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Allyl ether (AE)-modified unsaturated polyester oligomers were synthesized from polyethylene glycol (PEG), maleic anhydride (MAH), and trimethylolpropane mono allyl ether (TMPAE), and characterized by Fourier transform infrared (FTIR) spectra. The UV/air dual-curable coatings were prepared from the oligomers using vinyl ether (VE) as a reactive diluent. FTIR spectra showed that CAC bonds in the coating composition had polymerized partially after cured by UV or air. The investigation of rheological behavior of the dual curable composition suggested that all the systems belonged to pseudoplastic fluid, and the increasing allyloxy content in oligomer resulted in a higher viscosity.Differential scanning calorimetry (DSC) analysis showed that the increasing TMPAE-PEG molar ratio resulted in lower T g , and all samples had the same glass transition temperature irrespective of the type of curing. The results of TGA for cured films indicated that UV-cured film had better thermal stability than the air-cured one. The air-cured film showed superior pencil hardness, impact strength, and flexibility to the UVcured counterpart. However, the air-cured film had poor adhesion and electric resistance properties.

ABSTRACT:The photoinduced and peroxide-induced polymerization behavior of dual-curable allyl ether-modified unsaturated polyester (AUPE) and vinyl ether (VE) used as a reactive diluent for dual-curable coating have been studied by infrared spectroscopy (IR). For UV curing systems in N 2 atmosphere, the maleate's conversion and total conversion decrease with the increasing of allyloxy content. However, the rate and of copolymerization and conversion of VE are independent of allyloxy concentration. The copolymerization of allyl ether (AE) and vinyl ether occurs in the presence of maleate (MA) under UV irradiation. For air curing, the rate of copolymerization increases with allyloxy content. The ultimate conversion is the same irrespective of the allyloxy concentration. Because the electron-rich double bond of allyloxy would become an electron-deficient one through oxidation, the conversion of maleate decreases with increasing of the allyloxy content due to the enhancement of copolymerization of AE with VE. The ATR-IR showed that different curing mechanisms occur in AUPE/VE system during air-curing process.

A hyperbranched aliphatic poly(amide ester) ending with hydroxyl groups based on 4-N,N-di(2-hydroxy ethyl)-4-ketobutyric acid (DKBA) and 2-ethyl-2-(hydroxymethyl)-1,3-propanediol (TMP) was modified with acryloyl chloride, resulting in a radiation-curable, hyperbranched acrylated poly(amide ester). This hyperbranched polymer was characterized with respect to ultraviolet cure rate, unsaturation conversion, and mechanical properties.