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Jones, R. J.

Publications and source records attributed to Jones, R. J..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Polyimide matrix resins for up to 700 deg F service

TRW is in the process of data accumulation that strongly indicates that incorporation of the perfluorsisopropylidene linkage in molecular structures other than those employed in DU Pont's NR-150B polyimides likewise yield polymers demonstrating extremely high thermo-oxidative stability. Polyimide synthetic and characterization studies conducted to date on new polymers incorporating the perfluoroisopropylidene linkage are presented and discussed.

Jones, R. J.↗
NASA NTRS1983

Improved high temperature resistant matrix resins

The objective was to develop organic matrix resins suitable for service at temperatures up to 644 K (700 F) and at air pressures up to 0.4 MPa (60 psia) for time durations of a minimum of 100 hours. Matrix resins capable of withstanding these extreme oxidative environmental conditions would lead to increased use of polymer matrix composites in aircraft engines and provide significant weight and cost savings. Six linear condensation, aromatic/heterocyclic polymers containing fluorinated and/or diphenyl linkages were synthesized. The thermo-oxidative stability of the resins was determined at 644 K and compressed air pressures up to 0.4 MPa. Two formulations, both containing perfluoroisopropylidene linkages in the polymer backbone structure, exhibited potential for 644 K service to meet the program objectives. Two other formulations could not be fabricated into compression molded zero defect specimens.

Chang, G. E.↗
NASA NTRS1977

Poly /Diels-Alder/ matrix resins

A poly (Diels-Alder) (PDA) resin approach was investigated as a means to achieve autoclavability of high-temperature resistant resin/fiber composites under mild fabrication conditions. The results of the study were highly promising and program objectives were achieved. Low-void content Type A-S graphite reinforced composites were autoclave fabricated from a PDA resin/fiber prepreg prepared from an acetone:methanol:dioxane varnish. Autoclave conditions were 400 F and 100 psi for up to two hours duration. After postcure at temperatures up to 600 F, the composites demonstrated high initial mechanical properties at temperatures up to 550 F. The results from isothermal aging studies in air for 1000 hours indicated potential for long-term (over 1000 hours) use at 500 F and shorter-term use at 550 F.

Jones, R. J.↗
NASA NTRS1976

Capillary flow weld-bonding

The invention of a weld-bonding technique for titanium plates was described. This involves fastening at least two plates of titanium together using spot-welding and applying a bead of adhesive along the edge of the resistance spot-welded joint which upon heating, flows and fills the separation between the joint components.

Vaughan, R. W.↗
NASA NTRS1976

Development of autoclave moldable addition-type polyimides

Chemistry and processing modifications of the poly(Diels Alder) polyimide (PDA) resin were performed to obtain structural composites suitable for 589 K (600 F) service. This work demonstrated that the PDA resin formulation is suitable for service at 589 K (600 F) for up to 125 hours when used in combination with Hercules HTS graphite fiber. Sandwich panels were autoclave molded using PDA/HTS skins and polyimide/glass honeycomb core. Excellent adhesion between honeycomb core and the facing skins was demonstrated. Fabrication ease was demonstrated by autoclave molding three-quarter scale YF-12 wing panels.

Vaughan, R. W.↗
NASA NTRS1976

Fabrication of PDA/HTS prototype components

A process was developed for autoclave molding structural poly-(Diels-Alder) polyimide (PDA) resin/HTS graphite composites for short-term 600 F service. The autoclave molding process used to fabricate these composites required a maximum cure temperature of 427 K (400 F) and a maximum molding pressure of 0.7 MN/sq m (100 psig). This process then was adapted to the fabrication of co-cured polyimide sandwich panels consisting of PDA/HTS skins, PDA syntactic foam and polyimide/glass honeycomb core. Fabrication ease was demonstrated by manufacturing five three-quarter scale YF-12 wing panels using the PDA resin. It was concluded from successful evaluation of these prototype units that the PDA resin is suitable for fabrication of components using commercial equipment.

Sheppard, C. H.↗
NASA NTRS1974

Development of autoclavable polyimides

A poly(Diels-Alder) (PDA) resin approach was investigated as a means to achieve autoclavability of high temperature resistant resin/fiber composites under mild fabrication procedures. Low void content Type A-S graphite reinforced composites were autoclave fabricated from a PDA resin/fiber prepared from an acetone:methanol:dioxane varnish. Autoclave conditions were 477K (400F) and 0.7 MN/sq m (100 psi) for up to two hours duration. After postcure at temperatures up to 589K (600F), the composites demonstrated high initial mechanical properties at temperatures up to 561K (550F). The results from isothermal aging studies in air for 1000 hours indicated potential for long-term ( 1000 hours) use at 533K (500F) and shorter-term (up to 1000 hours) at 561K (550F).

