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

In this study, [PW12O40](3-) anions have been intercalated into Zn,Al-Layered Double Hydroxides(ZnAl-NO3-LDHs) to synthesize ZnAl-PW12O40-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-PW12O40-LDHs and CNF compound with H3BO3. The TG showed that ZnAl-PW12O40- LDHs significantly reduced the maximum decomposition rate and increased the carbon residual rate at 800 degrees C, which indicated that ZnAl-PW12O40-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-PW12O40-LDHs /2%H3BO3 showed best thermal stability and flame-retardant properties, which can be contributed to the decomposition products of ZnAl-PW12O40-LDHs, acting both as phase flame retardant and condensed phase flame retardant.