Selective Crystal Growth Regulation by Chiral α-Hydroxycarboxylic Acids Improves the Strength and Toughness of Calcium Sulfate Cements

2020 ◽  
Vol 3 (12) ◽  
pp. 8559-8566
Author(s):  
Hanan Moussa ◽  
Wenge Jiang ◽  
Amir El Hadad ◽  
Ammar A. Alsheghri ◽  
Tayebeh Basiri ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Calcium Sulfate ◽  
Growth Regulation ◽  
Hydroxycarboxylic Acids ◽  
Strength And Toughness

Research on Crystallization Kinetics of Calcium Sulfate Dihydrate Prepared by Bittern under 20°C and 120r/min Condition

2014 ◽  
Vol 926-930 ◽  
pp. 210-213
Author(s):  
Bi Jun Luo ◽  
Hai Hong Wu ◽  
Yu Qi Wang ◽  
Qi Zhang
Keyword(s):  
Experimental Data ◽  
Crystal Growth ◽  
Crystallization Kinetics ◽  
Residence Time ◽  
Calcium Sulfate ◽  
Nucleation Density ◽  
Growth Line ◽  
Calcium Sulfate Dihydrate ◽  
Kinetics Of

Crystallization kinetics experiment of calcium sulfate dehydrates, which is prepared by bittern under 20°C and 120r/min conditions, is carried out. According to the results of the experimental data, nucleation densityn0of gypsum crystals is proportional to the residence time, and the rate of crystal growth lineGis inversely proportional to the residence time. Meanwhile, the crystallization kinetics formula is derived to be:B0= 5.78×102G0.87.

Effect of Stabilizer on Morphology and Stability of Hemihydrate Calcium Sulfate Whiskers

2011 ◽  
Vol 374-377 ◽  
pp. 1495-1498 ◽  
Author(s):  
Hong Ye Liu ◽  
Yu Bin Wang
Keyword(s):  
Phase Composition ◽  
Crystal Growth ◽  
Sodium Oleate ◽  
Calcium Sulfate ◽  
Surface Group ◽  
Crystal Shape ◽  
Effect Mechanism ◽  
The Stability ◽  
Calcium Sulfate Whiskers

The influence of stabilizer on the crystal shape and stability of hemihydrate calcium sulfate whiskers was investigated in detail. Morphology, surface group and phase composition of stabilized hemihydrate calcium sulfate whiskers were characterized by means of SEM, FTIR and XRD, and then effect mechanism was discussed. The results showed that the absorption state of sodium oleate will be different with respectively additive amount which cause whiskers shape and stability to change, and that the stability of hemihydrate calcium sulfate whiskers can be achieved without affecting crystal growth by adding agents in different steps.

Kinetics of crystal growth of calcium sulfate dihydrate. The influence of polymer composition, molecular weight, and solution pH

1988 ◽  
Vol 66 (6) ◽  
pp. 1529-1536 ◽  
Author(s):  
Zahid Amjad
Keyword(s):  
Molecular Weight ◽  
Crystal Growth ◽  
Induction Period ◽  
Functional Groups ◽  
Polyacrylic Acid ◽  
Calcium Sulfate ◽  
Polymer Composition ◽  
Supersaturated Solution ◽  
Solution Ph ◽  
Calcium Sulfate Dihydrate

A seeded crystal growth technique has been used to study the influence of solution pH and temperature ranging from 25 to 50 °C on the performance of polymers of varying functional groups as calcium sulfate dihydrate (CaSO4•2H2O, gypsum) crystal growth inhibitors. Results indicate that at constant temperature and at a constant solution pH, crystallization in the presence of polyacrylic acids is preceded by an initial slow growth reaction, hereafter called induction period, following which crystal growth of gypsum proceeds with a rate close to that in pure supersaturated solution. Results suggest that at a constant pH, polyacrylic acid concentration, molecular weight, and temperature greatly affect the duration of induction period. Kinetic data collected as a function of solution pH in the range 2.5 to 9.0 suggest that solution pH has a marked effect on the induction period. The observed dependence of induction period on solution pH may be explained in terms of the degree of ionization of polyacrylic acid. Among the polymers of varying functional groups studied, i.e. carboxyl, sulfonate, acrylamide, dimethyldiallylammonium, etc., only those polymers having carboxyl group showed marked inhibitory activity for the growth of gypsum crystals.

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