| Polyurethane (PU) adhesive is being widely used in petrochemical, automobile, building, aerospace and other industry due to it's excellent low temperature resistance, oil resistance, impact resistance and abrasion resistance. However, the current used raw material of PU adhesive is derived from polymeric material, which highly depended on petrochemical resource. This paper described castor oil based polyurethane and castor oil based polyurethane-epoxy interpenetrating polymer adhesive to explore the application of renewable resource in adhesive industry. The specific research works are shown as following:(1) A two-component castor oil based PU adhesive was prepared using prepolymerization method. The excess-NCO content, viscosity and structure of the prepolymer were analyzed. Then, the effect of isocyanate index NCO/OH on the tack free time, viscosity, adhesion property, thermal resistance, damping properties and mechanical properties were also investigated. The results showed that the optimal reaction temperature and time for the production of prepolymer were70℃and2h.When NCO/OH=1.6in prepolymer and the mass ration of prepolymer to castor oil was5:3, the castor oil based PU adhesive exhibited excellent comprehensive properties, where tack free time, lap shear strength, T5%weight loss, damping temperature range, tensile strength and elongation at break were13h,0.903MPa,225.1℃,40℃,0.874MPa and168%, respectively. The castor oil based polyurethane adhesive can be potentially used in food packing, leather and potting industry due to it's low cost and suitable viscosity.(2) A castor oil PU/epoxy(EP) interpenetrating polymer network (IPN) adhesive was prepared via sequential polymerization method. The structure, thermal property, damping properties and surface morphology were investigated. The influence of value of mass ratio of prepolymer to EP on the tack free time, viscosity, shear strength and mechanical properties were also studied. It was shown that the shear strength, thermal stability, damping properties and tensile strength were further improved while the tack free time, viscosity and flexibility were impaired after modification. The surface morphology became rougher as evidenced by SEM analysis. The IPN adhesive where the mass ratio of Pre-1.6to epoxy was1:1showed the comprehensive optimal adhesion property, thermal stability and damping properties, which can be expected to be used as structural adhesive. |
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