High biocontent natural plant oil based UV-curable branched oligomers

A new, green approach to improve the performance and biorenewable content of natural plant oil based UV-curable materials is presented. A novel kind of soy-based UV-curable branched oligomer (ACSO) was synthesized by chemically introducing cashew nutshell liquid (CNL) onto the epoxidized soybean oil (ESBO) backbone, followed by epoxidization and acrylation. The synthesized ACSO were used to produce UV-curable films and coatings. The UV-curing behavior of ACSO was investigated using real-time IR. The properties of UV cured films were studied using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile testing, and nanoindentation technique. Compared to coating from acrylated epoxidized soybean oil (AESO), ACSO based coating exhibited higher impact resistance, better crosshatch adhesion, and enhanced thermal and mechanical properties. Meanwhile, high biorenewable content was maintained due to the biorenewable character of CNL in ACSO. The improved coating properties can be attributed to the incorporated aromatic ring from CNL and multi-branched structure of ACSO. This approach provided a new direction to the future development of advanced bio-based UV-curable oligomers with reasonably high biorenewable content.