Research Of Heat-resistance Coatings

A kind of polyurethane coating cured at room temperature had been prepared with polyester polyol and castor oil as the soft segments and PAPI as the hard segments. The ratio of polyester polyol and castor oil was supposed to be 5:5 and 4:6. Taking p-aminophenol as raw material, a kind of siloxane with end group of acetamide had been synthesized. The best condition of this synthesizing reaction was also been assured by experiments. To improve the heat-resistance performance of the PU coatings, AAPDS, as the chain extender, has been added into the system of the PU coating cured at room temperature. ATR analysis had shown that AAPDS reaced with the NCO successfully and had been introduced into the PU structure. The performance of the curing reaction and the thermal decomposition temperature had been researched by differential scanning calorimetric (DSC) and thermo gravimetric analyzer (TGA) respectively. Additionally, the ratio of mass loss of PU coating after treatments in the muffle with high temperature had been measured. The adhesive strength of PU coating on the metal matrix as the time of treatment in the high temperature and water varied, had also been researched. The results illustrated that the AAPDS could advance the curing reactions, improve the temperature of coating glass transition and decomposition, and enhance the adhesive strength on the metal matrix of PU coatings after the treatment under high temperature. The water-fast capability was also been improved.