Synthesis of a carbon nanotubes/ZnAl-layered double hydroxide composite as a novel flame retardant for flexible polyurethane foams

A composite consisting of carbon nanotubes and zinc aluminum-layered double hydroxide (CNT/ZnAl-LDH) with good solubility in liquid media was synthesized by a co-precipitation method. The structural characterization and morphological observation demonstrated that the composite displayed a heterostructure with CNTs embedded in ZnAl-LDH nanosheets. The influence of CNT/ZnAl-LDH on the thermal stability and flammability performance of flexible polyurethane (PU) foams was characterized. It was established that CNT/ZnAl-LDH could improve the thermal stability while reduce the peak heat release rate as well as the total smoke release of PU foams. The formation of a protective char with increased mechanical properties and high graphitization degree was mostly postulated for the improved flame retardancy. Copyright © 2015 John Wiley & Sons, Ltd.