Thermal Stability of Fire Retardants: IV. Decomposition of Aryl Bromo Ethers Under Process Conditions

Abstract

Thermal decomposition kinetics were determined for several brominated phenyl allyl ethers, for several brominated diphenyl oxides, and for several miscellaneous compounds used in the manufacture of fire retardant thermo plastics. The decompositions were carried out using bibenzyl as a model for the polystyrene system and at agent loadings of 10 wt.%. The diphenyl oxide deriv atives were stable at reaction temperature (234 ° C) having reaction rate con stants of < 5 x 10-6 min-1. The phenyl allyl ethers underwent rapid decomposi tions with rate constants of 3 to 4 x 102 min 1. The reaction of these ethers is primarily free radical in nature and generates radicals via the homolytic cleavage of the ether linkage.

Thermal Stability of Fire Retardants:* V. Decomposition of Haloalkyl Phosphates under Polyurethane Processing Conditions

“…The thermal stability of DBDPO in DPE has been reported previously [4]. In this study the agent was found to be stable at 216 ° C in the presence of the amine (TDA).…”

“…Decomposition rates of BCP and TCEEP at various temperatures. &dquo;TRIS&dquo; was found to decompose at 234 ° C primarily via a free radical mechanism and at a rate intermediate to the rate of the typical aliphatic vicinal dibromide such as hexabromocyclododecane (kllllr = 28 x 10-3 min-1) [3], and the typical aromatic bromides (k,,,r = 0.005 x 10-3 min-1) [4]. Plot of rate constants vs 110K TCEEP k,, 0, k,&dquo;, () BCP kHX 0, k,&dquo;, [J run neat in DPE to determine its thermal stability relative to those of the presently used agents.…”

“…WE HAVE REPORTED, previously, on the thermal stability and decomposition kinetics of a variety of FR agents, including both aliphatic and aromatic bromides, used in thermoplastics [1,2,3,4]. These studies were carried out with both neat agents and with agents dissolved in bibenzyl (1,2-diphenylethane, DPE) at temperatures normally encountered during extrusion of polymers.…”