A study of co-reaction mechanism and properties of propenyl-substituted monomer/bismaleimide system

A practical modifier, 4,4-bis[2-(1-propenyl)phenoxy]benzophenone (MT), has been synthesized and copolymerized with 4,4-bismaleimidodiphenylmethyene (4,4-BMI) to yield a low-temperature cure bismaleimide resin. Structural information of MT was obtained using Fourier transform infrared spectroscopy and nuclear magnetic resonance (proton and carbon) spectroscopy, elemental, and mass spectrometry analyses. The differential scanning calorimetric curve of the MT/4,4-BMI system shows two exothermic peaks at 164 degrees C and 210 degrees C, respectively. This value was compared with other polymerization reactions involving diallyl bisphenol A (DP) and diallyl bismaleimide (DBMI), with an exothermic peak at around 257 degrees C. Unlike normal bismaleimide resins with DP postcured at 250 degrees C for about 4-8 h, the MT/4,4-BMI resin was cured at 230 degrees C for a total of 6 h (i.e. MBMI-230) or at 200 degrees C for 6 h (i.e. MBMI-200). Furthermore, the resins exhibit high thermal resistance, excellent mechanical properties, and exceptionally low dielectric loss. For MBMI-230 and MBMI-200, the dielectric loss values are all in the range of 0.0024-0.0054 from 7 GHz to 18 GHz and feature excellent thermal stabilities (5% weight loss temperature (T-d5) > 415 degrees C under nitrogen atmosphere) and thermo-oxidative stabilities (T-d5 > 425 degrees C in air atmosphere). Additionally, the cured resins also display a high bending modulus (>3.2 GPa) at room temperature and an excellent mechanical stability at high temperature.