Grafting of oligosaccharides onto synthetic polymer colloids.
A new method to form colloidally stable oligosaccharide-grafted synthetic polymer particles has been developed. The oligosaccharides, of weight-average degree of polymerization approximately 38, were obtained by enzymatic debranching of amylopectin. Through the use of a cerium(IV)-based redox initiation process, oligosaccharide chains are grafted onto a synthetic polymer colloid comprising electrostatically stabilized poly(methyl methacrylate) or polystyrene latex particles swollen with methyl methacrylate monomer. Ce(IV) creates a radical species on these oligosaccharides, which then propagates, initially with aqueous-phase monomer, then with the methyl methacrylate monomer inside the particles. Ultracentrifugation, NMR, and total starch analyses together prove that the grafting process has occurred, with at least 7.7 wt % starch grafted and a grafting efficiency of 33%. The surfactant used in latex preparation was removed by dialysis, resulting in particles colloidally stabilized with only linear starch as a steric stabilizer. The debranched starch that comprises these oligosaccharides is found to be a remarkably effective colloidal stabilizer, albeit at low electrolyte concentration, stabilizing particles with very sparse surface coverage.
Mange
Siyabonga
S
Key Centre for Polymer Colloids, School of Chemistry F11, The University of Sydney, New South Wales 2006, Australia.
Dever
Cédric
C
De Bruyn
Hank
H
Gaborieau
Marianne
M
Castignolles
Patrice
P
Gilbert
Robert G
RG
D002563:Cerium / Q000737:chemistry; D002621:Chemistry / Q000379:methods*; D003102:Colloids / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008689:Methacrylates / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D015233:Models, Statistical; D009844:Oligosaccharides / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry; D055672:Static Electricity
D003102:Colloids; D008689:Methacrylates; D009844:Oligosaccharides; D011108:Polymers; D002563:Cerium; D019904:Polymethyl Methacrylate