Preparation and controlled release behavior of halloysite/2-mercaptobenzothiazole nanocomposite with calcined halloysite as nanocontainer

2-Mercaptobenzothiazole was loaded in calcined halloysite to prepare nanocomposite through vacuum loading and polyelectrolyte layers coating. The microstructure and morphology of treated nanotubes and synthetic composite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and automatic gas adsorption analyzer. The total loading and release behavior of 2-mercaptobenzothiazole in tubes with and without polyelectrolyte shell were investigated with the help of UV–Vis spectrophotometer. Results show that calcination keeps the basic tube structure, expands the inner diameter and shortens the tube length. Halloysite treated at 550 °C has the maximum loading of 8.2 wt%. The release time of inhibitor in uncoated halloysite is 3–10 days, which is closely related to the calcination temperature, and the release rules conform to the first order kinetic model. Polyelectrolyte shell makes it controlled and sustained for composite to release 2-mercaptobenzothiazole under the same condition. When the environmental pH changes from neutral to acidic or alkaline to dissociate the polyelectrolyte layers, 2-mercaptobenzothiazole will be released at different rates immediately. It is concluded that 550 °C treated halloysite is a worthy candidate to prepare halloysite/2-mercaptobenzothiazole composite.