Thermally stable polyimides from solutions of monomeric reactants

Abstract

A method to prepare thermally stable resin fiber‐reinforced composites using solutions of appropriate monomers is described. Solutions containing a dimethyl ester of an aryl tetracarboxylic acid, the monomethyl ester of 5‐norbornene‐2,3‐dicarboxylic acid and an aryl diamine were used to impregnate graphite fibers. Composites fabricated from these prepregs exhibited excellent thermo‐oxidative stability and retention of mechanical properties at 600°F. These results compare favorably with those obtained from composites made from amide‐acid prepolymers capped with reactive alicyclic rings. Monomeric solutions provide excellent shelf life and improved solubility compared to amide‐acid prepolymer solutions.

Effect of Substituted Phenylnadimides on Processing and Properties of PMR (Polymerization of Monomeric Reactants) Polyimide Composites.

“…These additives appear to increase the rate of nadimide polymerization at lower . 1 temperatures. The purpose of this report is to demonstrate the feasibility of using nitrophenylnadimides and other nitro substituted compounds to lower the cure temperature of PHR-15 composites and to identify the processing parameters and resultant composite performance characteristics.…”

Highly Heat and Oxidation-Resistant Materials Prepared Using Silicon-Containing Thermosetting Polymers with [Si(H)~C≡C] Units

“…The low bending strength could be improved by further studying the mechanical properties at high temperatures and by optimizing the preparation method of FRP. An FRP (Yokohama Rubber Co., Ltd.), which was prepared using polyimide resin (PMR-15); developed by NASA-Lewis Research Center [32] and a silicon carbide compact is shown on the graph below 300°C. Dynamic viscoelasticity and creep properties of MSP composite were determined and compared with those of a polyimide composite [30].…”

Improved thermal design of a compression mold

“…A common practice is to create a neat resin sample -one with no reinforcing material added -to allow for chemical and mechanical testing to be performed on the cured resin. For high-temperature resins, such as PMR-15 5 and its https://ntrs.nasa.gov/search.jsp?R=20070022453 2019-04-28T05:41:58+00:00Z descendents, production of the resin sample requires the application of high temperatures (up to 650 °F) and substantial pressure (several hundreds pounds per square inch) using a specified time-temperature-pressure profile. This requires the resin to be processed in a heated compression tool made of hardened tool steel.…”