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Chemically formed HAp-Ca poly(vinyl phosphonate) composites.
1Intercollege Materials Research Laboratory, Pennsylvania State University, Sciences and Engineering, University Park 16802, USA.
Biomaterials
|March 15, 2001
Summary
Biocompatible composites form from tetracalcium phosphate (TetCP) and poly(vinyl phosphonic acid) (PVPA). Reaction conditions control the formation of hydroxyapatite (HAp) and dicalcium phosphate (DCPA) for tailored biomaterials.
Area of Science:
- Materials Science
- Biomaterials Engineering
- Inorganic Chemistry
Background:
- Developing novel biocompatible organic-inorganic composites is crucial for advanced biomedical applications.
- Tetracalcium phosphate (Ca4(PO4)2O, TetCP) is a promising calcium phosphate biomaterial.
- Poly(vinyl phosphonic acid) (PVPA) offers functional groups for interaction with inorganic phases.
Purpose of the Study:
- To investigate the formation of organic-inorganic composites via reactions between TetCP and PVPA.
- To characterize the resulting inorganic phases and their dependence on reactant ratios and processing.
- To explore the potential of these composites as biomaterials.
Main Methods:
- Hot pressing of TetCP and PVPA powder mixtures at 300°C and 80 kpsi.
- Varying the TetCP/PVPA ratios to study their effect on composite formation.
- Investigating the influence of water addition on the reaction pathways.
Main Results:
- Composite formation involves an acid-base reaction between TetCP and PVPA.
- Two inorganic phases, hydroxyapatite (Ca10(PO4)6(OH)2, HAp) and anhydrous dicalcium phosphate (CaHPO4, DCPA), were produced.
- Lower TetCP/PVPA ratios favored DCPA formation, while higher ratios increased HAp content.
- Addition of water prior to pressing promoted HAp formation through reaction of DCPA with residual TetCP.
Conclusions:
- The reaction pathway and resulting phases (HAp and DCPA) can be controlled by adjusting the TetCP/PVPA ratio and processing conditions.
- Hot pressing provides a viable method for creating these organic-inorganic composites.
- The ability to tune the HAp/DCPA ratio suggests potential for tailored biomaterial properties.