Deng L.,Tangshan Zhonghao Chemical Co.
Hecheng Shuzhi Ji Suliao/China Synthetic Resin and Plastics | Year: 2017
The factors affecting the devolatilization efficiency of the twin-screw extruder, which include screw configuration, screw speed, feed rate, barrel temperature, and screw length/diameter ratio, were investigated on the basis of characteristics of the polyoxymethylene(POM)process, devolatilization theory of the extruder, and devolatilization process in POM production. The parameters for POM process were obtained, which include: the ratio of feed rate/screw speed is from 18 to 20, the barrel temperature ranges from 180℃ to 195℃, the vacuum degree is maintained below 0.01 MPa. The formaldehyde volatilization in POM is lower than 100 μg/g after devolatilization via the optimization of devolatilization system. © 2017, Beijing Yanshan Branch, Assets Management Corporation, SINOPEC. All right reserved.
Wang L.,Hebei United University |
Han B.,Tangshan Zhonghao Chemical Company |
Wang Z.,Peking University |
Dai L.,Hebei United University |
And 3 more authors.
Sensors and Actuators, B: Chemical | Year: 2015
An amperometric-type NO2 gas sensor using La10Si5AlO26.5 (LSAO) with the configuration of dense electrolyte| porous electrolyte, Ag-modified nano-structured CuO sensing electrode was investigated. The composition and microstructure of the sensor sample were characterized by SEM and XRD and the performance of the sensor was examined. The prepared Ag-modified nano-structured CuO particles sensing electrode by impregnation technique are homogeneously dispersed in LSAO porous backbone. The sensor displays good response to NO2 and the response currents are almost linear to NO2 concentrations in the range of 0-500 ppm at 550-700 °C. Ag addition to the CuO sensing electrode can remarkably increase sensor sensitivity, showing that the performance of the sensor is effectively improved by introducing Ag. The best performance is observed at molar ratio of 1:0.5 for CuO:Ag. The cross-sensitivities of the sensor to co-existant gases (H2, CH4, CO2, NH3 and toluene) are rather small. © 2014 Elsevier B.V. All rights reserved.
Deng L.,Tangshan Zhonghao Chemical Co. |
Lu Y.,Tangshan Zhonghao Chemical Co. |
Wang J.,Tangshan Zhonghao Chemical Co.
Hecheng Shuzhi Ji Suliao/China Synthetic Resin and Plastics | Year: 2014
The cationic ring-opening polymerization mechanism, polymerization reaction kinetics, implosion phenomenon and implosion mechanism of polyoxymethylene are analyzed according to its production characteristics. The main causes of implosion in the production of polyoxymethylene are the rapid increase of the catalyst dosages and the rapid decrease of the relative molecular mass regulator dosages. The amount of catalyst is about 100 μg/g with water content lower than 50 μg/g and the amount of relative molecular mass regulator is not less than 0.12% of the total feed combined with the actual production. Implosion can be avoided by changing the feeding methods of catalyst and relative molecular mass regulator, improving the depth of polymerization reactor feed pipe, etc.
Li P.,Hebei University of Technology |
Wang D.,Hebei University of Technology |
Liang D.,Tangshan Zhonghao Chemical Co. |
Zhang L.,Hebei University of Technology |
And 2 more authors.
Materials Research Bulletin | Year: 2014
The surface modification of zeolite L crystals with lanthanide complexes was achieved by electrostatic adsorption of ionic europium(III) complexes that are prepared by the reaction of tris(2-thenoyltrifluoroacetonate) europium(III) dehydrate with an organic salt containing terpyridine moieties on the negative charge-bearing surfaces of zeolite L crystals. Luminescent host-guest materials exhibiting tunable emission colors by changing the excitation wavelength are obtained by surface modification of terbium(III) bipyridine-loaded zeolite L crystals with the ionic europium(III) complexes. © 2014 Elsevier Ltd.
Xie Y.,Tangshan Zhonghao Chemical Co.
Hecheng Shuzhi Ji Suliao/China Synthetic Resin and Plastics | Year: 2015
The author studied the influences of composite additives including ultraviolet absorber, heat stabilizer, light stabilizer, etc. on weathering resistant performance of polyoxymethylene (POM). The artificial accelerated aging behaviors of POM before and after weathering resistant modification were evaluated. The results show that the retention of the tensile strength, flexural strength and Izod notched impact strength of the modified POM reach 104.0% and 106.0%, 106.0% and 107.0%, 68.9% and 62.2% respectively when the modified POM is aged for 500 h and 1 000 h. And the color of the modified POM before and after aging has little change, which is much better than the corresponding properties of POM without modification. ©, 2014, Hecheng Shuzhi Ji Suliao/China Synthetic Resin and Plastics. All right reserved.