Table of Contents
Cover
Title Page
Copyright
Preface
Foreword by A.Yu. Tsivadze
Foreword by V.M. Prikhod'ko
Chapter 1: Challenges of Technology of Dispersed Composite Materials
References
Further Reading
Chapter 2: Structure Formation in Dispersed Systems and Materials
2.1 Types of Contacts between Particles in Dispersed Systems and Materials
2.2 Criteria of Formation of Dispersed Structures
References
Further Reading
Chapter 3: Dynamics of Dispersed Systems in Processes of Formation of Composite Materials
3.1 Dynamic State of Dispersed Systems
3.2 Dynamics of Contact Interactions in Dispersed Systems
References
Chapter 4: Rheology, Vibrorheology, and Superfluidity of Structured Dispersed Systems
4.1 Rheology and Vibrorheology of Two-Phase Dispersed Systems
4.2 Vibrorheology and Plasticity of Powdered Materials
References
Further Reading
Chapter 5: Structure Formation, Rheology, and Vibrorheology of Three-Phase S–L–G Systems
5.1 Kinetics Structure Formation Process in Three-Phase Dispersed Systems under Vibration in the Course of Mixing
5.2 Structure Formation and Rheology of Three-Phase S–L–G Systems in Compaction Processes
References
Further Reading
Chapter 6: Application of Methods of Physicochemical Dynamics in the Technology of Dispersed Systems and Materials
6.1 General Principles
6.2 Technologies of Dispersed Systems
6.3 Dispersed Composition Materials
References
Further Reading
Conclusion
Endorsement
Appendix
Index
End User License Agreement
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Guide
Cover
Table of Contents
Preface
Foreword by A.Yu. Tsivadze
Begin Reading
List of Illustrations
Chapter 1: Challenges of Technology of Dispersed Composite Materials
Figure 1.1 (a) Scheme characterizing water segregation in concrete mixtures: V 0 is the initial volume of the concrete mixture, V 1 is the volume of water segregated under static conditions, V 2 is the volume of water segregated in the course of transportation to the site of placement, Vt is the final volume of the concrete mixture after placement and compaction. (b) Scheme of formation of a water “lens” under coarse filler grains as a result of sedimentation: (1) grains of chippings or gravel, (2) cement solution, and (3) water “lens” under filler grains.
Figure 1.2 Dependence of strength of concrete on the cement/water ratio. Curves 1 and 2 correspond to concretes made on usual (2) and quick-setting, highly dispersed (1) cements (S is the specific surface area of cements). Curve 3 is the dependence of R concrete on Cem/W according to Equation 1.1. Arrows point to the Cem/W limitation relation to loss of placeability of concrete mixtures.
Chapter 2: Structure Formation in Dispersed Systems and Materials
Figure 2.1 Main contact types between particles of dispersed phases according to Rehbinder [1] and the corresponding structures formed (see Figure A.1). Contacts: (A) direct (atomic) in powders ; (B) coagulation in pastes and suspensions; and (C) phase ones in dispersed material structures.
Figure 2.2 Scheme illustrating a transition of dispersed systems with (a) reversible-strength direct and (b) coagulation contacts to structures with irreversibly destroyed contacts in dispersed materials.
Figure 2.3 Scheme characterizing the combination of dispersion attraction forces and electrostatic repulsion forces (see Figure A.2): (a) manifestation of dispersion attraction forces and electrostatic repulsion forces and (b) dependence of energy E and interaction force fc on distance h [7, 9].
Figure 2.4 Character of solid-phase surface wetting in the case of (a) hydrophobic and (b) lyophilic (hydrophilic toward water) surfaces: θ is the wetting angle between the solid-phase surface and the tangent line to the liquid drop surface at the site of contact with the solid surface [1], according to Young's law [10]: .
Figure 2.5 Dependence of strength Pm of dispersed structures on the dispersed phase concentration (porosity) ϕ in the dispersion medium (see Figure A.3): (a) the general dependence and (b) the dependence found using percolation theory [15]; points correspond to experimental data [14].
Figure 2.6 Scheme of the experiment modeling the composite porous structure formed by monodispersed spherical particles; (1, 2, 3) ϕ = 0.74.
Figure 2.7 Kinetics of development and decrease of deformations under stress and unloading of solid structures, where (a) reversible deformation and (b) a combination of elastic and plastic irreversible (residual) deformation, after stress is removed.
Figure 2.8 Character of deformation of dispersed structures under stress with (a) direct, (b) coagulation, and (c) phase contacts.
Figure 2.9 Variation of shear stress in time from the start of deformation (t ≈ 0) for a suspension of hydrophobic particles in water; the mass concentration is 65%. 1 − = 200 s−1 ; 2 − = 1240 s−1 .
