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The development and evaluation of an alternative powder prepregging technique for use with LaRC-TPI/graphite compositesAn alternative powder prepregging method for use with LaRC-TPI (a thermoplastic polyimide)/graphite composites is investigated. The alternative method incorporates the idea of moistening the fiber prior to powder coating. Details of the processing parameters are given and discussed. The material was subsequently laminated into small coupons which were evaluated for processing defects using electron microscopy. After the initial evaluation of the material, no major processing defects were encountered but there appeared to be an interfacial adhesion problem. As a result, prepregging efforts were extended to include an additional fiber system, XAS, and a semicrystalline form of the matrix. The semicrystalline form of the matrix was the result of a complex heat treating cycle. Using scanning electron microscopy (SEM), the fiber/matrix adhesion was evaluated in these systems relative to the amorphous/XAS coupons. Based on these results, amorphous and semicrystalline/AS-4 and XAS materials were prepregged and laminated for transverse tensile testing. The results of these tests are presented, and in an effort to obtain more information on the effect of the matrix, remaining semicrystalline transverse tensile coupons were transformed back to the amorphous state and tested. The mechanical properties of the transformed coupons returned to the values observed for the original amorphous coupons, and the interfacial adhesion, as observed by SEM, was better than in any previous sample.
Document ID
19910013929
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Ogden, Andrea L.
(Virginia Polytechnic Inst. and State Univ. Blacksburg., United States)
Hyer, Michael W.
(Virginia Polytechnic Inst. and State Univ. Blacksburg., United States)
Wilkes, Garth L.
(Virginia Polytechnic Inst. and State Univ. Blacksburg., United States)
Loos, Alfred C.
(Virginia Polytechnic Inst. and State Univ. Blacksburg., United States)
St.clair, Terry L.
(NASA Langley Research Center Hampton, VA., United States)
Date Acquired
September 6, 2013
Publication Date
April 1, 1991
Subject Category
Composite Materials
Report/Patent Number
CCMS-91-08
VPI-E-91-07
NAS 1.26:188184
NASA-CR-188184
Accession Number
91N23242
Funding Number(s)
CONTRACT_GRANT: NAG1-343
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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