The castor oil based water borne polyurethane dispersion; effect of -NCO/OH content: synthesis, characterization and properties

• Main Authors: Panda Siva Sankar, Panda Bishnu Prasad, Mohanty Smita, Nayak Sanjay K.
• Format: Article
• Language: English
• Published: De Gruyter 2017-05-01
• Series: Green Processing and Synthesis
• Subjects: bio-based polyurethane dispersion; coating properties; ft-ir; polyurethane prepolymer; sem
• Online Access: https://doi.org/10.1515/gps-2016-0144
• ISSN: 2191-9542; 2191-9550

In this work, a novel bio-renewable castor oil (CO) based aqueous polyurethane (PU) anionic prepolymer dispersion was prepared successfully using isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as internal emulsifier maintaining NCO/OH molar ratios of 1:3 and 1:5, respectively. The intermolecular H-bonding change, type and intensity of the obtained films with change in molar ratio were investigated by analyzing with Fourier transform-infrared (FT-IR). The morphology of the films was recorded with scanning electron microscopy (SEM) and transmittance electron microscopy (TEM). The coating properties for the film were also studied and discussed. The structure-property relationship with different molar ratios of prepolymer revealed an increasing pattern showing increase in the hard segment content increases the physico-mechanical properties of the CO based PU prepolymer. The FT-IR deconvolution results are in agreement with the film properties. The excellent abrasion resistance properties of CO based films agree well with the surface morphology and FT-IR results. The outcome of the study also suggests use of CO as a better alternative to replace petroleum based polyol for feature perspective.