Thermal degradation and combustion behaviors of flame retarded glass fiber reinforced polyamide 6 composites based on cerium hypophosphite

In this work, cerium hypophosphite (CeHP) was synthesized and characterized by scanning electron microscope (SEM) and thermogravimetric analysis (TGA) test. CeHP presented rod‐like morphological feature with good thermal stability. Subsequently, CeHP was added into glass fiber reinforced polyamide 6 (GFPA) to develop flame retardant glass fiber reinforced polyamide 6 composites (FR‐GFPA). The flame retardancy of FR‐GFPA composites was characterized by limiting oxygen index (LOI), Underwriters Laboratories 94 testing (UL‐94), microscale combustion calorimeter, and cone calorimeter test. FR‐GFPA composite with 20 wt% CeHP loading passed UL‐94 V0 rating with a high LOI of 26.5 vol%. Cone Calorimeter test showed that peak of heat release rate (PHRR) and total heat release (THR) of FR‐GFPA composites were reduced 27.1% and 21.1% compared with those of GFPA. The mechanical measurement revealed that the tensile strength first increased and then decreased with the increase of CeHP loading. With 15 wt% CeHP loading, the tensile strength of FR‐GFPA composite was 43.0% higher than GFPA. TGA and char residue characterization revealed that the addition of CeHP could significantly promote the formation of condensed char residue. The FR‐GFPA composites obtained herein exhibited superior combined properties of fire resistance, thermal stability, and mechanical properties, demonstrating that CeHP will be a promising candidate for preparing high performance polyamide composites. POLYM. COMPOS., 37:3073–3082, 2016. © 2015 Society of Plastics Engineers