Melamine-phytate (MEL-PA) nanoflakes are formed by supramolecular self-assembly technology using melamine (MEL) and bio-based phytic acid (PA) as the building blocks. This work explores the possibility of this two-dimensional nanomaterial as flame retardant. The layered MEL-PA with the loading of 1, 2 and 3 wt% are incorporated into polypropylene (PP) matrix. MEL-PA is dispersed well in the PP matrix. Thermal stability and flame retardant performance of PP/MEL-PA composites are investigated. Compared with neat PP, the addition of 2 wt% MEL-PA decreases the peak heat release rate from 756 to 608 kW/m(2). Char yield of PP is improved by MEL-PA, and the chemical structure and graphitization degree of residual char are studied to reveal flame retardant mechanism. (C) 2019 Elsevier Inc. All rights reserved.