Graft modification of starch nanoparticles with pH-responsive polymers via nitroxide-mediated polymerization |
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Authors: | Jaime C Cazotti Alexander T Fritz Omar Garcia-Valdez Niels M B Smeets Marc A Dubé Michael F Cunningham |
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Institution: | 1. Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada;2. Department of Research and Development, EcoSynthetix Inc., Burlington, Ontario, Canada;3. Department of Chemical and Biological Engineering, Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, Canada |
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Abstract: | The grafting to approach and nitroxide-mediated polymerization (NMP) were used to graft modify starch nanoparticles (SNP) with pH-responsive polymers. SG1-capped poly(2-(dimethylamino)ethyl methacrylate-co-styrene), P(DMAEMA-co-S), and poly(2-(diethylamino)ethyl methacrylate-co-styrene), P(DEAEMA-co-S), with relatively low dispersity and high degree of livingness was synthesized in bulk via NMP using a commercial available alkoxyamine. These macroalkoxyamines were then grafted to vinyl benzyl-functionalized SNP (SNP-VBC) to obtain pH-responsive materials. The grafted SNP were characterized by proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and elemental analysis confirming the successful synthesis of these new materials. Low grafting efficiencies (~6%) were observed for both SNP-grafted materials with pH-responsive polymers, as expected when using the grafting to approach. The pH-responsiveness of SNP-g-P(DMAEMA-co-S) and SNP-g-P(DEAEMA-co-S) was confirmed by measuring the ζ-potential at different pH values. At acidic conditions (pH 3–6) the grafted materials were protonated and exhibited positive ζ-potential, whereas at basic conditions (pH 10–13) the same grafted materials were deprotonated and exhibited negative ζ-potential. |
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Keywords: | grafting to nitroxide-mediated polymerization pH-responsive polymers starch nanoparticles zeta potential |
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