Alkyd resin microcapsules

Scanning Electron Microscopy was performed to analyze surface morphology and shell wall thickness of the capsule. A dried microcapsule was placed on a conductive carbon tape attached to a mounting piece for imaging. Few microcapsules were mptured with a razor blade to confirm the presence of alkyd resin inside the UF shell. 

Thermal analyses of microcapsules were carried out to prove encapsulation of alkyd resin inside UF Shell. The TGA of microcapsule is done and the curve is shown in Figure 3. The first endothermic peak at 229.2°C corresponds to UF decomposition temperature (Siuyanarayanaa et al., 2008) and the endothermic peak at 350°C corresponds to the start of alkyd resin decomposition temperature which ends at 450.5°C. These results establish that microcapsules contain alkyd resin as core and UF resin as the shell. The weight loss of the sample was found to be 4.5 mg (98.11%)... 

The DSC curve of the microcapsule is shown in Figure 4. The endothermic peak at 115.7°C corresponds to melting of UF resin and at 199.4°C corresponds to melting of alkyd resin whereas at 147.4°C it corresponds to evaporation of solvent xylene. Deviations in the base line are said to be glass transition temperature... 

Alkyd resin along with solvent has been successfully encapsulated inside UF shell by In situ encapsulation technique. The SEM analysis shows that microcapsules were comprised of a thin continuous shell wall and a rough exterior shell wall. The FTIR spectra of original and soxhlet extracted resin proves the encapsulation of alkyd resin inside the shell. Moreover DSC and TGA analysis shows that the microcapsules contain both resin-solvent mixture as core and UF as shell material. These microcapsules incorporated in paints or coatings release the healing material when scratched which in turn heals the scratches and cracks. 

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