| Polyurethane adhesive was a kind of superior performance adhesives. Its molecular main chain contains strong polarity carbamate group (-NHCOO-) and high activity isocyanate group (-NCO). However the heat resistance of polyurethane adhesive was poor, decomposed at high temperature, not suitable for using at high temperature or hot and humid environment, so its application was restricted. In this article, through the chemical reaction between polyurethane, epoxy resin and acrylic ester, we made the three materials forming interpenetrating polymer network structure, combining their respective advantages in adhesive, and synthesized a new type and widely used adhesive.First of all, preparation of polyurethane adhesive materials was by prepolymer process and the materials’performances were tested by tensile, tear, thermogravimetric (TG) and dynamic mechanical analysis (DMA). The influence of the structure of polyols, isocyanates and chain extenders on properties of adhesive materials was discussed. The results of tested showed that:PTMG-MDI polyurethane adhesive materials had high tensile modulus. The thermal stability of adhesives materials prepared by polyester218was better than the materials prepared by PTMG. However, the glass transition temperature (Tg), the materials by PTMG was higher than the materials by polyester218.Next, based on the chemical reaction between polyurethane prepolymer and polyfunctional chain extender for forming cross-linked networks, the chemical reaction between epoxy resin and acrylic acid hydroxyl ethyl ester catalyzed by triethylamine to form cross-linked networks, the interpenetrating polymer networks of polyurethane/ep- oxy resin/acrylic ester was synthesized. And the structure characterization of interpen-etrating polymer networks was characterized. The results of tensile and tear testing, Fourier transform intrared (FTIR), differential scanning calorimetry (DSC), TG and DMA test showed that:reaction between the three groups was reflected and formed interpenetrating networks structure by curing, the tensile strength of IPN materials was16.1MPa, tear strength was56.8kN/m, the fracture temperature of EPN structure was245.8℃, the Tg of10.0Hz frequency was57.4℃, the tan δ was0.46.Finally, adjusting the proportion of polyurethane, epoxy resin and acrylic ester, the IPN adhesives which were suitable for bonding were prepared. The relation between three constituents content and the properties of adhesive was discussed. The results showed that:When the weight ratio of PU and EP-HEA was1:2, the maximum shear strength was6.8MPa. When the weight ratio of PU and EP-HEA was1:1, the stripping strength was5.3kN/m. |
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