The effect of SiO2 physical properties (Shore D hardness, impact strength, 3 pts bending, thermal conductivity, and weight gain) after and before immersion in different liquid solution (water, HCL 0.2 N , and NaOH 0.2 N), of (UP/PU) blend was studied. Hand lay-up technique was applied using unsaturated polyester and polyurethane blend as a matrix and silicon oxide nano particles (Nano SiO2) as a filler with volume fraction (3% Vf ) .
Results showed that liquids affected bending properties and thermal conductivity (k) by decreasing values, while the impact strength, and weight gain also studied for 4 weeks and it increase with increasing of immersion time in liquids.