Advanced Materials Research Vols. 311-313

Abstract: In this paper, a comparison between the Liang model and the Cogswell model is made by using them to simulate numerically the boundary streamline and the region length during the entrance converging flow of polymer melts. The results show that both of them can properly describe the flow conditions. Furthermore, the Liang model can accurately describe the geometry effect on the boundary streamline, and by introducing the Bagley correction factor e and the slip factor ξ, it can also describe the changes of the region length more precisely.

Abstract: Electromagnetic dynamic plasticating extrusion, as one of main novel forming methods, has many important benefits to the forming process and the properties of its products. Here a visualization technique of flow induced birefringence was used to study the effects of the vibration parameters of screw on the extensional stress in contraction die. It is shown that , the extensional stress vibrate with the screw vibration at the same frequency; the amplitude of the extensional stress increases with the amplitude of the screw increasing; the average extensional stress at dynamic extrusion is less than that without vibration force, and it decreases with the screw vibration frequency or amplitude increasing.

Abstract: It is found that additional dynamic tension triggered by eccentric shaft affects printing paper is obvious by analyzing the relation between tension and eccentric shaft of feeding mechanism in the paper. Using the dual-tensition control system has the advantages of high examination precision, compensating strip's length, reducing additional dynamic effects to the feeding mechanism, ensuring color printing position precision and improving printing quality.

Abstract: In the flocculation treatment of oilfield sewage, cationic polyacrylamide (CPAM), which was synthesized by the copolymerization of dimethyldiallylammonium chloride (DMDAAC), acrylamide(AM), and acrylic acid(AA), will react with the residue of oil displacement agent, causing the quick crimp of its linear-molecular-structure chain and deteriorating the flocculating effects. In order to solve the problem, cationic polyacrylamide (CPAM) was grafted by a cationic-terminated spheroidal-molecular-structure hyperbranched polymer (CHP), which was synthesized by introducing methacryloxyethyl trimethylammonium chloride (DMC) into a kind of amino-terminated hyperbranched polymer. Both CPAM and grafted CPAM were used in flocculation treatment of simulated ASP oilfield sewage. The comparison results in flocculating effects indicated that the flocculating effect of grafted CPAM is greater than CPAM, its optimal dosage is 12.5mg/L, and its transmittance of the treated sewage reached 98.6%.

Abstract: A new two-component polyurethane adhesive was prepared with castor oil used as main agent and castor oil modified TDI used as curing agent.The effect of castor oil on the mechanical properties, adhesion properties and thermal stability of this adhesive were studied.This paper show us that TDI could be used as curing agent after modification. When the NCO/OH in curing agent and main agent:curing agent were 1.6 and 3:5 respectively, high performance adhesive was obtained.

Abstract: For exploiting the multifunctional ecological cotton textile products and developing the green modified technology for cotton fabrics, a novel cotton fabric with aloe extract crosslinking was prepared using citric acid as a crosslink agent under the pad-dry-cure procedure. Scanning electron microscopic photographs showed that the modification with aloe extract occurred on the surface of cotton fabric. FT-IR spectra of the modified fabric illuminated that aloe extract crosslinked with cotton fabric through the bridge linkage of citric acid after a series of reaction. The wide angle X-ray diffraction analysis indicated that the crystallinity of aloe extract modified cotton fabric slightly decreased. Furthermore, the changes in the aggregating structure and crystallinity were also reflected in the mechanical property studies of these modified fabrics. After treatment by aloe extract, the breaking strength and elongation of cotton fabric decreased. However, the moisture regain of the modified cotton fabric increased. The results obtained are useful in explaining structure-property correlations with respect to the aggregating structure and crystallinity, and suggest valuable information in planning applications for the aloe extract modified cotton textile products.

Abstract: In order to improve the poor compatibility and storage stability of rubber modified asphalt,authors using theoretical and experimental methods, to investigate the influence of the stabilizer on the storage stability and the using performance of rubber modified asphalt, through adding the different types and different doses of stabilizer, to improve its storage stability and using performance of modified asphalt.

Abstract: Floating matrix tablets were designed and evaluated. Theophylline was used as a model drug. The system was prepared by mixing drug, matrix-forming polymer (hydroxypropyl methylcellulose, HPMC) and fillers together. The blended powder was compressed by hydraulic press. The effect of formulation variables such as type of matrix forming polymer (HPMC K100LV, HPMC K4M, HPMC K100M), amount of effervescent agent (0, 20, 30, 40% w/w) and compression force (0.5, 1 ton) on floating properties and drug release of floating matrix tablets were investigated. The results demonstrated that type of polymer affected floating properties of the floating matrix tablets. The floating matrix tablets prepared from lower viscosity HPMC (HPMC K100LV) showed faster drug release than those prepared from higher viscosity HPMC (HPMC K4M, HPMC K100M). Increasing amount of effervescent agent decreased time to float and increased drug release from the floating matrix tablets. Higher compression force did not affect time to float but decreased drug release from the floating matrix tablets. According to these results, floating properties and drug release of the floating matrix tablets could be modified by formulation variables. Some floating tablet formulations developed in this study showed good floating properties (time to float less than 15 minutes, floating time more than 8 hours) with sustained release as required. The system is promising as a carrier for gastroretentive drug delivery systems.

Abstract: MgO substituted polycrystalline BaTi₂O₅ (BT₂), Ba_1-xMgxTi₂O5 (BMT₂), was prepared by a floating zone method (FZ-melting). The dielectric property of BMT₂ was investigated by_{Subscript text} an AC impedance method. At x = 0.005 MgO, the permittivity (r) showed the maximum value of 5800 for FZ-melted specimens. The Curie temperature (T_c) decreased with increasing x and the permittivity showed a flat peak at x ≥ 0.03. Second phases of BaTiO₃, Ba₆Ti17O40 and Ba4MgTi11O27 were identified in polycrystalline BMT2. BaTiO3 and Ba6Ti17O40 could be due to the decomposition of BT2 at high temperatures.

Abstract: In order to release the relationship between technics variables and properties of PAN fiber, the evolvement of crystalline structure of PAN fiber during the wet spinning process was studied by X-ray diffraction(XRD), the measurement of the solvent residuals, boiling-water shrinkage and breaking tenacity. It is found that the drawing and removal of solvent can improve the tenacity, especially the drawing can improve degree of orientation and crystallinity, and the collapse process can stabilize the orientation and crystalline structure.