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  • 1
    Electronic Resource
    Electronic Resource
    Degradation of an acetylene terminated sulfone (ATS) resin (1990)
    Springer
    Journal of thermal analysis and calorimetry 36 (1990), S. 2643-2665 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mittels TG, TVA und SATVA wurde eine Untersuchung der Reaktionsgeschwindigkeit und des Reaktionsmechanismus des Abbaues von Sulfonharz mit endständigem Acetylen (von bis-[4-(3-ethinylphenoxy)phenyl]sulfon und seiner höheren Oligomere) im Hochvakuum bzw. in einer dynamischen Stickstoffatmosphäre durchgeführt. In Verbindung mit quantitativer IR- und NMR-Spektroskopie wurde eine gravimetrische Analyse der Produkte erstellt, um eine quantitative Produktezusammensetzung des Prozesses zu erhalten. Der Sulfonrest konnte somit als schwaches Kettenglied des Systemes erkannt und zwei überlappende Prozesse der thermischen Zersetzung des hauptkettigen Polyphenylethers identifiziert werden: ein Prozess bei niedrigerer Temperatur beinhaltet durch die Sulfonkomponente geförderte Spaltungen und ein zweiter Prozess verursacht bei höherer Temperatur Random-Spaltungen des verbleibenden sulfonfreien Polyphenylethers.
    Notes: Abstract A study of the rates and mechanisms of degradation of an acetylene terminated sulfone resin, more precisely, bis[4-(3-ethynyl phenoxy) phenyl] sulfone and its higher oligomers, under high vacuum conditions, and under a flowing atmosphere of nitrogen, was made using techniques such as programmed thermogravimetry (TG), Thermal Volatilization Analysis (TVA), and Sub Ambient Thermal Volatilization Analysis (SATVA). Gravimetric product analyses made in conjunction with quantitative Infrared and Nuclear Magnetic Resonance Spectroscopy were used to develop a quantitative product distribution for the process. By so doing, we established the sulfone residue as the thermal weak link in the system, and identified two overlapping processes of backbone polyphenylether thermal decomposition; a low temperature process involving scissions promoted by the sulfone moiety, and a higher temperature process involving more random scissions of residual sulfone free polyphenylethers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01913661
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  • 2
    Electronic Resource
    Electronic Resource
    Synthetic pH sensitive polyampholyte hydrogels: A preliminary study (1993)
    Springer
    Colloid & polymer science 271 (1993), S. 38-49 
    Details
    ISSN: 1435-1536
    Keywords: pKa ; pKb ; hydrogel ; membrane ; polyampholyte ; polyelectrolyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A combined capillary drop viscometer-pH cell has been constructed and used to study the solution properties of some polymeric weak acids, bases, and ampholytes containing methacrylic acid (MAA), dimethylaminoethyl methacrylate (DMAEMA), and 2-hydroxyethyl methacrylate (HEMA). The behavior of polyelectrolytes based on MAA or DMAEMA is consistent with established thinking, and is dominated by the chain expansions which accompany ionization of acidic (MAA) or protonation of basic (DMAEMA) functionality. The solution behavior of the polyampholytes is complex and was studied as a preliminary to investigations of crosslinked hydrogel analogues. Briefly, it was found that changes in polymer coil dimensions were dictated by the formation or “breakage” of intramolecular salt bridges by, for example, lowering the solution pH to protonate weakly acidic, or raising the pH to deprotonate weakly basic functionality. Similar effects were observed on adding counterions which preferentially complex with one of the bound ions. The pH “sensitivity” of polymer coil dimensions increased with the concentration of charged functionality in the polymer. Chemically crosslinked polyampholytes were prepared and equilibrium water contents were measured as a function of pH. In contrast, due to network constraints, the pH “sensitivity” of the hydrogels, as measured by changes in equilibrium water uptake, increased with a decrease in the level of charged functionality in the polymer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00652301
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  • 3
    Electronic Resource
    Electronic Resource
    Microcapsules for cell entrapment by template polymerization of a synthetic hydrogel coating around calcium alginate gel: preliminary development (1993)
    Springer
