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Compressive Yield Stress (compressive + yield_stress)
Selected AbstractsEffect of polymerization method on structure and properties of cationic polyacrylamideJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Yinghua Shen Abstract Acrylamide and 2-(methacryloyloxy)ethyltrimethylammonium chloride (AM/MADQUAT) copolymers were synthesized by solution and inverse microemulsion polymerization using (NH4)2S2O8/NaHSO3 as redox initiator at the same feed mole ratio, and their microstructure, such as sequence distribution and composition distribution, was calculated from monomer reactivity ratios of different polymerization methods. The results show that charge distribution is more uniform for copolymer prepared in inverse microemulsion than that in solution, and copolymer composition distribution is close to unity, and maintains approximately at the feed ratio. Furthermore, the influence of the two structures of cationic polyacrylamides on kaolinite floc size and effective floc density, reduction of Zeta potential and floc compressive yield stress had been investigated at pH 7. The results show that the kaolinite floc size and effective floc density are strongly dependent upon copolymer microstructure, with greater floc size and lower effective floc density being observed for copolymer prepared in inverse microemulsion than for that in solution. Copolymer microstructure has a marked effect on the Zeta potential, whose reduction in the magnitude was much greater in the presence of copolymer prepared in inverse microemulsion than that in solution. Greater compressive yield stress was achieved for the strong flocs produced by copolymer prepared in inverse microemulsion than for the weak flocs produced by that in solution. The difference in flocs compressive yield stress may be attributed to flocs structure. Therefore, in this article, a correlation between the cationic polyacrylamide structure and flocculation property for kaolinite suspension was established. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] One-dimensional model of vacuum filtration of compressible flocculated suspensionsAICHE JOURNAL, Issue 10 2010Anthony D. Stickland Abstract This work details the one-dimensional modeling of the different processes that may occur during the vacuum filtration of compressible flocculated suspensions. Depending on the operating conditions of the applied pressure and the initial solids concentration relative to the material properties of the compressive yield stress and the effective capillary pressure at the air,liquid interface, the dewatering process undergoes a combination of cake formation, consolidation, and/or desaturation. Mathematical models for these processes based on the compressional rheology approach are presented and appropriate solution methods outlined. Results using customary material properties are given for different operating conditions to illustrate the three dewatering processes. This approach lays the theoretical basis for further work understanding two- and three-dimensional effects during desaturation, such as cracking and wall detachment. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] Effects of microstructure on the compressive yield stressAICHE JOURNAL, Issue 1 2000Glenn M. Channell The effects of microstructure on the compressive properties of aggregated alumina suspensions are determined by intentionally introducing heterogeneities into the suspension. Suspensions are prepared at a high volume fraction and diluted with low shear hand mixing to a series of initial concentrations. As the initial concentration is increased, larger heterogeneities are introduced, and the suspension becomes more compressible relative to the compressive yield stress of the uniform suspension. A simple model is proposed in which the heterogeneous suspensions compress by rearrangement of the dense aggregates until a critical concentration (,c, which coincides with the volume fraction prior to dilution) is reached. Above ,c, the suspensions consolidate identically to the uniform suspension. With a single fitting parameter (the size of the heterogeneities), the model shows semiquantitative agreement with the experimental data. [source] Composites from PMMA modified thermosets and chemically treated woodflourPOLYMER ENGINEERING & SCIENCE, Issue 5 2003Betiana A. Acha The mechanical behavior of composites made from woodflour and a modified thermoset unsaturated polyester resin has been examined. Polymethylmethacrylate (PMMA), a common low profile additive (LPA), was used as the matrix modifier. Woodflour, the reinforcing filler, was used ,as received' and was also modified with a commercial alkenyl succinic anhydride (ASA), in order to enhance the compatibility with the resin. The composites exhibited higher flexural and compressive modulus and compressive yield stress than the neat resin, while flexural strength and ultimate strain were reduced. The addition of PMMA to the unfilled thermoset led to a LPA morphology and decreased the flexural modulus, but produced an increment in flexural strain at break, impact energy and toughness of the UP resin. No enhancement in the mechanical behavior of the composites was found when treated woodflour instead of unmodified woodflour was used. [source] | ||||||||||