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  • 1
    Publication Date: 2019-06-27
    Description: Bismaleimide resins are prime candidates for nonflammable aircraft interior panels. Three resin types with different structures and processing characteristics were formulated. Resin M 751 was used to fabricate 100 kg of glass fabric prepregs which were used for the preparation of face sheets for honeycomb sandwich panels. Prepreg characteristics and curing cycles for laminate fabrication are provided. In order to advance beyond the current solvent resin technology for fibre and fabric impregnation, a hot melt solvent-less resin system was prepared and characterized. Preliminary tests were performed to develop a wet bonding process for the fabrication of advanced sandwich honeycomb panels by use of polybismaleimide glass fabric face sheets and polybismaleimide Nomex honeycomb core. B-stage material was used for both the core and the face sheet, providing flatwise tensile properties equivalent to those obtained by the state-of-the-art 3-step process which includes an epoxy adhesive resin.
    Keywords: NONMETALLIC MATERIALS
    Type: NASA-CR-152206 , REPT-7807
    Format: application/pdf
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  • 2
    Publication Date: 2019-07-13
    Description: Several aspects of research on thermoplastics as toughness modifiers are discussed, including the contribution of the backbone chemistry and the concentration of the poly(arylene ether) thermoplastic to fracture toughness, influence of the molecular weight of the poly(arylene ether) thermoplastic on neat resin fracture toughness, and the morphology of the thermoplastic modified networks. The results show that fracture toughness of brittle bismaleimide resins can be improved significantly with poly(arylene ether) thermoplastic levels of 20 percent by weight, and that high molecular weight poly(arylene ether) based on bisphenol A provides the highest degree of toughening. Preliminary composite evaluation shows that improvements in neat resin toughness translate into carbon fabric composite.
    Keywords: NONMETALLIC MATERIALS
    Type: International SAMPE Symposium and Exhibition; May 08, 1989 - May 11, 1989; Reno, NV; United States
    Format: text
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  • 3
    Publication Date: 2019-07-13
    Description: A family of novel, low molecular weight functionalized poly(arylene ether) resins has been investigated to ascertain its members' toughness-imparting contribution to neat bismaleimide (BMI) resin and BMI-matrix laminate composite properties. Attention is given to the contribution of the reactive poly(arylene ether)'s backbone chemistry to fracture toughness, as well as to the comparative influence of high and low molecular weight reactive poly(arylene ether) types on the modified BMI resin systems. The modified BMIs possess a polyphase morphology, with good adhesion between the thermoplastic nodules and the host thermoset systems.
    Keywords: COMPOSITE MATERIALS
    Type: International SAMPE Symposium and Exhibition; Apr 02, 1990 - Apr 05, 1990; Anaheim, CA; United States
    Format: text
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 82 (1979), S. 103-127 
    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: Eine Reihe von urethan- und harnstoff- oder semicarbazid-verknüpften Polyethern für biomedizinische Anwendungen wurde katalysatorfrei hergestellt und systematisch auf mechanische Eigenschaften und Hydrolysierbarkeit untersucht. Besonders eingehend wurde wegen seiner überragenden Eigenschaften das System Poly(oxytetramethylen)diol (POTM)/4,4′-Diisocyanatodiphenylmethan (DDM) untersucht; die Polyether-Diisocyanate wurden mit ausgewählten Diaminen oder Dicarbonsäuredihydraziden umgesetzt. Das Molverhältnis DDM/POTM und die Art des Kettenverlängerers bestimmen die hydrolytische Stabilität. Die besten mechanischen Eigenschaften, gute Hydrolysebeständigkeit und gute Blutverträglichkeit zeigten Polyetherurethansemicarbazide.
    Notes: A series of urethane- and urea- or semicarbazide-linked polyethers for biomedical applications were synthesized without the use of a catalyst. Mechanical properties and hydrolyzability of the polymers were investigated. Due to its superior properties, the system poly(oxytetramethylene)diol (POTM)/4,4′-diisocyanatodiphenylmethane (DDM) was studied quite thoroughly. Its resistance against hydrolysis was determined by the molar ratio DDM/POTM and by the kind of chain extender. Polyetherurethane-semicarbazides showed the best mechanical properties, good resistance against hydrolysis and good blood compatibility.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    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: Die IR-Spektren von urethan-, harnstoff- und semicarbazid-verknüpften aliphatischen Polyethern (Poly(oxyethylene), Poly(oxytetramethylen) und Poly(oxypropylen)) wurden bei 300 K und 153 K gemessen. Die Zuordnung der verschiedenen Struktureinheiten zu bestimmten Gruppen von Absorptionsbanden (charakteristische Bandenkombinationen) geschah durch die Auswetung der Spektren von Vergleichssubstanzen und von Literaturwerten. Die bei tiefen Temperaturen auftretenden Effekte lassen sich nicht als das Auftreten von Kristallinität, sondern nur als beginnende Kettenregularität in den Poly(oxyethylen)- und Poly(oxytetramethylen)-Sequenzen deuten.
    Notes: The infrared spectra of urethane-, urea-, and semicarbazide-linked aliphatic polyethers (poly(oxyethylene), poly(oxytetramethylene) and poly(oxypropylene)) have been measured at 300 K and 153 K. The assignment of the different structural units to certain groups of absorption bands (“characteristic band combinations”) was made by the evaluation of the spectra of reference compounds and of literature data. The low-temperature effects (band splitting, shift of band maxima) facilitate the identification of structural units in these polymers. The observed effects do not signify crystallinity but beginning regularity of the poly(oxyethylene) and poly(oxytetramethylene) sequences.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 14 (1976), S. 2911-2925 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal decomposition of poly(bismaleimides) has been investigated by using programmed and isothermal thermogravimetric analysis (TGA) in nitrogen. Reaction rates and overall activation energies were calculated from isothermal weight less studies. For five aliphatic poly(bismaleimides) a linear correlation between the activation energies and the number of methylene groups in the sequence between the maleimide residues was found. Aliphatic poly(bismaleimides) follow first-order kinetic law up to a conversion of 60-70% having activation energies between 196 and 256 kj/mole. poly(2,4-bismaleimidotoluene) which was found to have in highest polymer decomposition temperature (PDT) did follow the first-order kinetics up to a conversion of 60% in contrast to other aromatic poly(bismaleimides). In addition to the TGA, the pyro-field ion mass spectra of the polymers were recorded and are discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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