Chemically formed HAp-Ca poly(vinyl phosphonate) composites

Citation
Ye. Greish et Pw. Brown, Chemically formed HAp-Ca poly(vinyl phosphonate) composites, BIOMATERIAL, 22(8), 2001, pp. 807-816
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary
Journal title
BIOMATERIALS
ISSN journal
0142-9612 → ACNP
Volume
22
Issue
8
Year of publication
2001
Pages
807 - 816
Database
ISI
SICI code
0142-9612(200104)22:8<807:CFHPPC>2.0.ZU;2-F
Abstract
The formation of biocompatible organic-inorganic composites by reactions be tween tetracalcium phosphate (Ca-4(PO4)(2)O, TetCP) and the biomedical poly mer poly(vinyl phosphonic acid) (PVPA) is described. Composites were prepar ed by hot pressing mixtures of these powders at 80 kpsi and 300 degreesC fo r 30 min. Composite formation was investigated depending on the proportions of reactants and the processing route used. Two inorganic phases were prod uced as a result of the acid-base reaction between TetCP and PVPA: hydroxya patite (Ca-10(PO4)(6)(OH)(2), HAp) and anhydrous dicalcium phosphate (CaHPO 4, DCPA). The later phase preferentially formed at lower TetCP/PVPA ratios while the amount of HAp increased with increasing TetCP/PVPA ratio. The rea ctions appear to start with the softening of the polymer when heated to T > T-g. The flowing polymer surrounds the TetCP grains permitting the TetCP t o initially form DCPA crystallites in a matrix of the Ca salt of the polyme r. When H2O is added prior to pressing, the DCPA produced reacts with the r emaining TetCP forming HAp. (C) 2001 Elsevier Science Ltd. All rights reser ved.