Li-Xia Pei

Preparation of Well-shaped Microcapsule Immobilizing Inorganic Nanoparticles

A facile and efficient method has been developed for microencapsulation of metal oxide nanoparticles in polyurea via interfacial polymerization of toluene-2, 4-diisocyanate and H2O through the atomizing emulsification approach. The resultant microcapsules were well-shaped and uniform sphere with diameter ranging from 2 to 6 μm. Thermogravimetry (TG) and differential scanning calorimetry (DSC) curves revealed that the microcapsules showed good thermal stability (no decomposition observed under 245℃). Besides, the microencapsulated TiO2 has been used as an efficient catalyst for photocatalytic degradation of methyl orange. Furthermore, the photocatalysis of immobilized TiO2 could be enhanced by introducing UV absorbing agent to the wall of microcapsules.

Low Breakage and Size-controlled Preparation of NiCl2 Immobilized Hollow Polyurea Microcapsules

Abstract Polyurea microcapsules containing NiCl 2 were prepared by interfacial polymerization between diisocy-anate and water witii triethylamine as a catalyst in water-in-oil emulsion system. The influence of preparation conditions such as the dosage and feed mode of die catalyst, concentration of the encapsulated NiCl 2 , and concentration and structure of diisocyanates on the breakage of the microcapsules have been evaluated. The results show that breakage is strongly dependent on the rate of polymerization and stability of initial emulsion. The improved microcapsules with low breakage have been produced under the optimum conditions. Furthermore, die obtained microcapsules immobilizing NiCl 2 as a recyclable catalyst is successfully used in benzaldehyde reduction.