Chapter 3: Dynamics of Dispersed Systems in Processes of Formation of Composite Materials
Figure 3.1 Scheme explaining the conditions of development of the optimum dynamic state of dispersed systems: (a) a structured dispersion and (b) full limiting disaggregation.
Figure 3.2 Dependence of characteristic times of microprocesses on the size of dispersed phase particles [1]: (1) inertial effects, (2) molecular attraction, (3) electrostatic repulsion, (4) Brownian motion, and (5) sedimentation.
Figure 3.3 Dependence of the critical coagulation rate on particle radius r : (1) spherical particles (r = r 0 ) and (2) anisometric particles ( ). Dashed lines correspond to particles with hydrophobic surface.
Figure 3.4 Model illustrating interaction between particles and the adsorption surfactant layer under dynamic conditions: U is the interaction energy; h is the distance between the particles; h min is the distance between the particles in the position of near coagulation; h max is the distance between the particles in the position of far coagulation.
Figure 3.5 Scheme of formation of the vibration fluidization (region I) or vibration fluidization (region II): a is vibration amplitude; ω 2 is the circular vibration frequency.
Chapter 4: Rheology, Vibrorheology, and Superfluidity of Structured Dispersed Systems
Figure 4.1 Main rheological characteristics of dispersions. Shear stress ; V is the shear rate of the upper plate; rate gradient ; viscosity . Viscosity is a proportionality factor between deformation rate and shear stress P .
Figure 4.2 Standard (conventional) design of coaxial cylinders minimalizing end effects [3].
Figure 4.3 Principle scheme of a rotation vibroviscometer with coaxial cylinders [8]: (1) rectifier unit; (2) dc motor; (3) seven-stage gear box; (4) electromagnetic coupling box; (5) selsyn transmitter; (6) measuring selsyn, (7) rotating-mirror oscillograph; (8) measuring synchrotransformer; (9) power selsyn receiver; (10) outer cylinder; (11) inner cylinder; (12) vibrating table; (13) push bar; (14) eccentric; (15) five-stage gear box; (16) coupling boxes; and (17) electric actuator of the eccentric-type vibrator.
Figure 4.4 The measuring system of a cone-plane type with a truncated cone [3]: Rc is the outer cone radius; α is the cone angle; RT is the radius of the truncated cone part; and a is the gap between the truncated cone part and the plane.
Figure 4.5 Plane–plane measurement system [3]: R is the plane radius, and h is the gap.
Figure 4.6 Scheme of a rheological capillary [3]: P 1 is the inlet pressure, P 2 is the ambient pressure (pressure P 1 + P 2 measured in points I and II at distance Δ L ); Q is the bulk flow rate.
Figure 4.7 Scheme of a vibroviscometer with a planar slot capillary [8]: (1) nitrogen gas bottle; (2) reducing valve with manometers; (3) reducing valve for precise regulation of pressure in the system; (4) standard precision manometer; (5) high-pressure hose; (6) vibroviscometer lid; (7) vibroviscometer casing; (8) planar slot capillary; (9) capillary closure; (10) vibration area; (11) studied dispersed system; (12) receiving vessel for a dispersed system flowing out of the capillary; (13) chambers for thermostating of the viscometer lid and casing; and (14) hoses for supplying the heat-transfer medium to the thermostat.
Figure 4.8 Sinusoidal voltage and deformation at the established periodical deformation of a linear viscoelastic material: (1) stress in phase with deformation and (2) stress out of phase with deformation.
Figure 4.9 Resolution of deformation and stress vectors.
Figure 4.10 Typical full rheological flow curves of SDS [17] (see Figure A.4): (1) liquid systems; and (2) solid systems; P′r is the limiting value of shear stress corresponding to the highest Newtonian viscosity η 0 of a practically intact structure according to [16]; is the conditional static flow limit; is the conditional dynamic (Bingham) flow limit; is plastic viscosity (P → PK ), ; is plastic viscosity in the descending branch of the full curve, ; is the lowest Newtonian viscosity of an extremely degraded structure.
Figure 4.11 (a) Full rheological flow curves and (b) log η [Pa·s] of the model system (aqueous suspensions of bentonite clay) at different values of the water–solid (W /S ) ratio; (1) 8; (2) 6; (3) 4; (4) 2.5; (5) 2; and (6) 1.45.
Figure 4.12 Full rheological flow curves of cement–aqueous suspensions in the form of the , f (P )- dependence: (1) W /Cem = 0.35, S sp = 5000 cm2 /g; (2) W /Cem = 0.35 + 0.1% sulfite–yeast mash (SYM), S sp = 5000 cm2 /g; (3) W /Cem = 0.35 + 0.3% SYM, S sp = 5000 cm2 /g; (4) W /Cem = 0.35 + 0.5% SYM, S sp = 5000 cm2 /g; (5) W /Cem = 0.35, S sp = 3000 cm2 /g; and (6) W /Cem = 0.45, S sp = 5000 cm2 /g.
