Phosphotungstic acid intercalated Zn,Al-layered double hydroxides/ nanocellulose based 3D lightweight foam thermal insulation materials

In this study, [PW _12 O _40 ] ^3− anions have been intercalated into Zn,Al-Layered Double Hydroxides(ZnAl-NO _3 -LDHs) to synthesize ZnAl-PW _12 O _40 -LDHs by ion-exchange reaction. The chemical composition and structure were analyzed by XRD, FT-IR, ICP, and SEM. Then, the nanocellulose based 3D lightweight foam thermal insulation materials was prepared by ZnAl-PW _12 O _40 -LDHs and CNF compound with H _3 BO _3 . The TG showed that ZnAl-PW _12 O _40 - LDHs significantly reduced the maximum decomposition rate and increased the carbon residual rate at 800 °C, which indicated that ZnAl-PW _12 O _40 -LDHs can improve the oxidation resistance of CNF composite materials at high temperature.The fire resistance of different samples were evaluated by back temperature test and alcohol lamp flame test, CNF/50%ZnAl-PW _12 O _40 -LDHs /2%H _3 BO _3 showed best thermal stability and flame-retardant properties, which can be contributed to the decomposition products of ZnAl-PW _12 O _40 -LDHs, acting both as phase flame retardant and condensed phase flame retardant.