Preparation And Study On Properties Of Bismaleimide Resin Abrasive Binders

In this paper, we use phenolic resin (F-51) modified bismaleimide (BMI) as binder resin abrasives, and study the performance of the modified resin system. The specific process of experiment are next:First DDM as chain extender into the BDM system, after the chain extension reaction, we add a certain amount of F-51resin into the modified BMI resin systems. Test the mechanical properties of the resin system with different F-51content, and then add the chopped carbon fibers into the composites,SiC as abrasive.Then study the flexural and impact strength with different fiber content. Infrared spectroscopy (FT-IR) analysis are used before and after the curing of the resin system on the changing in the molecular structure, thermal analysis (TG-DSC) are used to test the thermal stability of the resin and the curing process,scanning electron microscope (SEM) are used to show the distribution of carbon fiber in the composite material.The results shows that:When the short carbon fiber content in a certain range, the flexural strength and impact toughness of SiC abrasive composite material shows an increased trend,indicating that the chopped carbon fibers can improve the mechanical properties of the composites. With1.5%content of carbon fiber has the best performance among the tested materials, the corresponding bending strength and impact toughness are123MPa and7.67KJ/m2.SEM are used to study the crack section of the composites with different carbon content, showing that when the fiber content is less than1.5%, it can be evenly distributing in the composite material well; When the fiber content is2%, some agglomeration phenomenon occurs. By comparing the FT-IR analysis before and after curing reaction, it shows a reaction between epoxy group and primary amine group and addition reaction on carbon-carbon double bond in modified BMI resin system. DSC curve analysis shows two exothermic peaks of the curing reaction in modified BMI resin, compare with the process of curing mechanism, obtaining that the first exothermic peak is the reaction between epoxy group and the secondary amine, and the second exothermic peak is the Michael addition reaction on carbon-carbon double bond of BMI resin. From the TG curves, the modified BMI resin has good heat resistance, the initial decomposition temperature is372.6℃, the maximum decomposition temperature is407.6℃, the residual amount at800℃is43.36%, indicating that the modified resin has excellent BMI heat resistance.By studying the kinetics of the modified resin, we get two kinetic equations, they are dα/dt=2.83×107exp(-64100/RT)α0.23(1-α)0.78and dα/dt=4.32×1010exp(-101885/RT)α0.21(1-α)1.1.According to the practical considerations, the curing process are:95℃/1h preheating, the remaining stages of the curing temperatures are135℃/2h+170℃/3h+195℃/3h+235℃/2h.