Peter I Delvigs

42448530, Jan 13, 1981

Apr 6, 1979

6/027557

Tito T. Serafini - Middleburg Heights OH
Peter Delvigs - Fairview Park OH

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

C08K 505
C08K 513

260 334R

A composition for making polyimide resin-reinforced fibers or fabric. The composition is of the type disclosed in U. S. Pat. No. 3,745,149 and includes a polyfunctional ester, a polyfunctional amine, and an end-capping agent. The composition is impregnated into fibers or fabric and heated to form prepreg material. The tack retention characteristics of this prepreg material are improved by incorporating into the composition a liquid olefinic material compatible with the other ingredients of the composition. The prepreg material is heated at a higher temperature to effect formation of the polyimide resin and the monomeric additive is incorporated in the polyimide polymer structure.

42448573, Jan 13, 1981

Aug 30, 1979

6/070771

Tito T. Serafini - Middleburg Hts. OH
Peter Delvigs - Fairview Park OH
Raymond D. Vannucci - Brooklyn OH

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

C08K 706
C08G 5902
C07D20706

260 37EP

A curing agent for a polyepoxide has the formula: ##STR1## wherein R. sub. 1 is a divalent aryl radical such as phenylene and wherein R. sub. 2 is a tetravalent aryl radical such as a tetravalent benzene radical. An epoxide is cured by admixture with the curing agent. The cured epoxy product retains the usual properties of cured epoxides and, in addition, has a high char residue after burning, on the order of 45% by weight. The high char residue is of value in preventing release to the atmosphere of carbon fibers from carbon fiber-epoxy resin composites in the event of burning of the composite.