Synthesis And Properties Of Polyaniline/Grafted Intercalated ZnAl-layered Double Hydroxide Nanocomposites

Polymer/LDH nanocomposites have been focused more extensively in many fieldsdue to its excellent and unique properties. Polyaniline (PANI) has been widely used incompositing and modifying the traditional inorganic anticorrosive materials due to itspitting corrosion resistance, environmental stability, simple synthesis process andvarious applications. Thus, in the present work, PANI/ZnAl-LDH nanocomposites wereprepared by in situ chemically oxidative polymerization in order to improve theantiseptic property. However, no work is reported in the literature related to thesynergistic effect of organomodification and interlamellar grafting of LDH in thereinforcement of the polymer matrix.In the present study, PANI/ZnAl-LDH composites were prepared for the first timevia in situ chemically oxidative polymerization. And the effect of the molar ratio of HClto An, APS to An, ZnAl-V10O286-LDH to An and the reaction time on the ACimpedance spectrum curves, tafel curves and yield for PANI/ZnAl-LDH compositeswere discussed. The structure and micro-morphology of PANI, ZnAl-V10O286-LDH andPANI/ZnAl-LDH composites were characterized by XPS, FTIR, XRD and SEM. Thethermal stability was tested by TGA. The electrochemical parameters and antisepticproperties were measured by electrochemical workstation system.The experimental results indicated:①Through the selection of experimentalconditions optimized, the optimum preparation conditions of surface modification ofgrafted intercalated ZnAl-LDH were achieved when the mass ratio of APTS to LDHwas1:20, the pH was8.0, the reaction time was6h, the reaction temperature was80℃.Then, The effect of concentrations of LDH, HCl, APS and the reaction time onelectrochemical properties and yield of PANI/ZnAl-LDH composites was discussed.When mLDH/mAn=10%, nHCl/nAn=2:1, nAPS/nAn=1.5:1, t=12h, the impedance value,corrosion potential and yield of PANI/ZnAl-LDH composites were the highest.②Thestructure and morphology of the composites were characterized by X-ray photoelectronspectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction(XRD) and scanning electron microscope (SEM). The XPS, FTIR and XRD resultsindicated that there existed an interaction between PANI molecules and ZnAl-LDHparticles. The SEM results indicated that ZnAl-LDH particles were covered with thepolyaniline. The TGA test manifested that the thermal stability of PANI/ZnAl-LDH composites was much better than PANI.③Anticorrosive properties were investigatedby measuring electrochemical parameters within certain limits. The results showed thatthe open circuit potential, the corrosion potential were improved after modified by PANI.Moreover, the impedance modulus value of PANI/ZnAl-LDH composites exhibitedsignificant improvements compared with pure PANI and ZnAl-V10O286-LDH and|Z|0.01Hzincreased nearly two orders of magnitude. Thus it can be seen that thePANI/AD-LDH nanocomposites offered better protection against corrosion than thePANI and D-LDH did. This provides a way for the study on high anticorrosiveproperties self-healing materials.