A

#ABS Alkyl benzene subnate.

Absolute (Dynamic) Viscosity Ratio of stress to rate of shear strain.

Acid Number Number of mg of KOH required to neutralize the free fatty acids in 1 gram of fat, wax, or resin.

Adhesion Condition in which unlike substances stick to each other.

Adhesional Wetting Formation of a solid/liquid interface at the expense of solid/air and the liquid/air interface.

Adhesive Material that can hold other materials together by physical or chemical attachment at the surfaces.

Adsorbate Material that adheres to the surface of another.

Adsorbent Material on whose surface adsorption takes place.

Adsorption Adhesion of a substance to the surface of a solid or liquid.

Adsorption Curve Amount adsorbed from a solution plotted as a function of the concentration of the solute.

Aerosol Colloidal suspension in which gas is the dispersant. Dispersionor suspension of extremely fine particles of liquid or solid in a gaseous medium.

Agglomerate Cluster of particles adhering to one another.

Aging Process of growing old shown by continued influence of light, temperature, external atmosphere, time, etc.

Alginates Vegetable products made from kelp and seaweed.

Aliphatic Hydrocarbon Straight-chain organic compounds such as the paraffins and their derivatives; e.g. propane, ethylene, acetylene.

Alkyd Group of thermoplastic synthetic resins made from dibasic organic acids, anhyrides, alohols, and drying oils.

Ampholytic Capable of acting either as a base or as an acid, depending on the nature of the surrounding medium.

Amphoteric Reacting chemically as an acid to strong bases and as a base to strong acids.

Angstrom Unit of wavelength equal to 10-10m.

Anhydrous Not containing water of hydration, or completely dry.

Anion Negatively charged ion such as hydroxide (OH-), carbonate (CO3=), phosphate (PO4=).

Anionic Surfactants Ionic surface-active agents in which the portion that associates with the internal phase is the anion, negatively charged hydrophobe; they include car boxylic acids, sulfuric acid esters, and sulfonic acids.

Antifoamer Liquid of low intrinsic surface tension that prevents formation of a foam.

API American Petroleum Institute.

Apparent Viscosity Viscosity of a complex (non-Newtonian) fluid under given conditions.

Aromatic Hydrocarbons Organic compounds that contain a benzenoid structure or ring. The simplest such compound is benzene, C6H6.

ASA American Standards Association.

Asphalt Base Oil Type of petroleum that yields a pitch-like residue on distillation.

Association Combination of molecules of the same substance, resulting in multiple molecules.

ASTM American Society for Testing and Materials.

ASTM Time Tube Viscometer of the rising-bubble type.

Atlantic Viscometer Apparatus used to determine the kinematic viscosities of transparent Newtonian liquids of 0.6-5000 cS.

Attrition Pulverization through abrasion.

B

Baffle Partition or plate that changes the direction or restricts the cross section of a fluid, thus increasing velocity or turbulence.

Base Stock Blend of materials that makes up the bulk of a product.

Batch Fixed unit charge in the processing of materials.

Bentonite A colloidal clay used as an adsorbent.

Benzin (Petroleum Benzin) A refined light naphtha meeting USP specifications.

Binder to bind the pigment particles together.

Biodegradability Susceptibility of a chemical compound to depolymerization by the

action of biological agents.

Bingham Plastic A substance that will not flow until its yield value is reached; thereafter, it flows like a normal liquid.

Binodal Curve Curve in a triangular isothermal equilibrium plot that connects miscibility points.

Biocolloid Lyophilic colloidal system found in living organisms.

Bitumen Mixture of natural and pyrogenous hydrocarbons that is soluble in carbon disulfide.

Bleeding Separation of the oil constituent of a grease from the base.

Blending Mixing of several components to obtain a homogeneous material.

Bloom Appearance of an emulsion as it is poured into a large amount of its continuous phase.

Blowing Injection of compressed air into tanks to agitate and mix the contents; the act of foaming a system.

Blowing Agent Material used to provide the gas needed for foaming operations.

Bond Linkage between atoms in a molecule.

Branched Condition in the structure of molecules polymers where the molecule has side chains attached to the main chain.

Breakdown Time (gasoline) Time elapsed before gasoline forms gums in storage.

Brookfield Viscometer Instrument that measures the viscosity of a liquid as a function of the torque produced by rotating a spindle at fixed rpm in a liquid.

