Preparation and Characterization of Castor Oil-Based Cationic Waterborne Polyurethane

Abstract

A variety of castor oil-based cationic polyurethane dispersions (PUDs) were synthesized. The effects of hard segment content on the properties of PUDs and the resulting polyurethane films were investigated by mastersizer, Fourier transform infrared (IR), thermal gravimetric analysis (TGA) and stress-strain test. As the hard segment content increased from 37.1 to 45.6 wt %, the particle size of the PUDs increased from 10 to 190 nm. IR analysis showed that hydrogen bonding between hard segments enhanced with the increase of hard segment content. For this enhancement the films had an increased tensile strength from 2.0 to 9.4 MPa and an improved glass transition temperature (Tg) from 48oC to 75oC. TGA showed the films were thermally stable up to 200oC and had biphasic degradation at around 330oC and 440oC. The versatile castor oil-based cationic waterborne polyurethanes are promising in applications as adhesives and coatings.

Enhanced Mechanical Properties and Functional Performances of Cationic Waterborne Polyurethanes Enabled by Different Natural Phenolic Acids

“…The results are presented in Figure 4 and Table 2. The tensile strengths of CWPUs with phenolic acid neutralizers (9.8−16.7 MPa) were higher than those of HCLPU (7.8 MPa), AAPU (3.3 MPa), and polyurethanes with similar structures neutralized by common neutralizers reported in other literature works (1.0−2.0 MPa), 8,30 while there was almost no reduction in the elongation at break. Meanwhile, the toughness and Young's modulus of these phenolic acidneutralized samples also displayed similar enhancement.…”