Figure 4.13 Typical aperture of discontinuity in deformation in a concentrated dispersion with ϕ > ϕc (microphotograph of the structure with an aperture of discontinuity at the example of deformation of kaolinite suspension in water (×2500): arrows designate the shear directions).
Figure 4.14 Regularities of degradation and formation of coagulation structures at the example of low-concentration aqueous CaB dispersions, ϕ max = 11% (×1000) (see Figure A.5). (a) Structure before the start of deformation (static conditions). (b) Structure under conditions of continuous shear ( ). (c) Structure under the conditions of a combination of continuous shear ( ) and orthogonal oscillation (fv * = 50 Hz, a = 10−3 m).
Figure 4.15 Typical full rheological flow curve of plastic–elastic systems under conditions of application of a vibration field with attainment of the limiting structure degradation: η is effective vibration viscosity; I is vibration intensity (power density); a is vibration amplitude; f is the vibration frequency; P is shear stress. Rheograms 1–6 are equilibrium Newtonian levels of effective vibroviscosity corresponding to the given constant value of intensity.
Figure 4.16 Consecutive stages of degradation under vibration of a layered structure formed as a result of fluid motion of a dispersion of lyophobic particles (data of computer modeling); the shear rate is 150 s−1 , concentration ϕ = 40%. Vibration parameters a = 0.13 mm, f = 200 Hz [22] (see Figure A.6).
Figure 4.17 Full vibrorheological flow curves of two-phase structures formed in aqueous cement dispersions with W /Cem = 0.35 and with the additive of 0.3% surfactant to the solid phase, S BET = 1 m2 /g: (1) surfactant-free system; (2) system containing a nonionogenic OP-10 surfactant; and (3) system with an organosilicon GKZh-10 surfactant.
Figure 4.18 Dependence of log (η v 0 /η v 0 ) on logarithms of intensity log I of mechanical vibrations: (1) comparison of a surfactant-free system and a system containing the GKZh-10 surfactant and (2) the same with the OP-10 surfactant.
Figure 4.19 Dependence of logarithm of effective viscosity (log η , [Pa·s]) of a 6 wt% Aerosil suspension ( ) in water on shear stress P (see Figure A.7): (1) flow curve in the absence of the surfactant and (2) flow curve with modification of Aerosil by a mixture of surfactants: low-molecular alkylbenzenesulfonate, ABS (0.5%), and high-molecular nonionogenic surfactant, proxanol (0.5% of the solid phase), with simultaneous addition of the surfactant; (3) same as in (2), but with addition of first ABS and then proxanol.
Figure 4.20 Scheme of manifestation of the Rehbinder effect [16, 32]: (a) character of the metal (zinc) structure containing grain boundaries (×500) and microcracks in the tensile zinc single crystal in the presence of the thinnest mercury layer, P is the load on the sample under tension; (b) migration of surfactant molecules in the mouth of the microcrack under sample tension; and (c) example of tension with ductile failure and brittle fracture in the presence of PVA (the lower sample).
Figure 4.21 Rheograms of filled bitumen at 150° for different bulk solid phase concentrations ϕ : 0 (1); 0.143 (2); 0.345 (3); 0.402 (4); 0.456 (5); and 0.588 (6): (A) Rheograms corresponding to static conditions of linear deformation and (B) vibrorheograms of filled system (2′)–(6′). The frequency is 30 Hz, vibroacceleration is ≈2g , where g is gravity acceleration.
Figure 4.22 Dependence of effective viscosity at deformation rate gradient on the bulk mineral powder concentration under the conditions of linear continuous deformation (A) and when vibration exposure is superimposed onto the deformation process (B); (1, 2) at 100°; (3, 4) at 150°.
Figure 4.23 Dependence of viscosity of the filled system on the vibration amplitude at the filler concentration of (1) 0.40; (2) 0.45; and (3) 0.588 at the vibration frequency (Hz) being 125 (I), 75 (II), and 30 (III).
Figure 4.24 Dependence of viscosity of the system on (a) vibration intensity at the temperature of 150° and at frequencies (Hz): 125 (1); 75 (2), and 30 (3) and (b) on the vibration gradient at the temperatures of 150° (1), 140° (2), and 120° (3).
Figure 4.25 Flow curves of a filled system at 150° and deformation (1) without vibration; (2–4) with applied vibration with the acceleration of 20 m/s2 ; (5–7) at the vibration acceleration of 40 m/s2 . Frequency designations are similar to those in Figure 4.24.