    Journal of materials science 4 (1993), S. 23-31 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Stable, water-soluble copolymers of glycidyl methacrylate with n-vinyl pyrrolidinone (I) were prepared by free-radical polymerization. Water-soluble copolymers of 2-hydroxyethyl methacrylate with methacrylic acid (II) were examined as co-reactants with (I) to form hydrogel matrices. Upon mixing of (I) and (II) in solution, a covalently crosslinked hydrogel was formed, presumably by etherification of epoxy functionality on (I) with hydroxyls on (II). Synthetic hydrogel-coated gel beads were prepared from an aqueous mixture of sodium alginate and (II) by treatment with solution containing (I) and calcium ion. An elastic, defect free and indefinitely stable covalently crosslinked hydrogel coating was formed around the calcium alginate by surface reaction of (I) and (II). Encapsulated guinea-pig red blood cells suffered minimal lysis over a 4 day period due to isolation and protection from the reacting species by the interior alginate gel matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00122973
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  • 4
    Electronic Resource
    Electronic Resource
    Degradation of an Acetylene Terminated Sulfone (ATS) resin (1990)
    Springer
    Journal of thermal analysis and calorimetry 36 (1990), S. 2667-2691 
    Details
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Unter Anwendung eines spezialangefertigten Reaktors modellierten wir die Zersetzung eines acetylenendständigen Sulfonhochleistungsharzes (ATS), genauer gesagt von bis[4-(3-ethinylphenoxy)phenyl]sulfon und seiner höheren Oligomere, unter partiellen anaeroben Bedingungen. Die im Endergebnis des thermischen Abbaues erhaltene Substanz verfügt über eine höhere oxidative Stabilität als die während des thermischen Abbaues vorher erhaltenen Produkte, die im Reaktor mit Sauerstoff sekundäre Produkte wie Kohlenmonoxid, Kohlendioxid und Wasser bilden; somit wird einer direkten Oxidation des Harzes vorgebeugt. Bei Entfernung der flüchtigen Produkte des thermischen Abbaues wird der kohlenstoffreiche Halbkoksrest des thermischen Abbaues direkt zu Kohlenmonoxid, Kohlendioxid und Wasser oxidiert.
    Notes: Abstract Using a custom built reactor, we modelled the decomposition of a high performance Acetylene Terminated Sulfone (ATS) resin, more precisely bis[4-(3-ethynyl phenoxy) phenyl] sulfone and its higher oligomers, under partially anaerobic conditions. The residue of thermal degradation was shown to possess a higher oxidative stability than early products of thermal degradation, which “scavanged” oxygen in the reactor to form secondary products such as carbon monoxide, carbon dioxide, and water: thus preventing direct oxidation of the resin. On removal of volatile products of thermal degradation, the carbonaceous char residue of thermal degradation is directly oxidized to carbon monoxide, carbon dioxide, and water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01913662
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  • 5
    Electronic Resource
    Electronic Resource
    Degradation of poly(p-phenylene benzobisthiazole) (PBT) rigid rod, poly(ether ether ketone ether ketone) (PEEKEK) semi-flexible coil, and a grafted “hairy rod” polymer containing PBT and PEEKEK (1992)
    Springer
    Journal of materials science 27 (1992), S. 6171-6182 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Thermal degradation pathways of the rigid-rod polymer, poly (p-phenylene benzobisthiazole, PBT) have been elucidated by thermal volatilization analysis and related techniques. Processes are characterized by the expulsion of hydrogen sulphide, acetylene, and some carbon disulphide. Evidence is presented for the production and subsequent polymerization of aromatic nitriles and for the existence of thermal rearrangements to produce quinoline derivatives. A similar analysis of the semi-flexible coil polymer, poly (ether ether ketone ether ketone, PEEKEK) revealed the importance of directed chain-scission processes to form oligomers, carbon monoxide expulsion with radical recombination to produce biphenyl linkages, and aromatic fusions to produce fluorenone-type derivatives. Examination of a “hairy rod” comb-type graft copolymer of PBT and PEEKEK revealed some instability introduced by the grafting process and determined that the graft site thermally isomerized through oxygen migration to yield xanthone-based heterocyclic intermediates of degradation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01133767
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  • 6
    Electronic Resource
    Electronic Resource
    Characterization of acetylene terminated sulfone (ATS) resin. I. Chemical characterization of the resin (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 665-677 
