Flame-retardant polyamide 11 nanocomposites: further thermal and flammability studies

Polyamide (nylon) 11 (PA11) were melt-blended by dispersing low concentrations of nanoparticles (NPs), namely nanoclays (NCs) and carbon nanofibers (CNFs) via twin-screw extrusion. To enhance their thermal and flame retardant (FR) properties, an intumescent FR additive was added to the mechanically superior NC and CNF PA11 formulations. For neat and NP-reinforced PA11 as well as for PA11 reinforced by both intumescent FR and select NPs (NC or CNF), decomposition temperatures by TGA, flammability properties by UL 94, and cone calorimetry values were measured. All PA11 polymer systems infused with both NPs and FR additive had higher decomposition temperatures than those infused with solely FR additive. For the PA11/FR/NC polymer blends, Exolit® OP 1312 (FR2) is the preferred FR additive to pass the UL 94 V-0 requirement with 20 wt%. For the PA11/FR/CNF formulations, all Exolit® OP 1311 (FR1), OP 1312 (FR2), and OP 1230 (FR3) FR additives passed the UL 94 V-0 requirement with 20 wt%.