Effect of Nonisocyanate Polyurethane and Nanoclay on the Mechanical Properties of an Epoxy Resin

The effect of condensation nonisocyanate polyurethane (NIPU) addition on the mechanical properties, chemical structure, and morphology of an epoxy resin (EP) modified with nanoparticles (Nanobent) was investigated. The impact strenght (IS), flexural strength, and critical stress intensity factor (KC) of the epoxy resin was determined as functions of NIPU and Nanobent content. The highest values of IS and KC were found for the hybrid composition containing 10% NIPU and 1% Nanobent. SEM micrographs suggested that the enhancement of mechanical properties might be due to the extensive yielding of EP associated with the formation of stratified elongated structures. Based on an IR analysis, the characteristic bands for both the epoxy matrix and the condensation NIPU were identified, indicating that the polymers formed the NIPU network without a grafting reaction.