Figure 4.26 Flow curves of a filled system at the filler concentration of (1) 0.588, (2) 0.45; (3) 0.40; and (4) 0.34; (1)–(4) under deformation with no vibration; (1′–4′) under vibration with f = 30 Hz, a = 20 m/s2 .
Figure 4.27 Dependence of (1) storage modulus, (2) loss modulus, and (3) dynamic viscosity at 80 °C on deformation frequency at the deformation amplitude in the continuous shear plane (5 min) in log–log coordinates for a bitumen–shungite composition.
Figure 4.28 Typical cone immersion (apex angle of 60°) into bitumen at the temperature of 0 °C; Fn is the force, Sk is the cone section, hm is its immersion depth, h 0 is the deformation zone depth; (a) is the general view of the cone extracted from the shungite–bitumen composite (SBC); (b) an enlarged fragment of the contact region between the cone and SBC; (c) the SBC surface after extraction of the cone; and (d) scheme of deformation under immersion of the cone into the plastic-viscous dispersed system [41, 42].
Figure 4.29 Dependence of limiting shear stress of the bitumen–shungite composition on the shungite content at different temperatures.
Figure 4.30 Drops of emulsion coated by a layer of microemulsion (a) and with no layer of microemulsion (b).
Figure 4.31 Model of a drop (1) moving in the dispersion medium (2) in the gravity field.
Figure 4.32 Stability of the emulsion stabilized by microemulsion under dynamic conditions.
Figure 4.33 Typical full rheological flow curve of structured SDS (suspension of sterically stabilized monodispersed spherical particles of polymethyl methacrylate in decaline, ϕ = 59.5%): (1) the region of structure decomposition to superaggregates; (2) the same, to microaggregates; (3) the region of complete disaggegation and lowest Newtonian viscosity; and (4) region of dilatant flow. (b) Scheme of SDS spreading over the solid surface: Vp is the spreading rate, V p max is the maximum rate, θ 0i is the spreading angle, RT is the spreading radius. (Arrows designate the distribution of Vp by the layer height: (left) at slowdown on a rough surface, (right) at sliding over the hydrodynamic layer).
Figure 4.34 (a) Dependence of viscosity on shear stress P for an aqueous dispersion of calcium bentonite (S BET = 70 m2 /g, ϕ max = 11%); (1) at a consistent increase in P from the minimum to the maximum value, (2) at a consistent decrease in P ; (b) a microphotograph of the structure in the course of flow (ruptures of continuity and the layered structure can be observed); and (c) scheme of SDS spreading over the solid surface; the horizontal lines are zones of :sliding: over liquid flowing layers.
Figure 4.35 Evolution of the structure formed by quartz particles (d = 5–10 µm, ϕ bulk = 35%) in water under shear with the rate of according to the data of computer simulation [51].
Figure 4.36 Example of the spreading of a structured aqueous dispersion of a mixture of highly dispersed quartz and aluminosilicates.
Figure 4.37 Density distribution along the height of the dispersion layer as a result of sedimentation (the particle diameter is 42 nm, their concentration in water ϕ = 28%).
Figure 4.38 Specifics of SDS spreading under the conditions of continuous shear deformation combined with oscillation: the oscillation is orthogonal with respect to the direction of shear and spreading.
Figure 4.39 Main dynamic state of bulky two-phase (S–G) systems: the boundary of transition from the state of pseudoliquefaction to the state of vibrofluidization: (1) coarsely dispersed systems; (2) highly dispersed powder materials; and (3) the same, in the presence of small amounts of surfactant additives; a is the vibration amplitude; ω is the angular frequency of vibrations of a source of vibroexcitation; g is the gravity acceleration; is the vibration acceleration in g units; is the power density of vibration; h 0 is the initial height of a layer of the bulky system; h 1 is the height of the layer under vibration; ρ 0 and ρ 1 are densities of the structures of powder materials, accordingly.
Figure 4.40 Setup with a capillary viscometer for highly dispersed powders: (1) nitrogen bottle; (2) high-pressure gage; (3) precision manometers; (4) lid; (5) cylindrical vessel, viscometer casing; (6) ring chamber with perforation; (7) frame for fixation of a viscometer on a vibrating table; (8) diaphragm (seal) of the capillary tube; (9, 10) inlet chamber with a perforated lid; and (11) vibrating table [8].
Figure 4.41 Dependence of effective vibroviscosity of highly dispersed CaCO3 powder, SBET = 3 m2 /g, on parameters of vibration with powder outflow from the vessel through the capillary in the (a) pseudoliquefaction and (b) fluidization regions: (1, 2) at the atmospheric gas pressure of 104 Pa; (1, 3) in the absence of surfactants; (1′) with a coating layer of stearic acid, (I–I) is the boundary between the regions of pseudoliquefaction and fluidization.
