Cindy Mei

Publication Date

5-1997

Advisor(s) - Committee Chair

Wei-Ming Lee, T.K. Green, J.W. Reasoner

Comments

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Degree Program

Department of Chemistry

Degree Type

Master of Science

Abstract

PMR-15 resin consists of three monomers: monomethylester of 5-norbornene-2,3-dicarboxylic acid; dimethyl ester of 3,3’, 4,’-benzophenone tetracarboxylic acid; and 4,4’-methylene dianiline, in the mole ratio of 2:2.087:3.087. PMR-15 can be cured by heat to form a cross-linked high temperature polyimide having Tg in excess of 316°C.

The curing chemistry of PMR-15 will be studied in the form of a prepreg which is made from the impregnation of a “B” staged PMR-15 resin on an intermediate modulus graphite fiber. PMR-15 prepreg is routinely used for the aircraft engine and aerospace application.

When PMR-15 resin is cured, the formation of Ch3OH2, H2O, and cyclopentadiene has been theorized and identified. Therefore, these condensation gases should be identifiable by TGA/FTIR/MS in real time during the PMR-15 curing process, thus allowing one to determine more precisely the onset of methanol and water evolutions and their peak temperatures. Furthermore, it permits one to establish the onset of cross-thinking and the extent of polymer structure buildup in the presence of cyclopentadiene. In this manner, the major curing reactions involved in PMR-15 polyimide can be monitored, studied and modified.

In the present study, a 10°C/min curing run is made first to examine the onset temperature, reaction temperature range, and peak temperature for methanol, water, and cyclopentadiene using real time FTIR as well as mass spectroscopy. The effect of curing rate on polyimide chemistry is explored by varying the heating rate and conducting isothermal curing runs. In addition, the effects of purge gas are investigated. Real time curing FTIR and MS results are presented and discussed. The curing chemistry fundamentals for PMR-15 polyimide are established.

Disciplines

Chemistry | Physical Sciences and Mathematics

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