Synthesis of novel poly(aminophosphonate ester)s flame retardants and their application in EVA copolymer
writer：Liu Y, Zhang Y, Cao ZH, Peng M*, Fang ZP
keywords：polyschiff base; phosphoramidate; flame retardant; ethylene-vinyl acetate
source：期刊
specific source：Polym Advan Technol, 2013.2, 24(2): 197-203
Issue time：2013年
Two novel oligomeric phosphorous and nitrogen containing intumescent flame retardants, poly (amino phosphonate ester)s (PAPEs) were synthesized by reacting diethyl phosphite with polyschiff bases, which were obtained from the reaction of diamine with dialdehyde. The target PAPEs (designated as PAPE-e and PAPE-d respectively) were characterized by 1H-NMR, FTIR, elemental analysis, static light scattering and TGA techniques. Thermal stability and flammability properties of ethylene-vinyl acetate (EVA)/PAPE blends with various PAPE content were investigated by thermogravimetric analysis (TGA), limited oxygen index (LOI), vertical burning test (UL-94) and microscale combustion colorimeter (MCC). The results indicate that PAPE could improve the flame retardancy of EVA. EVA/30%PAPE-e blend has a LOI value of 28 and a reduction of 36% for the PHRR in MCC measurement. EVA/PAPE blend has a high yield of residual char, indicating that PAPEs are both effective charring agents. From the scanning electron microscopy (SEM) observations of the residues of the EVA/PAPE blends, the tight charred layer can be seen which was responsible to improve the flame retardancy of EVA.