A current study involves the synthesis of highly branched poly-methylsiloxane-branched epoxy resin copolymers for efficient ablation of thermal protection coatings.
researchers prepared an ablation thermal protection coating (ATPC) using HBPSE co-justs.
the silicone intermediates are attached to the epoxy resin through the contraction between methoxy and hydroxyl, a highly branched poly-methylphenidated silica bonding epoxy resin (HBPSE)
. The chemical structure of highly branched comers is indicated by FT-IR, 1H-NMR and GPC. The thermal stability of HBPSE copolymers was indicated by the TGA and Maffer furnace ablation tests. In addition, an ablation thermal protection coating (ATPC) with HBPSE co-polymers has been prepared.
better thermal stability and wider pyration temperature range
HPPSE-based ATPC has better thermal stability and a wider pyration temperature range than traditional epoxy-based ATPC. After the oxygen-acetylene test, the microscopic morphological and chemical composition of ATPC based on HPPSE is indicated by SEM, EDS and FT-IR. Finally, HPPSE-based ATPC and epoxy-based ATPC are evaluated for 320 seconds at a hot current of 200kW / m2, and ATPC with ANBPSE substation has a lower back temperature and better surface condition.
ablation thermal protection coating (ATPC), which accommodates the high thermal load through mass loss, is an efficient and simple method for thermal protection, especially for spacecraft with complex aerodynamic structures. Under aerodynamic heating, atPC's polymer substation undergoes thermal solution to absorb heat, resulting in pyrical gases and porous carbon layers. The pyration gas that diffuses from the porous carbon layer changes the gradient of the air flow out of the material, blocking the heat transmitted to the material. As mentioned above, polymer substrings are one of the key factors affecting the efficiency of thermal protection.
polymers with highly brosed molecular structures have low viscosity and many high functional ends, making them ideal coatings. In the highly branched polymer family, the joint copolymer has received more and more attention because of the interaction between different chain segments in its chemistry. High-branched poly-methylsiloxane-branched epoxy resin (HBPSE) is a polymer substate that is conducive to thermal protection materials and combines the advantages of epoxy and silicone resins. After ablation, the material can form a dense carbon layer, reduce the ablation rate and harden the polymer substate. The thing method is commonly used to synthesize silicone modified epoxy resins. Chen synthesized the sioxane bridge-linked epoxy resin by reactions of Z-6018 and E51, catalyzed by the two-butyl tin of laurel acid. The residue of the modified epoxy resin at 600 degrees C increases with the increase of silica. By promoting the shrinking reaction between Si OCH 3 of the silicone intermediate and OH of E51, Lee synthesizes a series of epoxy copolymers containing machine silicon. This work mainly focuses on the effect of silicone content on the physical properties of resin-based properties, and does not significantly promote the thermal stability of epoxy resins. These efforts provide a theoretical basis for the preparation of HPPSE
in our study, polymeric acid silica was synthesized by anion open-loop activity polymerization. The highly branched copolymers are then synthesized by twiging polythyl benzene to epoxy resins. HBPSE is evenly mixed at the macro level, which not only meets the requirements of epoxy resin toughening, but also improves thermal stability and widens the thermolytic temperature range of polymer substations. Further preparation of ATPC with HPPSE substation. ATPC based on EPPSE exhibits better thermal stability and a wider thermolytic temperature range than EPOx-based ATPC, and we discussed its ablation in this study. Finally, at 320 seconds at a hot current of 200 kW/m2, the back temperature of the HPSE-based ATPC reaches only 160 degrees C, and its ablation surface is smooth.
the study was published in Progress in Organic Coatings, volume 126, January 2019, pp. 178-186.