Title Liquid Crystalline Thermosets for High Temperature Adhesive Applications
Source Proc. 50th Intl. SAMPE Symp. and Exhib.
Year 2005
Author(s) Hoyt Haight, A. E.; Allred, R. E.
Abstract The aerospace industry has a need for adhesives with high strength and toughness for use in structural bonding applications as well as in repair applications. In addition to the requirements for high strength and toughness, the ideal adhesive should be capable of long-term service at temperatures as high as 371°C (700°F). Chemical resistance is also desirable. Liquid crystalline thermoset (LCT) materials should be ideal candidates for aerospace bonding needs due to expected enhancements in thermal and mechanical properties relative to conventional non-liquid crystalline adhesives. Adherent Technologies has investigated melt-processable LCTs based on ester bismaleimide monomers cured with non liquid-crystalline comonomers to target these high temperature applications. Some of these systems exhibited a wide processing range (approximately 100°C) with the cured material showing outstanding thermal stability in air; decomposition temperatures were all above 400°C. Additionally, liquid crystalline order was retained in the cured systems, critical if many of the beneficial properties of liquid crystalline materials (high strength, high fracture toughness, and low coefficients of thermal expansion) are to be realized. The status of these systems, including results of preliminary adhesion testing on aluminum, titanium, and composite substrates are discussed.
Keywords Adhesives/Adhesive Bonding, Resins/Materials – High Temperature, Resins/Materials – Bismaleimide (BMI), aerospace, repair, liquid crystalline thermoset (LCT)