Thermal degradation of phosphonated polystyrenes. Part 1: Chain and condensation

Polystyrenes substituted with chloromethoxyphosphonated groups at chain ends undergo a condensation reaction at a relatively low temperature (ca. 200°C) prior to extensive degradation of the polymeric chain (280–430°C). The condensation leads to an increase in the molecular weight through the formation ofPOPbonds between phosphonated chain ends with elimination mainly of CH3Cl. Trace amounts of CH3OH are also evolved in this step. Mechanisms for the condensation reaction are proposed and its relevance to the fire retardant activity of these polymers is discussed.