Figure 4.42 Dependence of powder volume flow on the width of the output hole of the vessel at the vibration outflow of pseudoliquefied HDP: (1) glass St-1 (10.2·103 N/m3 ); (2) cationite KB-4P2 ηV = 4.2·103 N/m3 ; (3) polystyrene (7.6·103 N/m3 ); (4) polyvinyl chloride S-63 (7.6·103 N/m3 ); and (5) glass St-2 (18.3·103 N/m3 ).
Figure 4.43 Scheme of a rotary viscometer with coaxial cylinders (on the basis of a REOTEST device) for studies of bulky two-phase (S–G) systems: (1) base frame; (2, 5) holders; (3, 8) levers; (4) gear actuation indicator; (6) torque indicator ; (7) indicator of the rotation rate of the inner cylinder; (9) drive shaft; (10) flat clock spring; (11) ohmic sensors; (12) slave cylinder; (13) thermometer; (14) sleeve; (15) outer cylinder; (16) inner cylinder; (17) thermostat; and (18) vibrating table.
Figure 4.44 Dependence of effective viscosity of a layer of polyethylene HDP on the shear deformation rate under vibration exposure. The points correspond to the experimental dependence; the curves describe the theoretical dependence. The vibration frequency is 200 Hz; the vibration amplitude (in millimeter) is: (1) 0.367 (vibration fluidization); (2) 0.269; (3) 0.190; (4) 0.127; and (5) 0.063.
Chapter 5: Structure Formation, Rheology, and Vibrorheology of Three-Phase S–L–G Systems
Figure 5.1 Continuous vibromixer [9, 10]: (1) engine with a joint box; (2) mixing chamber; (3) unbalanced mass vibration generator; (4) spring support; and (5) mixer support.
Figure 5.2 Kinetics of variation of nonuniformity of dispersion in the course of mixing: (a) on the basis of indicator Kn for model system I*: (1) mixing without vibration (n = 14 rpm); (2–6) with application of mechanical vibrations with the acceleration of: (2) 1.16, (3) 2.33, (4) 3.5, (5) 4.65, and (6) 5.8 g units. (b) On the basis of indicator Pn : (1–3) under vibration; (1) bulky powdered two-phase S–G system; (2) model system I*: a plasto–viscous system; and (3) model system II*: an elasto–visco–plastic system.
Figure 5.3 Kinetics of variation of effective shear stress in the structure of highly dispersed powders (to model system I*) under mixing: (1) in the absence of vibration; and (2–4) under vibration with = 1.16 (2), 3.5 (3), and 4.65 (4).
Figure 5.4 Kinetics of variation of effective viscosity in the course of mixing of solid and liquid dispersed phases and formation of high-concentration three-phase plasto–viscous system (model system I*, W /S = 0.163): (1) mixing in the absence of vibration (n = 14 rpm; (2–5) under mechanical vibrations with acceleration : (2) 2.3, (3) 3.5, (4) 4.56, and (5) 5.8).
Figure 5.5 (a) Main stages of formation of high-concentration dispersed structures (model system I*) including solid, liquid, and gas phases with transition from three-phase (S–L–G) to two-phase (S–L) systems: (1) variation of effective shear stress in the structure under mixing without vibration (v = 0.07 m/s, τ eff − t ) and (2) the same under exposure to mechanical vibrations: = 4.6, I = 600 × 10−4 m2 /s3 . (b) Microphotographs of the structure in different time periods after the start of the mixing process: (A) t = 15 s, (B) t = 30 s, (C) t = 1 min, (D) t = 2 min, (E) t = 3–5 min, and (F) t = 10–15 min.
Figure 5.6 Microphotographs of the structure of model system II* (×150) obtained as a result of the mixing of solid and liquid phases: (a) t > 900 s, n = 220 rpm and (b) t = 15 s, n = 20 rpm under application of mechanical vibrations with I = 6 × 10−2 m2 /s3 .
Figure 5.7 (a) Kinetics of changes in effective viscosity in the course of formation of the structure of model system I* at 31 °C, n = 220 rpm, v = 1.15 m/s at different content of water: (1) 15, (2) 15.8, (3) 16.1, (4) 17.3, (5) 18.2, and (6) 22.2 wt%. (b) Kinetics of variation of effective viscosity as dependent on rate v of convective mass transport in the case of formation of a structure of model system II* under conditions of mixing under vibration with acceleration = 4.6 with the content of water of 15% and v being (1) 0.07, (2) 0.16, (3) 0.26, (4) 0.52, and (5) 1.15 m/s.
Figure 5.8 Kinetics of variation of effective viscosity η eff (1′, 2′) and specific power N (1, 2) consumed by unit system mass (model system I*) under mixing in the absence of vibration (1, 1′) and under vibration (2, 2′), = 4.6.
