymers. Also considered were the electrical conductivity, moisture-vapor transmission, and oxygen permeability of these materials.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1987.080250109
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  • 19
    Electronic Resource
    Electronic Resource
    Synthesis of novel polyxanthenes from poly(arylene ether)s containing benzoyl groups (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2267-2272 
    Details
    ISSN: 0887-624X
    Keywords: poly(arylene ether)s ; pendant benzoyl groups ; polyxanthenes ; Friedel-Crafts cyclization ; thermal stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(arylene ether)s (3), (4) containing pendant benzoyl groups as precursors for novel polyxanthenes (7), (8) were prepared by nucleophilic substitution reaction of 2,5-difluoro-4-benzoylbenzophenone (1) or 2,5-difluoro-4-(4-dodecylbenzoyl)-4′-dodecylbenzophenone (2) with hydroquinone derivatives in the presence of potassium carbonate in N,N-dimethylacetamide. The polycondensation proceeded smoothly at 165°C and produced poly(arylene ether)s with inherent viscosities up to 0.80 dL/g. The novel polyxanthenes were synthesized via the reduction of poly(arylene ether)s followed by the Friedel-Crafts cyclization of diol polymers. The structure of the polyxanthenes was characterized by 1H-NMR and IR spectroscopies. Polyxanthene 8 was quite soluble in chloroform and THF. The 10% weight loss temperature of polyxanthene 7 was 510°C in nitrogen and it was 90°C higher than the corresponding poly(arylene ether) 3. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2267-2272, 1997
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Polyamides incorporating phosphine oxide groups. I. Wholly aromatic polymers (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 1561-1566 
    Details
    ISSN: 0887-624X
    Keywords: phosphine oxide ; polyamide ; polycondensation ; thermal properties ; fire-retardant materials ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Five novel polyamides incorporating phosphine oxide groups have been synthesized by the condensation reaction of bis(4-carboxyphenyl)phenylphosphine oxide with a series of aromatic diamines. The thermal properties of these polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. Glass transition temperatures in the 225-254°C range were recorded, together with good thermooxidative stability (5% weight loss occurring at 〉420°C) and high char yield upon prolonged heating at 650-800°C (24-50%). Also, good solubility in aprotic polar solvents was observed for all polyamides synthesized. © 1996 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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