In the present study, UV-curable urethane acrylate was synthesized by the reaction of isophorone diisocyanate with1,4-butanediol and 2-hydroxyethyl methacrylate in the presence of dibutyltin dilaurate as a catalyst and acetone as a solvent. The structure of urethane acrylate oligomer was characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. In order to examine the influence of inorganic phase of zirconium oxide nanoparticles on characteristics of synthesized resin, organic–inorganic nanocomposites were prepared by urethane acrylate resin and nano zirconium oxide with 1, 3, and 5 wt%. In order to improve nanoparticles dispersion, the surface of zirconium oxide nanoparticles was modified by vinyltrimethoxysilane coupling agent. The analysis of nanoparticle surface modification by Fourier transform infrared spectroscopy and scanning electron microscopy suggested a good reaction of vinyltrimethoxysilane with the surface of zirconium oxide nanoparticles. The characteristics of the prepared nanocomposites were evaluated through thermogravimetric analysis and dynamic mechanical thermal analysis. All of conducted tests represented improved thermal stability properties, storage modulus, and viscoelastic properties of urethane acrylate–zirconium oxide nanocomposites in comparison with polymeric coatings without nanoparticles.

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This research focuses on synthesis and study of the properties of castor oil-based epoxy/carbon quantum dots (COEp/CQDs) nanocomposite coatings possessing resistance against UV. First, CQDs were synthesized by pyrolysis of starch using microwave-assisted method and characterized via various spectroscopic and microscopic methods. Next, certain quantity of castor oil as a renewable resource, CQDs with different weight percentages and a curing agent were added to epoxy resin and consequently COEp/CQDs were prepared. Through findings of FTIR, photoluminescence and UV-visible spectroscopy analyses, existent functional groups and fluorescent feature of the nanocomposite coatings were confirmed. UV-vis spectroscopy approved UV resistance of the COEp/CQDs coatings. As concentration of CQDs increased in resin matrix, UV absorption was maximized. The morphology and uniform dispersion of CQDs in the coatings matrix were verified by FESEM analysis. Results of TGA, pull-off adhesion strength and tensile tests, and DMTA analysis proved adding CQDs to the resin matrix led to progress of thermal endurance, adhesion strength, mechanical and viscoelastic properties of the synthesized coatings including an increase in storage modulus and Tg.

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Attention to environmental problems and the importance of maintaining it have caused the researchers to pay more attention in this regard. The production of polymers and resins has increased in recent years and has affected by environmental pollution due to their long-term degradation. An appropriate solution to this problem is the synthesis of degradable and environmentally friendly polymers and resins. Using natural materials in the synthesis of polymers and resins can help them to be environmentally friendly. The purpose of this research is to synthesize urethane acrylate resins using natural resources. For this purpose, the urethane acrylate pre-polymer was synthesized with castor oil. Then, using modified zinc oxide nanoparticles with 1, 3 and 5 wt% urethane acrylate zinc oxide nanocomposites were produced. The use of castor oil as a degradable part and lack of organic solvent in radiation systems led to the creation of an environmentally friendly resin. Subsequently, the viscoelastic behavior of the prepared nanocomposite was evaluated. Spectrometry results confirm the synthesized resin structure. The morphology of nanocomposites confirmed the proper particle size distribution in a 3 wt.% sample. The results of the dynamic mechanical thermal analysis test showed that increasing the amount of modified nano ZnO could increase the glass transition temperature, and the maximum value was observed in 5 wt.% modified nano ZnO (69.7℃).