Figure 5.9 Viscometer for three-phase (S–L–G) systems: (a) general view of the measuring device and (b) principal diagram of the device for studies of structural–mechanical properties of three-phase mixtures in the course of compaction: (1) electric motor, (2) gear case, (3) cardan shaft, (4) support frame, (5) potentiometric motion sensor, (6) flywheel, (7) spindle, (8) worm–gear reducer, (9) cylindrical mold, (10) support pillar, (11) bed plate, (12) support frame, (13) potentiometric displacement controller with input signal compensation, (14) N3031 fast X,Y-recorder, (15) UT4-1 four-channel strain–gauge amplifier, (16) mounting screws, (17) cone, (18) star, (19) studied system, (20) strain–gauge system consisting of three console beams with strain–gauge sensors, and (21) rammer.
Figure 5.10 (a) Dependencies of the gradient of the continuous shear deformation rate in a vibrating three-phase system (W /S = 0.30) on shear stress P at different compaction degrees ϕ eff : (1) 0.77, (2) 0.85, (3) 0.9, and (4) 0.99. (b) Dependence of logarithm of effective shear viscosity in the course of vibration compaction of the same system on ϕ eff .
Figure 5.11 Variation of logarithm of effective shear viscosity of a three-phase system at an increase in ϕ eff under conditions of vibration compaction at a different ratio in the solid and liquid phase: (1) W /S = 0.235, (2) 0.30, (3) 0.367, and (4) 0.434; f = 50 Hz, a = 6 × 10−4 m, and P = 104 Pa.
Figure 5.12 Variation of logarithm of effective shear viscosity log η eff and compaction degree ϕ eff in time t in the course of transition of three-phase (S–L–G) structures to two-phase (S–L) ones under vibration compaction (f 1 = 50 Hz, a = 6 × 10−4 m, and P = 104 Pa) for systems with a different W /S ratio: (a) 0.235, (b) 0.30, and (c) 0.367 (1, 2) and 0.435 (1′, 2′); (1′) and (2′) with imposition of the second frequency f 1 = 150 Hz with acceleration of oscillations of two-phase vibration being 30 g .
Figure 5.13 Dependence of the maximum compaction degree ϕ eff of a three-phase dispersed system (W /S = 0.30) on thickness @H of the compacted layer at one frequency, with frequency f 1 = 42 Hz (a) and two-frequency, with frequencies f 1 = 42 and f 2 = 84 Hz (b) vibration compaction modes: (a) kinetic momentum Mk of the vibrator is (1) 1.0, (2) 0.667, (3) 0.334, and (4) 1.0 nm; static load P is (1–3) 50, (4) 80 N. (b) Kinetic momentums and for frequencies 42 and 84 Hz are, accordingly, (1) 1.0 and 0.24, (2) 1.0 and 0.149, (3) 0.667 and 0.24, (4) 0.334 and 0.24, and (5, 6) 1.0 and 0.24 nm; static load P is (1–4) 50, (5) 80, (6) 100 N.
Figure 5.14 Variation of longitudinal effective viscosity of high-filled dispersed systems I (based on electrocorundum and liquid glass) and II (based on silicon carbide and water) on their density under static compaction (1 and 2, accordingly) and vibration compaction (3 and 4). The compaction parameters are (1) specific molding pressure P sp = 5 × 107 N/m2 , (2) P sp = 4.7 × 107 N/m2 , (3) f = 25 Hz; a = 1 mm, P sp = 500 N/m2 , and (4) f = 25 Hz, a = 1 mm, P sp = 500 N/m2 .
Chapter 6: Application of Methods of Physicochemical Dynamics in the Technology of Dispersed Systems and Materials
Figure 6.1 Scheme of spheres of practical application of principles and methods of physicochemical dynamics of dispersed systems and materials.
Figure 6.2 Flow diagram of wasteless technology of ore production with the filling of cavities in mine openings by a hardening mixture of waste rock, cement, surfactants, and water. Ore is extracted from mine openings 1, while a part of it remains underground in the form of blocks 2. After valuable components are removed, waste rock is transported to dumps 3 and therefrom through batchers 4 – together with cement, water, and surfactants – arrives to continuous mixer 5. Then the mixture is transported through pipeline 6 into cavities of mine openings, fills them and hardens there. A part of the pipeline rests on elastic vibration dampers 7; this is necessary, as vibrators fixed on the pipeline cause vibration resulting in a decrease in viscosity of the high-concentration mixture, which promotes transportation at a decrease in the risk of layering.
