SYNERGISTIC EFFECT OF Cu-ZSM-5 ZEOLITE ON FLAME RETARDED PP BY MELAMINE SALT OF DIPENTAERYTHRIOL PHOSPHATE

A novel intumnescent flame melamine salt of dipentaerythriol phosphate (MDP),was prepared from dipentaerythritol (DPE) polyphosphoric acid,and melamine.The flammability,combustion behavior,and thermal degradation and stability of PP-MDP were characterized.When MDP loading was 20 wt%,LOI values of the composites reached up to 27%,and UL94 rating,V-2.PP-MDP containing 1 wt% Cu-ZSM-5 presented the highest LOI value of 30.5% and UL94 rating,V-0,and released lest heat during cone test.TG data showed that the thermal degradation of PP was improved by the addition of MDP.While the loading of ZSM-5 was 1 wt% or higher,the main weight loss delayed with 50℃,and 80℃,compared with PP and PP-MDP respectively.The appropriate loading Cu-ZSM-5 made PP-MDP possess higher thermal oxidative stability.By SEM,the formation of a dense and thick char layer was observed on the char layer of PP-MDP-containing Cu-ZSM-5,responsible for high flame retardancy.So,the synergistic flame retardancy effects of MDP and Cu-ZSM-5 on PP existed.The mechanism of synergistic effect of Cu-ZSM-5 zeolite on flame retarded PP by MDP was discussed.