Xixi Yu

Developing environmentally friendly UV-curable polymers with multi-functionality is very significant for sustainable development and environmental protection. In this work, a novel tung-oil-based UV-curable oligomer (TOMAH) was synthesized by Diels–Alder and ring-opening reactions via microwave technology. Subsequently, catalyst-free self-healing UV-curable materials based on a maleate monoester transesterification (MMETER) were developed by co-photopolymerization of TOMAH and hydroxyethyl methacrylate (HEMA). The obtained UV-cured materials possessed a high glass transition temperature (T_g > 81 °C), excellent adhesion (grade 1), and flexibility (2 mm). Particularly, the outstanding photopolymerization activity of the UV-curable resins was proved by UV-curing kinetics. In addition, dynamic transesterifications occurred without an external catalyst at a moderate temperature, resulting in good self-healing properties (with a scratch-repair efficiency of 78.6–93.3%) and shape-memory properties for the obtained UV-cured materials. This work combines the multiple advantages of biomass raw material, microwave synthesis technology, UV-curing method, and multifunctional polymers, thus providing an innovative strategy to fabricate sustainable and intelligent coatings.

Novel UV-curable polyurethane acrylate (PUA) resins were developed from rubber seed oil (RSO). Firstly, hydroxylated rubber seed oil (HRSO) was prepared via an alcoholysis reaction of RSO with glycerol, and then HRSO was reacted with isophorone diisocyanate (IPDI) and hydroxyethyl acrylate (HEA) to produce the RSO-based PUA (RSO-PUA) oligomer. FT-IR and ¹H NMR spectra collectively revealed that the obtained RSO-PUA was successfully synthesized, and the calculated C=C functionality of oligomer was 2.27 per fatty acid. Subsequently, a series of UV-curable resins were prepared and their ultimate properties, as well as UV-curing kinetics, were investigated. Notably, the UV-cured materials with 40% trimethylolpropane triacrylate (TMPTA) displayed a tensile strength of 11.7 MPa, an adhesion of 2 grade, a pencil hardness of 3H, a flexibility of 2 mm, and a glass transition temperature up to 109.4 °C. Finally, the optimal resin was used for digital light processing (DLP) 3D printing. The critical exposure energy of RSO-PUA (15.20 mJ/cm²) was lower than a commercial resin. In general, this work offered a simple method to prepare woody plant oil-based high-performance PUA resins that could be applied in the 3D printing industry.