Preparation Of Flame Retardant Nano-powder/polyacrylate Composite Emulsion And Coatings And Investigation On Their Performance

Polyacrylate emulsion has many excellent properties, such as low cost, good film, strong adhesion with the textile, soft handle and forming close film after being coated. Due to these properties, it is widely used as a coating agent in domestic and abroad. When it is coated on the glass fiber grid, the mechanical properties of glass fiber can be reinforced. Meanwhile, the coating can prevent the glass fiber from cement directly, so the glass fiber grid can be free from being corrozied. Because of this reason, the alkali resistance of glass fiber grid and the durability of the cement can be improved at the same time. However, polyacrylate emulsion is a saturated polymer, which is easy to be burned. For materials, there may be some safe problems after being coated with the polyacrylate emulsion.In this paper, nano-inorganic flame retardant powder of aluminum hydroxide (ATH) and antimony trioxide (Sb₂O₃) were used as a modifier to prepare the flame retardant powder/polyacrylate composite emulsion. Then these composite emulsions were coated on the glass fiber grid. The purpose of this paper was to investigate the effect of nano-inorganic flame retardant powder on the performance of polyacrylate emulsion and glass fiber grid coatings. Nano-inorganic powder is easy to agglomerate due to the high specific surface area of itself. For this reason, some surface modifiers were used to improve the poor compatibility between nano-powder and polymer firstly. Second, the nano-inorganic flame-retardant/polyacrylate composite emulsions were prepared by a seed emulsion polymerization method. Last the glass fiber was coated with these composite emulsions. Some coated glass fiber grid samples were treated with alkali solution to be tested.The results of the experiments were listed as follow. The saline coupling agent KH-550 could modify the nano-inorganic powder better than other coupling agent. The modified inorganic powder could be dispersed even by combing mechanical stirring and ultrasonic method together. The process of polymerization could finish smoothly through the semi-continuous seed emulsion method.Performance testing showed that the ATH/polyacrylate composite emulsion got best composite properties when the amount of ATH was 3‰of the total monomer. At this time, it has higher solid content, moderate viscosity and narrowest size distribution. The film forming ability and thermal stability of the emulsion were all improved some extent. When the content of ATH and Sb₂O₃ were 1‰and 3‰respectively, ATH-Sb₂O₃ / polyacrylate composite emulsion had the narrow size distribution and best thermal stability.During the test of the coated glass fiber, it was found that the emulsion, modified with moderate amount of ATH and Sb₂O₃ powder, could form even and compact films on the surface of glass fiber. Due to this uniform film, the mechanical properties of the glass fiber got some improvements. ATH powder couldn't improve the alkali- resistance of the emulsion coatings because of its characterizations. While the ATH and Sb₂O₃ were all used as the emulsion modifier, the alkali resistance of the emulsion coatings could be enhanced some extent. The limit oxygen index of polyacrylate tings increased slightly after being modified with inorganic flame-retardant powder, but the flame-retardant effect was not obvious.