Microstructure and properties of polycaprolactone/calcium sulfate particle and whisker composites

2012 ◽  
Vol 33 (4) ◽  
pp. 501-508 ◽  
Author(s):  
Jinyan Liu ◽  
Li Ren ◽  
Qiang Wei ◽  
J.L. Wu ◽  
Sa Liu ◽  
...  
2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Jianwu Zhang ◽  
Xuemao Guan ◽  
Xiao Wang ◽  
Xianwei Ma ◽  
Zhixin Li ◽  
...  

Effect of calcium sulfate variety on the microstructure and properties of cement-based grouting materials made by sulfoaluminate cement clinker, calcium sulfate resource, and quicklime was investigated in this paper. Isothermal calorimetric, XRD, DTA-TG, and SEM-EDS were used to characterize the reaction process of cement-based grouting materials. The mechanical property and expansion of the harden body were also tested. The results showed that (1) the formation of ettringite can be completed during the first 2 h when gypsum was selected, causing nonexpansion of the harden body, and ettringite tends to be precipitated near the clinker grain, which has a negative influence on the “skeleton effect” of ettringite, resulting in lower strength of the hardened body. (2) Ettringite can be continually and slowly precipitated when an anhydride was chosen, and the hardened body shows significant expansion characteristic. Besides, ettringite in anhydride paste tends to be precipitated in the form of complex interleaving, which can generate a positive influence on mechanical property of the hardened paste.


Author(s):  
K. Cowden ◽  
B. Giammara ◽  
T. Devine ◽  
J. Hanker

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).


1987 ◽  
Vol 48 (C3) ◽  
pp. C3-643-C3-652 ◽  
Author(s):  
R. E. LEWIS ◽  
E. A. STARKE ◽  
Jr. ◽  
W. C. COONS ◽  
G. J. SHIFLET ◽  
...  

TAPPI Journal ◽  
2011 ◽  
Vol 10 (1) ◽  
pp. 17-23
Author(s):  
KEVIN TAYLOR ◽  
RICH ADDERLY ◽  
GAVIN BAXTER

Over time, performance of tubular backpulse pressure filters in kraft mills deteriorates, even with regular acid washing. Unscheduled filter replacement due to filter plugging results in significant costs and may result in mill downtime. We identified acid-insoluble filter-plugging materials by scanning electron microscope/energy-dispersion X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis in both polypropylene and Gore-Tex™ membrane filter socks. The major filter-plugging components were calcium sulfate (gypsum), calcium phosphate (hydroxylapatite), aluminosilicate clays, metal sulfides, and carbon. We carried out detailed sample analysis of both the standard acid-washing procedure and a modified procedure. Filter plugging by gypsum and metal sulfides appeared to occur because of the acid-washing procedure. Gypsum formation on the filter resulted from significant hydrolysis of sulfamic acid solution at temperatures greater than 130°F. Modification of the acid-washing procedure greatly reduced the amount of gypsum and addition of a surfactant to the acid reduced wash time and mobilized some of the carbon from the filter. With surfactant, acid washing was 95% complete after 40 min.


2012 ◽  
Vol 53 (6) ◽  
pp. 1154-1158 ◽  
Author(s):  
Wei-Luen Chen ◽  
Nai-Yen Fan ◽  
Jing-Wei Lee ◽  
Ruey-Mo Lin ◽  
Chien-Ping Ju ◽  
...  

2020 ◽  
Vol 62 (7) ◽  
pp. 698-702
Author(s):  
Lin Yinghua ◽  
Wang Kaiming

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