    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: An acetylene terminated sulfone resin mixture, prepared under contract for the Air Force, was subjected to a fairly extensive compositional analysis. Monomer, dimer, higher oligomers, solvents, and anomalous side products of synthesis were isolated, identified, and quantified using separatory procedures such as column chromatography and thin film flash distillation, in conjunction with techniques of chemical analysis such as infrared and nuclear magnetic resonance spectroscopy, size exclusion chromatography, and elemental analysis. By these means we were able to precisely characterize the resin mixture and, by so doing, identify some side products of synthesis; most notably, a class of abnormal coupling product able to chelato palladium (a catalyst used in acetylation of the resin) and, therefore, accelerate subsequent acetylene polymerizations in the resin mixture.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070420312
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  • 7
    Electronic Resource
    Electronic Resource
    Characterization of acetylene terminated sulfone (ATS) resin. II. Thermal analysis of the resin (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 679-691 
    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 kinetics and thermodynamics of the cure and post-cure reactions of an acetylene terminated sulfone (ATS) resin mixture and pure fractions from that mixture were studied using differential scanning calorimetry. Thermal stabilities were measured by programmed thermogravimetry under helium, and oxidative stabilities using isothermal thermogravimetry in air. Microstructural changes accompanying the cure reaction were identified using infrared spectroscopy. Early products of thermal degradation were trapped for identification and quantitative analysis using the technique of sub-ambient thermal volatilization analysis. We found that glass transition temperatures increase with crosslink density in the resin, that oxygen is able to copolymerize or couple with the polyenes to produce peroxides or hydroperoxides (respectively) which subsequently decompose to form terminal alcohols on the polyene, that weight loss in air at 600°F is an oxidative process that is insensitive to resin crosslink density, and that sulfone functionality constitutes the thermal weak link in the ATS resin system.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070420313
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  • 8
    Electronic Resource
    Electronic Resource
    The equilibrium water content of some thermoplastic hydroxyalkyl methacrylate polymers (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 36 (1988), S. 1541-1553 
    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 equilibrium water content (EWC) of thermoplastic 2-hydroxypropyl methacrylate and 2-hydroxyethyl methacrylate homopolymers from technical grade monomer and of copolymers of the latter with methyl methacrylate has been measured in distilled water and in phosphate-buffered saline (PBS). In distilled water, as expected, EWCs increased monotonically with the proportion of hydrophilic monomer in the polymer and showed only a small dependence on molecular weight. In contrast, the degree of swelling (and in some cases dissolution) and “freezable” water content of polymers in PBS were shown to be anomalously high and to be a consequence of ionization at pH 7.4 of methacrylic acid incorporated into the polymer in small quantity (〈 1 mol %) as an impurity. Initial studies indicated a strong relationship between copolymer molecular weight and small molecule permeability in distilled water.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070360703
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  • 9
    Electronic Resource
    Electronic Resource
    Preparation and characterization of thermoplastic polymers from hydroxyalkyl methacrylates (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 34 (1987), S. 65-83 
    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: Soluble polymers have been produced from technical-grade 2-hydroxyethyl methacrylate (HEMA) and hydroxypropyl methacrylate (HPHA) using a combination of vacuum distillation and solvent extractions to purify the monomers prior to solution polymerization. These extractions, particularly of HEMA with hexane and corn oil, were found to reduce the level of ethylene glycol dimethacrylate to 〈 1%, according to gas chromatographic analysis. Homopolymers of HEMA and HPMA and copolymers of HEMA with methyl methacrylate were prepared with a wide range of molecular weights and characterized by viscometry in dimethyl formamide, infrared spectroscopy including deuterium exchange experiments, and high resolution proton and carbon nuclear magnetic resonance (NMR) spectroscopy. The latter was used to determine copolymer composition and tacticity distribution.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070340106
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  • 10
    Electronic Resource
    Electronic Resource
    Antiplasticization of poly(bisphenol A, 2-hydroxypropylether) (“phenoxy”) (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 24 (1986), S. 717-722 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1986.090240318
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