Figure 6.3 Scheme of the method of regulation of structural–rheological properties of high-concentration suspensions (ϕ > ϕc ). 1 – Region of low-concentration suspension, ϕ < ϕc , prone to sedimentation in the course of hydrotransport; 2 – character of rate distribution in the shear flow typical for concentrated suspensions, ϕ > ϕc (“plug” glow); and 3 – character of rate distribution in the same suspension under the conditions of combination of orthogonal oscillation (ξ ) and addition of surfactant additives (Q ); the shaded area corresponds to a decrease in the limiting shear stress Pm → 0, P is the pressure in the pipeline.
Figure 6.4 Variation in time of shear stress for 12% bentonite clay suspension subjected to electrohydrodynamic treatment ( under shear of 0.75 a−1 ); the three curves are obtained under exposure to vibration: (a) – at the frequency of 20 Hz and (b) – at the frequency of 50 Hz; in both cases, the acceleration was (1) 10, (2) 20, and (3) 30 m/s2 .
Figure 6.5 Variation of effective viscosity in time in a flow of aqueous suspension ( ) of bentonite clay. Region I: increase in viscosity up to reaching the limiting shear stress; II: region of reaching the equilibrium viscosity level; III: is the region of vibration destruction of the structure and its thixotropic restoration; IV and V: regions of shear deformation under constant rate gradient. The arrows point to the start ↓ and end ↑ of vibration exposure. Curves (1), (2), (3), (4), (5) correspond, accordingly, to the frequencies of 30 Hz (1) and (5), 50 Hz (2), 100 Hz (3), 150 Hz (4) with the amplitude of 0.5 mm. Curve 1: in the absence of the surfactant additive; curve 2: a monolayer of OP-10; a: the region of structure destruction under vibration; b: the equilibrium viscosity level; c: thixotropic structure restoration after termination of vibration with the hardening effect; b, c: at shear rate ; b: at the harmonic vibration frequency of 20 Hz; c: at the vibration frequency of 50 Hz.
Figure 6.6 Scheme of preventing consolidation of hygroscopic powders (see the description in the text).
Figure 6.7 Dependence of main structural parameters of hardened CCG on vibration intensity log J in the course of its formation; R is the strength, D is the average pore diameter, and d is the average diameter of interporous space (crystalline intergrowth).
Figure 6.8 Character of water transport under pressure through the structure of conventional hardened cement paste (curve 1) and through the CCG layer (curves 2–4); P is the pressure of water and q is the amount of water that penetrates the material in 1 s.
Figure 6.9 General view of a building with panel CCG finishing in Moscow.
Figure 6.10 Distribution of effective structure density in the abrasive disk depending on the distance (from the center) to the periphery in various methods of abrasive mixture compaction; 1 – vibration compaction under the nonlinear stress mode, 2 – vibration compaction under the unstressed mode with harmonic oscillations, and 3 – static compaction.
Figure 6.11 Microphotographs of structures in the system obtained under (a) static compaction and (b) vibration compaction; magnification: (a) ×500 and (b) ×100.
Figure 6.12 Effect of operation time on friction coefficient μM of wearing layers of various CRMAC and ABN. CRMAC and ABN are standard types of coarse rock-mastic compact asphalt concrete, accordingly; CRMAC-T and ABN-T are new types of asphalt concrete (lower curves) [15].
Figure 6.13 Examples of efficient regulation of properties of dispersed materials in the initial structure-formation stage: (a) Colloid cement glue: hardened cement paste prepared (1) according to the conventional technology; (2) according to the new technology (CCG). (b) Composition based on epoxy resin ED-5 filled by highly dispersed quartz: (1) in the absence of regulation of properties at η eff ≈ η 0 , (2) under vibration. (c) Effect of regulation of viscosity η eff using vibration in paper production; (I) breaking length, (II) number of double kinks: concentration of cellulose fibers in water: 1 – 1.8%, 2 – 2%, 3 – 3%; is the acceleration of vibration in gravity g units.
Appendix
Figure A.1 Scheme of contact types between particles in dispersed systems.
Figure A.2 Scheme of interaction among the dispersed particles with sizes d ≤ dc and d ≥ dc (d – diameter of particle).
Figure A.3 (a) Relationship between strength/viscosity of dispersed systems and concentration of dispersed phase. (b) Relationship between strength of structure and force of interaction in contacts among particles, the number of contacts, and also concentration of dispersed particles in the system's volume (V – volume).
Figure A.4 Relationship between logarithm of effective viscosity (log η ) and rate of shear deformation (dϵ /dt ): η 0 – highest Newtonian viscosity of undistorted structure; η m – lowest Newtonian viscosity of absolutely destroyed structure.
Figure A.5 (a) Coagulation structure destruction under shear: 1 – initial structure; 2 – structure under shear with appearance of discontinuities; 3 – structure under shear in combination with orthogonal oscillation; is dispersed-phase concentration below the critical value; is the concentration equal to the critical value or exceeding it, . (b) Scheme of flow and destruction of the dispersed system under conditions of shear deformation with formation of structured layers.
