The Study Of Composite Flame Retardant Containing Nitrogen, Sulfur And Phosphorus And Its Application To PC

Compared to normal engineering plastics, polycarbonate (PC) has higher flame retardancy.But it was difficult to meet the requirements of flame retardancy in some special fields.Among the flame retardants of PC, halogen flame retardants have been limited in more andmore environment protection laws and regulations. And they have been replaced byhalogen-free flame retardants which were more environmentlly friendly and safe. Moreover,the combination of multiple flame retardant elements has become a hot topic in the field ofpresent halogen flame retardants.The aromatic sulphonate flame retardant containing triazine ring (KTS) and bisphonal A bis(diphenyl phosphate)(BDP) were blended with PC to prepare a series of flame retardantPC/(KTS+BDP) systems. The flame retardancy, mechanical properties and thermal stabilitiesof PC/(KTS+BDP) composites have been studied by limited oxygen index (LOI) tests,vertical burning (UL-94) test, TGA tests and mechanical properties tests. It was found that0.1mass%of KTS and7.5mass%of BDP was incorporated, the LOI value achieved35.5%andclass V-0of UL-94test at3.2mm thickness was passed. TG tests indicated that the initialthermal degradation temperature (IDT) of PC/KTS(0.1%)/BDP(7.5%) system in nitrogen wasincreased by18.7℃and the char residue at900℃was22.1%.Single composite flame retardants of NPS (NPS-K and NPS-Na) containing nitrogen,phosphorus and sulfur have been synthesized with cyanuric chloride (TCT),2-Aminoethanesulfonic acid,9,10-dihydro-9-oxa-10-phosph-aphenan-threne-10-oxide(DOPO). The structure and thermal properties of NPS were characterized. The results showedthat NPS had good thermal stability and char residue ability. The initial thermal degradationtemperature (IDT) of NPS was377.4℃.The effect of NPS on the thermal behaviors of PC was investigated by LOI tests, UL-94test, TGA tests and CONE tests. The results showed that NPS had excellent flame retardancy of PC. When0.075mass%of NPS was incorporated, the LOI value of PC/NPS-K andPC/NPS-Na achieved the maximum of34.25%and35.25%, respectively. And class V-0ofUL-94test at3.2mm thickness was passed. TGA tests indicated that the IDT ofPC/NPS-K(0.075%) system in nitrogen was decreased by30.7℃and the char residue at900℃was20.8%. The activation energy (E) of PC/NPS-K(0.075%) degradation was190.2kJ/mol. Cone calorimetry tests showed that the peak heat release rate (pkHRR) and peaksmoke produce rate(pkSPR) of pure PC were410.2kW m-2and0.066m2s-1, respectively.Compared to pure PC, the pkHRR and pkSPR of PC/NPS-K(0.075%) composite weredecreased by64.7kW m-2and0.004m2s-1,respectively.