Chemical structure of TriA X.
A neat TriA X specimen in and after a bending test.
Researcher:
Yixiang Zhang
Summary:
Because of the high glass transition temperatures (Tg)and thermal stability, polyimides have been attractive to the fabrication of high-temperature composites. Recently, a new polymerization of monomeric reactant (PMR) resin system was developed by Kaneka Corporation. This new polyimide system is referred to as “TriA X” for the characteristics of the polymer: amorphous, asymmetric, addition-type and cross-linked (✕). A distinguishing feature of TriA X is the asymmetric backbone, derived from the asymmetric monomer, p-ODA. This distinctive feature results in a disordered chain packing arrangement which profoundly affects the behaviour of the cured polymer. The cured polyimide exhibited a Tg = 362 °C and a decomposition temperature (Td) = 550 °C. The cross-linked TriA X exhibited exceptional toughness and ductility (e.g., 15.1 % at 23°C) for a polyimide. The thermal and mechanical properties of TriA X surpass those of PMR-15 and AFR-PE-4.
TriA X exhibits great potential to open more high-temperature composite designs. Thus, a processing method was developed to fabricate aerospace grade (void-free) composites based on TriA X system. To explore the capability of TriA X composites, long-term aging studies (e.g. thermal cycling, thermal oxidative aging and hydrothermal aging) were conducted on neat TriA X and associated composites. TriA X composites exhibited high microcracking resistance in thermal cycling test between -54°C and 232°C. The retention of matrix-dominated mechanical properties of TriA X composites was >90% after 2000 cycles. Neat TriA X and associated composites exhibited superior stability upon long-term moisture exposure at 95°C. The tensile strength and modulus, thermal properties, and chemical structure of the neat polyimide exhibited no change after 2000-h aging, while the short-beam shear strength of the composites decreased by 7-13%.
Sponsor(s):
Kaneka Co. and Henkel Co.