Investigation of butyl acrylate grafting using model alkyds
In a recent study, four model alkyds (stearic, oleic, linoleic, and linolenic model alkyds) were copolymerised with butyl acrylate (BA) in the presence of AIBN or BPO. 1H and 2D gHMQC NMR, Soxhlet extraction, and gas chromatography were used to characterise model alkyd–BA systems.
BA homopolymer the predominate pathway
It was found that mechanisms of grafting BA onto model alkyds were dependent on the structure of fatty acids in the model alkyds. In stearic model alkyd hybrid systems, BA homopolymer was the predominate pathway with minimal grafting via hydrogen abstraction from polyol backbone followed by termination with propagating BA radicals.
Oleic model alkyd–BA systems improved the degree of grafting by direct addition of the BA free radical to the double bonds. Severe retardation of BA polymerisation was observed in both linoleic and linolenic model alkyd–BA systems due to the presence of double allylic sites. A chain transfer process subsequently dominates the other free radical pathways leading to a high degree of grafting.
The study has been published in Journal of Coatings Technology and Research, Volume 16, Issue 1.