Study On The Flame Retardancy And The Flame Retardant Mechanism Of CR And CM

Chlorinated polyethylene rubber (CM) replace part of chloroprene rubber (CR) in flame retardant conveyor belt can improve the processing performance, and does not harm the flame retardancy.CM is cheaper and environmentally friendly, but due to technical problems, it is rarely used in the production. The main purpose of this subject is to expand the CM application in the field of flame retardant conveyor belt. The main content is to research flame retarding performance and mechanism of CR and CM. The retardant performance of the sample is tested by the Oxygen Index (LOI) and Alcohol Burner. The thermo-gravimetric behavior, thermo-degradation kinetic and evolution of the condensed phase structure is studied in order to discover the flame retardant mechanism. The experiment mainly includes three parts:1. The CM retarded by Sb2O3 and ZB were studied. The results are as follows. Sb2O3 can obviously increase the LOI of the sample LOI, but the ZB cannot. When add both Sb2O3 and ZB the LOI is higher than single add Sb2O3 or ZB, so there is synergistic effect. The thermo weight loss process of CM in the air can be divided into three stages:dehydrochlorination, main chain decomposition, decomposition of the carbon layers. Sb2O3 and ZB can obviously reduce the activation energy of the first stage; the latter can generate C-B with CM, which can improve the stability of carbon layers.2. The CM retarded by Sb2O3 and ZB were studied. The results are as follows. The Sb2O3 can obviously increase the LOI of the sample, but make the smoldering time growth. ZB can significantly improve the effect of sample of smoldering but decrease the LOI; When add both Sb2O3 and ZB the LOI is higher than single add Sb2O3 or ZB, so there is synergistic effect. Double bonds in the CR cross-linked in the process of decomposition and formed the benzene ring structure; CR and ZB formed C-B key, which can improves the carbon residue content and increase decomposition activation energy, so the stability of the carbon layer is higher.3.The CR/CM blend rubber retarded by Decabromodiphenylethane (DBDPE) and chlorinated paraffin 70 (CP-70), ammonium polyphosphate (APP) and pentaerythritol (PER) expansion flame retardant system were studied. The results are as follows. when the CR/CM mixed in a ratio of 70/30, the LOI reached 32.8% which is higher than the single CR or CM; Added ten copies of DBDPE, the LOI of the sample reached 42.2%, which is higher than 20 copies of CP-70, so the flame retardant efficiency of DBDPE is much higher than CP-70; Expansion flame retardant system can significantly improve the effect of CR/CM smoldering. The LOI increased by 1.2% when 2phr OMMT add to APP/PER, and the smoldering time is decreased by 1 min.