Hide/Show Apps

Synthesis and characterization of high temperature resistant bismaleimide based resins and their composites

Download
2010
Günalp, Süreyya Esin
Bismaleimide resins are important in aerospace applications as matrix component of composite materials due to their high thermal and mechanical properties. 4,4’-bismaleimidodiphenylmethane (BMI) which is the most widely used bismaleimide, was synthesized starting from maleic anhydride and 4,4’-diaminodiphenylmethane (MDA). N,N’-diallylaminodiphenyl methane (ADM), N,N’-diallylaminodiphenyl sulfone (ADS) and N,N’-diallyl p-phenyl diamine (PDA) were synthesized by allylating primary aromatic diamines. Nine different prepolymers with 1:1, 1.5:1 and 2:1 molar ratios of BMI/diallyl compound were prepared and cured. The effect of increase in BMI ratio on thermal properties of the resin systems were investigated via Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analyzer (TGA). DSC results showed that the curing temperature of the resins increased due to the increase in BMI ratio in the resins. Thermal gravimetric analysis showed that incorporation of BMI monomer improved the thermal stability of the resins. BMI/ADM resin system showed better thermal stability compared to BMI/ADS and BMI/PDA resins. Processing characteristics of resins having 1:1 and 1.5:1 mole ratio of BMI/ADM were investigated by viscosity measurements and these resins were found to be suitable for composite production with Resin Transfer Molding (RTM). Composites were manufactured by RTM technique using two different mole ratios of BMI/ADM resins as matrix component. The effect of different matrix composition on thermal and mechanical properties of the composites were investigated. The concept of this thesis work was arised from the requirements of some projects carried out in Tübitak-SAGE. Keywords: Bismaleimide resins, composite, thermal properties, resin transfer molding.