Effect of reaction time on the molecular weight distribution of polyurethane modified epoxy and its properties

Abstract

This paper studied the synthesis of polyurethane modified epoxy via simultaneous reaction by varying the reaction time to 30, 60, and 90 min. The polypropylene glycol and tolonate as polyurethane components were reacted simultaneously with epoxy in the presence of catalyst dibutyltin dilaurate without prepolymer polyurethane first. The effect of various reaction times on polyurethane modified epoxy (PME) properties was studied by analyzing molecular weight distribution, viscosity, epoxy equivalent weight, pot life, dry-to-touch time, elongation at break, tensile strength, and compared to the unmodified epoxy. The various reaction time processes of polyurethane-modified epoxy tend to increase the molecular weight and influence the molecular weight distribution of PME. It indicated that the reactivity polymerization of epoxy resin with polyurethane component increased with reaction time. Furthermore, these properties affect other properties, i.e., viscosity, epoxy equivalent weight, pot life, and tensile strength increase.

Keywords

• Epoxy
• Polyurethane
• Modification
• Molecular weight
• Reaction time