Synthesis and Characterization of High-Performance UV-Curable Resins Derived from Propylene Carbonate

Diols (PCD and IPCD) were synthesized by the reaction of propylene carbonate (PC) with ethylenediamine (EDA) or 2-methyl-1,5-pentanediamine (DAMP), respectively, and the diols were then reacted with isophorone diisocyanate (IPDI), and finally were terminated with hydroxyethyl acrylate (HEA) to obtain ultraviolet (UV)-curable oligomers (HPD and HDPD). The chemical structures of the oligomers were analyzed by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H NMR). The two oligomers were separately mixed with the diluent tetrahydrofuran acrylate (THFA) and the photoinitiator ethyl (2,4,6-trimethylbenzoyl) phenylphosphonate (TPO-L) to form homogeneous mixtures. The UV-curing reaction of the mixtures was carried out under UV light intensity of 120 mW/cm2, and the unsaturation conversion was monitored by real-time infrared spectroscopy (real-time FT-IR). The thermal stability of UV-cured product was analyzed, and the mechanical properties, surface properties, and three-dimensional (3D)-printed samples of the UV-cured HPD and HDPD were compared with those of UV-cured bisphenol A-type epoxy acrylate (EA). The results showed that UV-cured HPD and HDPD had excellent heat resistance. Compared to UV-cured EA, UV-cured HPD and HDPD exhibited higher tensile strength and flexibility and better transparency and surface properties.