Synthesis of soybean oil based, photocurable, green coating materials and their applications in wood industry

Abstract

Surface coatings are very important for many industries, especially in furniture coating areas. It protects the wood from external factors, enhances the durability, and provides better appearance. Due to its usage area as end product, flame resistance is economically and vitally important for wooden products. In order to provide the properties, suitable surface coatings are used. Modern developments and research in coating technologies are on green technology and environmentally friendly coatings. That is why the UV curing technology is well-used method for coating materials. It does not contain solvents. Therefore, it eliminates the deformation of surfaces, and swelling problems. Curing processes need less time because of the technology, less energy, and low costs. Moreover, it does not waste the water, which is very important when the environmental effects are considered. In this thesis, it was aimed that the UV-curable oligomers for wood coatings by using epoxidized soybean oil (ESBO) and itaconic acid (IA) are produced. Since ESBO is bio-based oil which is environmentally friendly, it is widely used in the market. By using ring openning reactions, 2 different oligomers (ESBO-IA and ESBO-IA-UA) were synthesized in the research. The oligomers were blended with different types of reactive diluents in different ratios in order to prepare coating formulations. The prepared formulations were applied to MDF wood surfaces after the photo-initiator was added to the formulations. By using UV light, the coatings were cured and different tests were applied to the wood surfaces in order to identify the qualities and performances of the formulations. Then, ESBO-IA and ESBO-IA-UA oligomers were characterized by fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopies. After, UV-cured free films of the formulations were characterized as mechanical, physicochemical and thermal properties. For mechanical properties; cross cut, water immersion, and taber abbrasion tests were applied. For physicochemical properties, degree of swelling (DS), chemical resistance and gel fraction (GF) tests were used. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis were applied to the UV-cured films in order to evaluate the thermal properties.