Chemistry and Properties of a Phenylethynyl-Terminated Imide Blend

Abstract

As part of an effort to develop a low-volatile, essentially dry, carbon fiber tape from a phenylethynyl-terminated imide for use in heated head automated tow placement, a 70:30 blend of LaRCTM PETI-5 and LaRCTM PETI-IAX was prepared in N-methyl-2-pyrrolidinone by mixing the phenylethynylterminated amide acid solutions together. Solutions of the amide acids and the blend were characterized by size exclusion chromatography after aging at room temperature and at 5 °C over a 30-day period. Thin films were periodically cast from the solutions, thermally cured, and the tensile properties determined. Unoriented thin-film tensile properties were unaffected by aging conditions over the 30-day period whereas the weight average molecular weights of the phenylethynyl-terminated amide acids decreased. Imide oligomers were prepared from the amide acids, characterized, and thermally cured. A low-volatile tape prepared from prepreg of the 70:30 blend was fabricated into composites by processing in a vacuum press. The thin-film tensile and composite properties of the blend generally followed a rule of mixtures.

Facilely Synthesizing Ethynyl Terminated All-Aromatic Liquid Crystalline Poly(esterimide)s with Good Processability and Thermal Resistance under Medium-Low Temperature via Direct Esterification

“…Besides melt polycondensation, solution polymerization is an alternative method to synthesize poly­(esterimide)­s. Generally, poly­(esterimide)­s are synthesized through a two-step procedure; the first step is the reaction between ester-amine based compounds and anhydride derivatives to form poly­(ester amic acid) precursors, and the second step is imidization that needs high temperature (250–300 °C) or long reaction time (∼24 h under a nitrogen atmosphere). , Up to date, direct esterification to synthesize all-aromatic thermosetting LCPEIs under medium-low polymerization temperature is still a big challenge.…”

Synthesis and characterization of melt‐processable polyimides derived from 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene

“…In recent years, it has been found that phenylethynyl‐end‐capped imide oligomers4–22 with low molecular weights (5000–9000 g/mol) can be melt‐processed at 350–371°C to yield high‐toughness polyimides. Moreover, phenylethynyl‐end‐capped imide oligomers with calculated molecular weights as low as 750 g/mol can be melted at 280°C to produce low‐viscosity and stable molten fluids that can be thermally cured at 350–371°C, exhibiting good features for resin transfer molding (RTM) processing.…”