Curing of Bismaleimides

The double bonds in bismalemide are highly electron-deficient due to two flanking carbonyl groups, and are reactive towards a bimolecular addition reaction. Hence the maleimide groups of a bismaleimide monomer or chain-extended prepolymer can undergo homopolymerisation to produce 3D network structures. To manipulate the structure and properties, different types of maleimide monomer or prepolymer can be used. The reactivity of such resins depends on their chemical structure and UPE. 

Bismaleimides can also be cured using a Diels-Alder comonomer [187]. When a bisdiene is reacted with excess bismaleimide, a prepolymer-carrying maleimide termination is formed as an intermediate, which can be further crosslinked to form a 3D cured network. Bis-(o-propenylphenoxy) benzophenone (Compimide TM123, Technochemie, Germany) is an example of a commercial Diels-Alder comonomer. CompimideTM123 is a low melting, low viscosity material and can be readily melt-blended with bismaleimide (BMI) and cured at high temperature to get a heat-resistant network. 

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