Novel nanocomposites consisting of a semi-crystalline polyamide and Mg-Al LDH: Morphology, thermal properties and flame retardancy

New long aliphatic chain polyamide/Mg-Al layered double hydroxide (LDH) nanocomposites were successfully prepared via a solution intercalation technique under ambient condition in N,N-dimethylacetamide as solvent. The polyamide was synthesized using direct polycondensation reaction from an oleic acid based monomer which was characterized by proton nuclear magnetic resonance and size exclusion chromatography. The polyamide showed a semi-crystalline structure with melting temperature of 223 degrees C. Organo-modified Mg-Al LDH was produced by one-step method and used to improve properties of the polyamide. Thermal properties and flame retardancy of the nanocomposites were studied by thermogravimetric analysis, differential scanning calorimetry and microscale combustion calorimeter. The thermal degradation results in both air and nitrogen atmospheres showed that the addition of organo-modified LDH resulted in a substantial increase in the thermal stability and char yields of the nanocomposites as compared to the neat polyamide. The flammability tests revealed that incorporation of the organo-modified LDH in the polyamide resulted in a reduction of the heat release rate, heat release capacity and total heat release. (C) 2014 Elsevier B.V. All rights reserved.