In this paper, Brookfield viscometer was used to test the rheological properties of sodium alginate solution and blends of sodium alginate/polyethyleneglycol(PEG)/molecular sieve in which the molecular weight of sodium alginate solution was respectively 1.59*105Da and 3.27*105Da. Besides, thermal stability and the thermal property of alginate fibers were also investigated by TGA and DSC. The fracture strength of blended alginate fibers was discussed by electronic monofilament tensile strength tester. The results showed that the system was a typical kind of non-Newtonian fluid. The apparent viscosity declined with the increase of shear rate. Rheological properties were affected by temperature and contents of the blends, at the same time, non-Newtonian index and structure viscosity index also changed. Research results were very important to the choice of wet spinning process. The thermal property and energy storage effect of alginate fibers was good, so was the fracture strength.
Due to the influences of climate change and human activities, the water and sediment flux of the Yellow River are certainly changing. This paper selects monthly time series of runoff and sediment flux from 1950 to 2009 for study at Lijin station, in lower Yellow River. A widely used identification method, wavelet analysis, is applied for recognizing changing point and cycle of the runoff and sediment respectively in multi-scale of annual, flood season and non-flood season. The results indicate that there are two significant changing points in 1985, 2002 year, and cycle recognized results are different in multi-scale as well as with different hydrology factors.
protein was extracted from Antarctic krill (AK), then blended with sodium alginate (SA) , prepare the spinning solution, the rheological properties of spinning solution were studied by Brookfield DV-C digital viscosimeter. AKP/SA fibers were prepared via wet spinning with CaCl2 and PEG as coagulator .The morphology, tensile strength and thermal property of AKP/SA fibers were characterized by polarized light microscopy, monofilament strength tester and thermal gravimetric analysis (TGA) instrument. The result shows that the shear viscosities of spinning solution decrease with the increasing of shear rate and decreasing of concentration. the optimal Preparation Process of AKP/SA fibers were 5% concentration of SA, proportion of 1: 9 for AKP solution to SA solution, and proportion of 5:1 for CaCl2 to PEG. The cross-section of AKP/SA fiber is a jagged shape. Thermal property of AKP/SA fibers is similar to SA fibers.
Alginate/polyvinyl alcohol (PVA) composite fibers containing copper ions were prepared by wet spinning. The spinning solution and manufacturing process were researched. The composite fibers were characterized by Tensile Strength Tester, SEM and TGA. This report shows that the spinning solution is a typical kind of pseudoplastic fluid. Adding boric acid to coagulation bath and putting Cu ions into composite fibers can improve the strength. The structure of composite fibers with Cu ions is denser and there are grooves on the fiber surface. In addition, the thermal property of composite fibers is steady.
A nanoSiO2/polyacrylamide (PAM) organic–inorganic nanocomposite system was prepared using acrylamide as the monomer, nanoSiO2 as the modifier, and ammonium persulfate as the initiator. The system was then used to investigate the impact of various factors, including amount of modifier and concentration of monomer, thereby determining the conditions for optimal reaction. Infrared spectroscopy was then used for structural characterization. Measurements using the viscosity method indicated that the viscosity average molecular weight of the product exceeded 1 million. Electron microscopy images showed that a good organic coating layer formed on the surface of the microspheres.
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