الملخص

Hybrid composites were prepared by two step. First step, different ratios of the base material represented by the blend of Epoxy and unsaturated Poly Ester (Ep/UPE) to determine the best blending ratio by means of studying the tensile strength and homogeneity of the samples. second step: preparing hybrid composites (B1, B2 and B3)after specifying the blend ratio of the basic material(B) and then mix it with various reinforcing materials, as E-glass fibers woven roven mat and Nano alumina particles with a grain size of (30 nm), with volume fraction 30%. Studying involved tensile strength and homogeneity tests and some mechanical tests (bending, impact, compression and hardness) also, some physical tests such as (absorption and thermal conductivity) in natural conditions, as well as studying the hot environment effect on the behavior of the prepared composites. The best (optimum) mixing ratios of these blend have been.selected is (Epoxy95%, UPE5%), And Reinforcing this blend with E-glass fiber and Nano Alumina leads to improves mechanical properties at room temperature ,when the composites exist in hot environmental conditions ranged from (25-55)°C, which lead to decease Young's modulus, but increase the impact strength as the temperature  increase with different percentage depending on the ratio of the reinforcement material add to the blend. About the physical  properties, it was noticed that the type of the solution and its concentration effect the absorption of the composites,  that was identified by the calculating diffusion coefficient values (D) for all the samples. The lowest value of the diffusion coefficient was for submersed samples in HCl solution, while the highest value was for the samples submersed in NaOH solution. It was also found that the reinforcing with glass fibers and Alumina powder leads to an  increase in the thermal conductivity with varying values depending on the type and ratios of the reinforcements added to the polymer blend. The effect of the reinforcing on thermal conductivity of the samples in hot environment ranged from (30-70)°C, Found that the thermal conductivity increases largely for both samples B3, B2 with increasing temperature.