Preparation And Properties Study Of Organically Intercalated Kaolinite/Poly(2,3-dimethylaniline) Nanocomposites

Recently, polyaniline (PANI) has become a novel anticorrosion coating materials.Although PANI has good corrosion protection properties, its poor solubility andprocessability due to its high aromatic nature and intermolecular hydrogen bondingbetween amine groups and imine groups of the adjacent chains have strongly limited itspractical applications. Some derivatives of PANI have been proved to have goodsolubility and anticorrosion performance, and the electronic-donating group substitutioncould achieve more significant improvement in the anticorrosion performance ofpolymer compared with the electronic-attracting group substitution.2,3-dimethylaniline(2,3-DMA) is one kind of the derivatives of aniline, it has been reported thatPoly(2,3-dimethylaniline)(P(2,3-DMA)) has good solubility in solvent and remarkablecapability to protect metallic materials against corrosion. So it has a great potential ofcommercial application in the field of metallic protection.Kaolinite is a non swellable1:1-type dioctahedral aluminosilicate, whose one sideof the interlayer space consists of hydroxyl groups of Al2(OH)4octahedral sheets andthe other side is covered by oxygens of the SiO4tetrahedron. It has been reported thatorganically modified layered silicates can effectively improve the thermal and optical,mechanical and anticorrosive properties of polymer. Organic-kaolinite has beenintroduced into the polymeric coatings to effectively increase the length of the diffusionpathways for oxygen and corrosion irons as well as decrease the permeability of coating.Therefore, we attempt to prepare and explore the performance ofP(2,3-DMA)/organic-kaolinite (POK) nanocomposite materials.In this paper, the non-expandable kaolinite was intercalated with2,3-DMA, and theintercalation-exfoliation POK nanocomposite was prepared via in situ intercalativepolymerization. The concentration of APS and H3PO4, the reaction time, the reactiontemperature on the OCP curve, tafel curve and yield of POK nanocomposite werediscussed. The as-prepared materials were characterized by means of XRD, FTIR, SEMand TGA-DTA, and the anticorrosion performance of the coating containing POK oniron samples was estimated by a series of electrochemical measurements in3.5%NaClsolution. Moreover, P(2,3-DMA)/layered silicate (PLS) nancomposite has beensuccessfully synthesized by in situ intercalative emulsion polymerization in thepresence of organic-kaolinite with DBSA and APS as emulsifier and initiator, respectively. The corrosion protection effect of PLS materials in comparison to P(2,3-DMA) wasdemonstrated by a series of electrochemical measurements in3.5%NaCl electrolyte. The effect ofclay content on the PLS corrosion protect properties was investigated.The results showed that the POK nanocomposite has been successfully prepared byeffectively dispersing the organic-kaolinite in P(2,3-DMA) matrix via in situintercalative polymerization. The POK nanocomposite with the best properties when themass ratio of organic-kaolinite to2,3-DMA was5:95, the mole ratio of APS to2,3-DMA is2.5:1, the mole ratio of H3PO4to2,3-DMA is2and the reactiontemperature is30℃. The XRD and FTIR profiles showed that the clay innanocomposites was almost complete exfoliated with the lower clay level, the SEMimages illustrated good dispersion of clay in the P(2,3-DMA) matrix in POKnanocomposites. TGA-DTA curves showed that the incorporation of organic-kaolinitewith polymer resulted in an increase in thermal stability with respect to theP(2,3-DMA).The POK nanocomposite containing coating was found to offer excellentcorrosion resistance than that of P(2,3-DMA). The result indicated that the dispersingsilicate layers of clay in the P(2,3-DMA) matrix increased the tortousity of the diffusionpathway of O2and corrosion ions. P(2,3-DMA)/Kaolinite nanocomposite baseddifferent system can be considered a potential coating material for corrosion protectionof metal.