Flammability Performance and Char Behavior of Poly(vinyl alcohol)-Zirconium Phosphate-Montmorillonite Composites

Flammability performance and the microstructure of chars from poly(vinyl alcohol) (PVA) with α-type zirconium phosphate (α-ZrP) and montmorillonite (MMT) hybrid composites and multilayer composite were elucidated with microscale combustion calorimetry (MCC) and scanning electron microscopy (SEM). MCC revealed that the combination of α-ZrP and MMT did not impart synergistic effect in improving flame retardancy to PVA/ZrP/MMT hybrid composites, while multilayer composite showed better flame-resistant properties than hybrid composite. SEM demonstrated that the minimal loading levels of MMT in PVA/ZrP/MMT composites obstructed the development of intumescent chars in hybrid composites, but on-site mechanically reinforced the intumescent char in multilayer composite.