The Investigation On Morphology And Mechanical Properties Of Modified Epoxy Resin

In this study, the epoxy resin, diglycidyl ether of bisphenol A, was cured by methylenedianiline(DDM) or isophoronediamine(IPD). And the curing kinetics of epoxy resin modified by acrylonitrile-butadiene-styrene (ABS), the micro-morphology of epoxy resin/the carboxyl terminated butadiene acrylonitrile rubber (CTBN), and the relationship between morphology and the mechanical properties of epoxy resin modified with the CTBN-1, preprocessed of CTBN and epoxy pre-polymer, were investigated.1. Compared with the pure epoxy resin, the apparent curing reaction activation energy, the curing process conditions and curing reaction kinetics equation of epoxy resin system which was modified by ABS modifier were studied by nonisothermal DSC and isothermal DSC. The adding of ABS resin was affected the curing kinetics of epoxy matrix and the activation energy of the curing reaction of epoxy resin was decreased. During the curing reaction, the initial chemical control stage of the curing reaction mechanism was fit of Kamal self catalytic model; curing reaction at the later stages, with the increasing of the system viscosity, the curing reaction began to enter the diffusion control stage which was appearing deviation to the Kamal self catalytic model. At the same time, ABS resin could decrease the reaction rate of curing reaction, and curing temperature, gel temperature and the matrix resin.2. CTBN which contains different acrylonitrile(8,13 and 31%) was used to modified epoxy resin. For this purpose three samples were prepared by mixing DGEBA with CTBNs which were mentioned above and three curing conditions were used to cure the epoxy resin. The epoxy oligomers were cured with isophorone diisocyanate as curing agent. The aim of this study is to illustrate the process of phase separation between epoxy matrix and liquid particles using transmission electron microscopy (TEM). And the effect of tenninal microscopy morphology of modified epoxy resin was also deliberated. The glass transition temperature of neat and modified epoxy resin was measured by dynamic mechanical analysis (DMA). The mechanical properties were measured.3. The curing process and the microstructure of epoxy matrix modified by different prepreatment rubbers was studied. The relationship between the microstructure and mechanical properties was analyzed. The CTBN-1 was modifier which was the liquid rubber and epoxy pre-polymer pre-mixed and pre-reacted to each other. The initial curing reaction rate and the maximum reaction rate of CTBN-1 modified epoxy resin are lower than those of CTBN modified epoxy resin. The initial curing reaction rate would affect the material morphology. And different interfacial binding force could affect the shear rubber particles in the deformation of the epoxy matrix. At the same time, the degree of curing reaction was affected by the pretreatment of rubber phase. Therefore, the value of impact of CTBN-lmodified epoxy matrix was higher than the CTBN modified one. The elongation at break and the tensile properties were also decreased such as tensile modulus, yield stress and fracture stress to a certain extent. Therefore, the influence of the interface binding force on mechanical properties of modified epoxy matrix was seriously significant. In order to obtain the better mechanical properties, some methods should be done on the binding force of the interface between rubber modifier and epoxy matrix.