Skip to content
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Menu
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Menu
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
chemistry
Rheological behavior of environmentally friendly castor oil-based waterborne polyurethane dispersions
Macromolecules, Volume 46, No. 11, Year 2013
Notification
URL copied to clipboard!
Description
Novel biorenewable, waterborne, castor oil-based polyurethane dispersions (PUDs) were successfully synthesized via homogeneous solution polymerization in methyl ethyl ketone followed by solvent exchange with water. Small-amplitude oscillatory shear flow experiments were used to systematically investigate the rheological behavior of these environmentally friendly, biorenewable, aqueous dispersions as a function of angular frequency, solid content, and temperature. In addition, the morphology of the dispersions was investigated at 60 C for different time intervals using transmission electron microscopy (TEM). The solid content and temperature were found to significantly affect the rheological behavior of the PUDs. The composition dependency of the complex viscosity (η*) was found to be well described by the Krieger-Dougherty equation. Thermally induced gelation was observed for PUDs with a solid content ≥27 wt %. Although the viscoelastic behavior of the PUDs was well described by the time-temperature superposition (TTS) principle in a temperature range lower than the gel point, TTS failed to represent the behavior of the PUDs at temperatures near the critical gel point. The real time gelation behavior was also studied for different solid contents of PUDs under isothermal conditions over a wide range of angular frequencies. Furthermore, both G′ and G″ showed a power law relationship with the angular frequency at the gel point, with critical power law exponents similar to those predicted theoretically by percolation theory. Aggregation and interconnection of the nano-PU particles caused the formation of fractal gels at a critical temperature, as confirmed by TEM. © 2013 American Chemical Society.
Authors & Co-Authors
Madbouly, Samy A.
United States, Ames
Iowa State University
Egypt, Giza
Faculty of Science
Xia, Ying
United States, Ames
Iowa State University
Kessler, Michael R.
United States, Ames
Iowa State University
United States, Washington, D.c.
United States Department of Energy
United States, Pullman
Washington State University Pullman
Statistics
Citations: 128
Authors: 3
Affiliations: 4
Identifiers
Doi:
10.1021/ma400200y
ISSN:
00249297
e-ISSN:
15205835
Research Areas
Environmental