Engineering topics
Publications and source records attributed to Kimmel, B. G..
Foam formulations may be readily emplaced in honeycomb structures after heating to soft, doughlike consistency and forcing heated mixture into honeycomb cells. Final cure can be accomplished by simple oven cure, with no need for containment or restriction of foam formulation during cure.
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The development of techniques for the preparation of Pyrrone structural foams for use as honeycomb filler is described. The feasibility of preparing foams from polymers formed by the condensation of 3,3'-diaminobenzidine (DAB), or 3,3',4,4'-tetraaminobenzophenone (TABP), with 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) was investigated. Initially, most of the effort was devoted to preparing Pyrrone prepolymers with improved and more reproducible foaming properties for making chemically blown foams. When it became apparent that very high curing shrinkages would not allow the use of unfilled Pyrrone prepolymers in a foam-in-place process, emphasis was shifted from chemically blown foams to syntactic foams. Syntactic foam formulations containing hollow carbon microspheres were developed. Syntactic foams made from selected formulations were found to have very low coefficients of thermal expansion. A technique was developed for the emplacement of Pyrrone syntactic foam formulations in honeycomb core structures.
Syntactic foam formulations were prepared from mixtures of Pyrrone prepolymers and hollow carbon microspheres. Very low curing shrinkages were obtained for high volume loadings of microspheres. The resulting syntactic foams were found to be remarkably stable over a wide range in temperature. A technique was developed for the emplacement of these foam formulations in polyimide-fiberglass, titanium alloy and stainless steel honeycomb without sacrificing low curing shrinkage or thermal stability.
Development of technique for preparing foam materials to be used as thermal structural components in spacecraft construction
Feasibility and characterization of Pyrrone foams
Development and optimization of pyrrone polymers
Dielectric window development for spacecraft antennas - reinforced plastics and ceramics
Dielectric windows for spacecraft antennas - screening tests of reinforced plastics