Modification And Properties Of BDM Resin Toughened By Amino-terminated PPENS

Bismaleimides (BMIs) are widely employed in the aerospace industry as composite resin and for electronic materials, due to their excellent thermal and mechanical properties. However, the ordinary BMI, with their unique rigid and symmetric molecular structure, suffer from high melting temperature and poor solubility in common solvents. Also the cured BMI resins have inherent brittleness because of their high cross-linked density, which greatly limited the application and development of BMI resins. Therefore, toughening modification and rheological behavior are always a research point in the BMI field. In this paper, we chose a kind of thermoplastic resin to modify the N,N’-(4,4’-methylenediphenyl)dimaleimide (BDM) resin and improve its processing behavior.First, a kind of thermoplastic resin (abbreviated as PPENS-DA), with different cyano contents and various molecular weight, were designed and prepared also applied to toughening the BDM resins. We got DABPA/PPENS-DA/BDM blends by melting method and calculated the kinetic parameters, and finally determined curing process through DSC test.Secondly, mechanical and properties of DABPA/PPENS-DA/BDM blends, with different cyano contents and various molecular weight, were investigated in detail through impact and flexural strength tests. The tests showed that mechanical properties reached the highest with75-phrcyano contents and10-phrPPENS-DA addition. Thermo properties were estimated by TGA and DMA analysis. The phase of the blends fracture surfaces was investigated by SEM.Thirdly, the rheological properties of DABPA/PPENS-DA/BDM blends were measured with the rheometer AR2000ex. In order to optimize the RTM process parameters, the rheological behavior of the blends was studied, which rheological model was established using Dual Arrhenius Model, and the RTM processing window was predicted. As a result, the viscosity of the blends maintains a minimum between70℃and165℃. Thus, isothermal viscosity measurement was selected in the range of70-165℃. According to the dynamic viscosity and DSC curves, isothermal viscosity measurement was carried out at120℃,130℃,140℃,150℃and160℃, respectively. The results showed that the viscosity would ascend with temperature and time. Last but not least, we synthesized a kind of new curing agent for BDM and prepared DABP/PPENS-DA/BDM blends, so as to improve the mechanical and processing properties. The mechanical and thermo tests showed that the blends owned more excellent properties with10-phrPPENS-DA than pure BDM resin. Also, the BDM resin cured by DABP showed higher impact strength than DABPA curing agent. Furthermore, the rheological properties of DABP/PPENS-DA/BDM blends were measured with the rheometer AR2000ex, just like DABPA/PPENS-DA/BDM blends. The results showed that DABP/PPENS-DA/BDM blends have better rheological property than DABPA/PPENS-DA/BDM blends.