Alkyd Resin
Definition
A polyester binder modified with fatty-acid chains from drying oils; cures by oxidative crosslinking and is characterised by FTIR ester carbonyl absorption at 1735-1745 cm-1.
- Composition
- Polyester binder with fatty-acid drying-oil chains
- Cure mechanism
- Oxidative crosslinking
- FTIR signature
- Ester carbonyl absorption at 1735 to 1745 cm-1
- Material role
- Paint binder
Common questions
What does 'oxidative crosslinking' mean for how an alkyd paint dries?+
Rather than drying purely by solvent evaporation, the fatty-acid chains react with atmospheric oxygen over time to form a crosslinked polymer network, which is why alkyd paints continue to harden and cure for days or weeks after they feel dry to the touch.
How does the FTIR carbonyl peak help distinguish alkyd from other binder types?+
The specific wavenumber range of the ester carbonyl stretch is characteristic of the alkyd's polyester backbone, letting an examiner differentiate it from acrylic or vinyl binders that produce carbonyl or other functional group absorptions at different, though sometimes overlapping, positions in the spectrum.
Related terms
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- PDQ
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- SWGMAT
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