ISSN:
0887-624X
Keywords:
addition polyimides
;
biphenyldiamine
;
benzidine
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A new series of high flow PMR-type addition curing polyimides was developed, which employed the substitution of 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (BTDB) for p-phenylenediamine (p-PDA) in a PMR-II formulation. These thermoset polyimides, designated as 12F resins, were prepared from BTDB and the dimethyl ester of 4,4′-(hexafluoroisopropylidene)-diphthalic acid (HFDE) with either nadic ester (NE) or p-aminostyrene (PAS) as the endcaps for addition curing. The 12F prepolymers displayed lower melting temperatures in DSC analysis, and higher melt flow in rheological studies than the corresponding PMR-II polyimides. Long-term isothermal aging studies showed that BTDB-based 12F resins exhibited comparable thermo-oxidative stability to p-PDA based PMR-II polyimides. The noncoplanar 2- and 2′-disubstituted biphenyldiamine (BTDB) not only lowered the melt viscosities of 12F prepolymers, but also retained reasonable thermal stability of the cured resins. The 12F polyimide resin with p-aminostyrene endcaps showed the best promise for long-term, high-temperature application at 343°C (650°F). © 1994 John Wiley & Sons, Inc.
Additional Material:
12 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pola.1994.080320715
