چكيده لاتين
Ablative coating are a group of special thermal insulators that are made from porous materials. These insulators are used to keep the temperature of a certain part of the systems constant. Novalac epoxy resins are a good choice for the field of these insulators due to their thermal properties and good adhesion to improve physical and mechanical properties. Glycidyl ether-containing polyhedraloxane oligomeric siloxane nanoparticles (GPOSS) are used. The advantages of these nanoparticles include increasing thermal resistance and adhesive strength, as well as reducing viscosity and flammability. Siloxane resins are used to create better compatibility between the nanoparticle and the epoxy substrate. In this research, after preparing the nanocomposites of Novolac/GPOSS epoxy and epoxy novolac/siloxane resin and the hybrid of these materials, the effect of GPOSS nanoparticles and siloxane resin on the adhesion, mechanical, thermal stability and ablation properties of epoxy novolac resin is studied. Based on the obtained results, in the combination of 3 phr percentage of GPOSS nanoparticles and siloxane resin, mechanical properties such as shear strength, tensile strength, and ablation properties reach their maximum value, and in the hybrid sample, the amount of 3 phr from each of the additives Added to the epoxy novolac background, in the hybrid sample compared to the pure epoxy, the shear, peel, and tensile strength increased by 218, 389, and 83%, respectively. Also, the toughness of the hybrid sample improved by 240% compared to the pure sample and reached from 47.55 kJ/m3 to 161.86 kJ/m3. Based On the thermogravimetric analysis test (TGA) results, the degradation starting temperature (Ta) of the hybrid sample has reached 354 °C from 256 °C for pure sample. In addition, in the hybrid sample, the amount of remaining coal and the maximum temperature of thermal degradation (Tp) have improved by 34.75 and 4.11%, respectively. Also, in the hybrid sample, the ablation rate has decreased by 71% compared to the pure sample. As a result of adding the hybrid of GPOSS nanoparticles and siloxane resin on the epoxy background, all the adhesion, mechanical, thermal stability and sacrifice properties improved, and this shows the synergistic effect of GPOSS nanoparticles and siloxane resin.
