Easy processable tris-phthalonitrile based resins and carbon fabric reinforced composites fabricated by vacuum infusion

Abstract

Easy-processable phthalonitrile resins were prepared from tris-phthalonitrile phosphate monomer TPP ( tris(3-(3,4-dicyanophenoxy)phenyl)phosphate), bis-phthalonitrile RP ( bis (3,4-dicyanophenoxy)benzene) and novel viscosity reducing comonomer CPN ( 4-(4-cyanophenoxy)benzene-1,2-dicarbonitrile). It was shown that TPP is more resistant to hydrolysis than reported phosphate based phthalonitriles ( k = 8.2·10 -4 s -1 at 65℃ and pH 10). Two different type of curing agents: aromatic diamine DDS and 4-(4-aminophenoxy) phthalonitrile APN were used to study their effect on properties of the obtained resins and composites. Carbon fabric composites with APN -cured matrix fabricated by vacuum infusion demonstrated compression strength up to 633 MPa and 100% retention of ILSS after oxidative aging for 200 h at 300℃. Post-curing of the matrix at 375℃ resulted in growth of Tg but at the same time microcracking occurrence in the composite leading to decrease in mechanical properties and thermal aging sustainability. • Phthalonitrile resins for VIMP processing were developed based on TPP • Tris-phthalonitrile TPP is more resistant to hydrolysis than bis-phthalonitrile DPP • APN as curing agent provides higher strength of the composites than DDS • CFRP with PN-TPP-APN matrix retains mechanical properties after 200 hours at 300 °С