Brownian Movement Random movement of colloidal-size particles that arises from collisions between the particles and molecules of the fluid medium in which they are suspended.

B Stage of Resin Partial cure of a resinous polymer in which it is more viscous with higher molecular weight, being insoluble but plastic and fusible.

Buffer Action Property of certain solutions of resisting changes in pH upon the addition of acid or alkali.

Buffer Substance that causes a resistance to change in pH when added to a solution.

Bulk Density Weight per unit volume of a quantity of solid particles; depends on packing density.

Bunker Fuel Fuel for marine boiler.

C

Calendering Subjecting a material to pressure between two or more counter-rotating rollers.

Cannon-Fenske Viscometer Modifies Ostwald-type viscometer used to determine the kinemataic viscosity of transparent Newtonian liquids (0.4-16,000 cS).

Capillary Action Phenomenon observed on the surface of liquids due to unbalanced molecular attraction at the liquid boundary.

Capillary Tube Viscometer Instrument for the measurement of viscosity as a function of the time required for a certain amount of fluid to flow through a small-box tube of known diameter and length under a known constant pressure difference. Assuming laminar flow, the viscosity is calculated from the Hagen-Poiseuille law.

Capillary Value of Adsorbent Difference between saturation and retentivity value. Amount of solvent held loosely in pores.

Catalyst Substance that alters the rate of chemical change and remains unchanged at the end of a reaction.

Catalyst Activity Measure of the relative performance of a catalyst in promoting the reaction of a material to give a desired performance.

Cataphoresis Particle migration in a colloidal solution between electrodes exhibiting a potential difference.

Cation Positively charged ion such as Na+, K+, NH4+.

Cationic Surfactants Ionic surface-active agents in which the portion that associates with the internal phase is the cation. Cationic surfactants have positively charged hydrophobes. They include simple amine salts, quaternary ammonium salts, amino imides and imidazolines. Cationic surfactants often have germicidal anticorrosive, and antistatic properties.

Centipoise (cP) Unit of viscosity equal to 1/100 dyne/sec2/cm2.

Channeling Physical parting or separating of the body of a lubricant.

Chemical Change Change in which new substances with new properties are obtained from a chemical composition or decomposition of a substance.

Chemisorption Adsorption process in which a polar group is bound to certain groups in a surface by chemical linkages.

Chiller Cooler for separating wax from petroleum fractions.

Clay Treatment Adsorption process used in oil refining.

Cloud Point Temperature at which solutions become cloudy on cooling or heating.

Coagulation Process in which the small particles in an emulsion are combined in agglomerates but still retain their character as individual particles.

Coalescence Process by which small particles (droplets) in an emulsion combine to form larger particles (drops).

Coarse Emulsion Emulsion that contains large droplets of the internal phase.

Cohesion Force of attraction of like molecules for one another within a substance.

Cold Pressing Separation of a solid petroleum product from a liquid petroleum medium by means of a filter press.

Collector Chemical additive controlling the wettability of ores in a flotation process.

Colloid Finely divided substance 0.001-1 µ in diameter. The physical properties of a colloid are controlled by the surface forces.

Colloidal Metals Colloidal suspension of metals.

Colloid Mill Machine used for the preparation of emulsions of fine particle size. The emulsion is forced through the adjustable small annular space between a stator and a rapidly revolving rotor.

Colloidal Suspension Two-phase system having small dispersed particles suspended in a dispersant.

Complex Liquid Liquid in which the rate of shear is not proportional to the shearing stress; a non-Newtonian liquid.

Complex Mixture Mixture of more than three components.

Compound Two or more elements chemically united in definite percentages by weight that are separable only by chemical means.

Compound Oils Oils made by mixing mineral oils with other oils, vegetable or animal.

Concentration of Emulsifying Agent Amount of surface-active agent in the emulsion. May be based on the volume or weight of the total emulsion or on one phase.

Conjugate Layers Coexisting layers in an extraction—the solvent and diluent.

Conradson Test Method for the determination of the percentage by weight of carbonization residue left from burning a petroleum product according to an ASTM standard method.

Consistency Resistance of a fluid to deformation. For simple (Newtonian) fluids the consistency is identical with the viscosity, for complex (non-Newtonian) fluids, identical with apparent viscosity.

Contact Surface Area of a phase interface.

Continental Method Procedure for preparing emulsions whereby the oil and surfactant(s) are thoroughly mixed and water is added to the mixture. As progressively more water is added, the emulsion will invert and water will become the continuous phase.

