Interfacial polymerization of an epoxy resin and carboxylic acids for the synthesis of microcapsules

Abstract

BACKGROUND: Microencapsulation technology promises new applications such as intelligent microstructures, phase change materials and self-healing composites. Microcapsule synthesis and characterization have been researched extensively; however, the well-known polymerization between epoxy resins and carboxylic acids has not been used to prepare microcapsules. RESULTS: Microcapsules were prepared by interfacial polymerization of an oil-in-water emulsion which contained a commercial epoxy resin and multifunctional carboxylic acids. The microcapsules obtained were characterized using optical microscopy and scanning electron microscopy. Experiments performed at lower stirring rates led to larger microcapsules, in the range 100-400 µm, while higher stirring rates resulted in microcapsules in the range 10-50 µm.CONCLUSIONS: Microcapsules can be prepared by interfacial polymerization of epoxy resins, an extensively studied and widely used class of polymers. By means of NMR characterization we gained insight into the mechanism of polymerization at the interface wherein products coming from the more hindered ring opening as well as from intermolecular transesterification are identified. The presence of a crosslinker affects the morphology of the external microcapsule surface.

Preparation of robust polyamide microcapsules by interfacial polycondensation ofp-phenylenediamine and sebacoyl chloride and plasticization with oleic acid

“…Interestingly, for PPD:DETA above 2:3 the wall morphology progressively changes from smooth to wrinkled, as also seen in Figure 8. This effect has been previously reported for polyamide capsules (Pascu et al, 2008;Salaün et al, 2009). The increase in cross-linker content makes the surface more uneven as a result of a more difficult diffusion of the monomers through the polymeric wall.…”

Diverting phase transition of high-melting-point stearic acid to room temperature by microencapsulation in boehmite

“…[25][26][27][28][29] And microcapsules offer thin closed structure within a restricted diameter range, and their internal van der Waals surfaces will regulate the phase change behavior of encapsulated PCMs in a precise fashion. The structure of PCMs results from a balance between short-range geometric factors and high pressure inside microcapsules compared to the unconned state.…”

Binder effectiveness of microcapsules applied onto cotton fabrics during laundry

“…In order to improve durability to washing or handle some auxiliary products are required to join microcapsules onto the fibres surface (Nelson, 2001); they are usually based on acrylic, polyurethanes, or silicone resins (Li et al 2008;Rodrigues et al, 2009). Some studies show how polycarboxylic acids can be used in encapsulation process (Pascu, Garcia-Valls, & Giamberini, 2008) or as a binder to join microcapsules (Voncina, Kreft, Kokol, Chen, 2009;Badulescu, Vivod, Jausovec, Voncina, 2008;Ziming, Genquan, Wai-man, Huiyi, 2011) or nanoparticles to fabrics (Montazer, Lessan, Moghadam, 2012;Wanga, Chen, 2005).…”