Preparation Of Intumescent Flame Retardant With Inverse Suspension Polymerization And Properties Of Flame Retardant SBR

This thesis is about the research of intumescent flame retardant SBR. In the experiment, free radical initiating system is used to initiate the copolymerization of sodium acrylate and acrylamide, then the three components (ammonium -uzhipolyphosphate APP, pentaerythritol PET, melamine MEL) of the classical chemical intumescent flame retardant (IFR) system are wrapped in situ. Mass matching of three components is studied in order to find the best flame retardant effect. The study showed that when the amount of MEL is 3wt% possession of intumescent flame retardant and the ratio of APP: PER is between 4 to 5.67, gave the highest residual carbon rate. Scanning electron microscopy (SEM) results showed that intumescent flame retardant with higher residual carbon rate has more homogeneous and thick foam wall, which also has good heat and quality insulation effect.In order to improve mechanical and flame retardant properties of SBR/IFR system, inverse suspension polymerization was used to prepare IFR powder, stable factors of inverse suspension polymerization system were also discussed. Conditions of stable polymerization were made: In the use of complex emulsion, 98% Span-80 +2% TX-10, precipitation amount of oil is significantly less than that of other single emulsion, when the amount of emulsion takes up ten percent of the mass of monomer, the polymerization system showed good stability; When the agitation speed increased to 1000r/min, the influence of stirring rate to the polymerization system is leveling off, the shear stress on the monomer droplet size has little effect after one and a half hours time, therefore, the emulsifying time is 1.5h, 30 copies dosage of the IFR were found to be best after the study of flame retardant properties.Finally, retardant mechanism of IFR to SBR was discussed through thermal dynamic analysis, SEM and TG-FTIR techniques. The results of SEM investigation showed that the size of particle prepared by inverse suspension polymerization mainly in the vicinity of 0.5μm, and the particle is regular sphere with smooth surface. After burning, the surface carbon layer of sample SBR / IFR (30wt%) is compact, the internal of carbon layer has uniform small room as honeycomb, which covers on the carbon layer evenly, and is almost a closed structure; The hot degradation process dynamics analysis of thermal decomposition of the SBR/IFR system showed that, under the N2 atmosphere and air atmosphere, both of SBR/IFR system hot degradation reaction orders are close to the theoretical value 1, thermal degradation reaction mainly controlled by the nuclear formation and growth mechanism, under the air condition, it is also controlled by spread out mechanism of the part of gaseous product in gas phase boundary layer, and is affected by the outward diffusion rate of the border, because the presence of oxygen causes the system's oxidation and the release of large amounts of CO2 is effected by the rate of diffusion heavily.