Continuous Phase External phase of an emulsion.

Convection Natural or forced motion in a fluid induced by heat or the action of gravity.

Copolymer Compound resulting from the chemical reaction of two different monomers or polymers with each other.

Couette Viscometer Rotational type of instrument for the measurement of viscosity. A fluid is placed in the annular space between two concentric cylinders, one of which is rotated. The measurement of torque and velocity gradient can be correlated with viscosity.

Coulomb Viscometer Instrument that measures the damping effect produced by a fluid upon a vibrating reed.

Covalent Molecule Molecule in which the bond between two atoms is a shared electron pair.

Creaming Separation of an emulsion into two distinct phases, one of which has a higher concentration of the dispersed phase than the original emulsion; the other contains more of the continuous phase. This is a reversible process.

Critical Micell Concentration (CMC) Saturation point of surfactant in a water system. The CMC is observable by discontinuities in the curves of physical properties of the system as a function of the amount of surfactant added.

Critical Quantity Minimum or maximum amount of a blended or homogenized material needed to obtain a desired result.

Critical Surface Tension Surface tension of a solid equal to that of the liquid of highest surface tension that will wet the solid.

Critical Velocity Transitional velocity at which the flow of a fluid changes from laminar to turbulent.

Crosslinks Bonds linking molecular chains

Cut-Back Product Material that has been diluted by adding a solvent.

D

Dead Oils Tardistillates that are heavier than water.

Deblooming Bleaching of oils to reduce fluorescence.

Deflocculate Converse of clumping or clustering of particles.

Defoamer Substance of low intrinsic surface tension that reduces or destroys frothing.

Denaturing Making a product unfit for human consumption, as by the addition of chemicals influencing the taste or toxicity.

Densimeter Instrument for measuring the density or specific gravity of liquids.

Detergent Surface-active material or combination of surfactants designed for removal of unwanted contamination from the surface of an article.

Dialysis Separation of colloids from dissolved substances by selective diffusion through a semipermeable membrane.

Diffusion Mixing of molecules or atoms by random molecular or atomic motion.

Dilatant Increasing instantaneously the apparent viscosity of a fluid with increasing rate of shear.

Diluent Diluting agent

Dilution Act of reducing the proportion of a substance in a solution by addition of more solvent.

Dilution Ratio Volume of solute divided by volume of solvent.

Dipole Molecule that has an electrical moment (charge separated by a distance).

Dispersed Phase Dissolved or suspended phase in a colloidal solution or suspension.

Dispersing Agent Surfactant that is used to separate, or keep separated, aggregations of particles by reducing the cohesive attraction between the particles.

Dispersion Physical, usually temporary, mixture of two insoluble phases.

Dispersing Medium Continuous phase of a dispersion.

Dissociation Breaking up of molecule or associated species into smaller entities.

Dissolving Formation of a solution by dispersion of one material (solute) at a molecular (or less) level in another material (solvent).

Distribution Ratio Ratio of concentrations of a dissolved substance in two immiscible solvents.

Double Layer Potential Electrical potential difference between a substance and a solvent.

Dropping Point Temperature at which a grease passes from a semi- solid to a fluid state.

Dual Emulsion Emulsion in which both the internal and external phase contain portions of the opposite phase instead of being homogeneous. This is also referred to as a mixed emulsion.

Dynamic Similarity Condition in which all corresponding forces between two systems are proportional.

Dynamics Behavior of bodies under the action of forces that produce changes of motion in them.

Dynamic Viscosity An index of molecular friction within a fluid that is proportional to the rate of deformation and the viscosity coefficient of a fluid (absolute viscosity).

E

Ebullioscopy Determination of the concentration of materials in a solution based upon boiling point deviations.

Eddy Viscosity Turbulent viscosity based upon ratio of shear stress to a velocity gradient.

Elastic Fluid Fluid in which elastic stresses and hydrostatic pressures are large compared with viscous stresses.

Elasticity Recovery of the original size and shape of a material after deformation.

Electrophoresis Migration of the electrically charged particles toward the oppositely charged electrode.

Electroviscous Effect Lyophobic particles that bear an electrical charge and therefore exhibit a viscosity exceeding that of a similar system of uncharged particles.

Emulsifying Process of uniformly dispersing one mutually insoluble material in another.

Emulsifying Agent Surface-active agent that is primarily used to effect the stability of an emulsion system. Emulsifying agents may be ionic (anionic, cationic, amphoteric) or nonionic in solution.

