Preparation of Microcapsules Containing Benzoyl Peroxide Initiator with Gelatin-Gum Arabic/Polyurea-Formaldehyde Shell and Evaluating Their Storage Stability

This work involves the optimized preparation and characterization of microcapsules which contain benzoyl peroxide (BPO) dispersed in dibutyl phthalate (DBP) with gelatin-gum arabic (Gel-GA)/polyurea-formaldehyde (PUF) shell. The microcapsules were prepared in two steps using complex coacervation and in situ polymerization techniques, respectively, at various mixing speeds and different core:shell ratios. The scanning electron microscopy (SEM), optical microscopy, and Fourier transform infrared (FTIR) spectroscopy were used for characterization of prepared microcapsules. The resultant microcapsules were spherical with average diameters about 120-200 μm, had no intercapsule bonding, and had thicknesses of 0.7-1.5 μm. The results revealed high core content loading, 82-89 wt % for microcapsules prepared at various mixing speeds. The differential scanning calorimetry analysis (DSC) indicated that the encapsulated BPO was not influenced by the encapsulation process and maintained its activity. Moreover, with a compact and double Gel-GA/PUF shell, the microcapsules were stable, and no leakage of core material in an acrylate-based resin and toluene as an organic solvent was recorded. The resultant microcapsules have the potential of usage in industries such as self-healing systems and structural adhesives where the impermeability of microcapsules is an important factor.