Effect of styrene-maleic anhydride as a compatibilizer on the mechanical properties and flammability of intumescent flame retardant polystyrene
writer：Y. Chen, Z. Guo, Z. Fang*
keywords：polystyrene; styrene-maleic anhydride copolymer; compatibility; mechanical property; flammability
source：期刊
specific source：J. Appl. Polym. Sci., 2010.10, 118(1): 152-158
Issue time：2010年
Polystyrene (PS) was flame-retarded with a polymeric intumescent flame retardant, poly (diaminodiphenyl methane spirocyclic pentaerythritol bisphosphonate) (PDSPB), and in situ compatibilized with styrene-maleic anhydride copolymer (SMA). Compatibilization reaction was verified by IR spectroscopy and gel content measurement. Electron microscopy images showed that compatibilization could considerably reduce the size of the flame-retardant domains and improve the interfacial adhesion between PS and PDSPB. With the same PDSPB loading (20 wt%), addition of 5 wt%, 10 wt% and 20 wt% SMA increased the impact strength of the flame retarded PS by about 29%, 103% and 201% respectively. Compared with PS/PDSPB sample, addition of 5 wt% of SMA improved the limiting oxygen index (LOI) from 23.8 to 24.2 and reduced the peak heat release rate (PHRR) of the blend by 18.3%. However, further increment of SMA content deteriorated the flame retardancy of the blend. It was found that the –NH2 groups changed into more stable imide groups at high temperature, causing the absence of gas source. Therefore, the intumescent char could not be formed during combustion process, which was the main reason for the deteriorate effect of flame retardancy at high SMA loading.