Preparation And Characterization Of Anti-flaming Phenolic Foam For Heat Insulating Material At Room Temperature

Phenolic foam is one new kind heat insulating material due to its high resist heat temperature, good inflaming retarding property, fewer smog and molten drop matter and black damp while firing. It can be prepared by foaming method utilizing modified and higher activity phenolic resin, non fluorine foaming agent and other assistants.Now the problems influencing the preparation of phenolic foam are the shaping difficulty at room temperature and lower mechanical strength, etc. In this paper, in order to solve the shaping difficulty at room temperature, the preparation methodology of phenolic foam was obtained by preparing phenolic resin for foaming at room temperature and studying the foaming technology.The influence of raw materials ratio, reactive time and temperature of base catalysis method on the properties of phenolic resin was studied. The optimal technological factors for base catalysis method were raw materials ratio(P/F) of 1/1.3, reactive temperature of 80~85°C and reactive time of 2h;and the optimal raw materials ratio (P/F) for acid(first)-base(second) catalysis method was 1/1.5. The phenolic resin synthesized by acid(first)-base(second) catalysis method has higher hydroxymethyl content, and its reactive activity and solid phase content are better than the phenolic resin synthesized by base catalysis method. However, the heat resistance of the phenolic resin synthesized by acid(first)-base(second) catalysis method becomes worse a little and should be improved further.The effects of hardening agent such as single acid hardening agent and complex acid curing agent were studied. The complex acid curing agent could improve the propertied of phenolic foam. By adjusting the ratio of chlorhydric acid to phosphoric acid, the addition of chlorhydric acid could be declined and the speed of trending to red change slow and the phenolic foam is more stable. The optimal ratio of chlorhydric acid to phosphoric acid is 1.5~2.5:1. By using the complex acid system of acetic acid, chlorhydric acid and phosphoric acid, the phenolic foam shrinked little and pore size was small and the strength was improved. The optimal ratio of acetic acid to chlorhydric acid to phosphoric acid is 1:1:(3~5).The reactive activity of phenolic foam was studied by the curve of temperature to time in the curing procedure of phenolic resin. It was verified that the phenolic resin synthesized by acid(first)-base(second) catalysis method had higher reactive activity. The foam morphology fabricated from the phenolic resin synthesized by acid(first)-base(second) catalysis method was better than the base catalysis method.Except the little decline of compact strength and resisting high temperature the properties of phenolic foam reached to the Chinese standard of phenolic foam products. The obtaining of phenolic foam at room temperature lost some compact strength and resisting high temperature, therefore this method should be improved in the future research.