Controlled architecture of polyhedral oligomeric silsesquioxane-functionalized poly(glycidyl methacrylate)/polyester composites using surface-initiated ICAR ATRP Technique for High Flame Retardancy and Smoke Suppression

To impart flame retardancy and smoke suppression properties to polyester fabrics, polyhedral oligomeric silsesquioxane (POSS)-functionalized polyglycidyl methacrylate (PGMA) coatings were synthesized via the initiators for continuous activator regeneration atom transfer radical polymerization (ICAR ATRP) and polydopamine chemistry. A well-distributed PGMA layer was observed with a low polydispersity index of 1.22. After 6.25 wt% NH2 POSS grafting, the total amounts of heat and smoke were reduced by 55.00% and 86.89%, respectively. The values of the smoke density for the DOPO-POSS- or NH2-POSS-modified copolyester fabrics were reduced by 51.00% and 57.55% at 4.75 wt% PGMA grafting content. SEM, FTIR, and XPS results of the residual char provided strong evidence that a higher graphitization degree of the char was achieved, which was attributed to the Si–O–C and P–O–C cross-linking formation in the condensed phase upon POSS grafting. The firm graphite char layer prevented the release of internal gas and the entry of external oxygen. Moreover, TG-MS showed that the presence of the POSS layer reduced the amounts of CO and H2O released during the pyrolysis of the fabric. More inert gasses, including NH2 and PH3, were generated through POSS layer decomposition, which in turn slowed the combustion process.