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Forced torsional properties of PMR composites with varying nadic ester concentrations and processing histories
Author(s) -
Hurwitz Frances I.
Publication year - 1982
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.750030309
Subject(s) - materials science , composite material , modulus , ultimate tensile strength , terephthalic acid , glass transition , fourier transform infrared spectroscopy , polymer , polyester , physics , quantum mechanics
PMR polyimide resin was prepared from 4,4′‐methylenedianiline (MDA), the dimethyl ester of 3,3′,4,4′‐ benzophenonetetracarboxylic acid (BTDE) and the monomethyl ester of 5‐norbornene‐2,3‐dicarboxylic acid (NE). The NE group serves as a chain terminator and crosslinking site. PMR/Celion 6000 composites were fabricated from resins having varying NE concentrations using two molding processes, and the laminates characterized in forced torsion. Glass transition temperatures ( T g ) of 360–390°C were observed in the crosslinked resins, as compared with the literature value of 284°C reported for the uncrosslinked system T g did not decrease with decreasing NE concentrations over the range from 2.0 to 1.25 moles. Stoichiometry, within the range studied, showed little influence on shear properties; however, a 25% variation in matrix shear modulus with processing was observed. The G 12 values determined in forced torsion were in excellent agreement with those reported from tensile tests of ±45° laminates. A branching and possible secondary crosslink mechanism is proposed based on dynamic mechanical behavior and infrared spectra of the composites.