Synthesis, curing kinetics and processability of a low melting point aliphatic silicon-containing bismaleimide

Abstract

An aliphatic silicon-containing maleimide monomer 1,1'-((1,1,3,3-tetramethyldisiloxane-1,3-diyl)bis(propane-3,1-diyl))bis(1H-pyrrole-2,5-dione) (TBB) with low melting point (56 °C) was successfully synthesized based on maleic anhydride (MA) and 3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bis(propan-1-amine) (BAT). The structure of TBB monomer was determined by FTIR, 1H NMR and 13C NMR. Meanwhile, the 3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bis(propan-1-amine) (BAT) and 4,4’-Bismaleimidodiphenylmethane (BDM) monomers were respectively prepared from diallyl bisphenol A (DBA), following a 1:0.87 molar ratio, and named TD resins and BD resins. The curing kinetics, thermal stability and processability of TD resins and BD resins were discussed and compared. The activation energy (E) value of TD resins was 26.2% higher than BD resins, resulting in exothermic peak temperature (TP) of TD resins was higher than BD resins at different heating rates. Compared with BD resins, the crosslinking density (ve) of TD resins was reduced by 93.5%, which effectively destroyed the thermal stability of TD resins. However, TD resins exhibited outstanding processing window of 195.6 °C. The processing window of TD resins was 110.1% wider than that of the BD resins, indicating that the former had excellent processability. Overall, this study has enriched the discussion on the curing kinetics of aliphatic bismaleimide resins and has a positive influence on the design of resins monomer with low melting point.