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標題: The preparation of hollow silica spheres with mesoporousshell via polystyrene emulsion latex templateand the investigation of ascorbic acid release behavior
關鍵字: Emulsifier-free polymerization;PS/silica coreshell;Silica;Hollow glass sphere;Release kinetics;Polystyrene (PS);Ascorbic acid
Project: J Polym Res, Volume 20, Issue 8.
In this study, the emulsifier-free polymerizationwas employed to prepare polystyrene (PS) latex particles.When the styrene conversion of 80 % was reached, appropriateamounts of methacryl oxypropyl trimethoxy silane(MPS) and divinylbenzene (DVB) were added to the emulsionsolution. Emulsion particle surfaces bear silanol functionalgroups that facilitate the rapid reaction with silicaprecursor solution, which is formed through the hydrolysisof tetraethyl orthosilicate (TEOS) and silanol groups of MPSon the emulsion surface. Consequently, a core-shell structurewith PS core and silica shell structure was developed. Usingextraction and calcination to remove the central polystyrenecore, a hollow glass sphere with porous shell structure wasobtained. Finally, ascorbic acid was placed and encapsulatedin these hollow glass spheres, as inspected by SEM andcarbon element mapping images, to examine their controlledrelease behavior. The cumulative release percentage wasanalyzed using the Higuchi model, a zero-order model, anda first-order model for kinetic study of release behavior.Results show that the zero order and first order modelsdescribe the release kinetics of ascorbic acid equally wellfor hollow glass spheres.
DOI: 10.1007/s10965-013-0220-7
Appears in Collections:化學工程學系所

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