High temperature organic/inorganic addition cure polyimide composites, part 1: Matrix thermal properties

Abstract

Structure-thermal property interrelationships are characterized and reported for organic/inorganic addition cure polyimide composite matrices based on 3,3 0 ,4,4 0 -benzophenone tetracarboxylic dianhydride, the reactive terminal group 4-phenylethynyl phthalic anhydride, and stoichiometric controlled diamine ratios of 1,3-phenylenediamine, 1,4-phenylenediamine, or 4,4 0 -(1,3-phenylenediisopropylidene) bisaniline, combined with bis(p-aminophenoxy) dimethyl silane or an a, x-bis(3-aminopropyl) polydimethylsiloxane oligomer. Polymerization of monomer reactants resin solutions, carbon fiber prepregs and composites, and imidized oligomers are characterized to relate molecular chemical structure and morphology to glass transition temperature, processing characteristics, thermodynamic properties, and thermal stability. Glass transition temperature, thermal decomposition temperature, and char yield were found to increase with increasing siloxane block length in the imide backbone. As the concentration of inorganic component in the imide oligomer backbone increased, the cured glass transition temperature decreased. Char yield and thermal decomposition temperature were observed to decrease as the inorganic component concentration increased. Incorporation of bis(p-aminophenoxy) dimethyl silane into the imide oligomer structure did not provide any significant advantages over traditional polyimides relative to thermal properties or composite processing, but aminosiloxanes improved composite toughness, prepreg tack, and composite processability.

Thermal curing of novel carborane-containing phenylethynyl terminated imide oligomers

“…The previous work demonstrates that making the polymer structure organic/inorganic hybrid could effectively address the issue. [9][10][11][12][13][14] Iscoahedral carboranes such as o-, m-, and p-C 2 B 10 H 12 have great thermal and chemical stability due to their stable cage structures and rich boron contents. The thermal stability of polymers could be greatly enhanced by the incorporation of carboranes into the matrices.…”

Improving the high temperature tribology of polyimide by molecular structure design and grafting POSS

“…Therefore, many researchers dedicated to improve the glass transition temperature of polyimide. Lincoln and coworkers 6 improved the glass transition temperature and mechanical properties of the polyimide by importing diamine siloxane structure into the molecular chain. Lee and coworkers 7 prepared POSS‐PETI oligomers and found that the addition of 3% mass fraction POSS‐PETI can increase the glass transition temperature of resin by nearly 50 K. Seurer and coworkers 8,9 also found that the shape, position and structure of POSS could affect the glass transition temperature of PI.…”

Carborane-Containing Aromatic Polyimide Films with Ultrahigh Thermo-Oxidative Stability

“…In those circumstances, high temperatures and repeated thermal cycles require thermal and thermos-oxidative stability of materials at elevated temperatures. In order to improve the thermal or thermo-oxidative stability, polyimide films are usually coated with metal or inorganic oxide protection layer or blended with inorganic fillers [23][24][25][26][27]. However, the mismatching of the coefficient of thermal expansion (CTE) between inorganic coatings and polymer matrices might result in serious troubles such as delamination, curl, or crack after harsh heat shocking [28].…”

“…However, the mismatching of the coefficient of thermal expansion (CTE) between inorganic coatings and polymer matrices might result in serious troubles such as delamination, curl, or crack after harsh heat shocking [28]. Although the addition of inorganic fillers into polymer matrices to form hybrid structures is an effective pathway in enhancing thermo-oxidative stability of polymer materials, the limited filler loadings and the poor miscibility of inorganic fillers and organic matrices are the big issues [26,27,29,30]. Hence, developing intrinsic thermo-oxidative stable polymers is still the desirable pathway.…”