THE PROCESS OF THE EMULSIFIER-FREE POLYMERIZATION IN THE PRESENCE OF BARIUM SULFATE POWDER

The process of emulsifier-free copolymerization of the Styrene-Butyl Acrylate-K_sS_sO_s-water in the presence of Barium Sulfate(BS)powder was investigated under varied conditions within the range of BS powder quantity,initiator concentration and reaction temperature.Experimental results showed that the rate of polymerization is proportional to 0.3-power of the BS quantity and 1.3-power of the initiator concentration.There is a linear relationship of 2/3-power for the conversion and time.A process for the polymerization is propose to explain the experimental results.

SOAPLESS EMULSION COPOLYMERIZATION IN THE PRESENCE OF BARIUM SULFATE POWDER

To investigate soapless emulsion copolymerization in the presence of a solid phase, copolymerization experiments were carried out for the styrene-butyl acrylate-K_2S_2O_8-water system by using barium sulfate powder,which is assumed to be chemically inert.Reaction conditions were varied with respect to barium sulfate powder quantity,initiator concen- tration and temperature.These factors were investigated with respect to the effect on reaction rate and conversion,polymer particle number and diameter,and latex stability.

EDTA-type Polymer Based on Diazacrown Ether as the Solubilizer of Barium Sulfate to Water

The EDTA dianhydride reacted with diazacrown ethers to obtain the water-soluble EDTA-diazacrown ether polymers 1~3. The effects of crown ether ring in the polymer chains including its cavity size on the solubilization of barium sulfate to water were investigated by comparison with the crown ring-free analogue 4. The result shows that the polymer 2 is the efficient solubilizer of BaSO4 and the highest solubilization efficiency of the BaSO4to water is up to 72.5%.

Surface Modification of Barium Sulfate Particles

In this study, surface modification of barium sulfate was investigated using several model molecules for chemical treatment: ethanesulfonic acid, butyric acid, trimethoxy(propyl) silane and phosphoric acid 2-hydroxyethyl methacrylate. Samples were characterized by FT-IR and TGA to check the capability of these model molecules to interact with BaSO4 surface. The results pointed out the presence of an organic layer around the surface after the chemical treatment even after several washings to remove all species in excess. Model molecules were grafted onto BaSO4 surface and grafted density was determined. It reveals that phosphoric acid and carboxylic acid are the best candidates for the modification of BaSO4 surface. Both can be used as anchoring groups to modify the hydrophilic balance of barium sulfate surface in order to avoid the formation of aggregates and to improve the compatibility of this filler within hydrophobic polymer matrix.

Fabrication of submicron barium sulfate aggregates in the presence of ethylenediaminetetraacetic acid anions

Barium sulfate aggregates with an average size of 0.5μm were synthesized at pH 7, directed by ethylenediaminetetraacetic acid （EDTA） anions. The particle morphology, chemical composition, and size distribution of the BaSO4 aggregates were characterized. The as-synthesized BaSO4 particles were spherical and comprised many interconnected nanoballs, of which the surface properties were affected by the EDTA anions. The adsorption of EDTA anions reversed the charge and weakened the surface polarity of BaSO4, instigating the formation of aggregates by a self-assembly and transformation process. The resulting BaSO4 particles at pH 9-10 were ellipsoidal and featured smooth surfaces. Based on the zeta potential of BaSO4, variations in the morphology induced by changes in pH were closely related to the adsorption of mono- and multi-valent anions onto the electrical double layer of BaSO4.

Effect of barium sulfate modification on the SO2 tolerance of V2O5/TiO2 catalyst for NH3-SCR reaction

Sulfur poisoning of V_2O_5/BaSO_4–TiO_2（VBT）,V_2O_5/WO_3–TiO_2（VWT） and V_2O_5/BaSO_4–WO_3–TiO_2（VBWT） catalysts was performed in wet air at 350℃ for 3 hr,and activities for the selective catalytic reduction of NO_x with NH_3 were evaluated for 200–500℃.The VBT catalyst showed higher NO_x conversions after sulfur poisoning than the other two catalysts.The introduction of barium sulfate contributed to strong acid sites for the as-received catalyst,and eliminated the redox cycle of active vanadium oxide to some extent,which resulted in a certain loss of activity.Readily decomposable sulfate species formed on VBT-S instead of inactive sulfates on VWT-S.These decomposable sulfates increased the number of strong acid sites significantly.Some sulfate species escaped during catalyst preparation and barium sulfate was reproduced during sulfur poisoning,which protects vanadia from sulfur oxide attachment to a great extent.Consequently,the VBT catalyst exhibited the best resistance to sulfur poisoning.