Emulsion System consisting of two incompletely miscible liquids, one being dispersed as finite globules in the other. A small amount of a third substance may render the dispersion stable. The liquid broken up into globules is the dispersed (discontinuous) phase; the surrounding liquid is the external (continuous) phase. Emulsion can also consist of gas in liquid (foams) or solids in liquids, such as liquid crystals.

Emulsion Polymerization Polymerization of a water insoluble monomer that takes place in the presence of water to form a latex. The monomer is usually emulsified and polymerization occurs within the emulsion system.

Emulsoid Colloidal system in which there is a strong attraction between the disperse substance and the dispersing liquid.

Emulsoid Sol Colloidal suspension in which both dispersion medium and dispersed phase are both liquids.

Endothermic Process Process that absorbs heat.

Engler Degree Measurement of kinematic viscosity that is obtained by dividing the outflow time of a specified amount of liquid through a standard orifice by the outflow time of water at 20˚C.

English Method Procedure for the preparing of an emulsion whereby a small portion of the water and the surfactants are mixed. The oil and remaining water are then added in successive small portions.

Eucolloid Colloid composed of relatively large particles (larger than 0.25µ).

Exothermic Process Process that liberates heat.

External Phase Dispersing medium of a colloidal suspension; the continuous phase of an emulsion.

Extrusion The process of forcing a material in plastic condition through an orifice.

F

Falling-Body Viscometer A device that utilizes a sphere, falling through a mass of the test fluid inside a cylindrical tube. The time for the sphere to fall a certain distance is measured and correlated with viscosity.

False Body Reversible work-softening that causes a high apparent viscosity of a material.

False Gel Unstabilized gel that breaks down upon standing.

Fire Point Lowest temperature of an oil at which it will ignite and continue to burn for at least 5 seconds.

Flash Point (Cleveland Open-Cup Test) Lowest temperature of an oil at which it gives off vapors that will ignite when a small flame is passed over the surface of the oil.

Fitzsimmons Viscometer Device that determines the kinematic viscosities of transparent Newtonian liquids in the 0.6-1200 cS range.

Flocculation Process in which the disperse particles in a liquid medium display a tendency for mutual adhesion.

Flotation Ore-dressing method in which surface-active additives cause one of the constituents to float to the surface in the froth produced by aeration and agitation.

Fluid Substance that cannot sustain shear forces when in static equilibrium. Real fluids in motion sustain shear forces because of the property of viscosity.

Fluidity Reciprocal of viscosity, expressed in inverse poise.

Fluxing Thinning of heavy oil by the addition of a more fluid oil.

Foaming Agent Surface-active material that is used specifically to form a dispersion of a gas in a liquid or solid medium.

Force-Type Viscometer Instrument that measure force at constant shear rate. Units of force can be converted directly into viscosity units.

Formula Weight Sum of the atomic weights of all the atoms in an empirical formula.

Friction Factor Used in the Fanning equation to compute the friction loss through length of tube and is a function of Reynolds number.

Frothing Agent Surface-active material that is used specifically to stabilize the dispersion of a gas in a liquid or solid medium.

G

Galling Metallic binding or seizure under load and relative motion.

Gardner Mobilemeter Instrument used to determine the thixotrophy of a material.

Gel Semisolid system that consists of a solid held in a liquid; a more solid form than a sol.

Gelometer Instrument used to measure the time required for a fluid to gel.

Gibbs Absorption Law When the concentration of a substance in the interfacial layers between two phases exceeds that in the bulk of either phase the substance is absorbed at the interface.

Gouy Diffuse Double Layer The gradual, exponential electrical potential drip from the interface of an emulsion into the bulk of the phase.

Gum Class of colloidal substances that is exuded by plants.

H

Hallikainen Shell Type of viscometer that yields continuous values of a pressure differential maintained in a capillary tube for the determination of fluid viscosity.

Hegman Gage Arbitrary scale for comparing fineness of grind, expressed in "mesh."

Helmholtz Double Layer The sharp and continuous decrease into the bulk of the fluid of the electrical potential of a single layer of oriented, ionized surfactant molecules at the interface. This effect can exist on both sides of the interface in an emulsion.

HLB Number (Hydrophile-Lipophile Balance) System for the selection of emulsifying agents. Lipophilic (nonpolar) emulsifiers have HLB numbers below 9; hydrophilic (polar) have HLB numbers above 11. The HLB of an emulsifier (or blend of emulsifiers) may be related to its performance in an emulsion system.

