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Huggins Equation
The Huggins Equation is an empirical equation used to relate the reduced viscosity of a dilute polymer solution to the concentration of the polymer in solution. It is named after Maurice L. Huggins Maurice Loyal Huggins (19 September 1897, Berkeley County, West Virginia – 17 December 1981) was a scientist who independently conceived the idea of hydrogen bonding and who was an early advocate for their role in stabilizing protein secondary .... The Huggins equation states: \frac= eta+ k_H eta2 c Where is the specific viscosity of a solution at a given concentration of a polymer in solution, eta/math> is the intrinsic viscosity of the solution, k_H is the Huggins coefficient, and c is the concentration of the polymer in solution. In isolation, n_s is the specific viscosity of a solution at a given concentration. The Huggins equation is valid when eta is much smaller than 1, indicating that it is a dilute solution. The Huggins coefficient used in this equation is an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empirical Relationship
In science, an empirical relationship or phenomenological relationship is a relationship or correlation that is supported by experiment and observation but not necessarily supported by theory. Analytical solutions without a theory An empirical relationship is supported by confirmatory data irrespective of theoretical basis such as first principles. Sometimes theoretical explanations for what were initially empirical relationships are found, in which case the relationships are no longer considered empirical. An example was the Rydberg formula to predict the wavelengths of hydrogen spectral lines. Proposed in 1876, it perfectly predicted the wavelengths of the Lyman series, but lacked a theoretical basis until Niels Bohr produced his Bohr model of the atom in 1925.McMullin, Ernan (1968), “What Do Physical Models Tell Us?”, in B. van Rootselaar and J. F. Staal (eds.), Logic, Methodology and Science III. Amsterdam: North Holland, 385–396. On occasion, what was thought to be an em ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reduced Viscosity
In fluid dynamics, the reduced viscosity of a polymer is the ratio of the relative viscosity increment (\eta_i) to the mass concentration of the species of interest. It has units of volume per unit mass. The reduced viscosity is given by: :\frac where \eta_i is the ''relative viscosity increment'' given by \eta_i = \frac (Where \eta_s is the viscosity of the solvent.) See also *Relative viscosity Relative viscosity (\eta_) (a synonym of "viscosity ratio") is the ratio of the viscosity of a solution (\eta) to the viscosity of the solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a s ... * Viscosity * Intrinsic viscosity * Huggins equation References Viscosity {{fluiddynamics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compounds, produces unique physical properties including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals. The term "polymer" derives from the Greek word πολύς (''polus'', meaning "many, much") and μέρος (''meros'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentration (chemistry)
In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', ''molar concentration'', ''number concentration'', and ''volume concentration''. The concentration can refer to any kind of chemical mixture, but most frequently refers to solutes and solvents in solutions. The molar (amount) concentration has variants, such as normal concentration and osmotic concentration. Etymology The term concentration comes from the word concentrate, from the French , from con– + center, meaning “to put at the center”. Qualitative description Often in informal, non-technical language, concentration is described in a qualitative way, through the use of adjectives such as "dilute" for solutions of relatively low concentration and "concentrated" for solutions of relatively high concentration. To concentrate a solution, one must add more solute (for example, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maurice Loyal Huggins
Maurice Loyal Huggins (19 September 1897, Berkeley County, West Virginia – 17 December 1981) was a scientist who independently conceived the idea of hydrogen bonding and who was an early advocate for their role in stabilizing protein secondary structure. An important polymer theory, Flory–Huggins theory, is also named after him. Controversies over the hydrogen bond Huggins believed that he had been the first to suggest the concept of the hydrogen bond, while he was a student under G. N. Lewis at the Chemical Laboratory of the University of California, Berkeley. According to his account, he wrote a thesis in 1919 in which the H-bond was introduced and applied to tautomerism in acetoacetic acid. Unfortunately, no hard copy of the thesis remains. The first extant publication of the H-bond was that of Wendell Latimer and Worth Rodebush in 1920, who cite Huggins' unpublished work in a footnote. (They were fellow scientists at the Chemical Laboratory.) Structure of the pepti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intrinsic Viscosity
Intrinsic viscosity \left \eta \right/math> is a measure of a solute's contribution to the viscosity \eta of a solution. It should not be confused with inherent viscosity, which is the ratio of the natural logarithm of the relative viscosity to the mass concentration of the polymer. Intrinsic viscosity is defined as : \left \eta \right= \lim_ \frac where \eta_0 is the viscosity in the absence of the solute, \eta is (dynamic or kinematic) viscosity of the solution and \phi is the volume fraction of the solute in the solution. As defined here, the intrinsic viscosity \left \eta \right/math> is a dimensionless number. When the solute particles are rigid spheres at infinite dilution, the intrinsic viscosity equals \frac, as shown first by Albert Einstein. In practical settings, \phi is usually solute mass concentration (c, g/dL), and the units of intrinsic viscosity \left \eta \right/math> are deciliters per gram (dL/g), otherwise known as inverse concentration. Formulae for ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentration (chemistry)
In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', ''molar concentration'', ''number concentration'', and ''volume concentration''. The concentration can refer to any kind of chemical mixture, but most frequently refers to solutes and solvents in solutions. The molar (amount) concentration has variants, such as normal concentration and osmotic concentration. Etymology The term concentration comes from the word concentrate, from the French , from con– + center, meaning “to put at the center”. Qualitative description Often in informal, non-technical language, concentration is described in a qualitative way, through the use of adjectives such as "dilute" for solutions of relatively low concentration and "concentrated" for solutions of relatively high concentration. To concentrate a solution, one must add more solute (for example, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the internal frictional force between adjacent layers of fluid that are in relative motion. For instance, when a viscous fluid is forced through a tube, it flows more quickly near the tube's axis than near its walls. Experiments show that some stress (such as a pressure difference between the two ends of the tube) is needed to sustain the flow. This is because a force is required to overcome the friction between the layers of the fluid which are in relative motion. For a tube with a constant rate of flow, the strength of the compensating force is proportional to the fluid's viscosity. In general, viscosity depends on a fluid's state, such as its temperature, pressure, and rate of deformation. However, the dependence on some of these properties is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rheology
Rheology (; ) is the study of the flow of matter, primarily in a fluid ( liquid or gas) state, but also as "soft solids" or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an applied force. Rheology is a branch of physics, and it is the science that deals with the deformation and flow of materials, both solids and liquids.W. R. Schowalter (1978) Mechanics of Non-Newtonian Fluids Pergamon The term ''rheology'' was coined by Eugene C. Bingham, a professor at Lafayette College, in 1920, from a suggestion by a colleague, Markus Reiner.The Deborah Number The term was inspired by the of |
Polymers
A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compounds, produces unique physical properties including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals. The term "polymer" derives from the Greek word πολύς (''polus'', meaning "many, much") and μέρος (''meros'', meani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
