Intumescent flame retardants for polymers. IV. The polycarbonate–aromatic sulfonates system

Abstract

and CONCETTO PUGLISI, DANIELE VITALINI, Istituto per la Chimica e la Tecnologia dei Materiuli Polimerici, Consigh Nazion.uk deUe Ricerche, Viak A. Doria, 6-95125 Cataniu, Italy, and S . CUCINELLA, Enichern SPA.-Sun Donuto Milanese, 20100 Milam, Italy synopsisThe mechanism of action of aromatic sulfonates as flame retardant (FR) agents on poly(bisphenol-A carbonate) (PC) has been investigated. These compounds are capable of inducing a self-extinguence in PC even when present in very low amounts (0.2-1%). Thermogravimetric and flash pyrolysis-GC-M!3 data show the thermal degradation rate of PC enhanced, and the distribution of the volatile pyrolysis products was modified by these additives. Oxygen Index (01) and Nitrous Oxide Index (NOI) measurements indicate a FR condensed-phase mechanism of these additives. Traces of polymer surface temperature against time, measured under forced flame conditions, show that the expanded carbon layer formed in the combustion of polycarbonatearomatic d f o n a t e blends produces a heat insulating effect toward the undecomposed bulk. The overall evidence leads us to conclude that aromatic sulfonates cause the flame extinguishment in polycarbonate by an intumescent phenomenon.

A polycarbonate/magnesium oxide nanocomposite with high flame retardancy

“…3–10 Representatively, aromatic sulfonate compounds, 3,4,10 silicon compounds, 6,11 and phosphorus compounds 12,13 were reported to be effective flame retardant for PC. Despite, the above organic compounds are effective to retard flame of PC, the complex of synthesis as well as the possibility to release deleterious organic compound during burning make them nonfriendly to the environment.…”

Thermal behaviors of flame‐retardant polycarbonates containing diphenyl sulfonate and poly(sulfonyl phenylene phosphonate)

“…As a consequence, the formation of a carbon layer at the burning surface is promoted. 10 In our experiments we used potassium diphenyl sulfonate (SSK) as a flameretardant additive for PC. When the loading level of SSK was 0.5-1.0 wt %, the limited oxygen index (LOI) values reached 33.…”

Flame retardants: intumescent systems

“…The sulfonates seem to act by accelerating the degradation/charring process, thus attaining the rate of gas evolution (e.g. CO 2 ) and viscosity of the charring mass necessary for intumescence to occur, without increasing the char yield [6].…”