Abstract
Summary Turbidity and rheological features during gelation of semidilute solutions of pectin via the Ugi multicomponent condensation reaction have been investigated at different polymer and cross-linker concentrations at ambient temperature. The gelation time of the system decreased with increasing polymer and cross-linker concentrations. At the gel point, a power law frequency dependence of the dynamic storage modulus (G'∼ω n' ) and loss modulus (G''∼ω n'' ) was observed with n'=n''=n. The value of the power law exponent is about 0.6~ 0.7 for all the gelling systems, which is close to that predicted (0.7) from the percolation model. The elastic properties of the gels continue to grow over a long time in the post-gel region, and a solidlike response is observed at later stages during the gelation process. The turbidity of the gelling system is higher as the polymer and cross-linker concentrations rise, but the turbidity is virtually unaffected during an extended time after the formation of the incipient gel. It was demonstrated that polymer and cross-linker concentrations could be utilized to tune the physical properties, such as transparency and viscoelasticity, of the Ugi hydrogels.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.