High performance alkyd resins synthesized from postconsumer PET bottles

The glycolytic recycling of waste PET presents a challenge for the production of secondary value-added products, such as alkyd resins. A way to overcome the unsatisfactory mechanical, drying and chemical resistance properties of alkyds obtained from difunctional glycolyzates was proposed. Waste PET was glycolyzed using multifunctional alcohols: glycerol (G), trimethylolethane (TME), trimethylolpropane (TMP) and pentaerythritol (PE), giving tetra-and hexa-functional glycolyzates and, for comparison, using diethylene glycol (DEG), propylene glycol (PG) and dipropylene glycol (DPG) giving di-functional glycolyzates. The obtained glycolyzates were examined by H-1 and C-13 NMR, FTIR spectroscopy and elemental analysis and further used in the synthesis of alkyd resins. The properties of the prepared alkyd resins (acid, hydroxyl and iodine values, color, average molar masses and molar mass distributions, viscosity, drying time, hardness, flexibility, gloss, adhesion and chemical resistance) were investigated with respect to the functionality and the structure of the used glycolyzates. Alkyd resins derived from multifunctional glycolyzates (TME and TMP) showed considerably enhanced properties compared to those produced from difunctional glycolyzates and also to conventional general purpose resins

Preparation and Properties of Short Oil Alkyd Resin/TiO2 Nanocomposites Based on Surface Modified TiO2 Nanoparticles

Alkyd resin/TiO2 nanocomposites (NC) were prepared from short oil alkyd resin and TiO2 nanoparticles (NPs) surface modified with in situ formed imine ligand, based on 3,4-dihydroxybenzaldehyde and oleylamine, or with three gallic acid esters. The short oil alkyd resin was synthesized from sunflower oil, phthalic anhydride, and trimethylolpropane. Unmodified and surface modified TiO2 NPs were examined by transmission electron microscopy. Rheological investigation revealed that prepared dispersions have higher dynamic viscosity than pure alkyd resin. Using different characterization methods it was obtained that NCs have similar thermooxidative stability as alkyd resin, lower glass transition temperature, better barrier properties, enhanced hardness, better chemical resistance, and lower adhesion to the metal, except in the case of NC prepared using TiO2 NPs surface modified with imine, which exhibited better adhesion to the metal than pure alkyd resin