Synthesis, thermal and mechanical properties of modified PMR/carbon fiber composites

Modified polymerization of monomeric reactants (MPMRs) prepolymer was prepared using the dimethyl ester of 3,3′,4,4′-benzophenonetetracarboxylic acid (BTDE), bis(3,5-dimethyl-4-amino phenyl)-4′-methyl phenyl methane (BAMPM) and monomethyl ester of 5-norbornene-endo-2,3-dicarboxylic acid (NE). The structural characterization of BAMPM and MPMRs prepolymer was performed by elemental analysis, FT-IR, 1H NMR and 13C NMR spectral techniques. Differential scanning calorimetry (DSC) analysis shows that the MPMRs prepolymer melts in the temperature range 205–240 °C and cures in the temperature range 260–325 °C. Thermogravimetric analysis (TGA) reveals two step (319 and 558 °C) and single step (565 °C) decomposition for uncured and cured MPMRs prepolymer respectively. The 10% weight loss temperature (T10%) of the cured MPMRs prepolymer was found to be 455 °C and a char yield of 48.58 wt% was obtained at 800 °C in nitrogen atmosphere. The cure behaviour of the MPMRs resin powder having only monomeric components and the MPMRs prepolymer (fully imidized), studied using FT-IR and TGA at different temperatures, reveal that amic acid formation, imidization and cross-linking due to addition/Retro Diels Alder reaction of norbornene end groups, take place in the temperature range 200, 250–275 °C and 275–325 °C respectively. The intensity of the absorption band at 273 nm in the UV spectrum of the MPMRs prepolymer irradiated with light (275 nm) for different time intervals was found to decrease with increasing irradiation time, indicating that the MPMRs prepolymer undergoes photo-crosslinking. Carbon fiber reinforced MPMRs composite was fabricated. The flexural strength, flexural modulus and interlaminar shear strength were found to be comparable to that of IM7/LARC™-RP46 and KH304-15.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► MPMRs prepolymer was prepared using non-carcinogenic diamine. ► Prepolymer undergoes photo-crosslinking by UV irradiated with light lamp (275 nm). ► A carbon fiber reinforced MPMRs composite was prepared using the mixture of monomers.