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Catalysis of intumescent flame retardancy of polypropylene by metallic compounds
Author(s) -
Lewin Menachem,
Endo Makoto
Publication year - 2003
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.265
Subject(s) - intumescent , catalysis , materials science , pentaerythritol , melamine , thermogravimetric analysis , ammonium polyphosphate , polypropylene , fire retardant , metal , transition metal , inorganic chemistry , polymer chemistry , nuclear chemistry , organic chemistry , chemistry , composite material , metallurgy
Abstract Divalent and multivalent metallic compounds catalyze the flame retardancy performance of intumescent systems based on ammonium polyphosphate (APP) and pentaerythritol (petol) in poly(propylene) (PP). The catalytic effect is shown by increases in the oxygen index (OI) and UL‐94 ratings. The effect is exerted by small concentrations of the metallic compounds in the range of 0.1–2.5 wt% of the compositions. The effect increases with the concentration of the catalyst until a maximum is reached. At higher concentrations of the catalyst a decrease in the flame retardancy parameters is observed, accompanied in several cases by a degradation and discoloration of the composition. The catalyst replaces melamine in intumescent systems. Catalytic effectiveness is defined and calculated for a number of compounds. Thermogravimetric parameters, such as initial decomposition temperature, temperature of the transition point and residue‐after‐transitions (RAT) change in parallel with the catalytic effect of the metal compound concentration. Metal compounds investigated include oxides, acetates, acetyl acetonates, borates and sulfates of Mn, Zn, Mg, Al, Ca, Ba, V, Co, Ni, Cu, Mo, Zr, and Cr. Mechanistic considerations on the activity of the catalysts are presented. Copyright © 2003 John Wiley & Sons, Ltd.