Castor oil-glycerol-based waterborne polyurethane dispersions

The incorporation of Gly has a positive effect on the mechanical properties of the WPU films, which experienced a significant improvement on tensile stress even in the presence of a small amount of Gly. As the ratio of Gly gradually increased to 50 %, the Young’s modulus and tensile strength of the films were both gradually increased. • WPU that uses water as the primary solvent, has emerged as an environment-friendly polymeric material compared to solvent-polyurethanes because of its low volatile organic compound (VOC) emission, nontoxic and nonflammable. • The introduction of glycerol-based polyols decreased the thermal conductivity coefficient and enhance the mechanical properties of foams. • when the Gly ratio increased from o to 60 %, all the samples exhibited excellent adhesion on tinplate with an adhesion grade of 5B (the best grade). • Tensile strength, Tg, water contact angle and so on, could be improved via partially substituting the long chain polyols (castor oil) with Gly. In this study, the castor oil-glycerol-based waterborne polyurethane was successfully synthesized. The molar ratio (the ratio between Gly and total polyols) of Gly was up to 50 % and the effects of Gly on the particle size, stability of dispersion, thermal and mechanical properties, surface wettability of the resulting WPU also has been extensively investigated. Notably, the introduction of Gly has extensively improved the tensile strength, T g , toughness, Young’s modulus, and pencil hardness. The tensile strength could reach up to 30 MPa and Young’s modulus to 333 MPa with elongation at break over 26 %, T g to 82 °C, pencil hardness to 6H. However, the surface wettability and v e of the resulting materials increases firstly and then decreases, and exhibit maximum water contact angle of 86.8° for 30 % Gly and maximum v e of 389 mol/m 3 for 40 % Gly. This work demonstrates that the introduction of Gly not only can increase the bio-content but also effectively improve the performances of WPU, and this work provides an interesting idea for the preparation of high-performance bio-based WPU.