Orell, M. K.↗
NASA NTRS1974

Development of autoclavable addition type polyimides

Two highly promising approaches to yield autoclavable addition-type polyimides were identified and evaluated in the program. Conditions were established for autoclave preparation of Hercules HMS graphite fiber reinforced composites in the temperature range of 473 K to 505 K under an applied pressure of 0.7 MN/m2 (100 psi) for time durations up to four hours. Upon oven postcure in air at 589 K, composite samples demonstrated high mechanical property retention at 561 K after isothermal aging in air for 1000 hours. Promise was shown for shorter term mechanical property retention at 589 K upon exposure in air at this temperature.

Jones, R. J.↗
NASA NTRS1974

Filament winding S-glass/polyimide resin composite processing studies

The work performed in selecting a TRW A-type polyimide resin that would be suitable for fabrication of filament wound reinforced plastic structures is described. Several different formulations were evaluated after which the P105AC formulation was selected as the most promising. Procedures then were developed for preparing P105AC/S-glass roving prepreg and for fabricating filament wound structural composites. Composites were fabricated and then tested in order to obtain tensile and shear strength information. Small, closed-end cylindrical pressure vessels then were fabricated using a stainless steel liner and end fittings with a P105AC/S-glass polar wound overwrap. These pressure vessels were cured in an air circulating oven without augmented pressure. It is concluded that the P105AC resin system is suitable for filament winding; that low void content, high strength composites are obtained by the filament winding process; and that augmented pressure is not required to effect the fabrication of filament wound P105AC composites.

Vaughan, R. W.↗
NASA NTRS1972

Low-void polyimide resins for autoclave processing

Development of an advanced A-type polyimide, which can be used to produce autoclave molded, low-void content composites suitable for use at temperatures up to 316 C is reported. It consists of a mixture of methyl nadic anhydride, an 80:20 molar ratio of methylene dianaline and thiodianilene, and pyromellitic dianhydride.

Jones, R. J.↗
NASA NTRS1972

Resin/graphite fiber composites

High temperature resin matrices suitable for use in advanced graphite fiber composites for jet engine applications were evaluated. A series of planned, sequential screening experiments with resin systems in composite form were performed to reduce the number of candidates to a single A-type polyimide resin that repetitively produced void-free, high strength and modulus composites acceptable for use in the 550 F range for 1000 hours. An optimized processing procedure was established for this system. Extensive mechanical property studies characterized this single system, at room temperature, 500 F, 550 F and 600 F, for various exposure times.

Cavano, P. J.↗
NASA NTRS1972

Thermally stable laminating resins

Improved thermally stable laminating resins were developed based on the addition-type pyrolytic polymerization. Detailed monomer and polymer synthesis and characterization studies identified formulations which facilitate press molding processing and autoclave fabrication of glass and graphite fiber reinforced composites. A specific resin formulation, termed P10P was utilized to prepare a Courtaulds HMS reinforced simulated airfoil demonstration part by an autoclave molding process.

Jones, R. J.↗
NASA NTRS1972

Low void content autoclave molded titanium alloy and polyimide graphite composite structures.

This paper discusses a resin developed for use in autoclave molding of polyimide graphite composite stiffened, titanium alloy structures. Both primary and secondary bonded structures were evaluated that were produced by autoclave processing. Details of composite processing, adhesive formulary, and bonding processes are provided in this paper, together with mechanical property data for structures. These data include -65 F, room temperature, and 600 F shear strengths; strength retention after aging; and stress rupture properties at 600 F under various stress levels for up to 1000 hours duration. Typically, shear strengths in excess of 16 ksi at room temperature with over 60% strength retention at 600 F were obtained with titanium alloy substrates.

Vaughan, R. W.↗
NASA NTRS1971

The development of autoclave processable, thermally stable adhesives for titanium alloy and graphite composite structures

The A-type polyimide adhesive resin P11B was modified by use of mixed diamines (thio-dianiline and meta phenylene diamine) which provided the desired autoclave processability. This new resin was termed P11BA. It was shown that copolymeric blends of P11BA and Amoco AI-1137 amide-imide resin provided improved adhesive properties when autoclave processed over the properties obtained previously by press bonding with P11B based copolymeric blended adhesives. Properties of bonded assemblies are presented for long-term aging at both elevated and low temperatures, and also stress-rupture tests at elevated temperature.

Vaughan, R. W.↗
NASA NTRS1971

Development of a low void polyimide resin for autoclave processing of glass and graphite reinforced composites.

Experimental studies are described in which new A-type polyimide prepolymer chemical modifications were investigated with the aim of increasing the melt phase duration and temperature range permitting autoclave processing, yet retaining the addition-type cure mechanism required for low-void content composites. Several modification candidates were examined, and one specific formulation was selected for detailed investigation. This A-type polyimide prepolymer formulation is shown to possess the desired characteristics.

Vaughan, R. W.↗