A polymeric blend nanocomposites were prepared using mixer of Epoxy and polysulfide rubber [EP+PSR] as a matrix material and the Zirconium Oxide Nano-powder ZrO2 as a reinforcement material, in different particle sizes and same adding ratio of 2% wt . Hand Lay-up molding method was used to prepare the samples. Impact strength, compression resistance and thermal conductivity tests, were carried out for the polymeric blend and composites samples before and after immersion in tap water. The results showed that adding Nano zirconia powder to the polymer blend improved the mechanical properties, while the thermal conductivity of the polymer blend was higher than that of the composites. Also, it was observed that water immersion caused a decrease in impact strength, compression resistance, modulus of elasticity and thermal conductivity in a manner proportional to the immersion time.

Abstract:-This research studies the effects of particle grain size of reinforcing material on mechanical properties of composite material. A polymeric blend of epoxy resin and poly sulphide rubber [Ep 70% + PSR 30%] was used as a matrix, and nanozirconia powder (Nano-ZrO2) as a reinforcement material with various grain sizes (20-40) nm, (40-50) nm with the same weight fraction (2% wt.), and research samples were prepared by Handle Lay-Up Modeling.Tensile Strength, Hardness tests and the study of Surface Topography were conducted using a scanning electron microscope (SEM) without immersion and after immersion in normal water for 10 weeks, and the inspection of absorbency material.The results of the tests before immersion revealed that reinforcement by zirconia nanoparticles powder improves the mechanical properties, especially in the case of small grain size (20-40) nm as composites recorded highest tensile strength (5.93 MPa), and the highest hardness of the surface (57), while it was less so in the case of big grain size (40-50) nm tensile strength it (2.036 MPa) and surface hardness (41).Absorbing material for water, after immersing the samples in ordinary water, negatively influenced the mechanical properties with the exception of increasing the hardness of the surface at the end of the period of immersion.