Tung based reactive diluents for alkyd systems: Film properties

Reactive diluents were prepared from tung oil via a Diels–Alder reaction with three different dienophiles: methacryloxypropyl trimethoxysilane (TOMAS), 2,2,2-trifluoroethyl methacrylate (TOF) and triallyl ether acrylate (TOTAE). The reactive diluents were mixed with a long oil soya alkyd, a metal drier package, and a wetting agent; and then cured. Formulations were prepared as a function of reactive diluent type and wt%. Tensile, thermomechanical, and coatings properties were evaluated after curing the films. The addition of two reactive diluents, TOMAS and TOTAE, improved the tensile strength and tensile modulus of the alkyd. The addition of the diluents, however, did not significantly change the elongation at break compared to the alkyd in any of the systems. Also, the addition of TOMAS and TOTAE increased both the crosslink density and glass transition temperature of the alkyd. Basic film properties including hardness, solvent resistance, impact resistance, adhesion, and gloss were not adversely affected by the introduction of any of the tung oil based diluents.

► New reactive diluents were prepared from tung oil.
► Formulations were prepared as a function of reactive diluent and an alkyd.
► Both viscosity and coatings properties were improved.