The Synthesis Of Flame Retardant Containing Nitrogen, Sulfur And Phosphorus And The Research Of Its Flame Retardant Performance In PC

Polycarbonate (PC) is a kind of high impact strength, transparency, heat resistance and dimensional stability of thermoplastic engineering plastic.Only limiting oxygen index (LOI) of 24-26% and UL-94 V-2 rating are achieved. It is very easy to cause the material burning near the firewhen PC combustion dripping melt.So, the flame retardant modification was carried out on PC in order to meet the higher requirements of PC in flame retardanance.At present, the single type flame retardant can not meet the requirement of PC, synergistic flame retardant between different flame retardant has become a hot research topic in the field of flame retardant. One of them is intramolecular synergistic flame retardant, it can overcome flame retardant additives, poor compatibility problems, but also works as an efficient flame retardannce. A kind of N-P-S association flame retardant (SBBT) was synthesized using cyanogen chloride, amino benzene sulfonic acid and triphenyl phosphine oxygen as raw materials the structure was characterized by using FTIR and ESI-MS.The thermogravimetric analysis showed that the SBBT has good stability, the initial thermal degradation temperature (IDT) of SBBT was 365 ℃.The flame retardant (SBBT) was added to the polycarbonate (PC) by the blending technology, and PC/SBBT composite materials was prepared, then the flame retardant performance and mechanical properties were studied. Results show that when the SBBTadding amount was 0.1%, the LOI value of the system achieves the 31.9%, vertical combustion grade reaches V-0 level; the plasticizing effect was increased,the impact strength of PC was kept when the adding amount was less than 0.2%.TG-MS analysis results show that the SBBT decomposition of the gas phase product PO-can be combined with Hand OH·, it is effect to interrupt the combustion chain reaction, and reach the effect of gas phase flame retardant. The real combustion environment of PC weresimulated by the cone calorimeter, the pkHRR of pure PC and PC/SBBT is respectively429.6kW·m-2 and 330.3 kW·m-2, showed that SBBT can slow down the heat release rate of PC in the process of combustion,and the condensed phase and gas phase flame retardant are existed all the time.The thermal stability properties of PC and PC/SBBT were studied by thermogravimetric, and the results showed that SBBT can raise the thermal decomposition activation energy of PC, and improvethe thermal stability of the PC.The microscope and Raman spectra was used to study the carbon residue after burning, residual carbon surface of pure PC is smooth and flat, and the residual carbon surface of PC/SBBT system is various and the tiny hole structure.This carbon layer structure can cut off oxygen and heat, have the effect of condensed phase flame retardant. Therefore, SBBT flame retardant mechanism can be considered as the gas flame retardant of phosphine oxide group and the condensed phase function of sulfonate and phosphorus.