Zinc phosphate as versatile material for potential biomedical applications Part 1.
Synthetic alpha - and beta -Hopeite, two polymorphs of zinc phosphate tetrahydrates (ZPT) have been synthesized by hydrothermal crystallization from aqueous solution at 20 degrees C and 90 degrees C respectively. Aside from their sub-title crystallographic differences originating from a unique hydrogen bonding pattern, their thermodynamic interrelation has been thoroughfully investigated by means of X-Ray diffraction (XRD) and differential scanning calorimetry (DSC), combined with thermogravimetry (TGA-MS). Using a new heterogeneous step-reaction approach, the kinetics of dehydration of the two forms of ZPT was studied and their corresponding transition temperature determined. Low temperature DRIFT, FT-Raman and (1)H, (31)P MAS-NMR reveal an oriented distortion of the zinc phosphate tetrahedra, due to a characteristic hydrogen bonding pattern and in accordance with the molecular tetrahedral linkage scheme of the phosphate groups. Biogenic Hydroxyapatite (HAP) and one of its metastable precursors, a calcium dihydrogen phosphate dihydrate (DCPD) or Brushite were also obtained and used to underline the resulting variations of chemical reactivity in zinc phosphates.
Herschke
L
L
Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128, Mainz, Germany. lieberw@mpip-mainz.mpg.de
Rottstegge
J
J
Lieberwirth
I
I
Wegner
G
G
D001672:Biocompatible Materials / Q000737:chemistry*; D018786:Bone Substitutes / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D018360:Crystallography, X-Ray; D017886:Durapatite / Q000737:chemistry; D006801:Humans; D006860:Hydrogen Bonding; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010710:Phosphates / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D013816:Thermodynamics; D013818:Thermogravimetry; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction; D017967:Zinc Compounds / Q000737:chemistry*
D001672:Biocompatible Materials; D018786:Bone Substitutes; D002130:Calcium Phosphates; D010710:Phosphates; D017967:Zinc Compounds; D014867:Water; C043952:zinc phosphate; D017886:Durapatite; C494366:calcium phosphate, dibasic, dihydrate