Effect of aluminum, iron, and magnesium upon the solubility of .alpha.-calcium sulfate hemihydrate in 40%, 45%, 50%, and 55% P2O5 phosphoric acid solutions at 80, 90, 100, and 110.degree.C: correlations with water concentration

1991 ◽  
Vol 36 (1) ◽  
pp. 77-80 ◽  
Author(s):  
Jack M. Sullivan ◽  
John J. Kohler ◽  
John H. Grinstead
Keyword(s):  
Phosphoric Acid ◽  
Calcium Sulfate ◽  
Water Concentration ◽  
Acid Solutions ◽  
Aluminum Iron ◽  
Calcium Sulfate Hemihydrate

Recrystallization of calcium sulfate in phosphoric acid solutions; batchwise operation

1990 ◽  
Vol 99 (1-4) ◽  
pp. 1117-1123 ◽  
Author(s):  
G.J. Witkamp ◽  
M.M. Seckler ◽  
O.S.L. Bruinsma ◽  
G.M. van Rosmalen
Keyword(s):  
Phosphoric Acid ◽  
Calcium Sulfate ◽  
Acid Solutions

Cadmium Incorporation in the Crystallization of Calcium Sulfate Hemihydrate from Phosphoric Acid

1986 ◽  
Vol 21 (10) ◽  
pp. 1287-1297 ◽  
Author(s):  
T. T. Tjioe ◽  
H. Der Van Woude ◽  
J. Verbiest ◽  
P. F. M. Durville ◽  
G. M. van Rosmalen
Keyword(s):  
Phosphoric Acid ◽  
Calcium Sulfate ◽  
Calcium Sulfate Hemihydrate

Effects of sterilization modes on the mechanical strengths of plaster of paris implants

1989 ◽  
Vol 47 ◽  
pp. 890-891
Author(s):  
K. Cowden ◽  
B. Giammara ◽  
T. Devine ◽  
J. Hanker
Keyword(s):  
Gamma Radiation ◽  
Calcium Sulfate ◽  
Significant Loss ◽  
Potassium Sulfate ◽  
Limiting Factors ◽  
Radiation Sterilization ◽  
Plaster Of Paris ◽  
Hardness Tester ◽  
Dry Heat ◽  
Calcium Sulfate Hemihydrate

Plaster of Paris (calcium sulfate hemihydrate, CaSO4. ½ H2O) has been used as a biomedical implant material since 1892. One of the primary limiting factors of these implants is their mechanical properties. These materials have low compressive and tensile strengths when compared to normal bone. These are important limiting factors where large biomechanical forces exist. Previous work has suggested that sterilization techniques could affect the implant’s strength. A study of plaster of Paris implant mechanical and physical properties to find optimum sterilization techniques therefore, could lead to a significant increase in their application and promise for future use as hard tissue prosthetic materials.USG Medical Grade Calcium Sulfate Hemihydrate Types A, A-1 and B, were sterilized by dry heat and by gamma radiation. Types A and B were additionally sterilized with and without the setting agent potassium sulfate (K2SO4). The plaster mixtures were then moistened with a minimum amount of water and formed into disks (.339 in. diameter x .053 in. deep) in polyethylene molds with a microspatula. After drying, the disks were fractured with a Stokes Hardness Tester. The compressive strengths of the disks were obtained directly from the hardness tester. Values for the maximum tensile strengths σo were then calculated: where (P = applied compression, D = disk diameter, and t = disk thickness). Plaster disks (types A and B) that contained no setting agent showed a significant loss in strength with either dry heat or gamma radiation sterilization. Those that contained potassium sulfate (K2SO4) did not show a significant loss in strength with either sterilization technique. In all comparisons (with and without K2SO4 and with either dry heat or gamma radiation sterilization) the type B plaster had higher compressive and tensile strengths than that of the type A plaster. The type A-1 plaster however, which is specially modified for accelerated setting, was comparable to that of type B with K2SO4 in both compressive and tensile strength (Table 1).

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