Smooth, stable and optically transparent microcapsules prepared by one-step method using sodium carboxymethyl cellulose as protective colloid

摘要

Stable, elastic and optically transparent microcapsules containing tetrachloroethylene (TCE) as internal phase were prepared by in situ polymerization of urea-formaldehyde (UF) using the one-step method. For the first time, sodium carboxymethyl cellulose (NaCMC) was applied into the one-step system as a protective colloid. Microcapsules prepared under different conditions were characterized by scanning electron microscopy, optical microscopy, and thermogravimetric analysis. The results show that NaCMC-based microcapsules can exhibit better thermal and barrier properties than Gum Arabic (GA)-based ones. By formation of capsule wall with more compact microstructures, the NaCMC-based microcapsules can give potential application in encapsulated electrophoretic display systems. The system combining sodium dodecyl sulfate (SDS) and NaCMC together was also investigated. It is suggested that SDS can play an important role during the microencapsulation process, by improving the yield as well as the barrier properties of the products, but also resulting in negative effects at higher ratios of SDS-NaCMC. Other operation conditions such as different molar ratio of reactants (formaldehyde/urea) and addition of ammonium chloride (NH4Cl) were been studied as well.