title: Phase development and structural characterization of calcium phosphate ceramics-polyacrylic acid nanocomposites at room temperature in water-methanol mixtures.
abstract: Calcium phosphate ceramics (CPCs) were prepared via an in-situ formation in the presence of polyacrylic acid (PAA) polymer under water-methanol (WM) mixture at room temperature. The PAA polymer was employed as both structure-directing agent and crystallization retardant to manipulate the development of resulting CPCs nano-crystallites which are observed to show a core-shell configuration with a thin layer of PAA molecules. A resulting phase evolution map with respect to the developing phases of calcium-deficient hydroxyapatite (CDHA), beta-tricalcium phosphate (beta-TCP), and an intermediate amorphous calcium phoshate (ACP) that were structurally and spectroscopically identified, was constructed in terms of fractions of water-to-methanol proportions and concentration of PAA. It is found that for the solutions in both water-rich and methanol-rich regions, pure CDHA and beta-TCP instead of intermediate ACP phase can be developed irrespective of the concentration of PAA, respectively. For conditions in between, i.e., with methanol fractions of 15%-90%, ACP appeared only when the PAA fell in a limited concentration range.
authors.affiliation: Department of Materials Science and Engineering, National Chiao Tung University, 1001 Ta-hsueh Rd, Hsinchu, Taiwan, 300, Republic of China.
authors.forename: Sz-Chian
authors.initials: SC
authors.lastname: Liou
authors.forename: San-Yuan
authors.initials: SY
authors.lastname: Chen
authors.forename: Dean-Mo
authors.initials: DM
authors.lastname: Liu
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D002130:Calcium Phosphates; D014867:Water; C006903:carbopol 940; C020243:calcium phosphate; D000432:Methanol