Abstract
Summary: Polymeric thermosetting composites can be used as metal substitutes for certain applications if they possess high temperature stability in air, low coefficient of thermal expansion (CTE), and sufficient flexural strength, in combination with competitive costs. Commercial bismaleimide, bisnadimide, and cyanate ester thermosetting materials were selected due to their excellent thermal stability. Low CTEs were achieved by adding high loading levels of fused silica or silicon nitride fillers. Several optimized composites were fabricated by varying the materials, composition, and cure conditions. Characteristic composite properties, such as CTE, thermal stability, glass transition temperature (T~g~), flexural strength, and filler distribution were investigated. The best system developed consists of Matrimide 5292, a commercial twoβcomponent bismaleimide resin, filled with 75% Silbond FW100EST, and additionally reinforced with 0.5% Twaron short fibers. This composite is distinguished by a CTE around 15 ppmβΒ·βK^β1^, a T~g~ around 340βΒ°C, flexural strength above 100 MPa, and attractive material costs.
Matrimid 5292 (75%)/Silbond FW100AST (24.5%), and Twaron 2 mm short fibers (0.5%). Three fibers are visible, embedded and well dispersed in the matrix.
magnified imageMatrimid 5292 (75%)/Silbond FW100AST (24.5%), and Twaron 2 mm short fibers (0.5%). Three fibers are visible, embedded and well dispersed in the matrix.