Research On Structure And Performance Of Bismaleimide Molecular Composite By Pre-insitu Polymerization

Imide oligmer with a similar molecular structure to BMI is selected for modification BMI resin. Based on the relations of different end groups,molecular structure of PEI on reaction-induced decomposition and performance of the curing resin, we can make sure the structure conditions and get the elements of optimum performance of BMI molecular composite.Eight different structure of PEI are polymerized in comonomer RS. we study the effect of the molecular structure of PEI on toughness of modification BMI resin. The greatest contribution to toughness in this paper is adding the ether linkage, e.g. modified BMI resin by DAEIa is synthesized by ODPA and DBPP has outstanding toughness, BMI molecular composite had better toughness besides equivalent reactivity, processing property and heat resisting property. The impact strength Compared with RS/BMI resin system improves 104.89% is 20.53 KJ/m2 in this paper.It benefits generating of phase separation and improving of the rate of phase separation to inactive end groups,more rigid groups in main chain and improve the content of polar latent groups. Phase separation weakens the modification effect.The toughening mechanism of BMI molecular composite is the complex foundation of microcrack-shear band,deviation and branching of microcrack.The isotropic composite laminate was tested through low speed drop-weight impact test. The delamination resistance of RS/BMI is 3.29×10^-3J/mm² and the delamination critical energy is 0.25 J; the delamination resistance of DAEIa/RS/BMI is 5.43×10^-3J/mm² and the delamination critical energy is 0.6 J, which is improved remarkably of the fracture toughness property.