Improved performance of microcapsules with polymer nanocomposite wall: Preparation and characterization

Polyurea/clay nanocomposite microcapsules containing dimethyl phthalate (DMP) as a model compound were prepared by interfacial polymerization technique. Nanoclays namely, montmorillonite Na+ (MMT) and Laponite were incorporated into microcapsule wall and their effects on morphology, thermal properties and release of DMP from microcapsules were investigated. All microcapsules were characterized using scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. The present preparation process results in formation of polyurea/clay nanocomposite microcapsule wall with intercalated clay layered as evidenced by XRD and TEM. Nanocomposite microcapsules have shown significant reduction in release of DMP and change in release mechanism as compared to the pristine microcapsules. Nanocomposite microcapsules show good improvement in the fracture strength as compared to pristine microcapsules. The approach used herein is simple and can be adopted to many other polymeric microcapsule systems prepared by different microencapsulation techniques, requiring reduction in release rate and/or mechanism for several applications like pharmaceuticals, agrochemicals, industrially important chemicals, consumer products, etc.