Preparation and systematic study of mechanical properties and suspension stability of polyurethane-polyurea double-shell perfume oil microcapsules

The perfume oil microcapsules are of considerable significance in personal care and household products due to their ability to control the targeted release of perfume oil under specific conditions, which enhances the longevity and overall performance of the product. In this study, double-shell perfume oil microcapsules were prepared using polyurea (PUA) and polyurethane (PU) as wall materials. The first PUA shell was formed at room temperature to encapsulate the perfume oil by adjusting the agitation speed, protective colloid concentration, and polymethylene polyphenyl isocyanate (PAPI) content. Subsequently, the second PU shell was formulated. Mechanical property analysis revealed that PU/PUA microcapsules exhibited superior characteristics, showing a threefold increase in mechanical strength compared to PUA microcapsules. Thermogravimetric analysis and dynamic release experiments in ethanol demonstrated that the PU/PUA microcapsules possessed higher thermal stability and greater compactness compared to the PUA microcapsules. Finally, by incorporating bacterial cellulose (BC) microgels and hydroxypropyl methylcellulose (HPMC) as stabilizing agents into the laundry detergent matrix (JJ), a stable suspension of PU/PUA microcapsules was achieved for over 180 days. [Display omitted] •Polyurethane (PU)/polyurea(PUA) double-shell microcapsules prepared successfully.•PU/PUA microcapsules are three times stronger mechanically than single-shell PUA ones.•PU/PUA microcapsules stably suspended in detergent mix for 180 days.