title: Preparation of thermoresponsive Fe3O4/P(acrylic acid-methyl methacrylate-N-isopropylacrylamide) magnetic composite microspheres with controlled shell thickness and its releasing property for phenolphthalein.
abstract: In this work, Fe3O4/P(acrylic acid-methyl methacrylate-N-isopropylacrylamide) (Fe3O4/P(AA-MMA-NIPAm)) thermoresponsive magnetic composite microspheres have been prepared by controlled radical polymerization in the presence of 1,1-diphenylethene (DPE). The shell thickness of thermosensitive polymer (PNIPAm), which was on the surface of the microspheres, can be controlled by using DPE method. The morphology and thermosensitive properties of the composite microspheres, polymerization mechanism of the shell were characterized by TEM, FTIR, VSM, Laser Particle Sizer, TGA, NMR, and GPC. The microspheres with narrow particle size distribution show high saturation magnetization and superparamagnetism. The thermosensitive properties of the composite microspheres can be adjusted indirectly via controlling the addition amount of monomer (NIPAm) in the second step during controlled radical polymerization. Phenolphthalein was chosen as a model drug to investigate drug release behavior of the thermoresponsive magnetic composite microspheres with different shell thickness. Controlled drug release testing reveals that the release behavior depends on the thickness of polymer on the surface of the microspheres.
authors.affiliation: Department of Applied Chemistry, School of Science, Northwestern Polytechnical University, Xi'an 710072, China.
authors.forename: Baoliang
authors.initials: B
authors.lastname: Zhang
authors.forename: Hepeng
authors.initials: H
authors.lastname: Zhang
authors.forename: Xinlong
authors.initials: X
authors.lastname: Fan
authors.forename: Xiangjie
authors.initials: X
authors.lastname: Li
authors.forename: Dezhong
authors.initials: D
authors.lastname: Yin
authors.forename: Qiuyu
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000179:Acrylates / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D020366:Methylmethacrylate; D008863:Microspheres; D020113:Phenolphthalein / Q000737:chemistry*
chemical_list: D000178:Acrylamides; D000179:Acrylates; D003692:Delayed-Action Preparations; D005290:Ferric Compounds; D020366:Methylmethacrylate; C000499:ferric oxide; D020113:Phenolphthalein; C067295:N-isopropylacrylamide; C036658:acrylic acid