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The effects of space radiation on a chemically modified graphite-epoxy composite materialThe effects of the space environment on the engineering properties and chemistry of a chemically modified T300/934 graphite-epoxy composite system are characterized. The material was subjected to 1.0 x 10 to the 10th power rads of 1.0 MeV electron irradiation under vacuum to simulate 30 years in geosynchronous earth orbit. Monotonic tension tests were performed at room temperature (75 F/24 C) and elevated temperature (250 F/121 C) on 4-ply unidirectional laminates. From these tests, inplane engineering and strength properties (E sub 1, E sub 2, Nu sub 12, G sub 12, X sub T, Y sub T) were determined. Cyclic tests were also performed to characterize energy dissipation changes due to irradiation and elevated temperature. Large diameter graphite fibers were tested to determine the effects of radiation on their stiffness and strength. No significant changes were observed. Dynamic-mechanical analysis demonstrated that the glass transition temperature was reduced by 50 F(28 C) after irradiation. Thermomechanical analysis showed the occurrence of volatile products generated upon heating of the irradiated material. The chemical modification of the epoxy did not aid in producing a material which was more radiation resistant than the standard T300/934 graphite-epoxy system. Irradiation was found to cause crosslinking and chain scission in the polymer. The latter produced low molecular weight products which plasticize the material at elevated temperatures and cause apparent material stiffening at low stresses at room temperature.
Document ID
19870001544
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Reed, S. M. (Virginia Polytechnic Inst. and State Univ. Blacksburg, United States)
Herakovich, C. T. (NASA Langley Research Center Hampton, VA, United States)
Sykes, G. F. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 5, 2013
Publication Date
October 1, 1986
Subject Category
Composite Materials
Report/Patent Number
IR-60
CCMS-86-06
NAS 1.15:89232
NASA-TM-89232
VPI-E-86-19
Accession Number
87N10977
Funding Number(s)
CONTRACT_GRANT: NAG1-343
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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