CHARACTERIZATION OF POLY(ETHYLENE - CO - ACRYLIC ACID) COMPOSITE WITH INTUMESCENT CHITOSAN FLAME RETARDANT

The purpose of this research is to develop a novel intumescent flame-retardant for polyethylene utilizing a green alternative, chitosan. Thermal and flammability properties were determined using thermal gravimetric analysis, cone calorimetry, and flame spread measurements. Addition of chitosan in poly(ethylene-co-acrylic acid) (PEAA) was found to reduce thermal stability, but form layer of char due to the decomposition of chitosan. An increase in the residual weight% was observed from 2.79% to approximately 10% for both additions of 20% chitosan dissolved in hypophosphourous acid and poly(acrylic acid) (ChitHP) and 20% chitosan dissolved in acetic acid and poly(acrylic acid) (ChitAC). Using cone calorimetry, peak heat release rate (PHRR) of the composite polymers containing chitosan were found to be 1546.59 and 1499.92 kW2 for ChitAC and ChitHP respectively while PEAA was 2005.15 kW/m2. The effective heat of combustion of PEAA decreased with the addition of chitosan as well proving that chitosan does inhibit combustion of the polymer. However, there is a significant difference between ChitHP and ChitAC char formation that was observed with SEM. Polymeric materials were all determined to meet the V0 classification based on horizontal burn and vertical burn UL-94 flammability tests. The crystallinity of both the ChitHP and ChitAC-PEAA polymeric materials was also found to be higher than that of pure PEAA from 34% to roughly 38%. After submersion in artificial saltwater and deionized water ChitHP samples disintegrated in artificial saltwater after 24 hours and broke apart in deionized water after 72 hours, and ChitAC samples disintegrated in deionized water after 72 hours and broke apart in artificial salt water after 72 hours. Overall the addition of chitosan was found to have promising performance as an intumescent flame-retardant, but compatibility issues must be addressed.