Improving self-healing performance of polyurethane coatings
In a recently published study, polyurethane-based microcapsules filled with bulky isophorone diisocyanate, IPDI, were prepared via interfacial polymerisation method in an oil-in-water emulsion.
For this purpose, at first, 2,4-toluene diisocyanate, TDI, based pre-polymer was synthesised and used for the preparation of microcapsules shell compound. n-Butyl acetate solvent was used in the synthesis of both pre-polymer and microcapsules as a low toxic solvent.
Investigation of mechanical and crack-healing properties
Various techniques and methods were used to characterised pre-polymer and microcapsules. Mechanical properties of microcapsule-embedded polyurethane, PU, coating was studied using tensile strength measurement under three different conditions (intact, scratched and healed). The standard salt spray test method was used to analyse the healing ability of microcapsules within the PU coatings. The crack healing properties of the PU coatings was defined using SEM micrographs.
Increasing healing efficiency
The results showed increasing healing efficiency by increasing microcapsule content. The best healing and corrosion performance was achieved for the coating with 1 wt % nanoclay and 5 or 10 wt % microcapsules as a result of barrier properties of intercalated and/or exfoliated clay platelets within the coating formulation.
The study is published in: Progress in Organic Coatings Volume 123, October 2018, Pages 350-361.
Event tips:
If you want to get to know the basics of polyurethane coatings visiting the European Coatings Seminar on Polyurethane Coatings is worth visiting (starts in only a few days).
To learn more about self-healing and other functionalities you may consider attending the European Coatings Seminar on Functional Coatings in November in Amsterdam.