Figure A.6 Relationship between interaction energy of dispersed particles and interparticle distance in accordance with DLVO theory (Derjaguin, Landau, Verwey, Overbeek): h – interparticle distance.
Figure A.7 (a) Scheme of interaction between dispersed particles in the presence of surfactants. (b) Flow of dispersed systems under the conditions of shear and orthogonal oscillation in the presence of surfactants.
Figure A.8 Effect of optimal combination of dynamic actions and introduction of surfactants in processes for making dispersed composite materials: E – binding energy; f c – force of interaction; h 2 – interparticle distance in the position of far coagulation.
List of Tables
Chapter 2: Structure Formation in Dispersed Systems and Materials
Table 2.1 Adhesion characteristics of contact interactions under static and dynamic conditions (at vibration at the frequency of 200 Hz)a [15]
Chapter 3: Dynamics of Dispersed Systems in Processes of Formation of Composite Materials
Table 3.1 Values of autoadhesion interaction forces in contacts between particles of SiO2 and CaCO3 powders
Chapter 4: Rheology, Vibrorheology, and Superfluidity of Structured Dispersed Systems
Table 4.1 Dependence of the highest η 0 and lowest ηm viscosities of cement–water pastes with different specific surface areaa at the constant value of W /Cem = 0.35
Table 4.2 Dependence of the highest η 0 and lowest ηm viscosity of cement–water pastes on W /Cem (specific surface area S sp = 5000 cm2 /g)
Table 4.3 Combined effect of vibration and surfactant additive on cement–water dispersions
Table 4.4 Some types of emulsifier surfactants
Chapter 5: Structure Formation, Rheology, and Vibrorheology of Three-Phase S–L–G Systems
Table 5.1 Duration of the initial structure formation stages (see Figures 5.4 and 5.5a,b) and the maximum values of effective viscosity of the system (model system I*) as dependent on the vibration parameters
Table 5.2 Kinetics of variation in structure parameters in the course of formation of a two-phase plasto–viscous system under vibration (20% CaB, S a = 70 m2 /g, 80% SiO2 , S = 1 m2 /g, W /S = 0.19, and I = 625 × 10−4 m2 /s3 )
Chapter 6: Application of Methods of Physicochemical Dynamics in the Technology of Dispersed Systems and Materials
Table 6.1 Main structural–mechanical properties of colloid polymer cement mixtures (CPCMs)
Table 6.2 Structural–mechanical indicators of the abrasive material of abrasive disks obtained according to the conventional and vibration processes
Author
Prof. Naum B. Uriev
Leningradskij Pr., d.35, kv.54
125284 Moscow
Russia
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The monograph summarizes the long-term studies of the author in a new field of physical chemistry of dispersed systems and surface phenomena: physicochemical dynamics of dispersed systems and materials. The author studied this new trend in the Laboratory of Highly Concentration Dispersed Systems founded in 1985 at the Institute of Physical Chemistry of the Academy of Sciences of the USSR.
A distinctive feature of the studies of the author and his laboratory presented in the book is that fundamental projects have been for many years implemented in many applied fields of engineering and technology. Moreover, a whole number of fundamental studies ensued and was induced by engineering challenges regarding various dispersed systems and materials.
The initial stage of studies by the author was related to his long-term work in the Department of Dispersed Systems headed by academician P.A. Rehbinder of the Institute of Physical Chemistry of Academy of Sciences of the USSR.
The breadth of his scientific interests and the diversity of implementation of his results in various fields, including applied projects, served as a good example for the author in his research activity. At the same time, the author's long experience of delivering lectures at the Moscow Institute of Road Traffic (State Technical University) also promoted the application of fundamental developments in many fields of engineering and technology.
In the opinion of the author, the present, often significant, gap between the results of fundamental studies and their practical implementation in the technology of dispersed systems and materials is the major obstacle in the way of transition to a new, qualitatively higher level of solving technological problems in this field.
It is for this purpose that the goal set in this book was to justify the necessity and show the fundamental possibility of eliminating this gap and also formulating the ways and methods of solving this problem using the example of technology of various dispersed systems and materials.
This book is meant for senior students, Masters students, Ph.D. students, and faculty members in higher educational institutions, researchers of research institutes specializing in the field of fundamentals of technology of dispersed systems, dispersed composite materials, and methods of control of their structural–rheological properties in the procedures of their synthesis and processing. It includes lecture notes
The author's research was financially supported by the Russian Foundation for Basic Research (project no. 12-03-00473).
The author is grateful to his colleagues and his family for their support. Special thanks for support to Flow-iD GmbH (www.flow-id.ch) and especially to Dr Boris Ouriev for his editorial work.
Moscow 2016
Naum B. Uriev