Polyurethane Modified Epoxy Structural Adhesive Preparation And Structural Characterization

Epoxy resin structureal adhesive with high temperature resistance cured at 150°C was prepared by polyurethane/epoxy interpenetrate polymer network (IPN) method in this research. Epoxy resin TDE-85 and epoxy resin E-51 was selected as resin matrix.The optimum curing condition was determined by examining the DSC curve of PU/EP IPN system. The characterization of the IPN structure was performed by the IR method. The phase compatibility and pattern features of two phase was analyzed by scanning electron microscopy (SEM). The curing reaction kinetics about this systems was studied and the apparent activated energy was examined. The thermostability of the PU/EP IPN materials was estimated by TG studies. Adhesive mechanical properties of different components and their addition have been evaluated in terms of the shear strength at room temperature and high temperature and peel strength at room temperature by the electronic powerful testing machine.The research results indicate: The kinetics calculation of the PU/EP IPN system is 69.18KJ/mol and the curing reaction order of PU/EP IPN system is 0.901. There are three kinds chemical reaction in the PU/EP IPN system: the chain-extended reaction between 1,4-butanediol and PU prepolymer, the two-phase chemical reaction between epoxy resin and PU prepolymer, the curing reaction between epoxy resin and aromatic amine.The network polymer is formed at end. The morphology of the PU/EP IPN materials from the "sea island" to "double continuous phase" as a function of the ratio of PU/EP rise, The mechanical properties of the PU/EP IPN materials improve obviously toward unmodified materials and increase then decline with the increasing of PU. The thermostability of the PU/EP IPN materials in the low temperature section affect by the structure of the PU/EP IPN.While the mass fraction of PU210 and aromatic amine are 30% and 33% respectively.The integrative properties of the adhesives reach to top, the shear strength is 25.81Mpa at room temperature and 12.85Mpa at 160°C, the peel strength is 51.68N/cm.The adhesives satisfy with the demand of structure adhesives with high temperature resistance.