Clinical pathology analysis of esophageal sarcomatoid carcinoma

Objective： The purpose of this study was to study the clinical, imaging characters and pathological characteristics of esophageal sarcomatoid carcinoma. Methods： We reviewed 23 cases of esophageal sarcomatoid carcinoma from Janu ary 2006 to December 2013 in four hospitals. The data of patients who were esophageal sarcomatoid carcinoma operated were retrospectively analyzed. All cases had completed upper gastrointestinal barium images materials and 14 of these cases had completed CT images materials. Upper gastrointestinal barium images and CT imaging features include tumor location, size, shape, and strengthen, etc. The biological parameters of lesions including the express of cytokeratin AE1/AE3, 34E12,, Vimentin, desmin, Actin, S100 and Ki67 detected by immunhistochemical UltraSensitiveTM SP method （n = 23）, and the patients＇ data of contrastographic picture （n = 23）, imaging characters of CT scan （n = 14）, and their relationship were studied. Results： Upper gastrointestinal barium images, CT imaging and gastrointestinal fiberscopy revealed Iobulated intraluminal filling defect 0.4 cm to 5.7 cm x 3.5 cmx 1.3 cm （mean = 3. 7 cm） in the mid （n = 14）, lower （n = 7） and upper （n = 2） intrathoracic esophagus. Among 23 cases of esophageal sarcomatoid carcinoma, 19 patients were of mushroom type, 2 patients was of ulcer type, and 2 patients were of medulla type; 19 patients were pedunculated, and 4 patients were no pedunculated （2 patients was of ulcer type）. The tumor surface was relatively smooth and esophageal compliance was maintained. The pathological changes of esophagus such as lightly locked, rigid wall nomanifest partly, esophageal lumens expand partly, major filling sublobe defect could be shown through contrast medium. Normal esophagus was no unpack obviously over pathological changes. Enhanced computed tomography showed tumors in the intrathoracic esophagus and 8 lymph nodes metastases in 3 cases. Histologically, carcinomatous and sarcomatous components coexist. Microscopically, the tumor comprised poorly differentiated squamous cell carcinoma and spindleshaped cells resembling leiomyosarcoma. Immu nohistochemically, spindleshaped sarcomatous cells displayed weekly positive reaction to cytokeratin AE1/AE3. Transitional zone was seen between sarcomatous and carcinomatous elements in 5 cases. The 17 lymph nodes metastases in 5 cases （53 lymph nodes） among 23 cases esophageal sarcomatoid carcinoma （187 lymph nodes） were observed. Conclusion： The clinical and radiologic features of esophageal sarcomatoid carcinoma overlap with those of other esophageal neoplasms. There are the radiologic imaging changes such as a large, intraluminal, polypoid mass, major filling sublobe defect and pedicle skin flap tumor in esophageal lumen, esophageal lumen extension partly, dissepiment rigidity wall no obviously, etc. Histologically, carcinomatous and sarcomatous components coexist and the biphasic pattern is the key diagnostic feature. However, esophageal sarcomatoid carcinoma has a more favorable prognosis than other malignant esophageal neoplasms. Immunohistochemical staining seems necessary to distinguish these lesions from other esophageal neoplasms.

Effect of BaSO_(4) on phase composition and sintering process of iron ore fines

Iron ore containing BaSO_(4) may have a series of effects on the quality of the sinter and performance of the blast furnace.Thus,the effect mechanism of BaSO_(4)(0-6.0 mass%)on the compressive strength,mineral composition,and microstructure of the sinter was investigated.The experimental results show that the compressive strength of the sintered samples initially increases and then decreases when the BaSO_(4) content increases from 0 to 6.0 mass%,reaching a peak value of 12.78 kN with a BaSO_(4) content of 1.0 mass%.Thermal analysis indicates that BaSO_(4) initially decomposes to produce BaO at 1468 K in the presence of iron ore.BaO combines with Fe_(2)O_(3) forming barium ferrite(Ba_(2)Fe_(6)O_(11)),which exists in the sintered sample with a granular form.BaO also dissolves in calcium ferrite and slag to promote the formation of calcium ferrite and barium glass,respectively.The content of needle-like calcium ferrite gradually increases and then decreases with the increase in BaSO_(4) content.Hematite exists in a plate-like form.The generation of dicalcium ferrite is promoted by increasing the BaSO_(4) addition from 2.0 to 6.0 mass%.