Combustion characteristics of halogen-free flame-retarded polyethylene containing magnesium hydroxide and some synergists

Halogen-free flame-retarded polyethylene materials have been prepared by us ing magnesium hydroxide (MH) as a flame retardant combined with red phospho rous (RP) and expandable graphite (EG) as synergists. The effects of these additives on the combustion behavior of the filled linear low density polye thylene (LLDPE), such as a limiting oxygen index (LOI), the rate of heat re lease (RHR), the specific extinction area (SEA), etc., have been studied bg the LOI determination and the, cone calorimeter test. The results show tha t RP and EG are good synergists for improving the flame retardancy of LLDPE /MH formulations. In addition, a suitable amount of ethylene and vinyl acet ate copolymer (EVA) added in the formulations can increase the LOI values w hile promoting the char formation and showing almost no effect on the RHR a nd SEA values. (C) 2001 John Wiley & Sons, Inc.