Preparation Of Flame Retardant Rigid Polyurethane Foam And TG-FTIR Application In Flame Retardant Mechanism Research

In recent years, the economic model based on low energy consumption, low pollution and low-emission is progressively popular. Rigid polyurethane foam not only has excellent physical and chemical properties, and more to meet saving65%energy requirements of the country, so it gets more and more applications in the field such as construction, bridges and roads and so on. So it is necessary to research the thermal degradation process and hazardous substances during the thermal degradation of rigid polyurethane foam, which is an important signification for fire risk assessment.In the experiment, we use one-step method synthesizing four kinds of flame retardant polyurethane foam and one kind of pure polyurethane foam. Rigid polyurethane foam is characterized by LOI test, heat release rate test, water absorption test and thermal conductivity test. Using TG-FTIR method, we analysis the thermal decomposition process. flame retardant mechanism and the influence in the main gas products of five kinds of polyurethane foam in a nitrogen atmosphere.This paper, the following conclusions and results are:1. Thermal decomposition of rigid polyurethane foam is mainly divided into three stages, the first stage consists of the loss of water and some additives and the cleavage of a main chain C-O bond which generate the isocyanate and the polyol, the second stage is the thermal decomposition of the isocyanate and the polyol, in the third stage, the residue continues decomposing, carbonization occurs at elevated temperature.2. Thermal decomposition products of the rigid polyurethane foam are mainly hydrocarbons, olefins, benzene, primary amine, amide, carbon dioxide, water and so on.3. DMMP mainly displays condensed phase flame retardation, it inhibits decomposition of the isocyanate and the polyol, the release of hydrocarbons, olefins and benzene are cut down. With the increase of DMMP. flame retardant decreases.4. DMMP and TDCP significantly inhibit the thermal decomposition of isocyanate, at high temperature (400℃above), the gas-phase flame retardant plays a major role. The release of hydrocarbons, olefins and benzene are cut down. With the increase of DMMP and TDCP. olefin increases. 5. DMMP and TCPP inhibit decomposition of isocyanate. they have a little function of char forming. The release of hydrocarbons, olefins and benzene are cut down. With the increase of DMMP and TCPP. benzene increases.6. DMMP and TCEP play a major role in the second stage to inhibit thermal decomposition of the polymer. There is a little function in the release of hydrocarbons, olefins and benzene. With the increase of DMMP and TCPP. flame retardant gets weakened.