Holdup Amount of liquid retained by a piece of equipment when the equipment is emptied.

Homogeneous Fluid Substance that is identical throughout.

Homogenization The process of making incompatible or immiscible components into a stabilized uniform suspension in a liquid medium.

Homogenizer Mixing machine used for the preparation of emulsions of fine particle size. The emulsion is forced at high pressure through the annular space between an adjustable valve and its seat.

Homopolymer Polymer that is produced from a single monomer species.

Hydrometer Densimeter Device used for the measurement of specific gravities.

Hydrate Crystallized substance that contains water of hydration.

Hydration Attachment of water molecules to ions or molecules.

Hydrogel Colloidal gel in which water is the solvent.

Hydrolysis Splitting of a chemical bond(s) by the addition of water.

Hydrophilic Attracted to water; water-soluble.

Hydrotopy Effect of large additions of various substances to water in increasing the solubility of other substances therein.

I

Ideal Fluid (Perfect Fluid) Hypothetical liquid (or gas) that offers no resistance to shear and has zero consistency.

Impeller Rotating member of an agitating or pumping device.

Implosion Inward collapse.

Inhibiter Substance that prevents or slows down a chemical reaction.

Initiator Substance that starts a polymerization reaction.

Interfacial Film A film of material (usually liquid) that forms at the point of contact of two immiscible liquids. The film may prevent coalescence.

Interfacial Viscometer Instrument used for the measurement of the physical properties of surface and interfacial films.

Internal Phase Dispersed or discontinuous phase of an emulsion.

Intumesce Foaming, swelling, or bubbling that may be a result of heating.

Inversion Transposition of the two phases of an emulsion (internal phase becomes external phase and vice-versa).

Ion Electrically charged portion of matter of atomic or molecular dimensions.

Ionic Surfactants Surfactants that dissociate in solution into an organic lipophilic group and a hydrophilic group. The molecules produce two ions, one positively charged (cation), the other negatively charged (anion).

Ionic Solutions Solutions of substances such as acids, bases and salts that dissociate in solution into charged particles called ions.

Iso Prefix meaning equal.

Isoelectric Point pH value of a hydrophilic sol (electrolyte) at which it will not migrate in an electrical field.

Isotropic Fluid Fluid whose properties are independent of the rotation of the axis of reference along which the properties are measured.

K

Key Material In a blend of two or more materials, material whose uniform dispersion is most important to the success of the operation.

Kinematic Eddy Viscosity Ratio of eddy viscosity to density.

Kinematic Viscosity Ratio of viscosity to density; the unit of kinematic viscosity is the stoke.

Kinematics Motion of bodies without reference to the forces producing the motion.

Krebs Units Arbitrary scale used for the comparison of viscosities.

L

Laminar Flow Streamline flow of a fluid. The mass of fluid advances in separate sheets with simple shear existing at the surface of contact of different layers if the layers move at different speeds.

Lantz-Zeitfuchs Viscometer Reverse-flow viscometer that permits the measurement of kinematic viscosities of opaque Newtonian liquids of 60-120,000 cS.

Latex Any stable dispersion of insoluble polymer particles in a water system. Generally an emulsion of a high molecular weight polymer in water, often formed by emulsion polymerization of the monomer(s).

Leaching Washing operation that removes a certain amount of dissolved substance(s) from a material.

Levigation Grinding of a solid to a fine smooth powder while in moist condition.

Lipophilic Attracted to oil; oil-soluble.

Liquid Substance that undergoes continuous deformation when subjected to shearing stress.

Livering Coagulation of a paint or enamel into a viscous rubbery mass.

Lubricating Greases Solid or semifluid products of the dispersion of a thickening agent in a liquid lubricant that may contain ingredients to impart special properties.

Lyophilic Pertaining to a colloidal system of the emulsoid type.

Lyophobic Pertaining to a colloidal system of the suspensoid type.

Lyophobic Colloid Irreversible colloid; the disperse phase when removed from suspension does not return to the colloidal state upon simple remixing.

Lyophilic Coilloid Reversible colloid; the dispersed phase when removed from suspension returns to the colloidal state on remixing with the dispersible medium. The suspension is a reversible sol.

M

MacMichael Viscometer Viscometer that consists of an outer cylinder rotated by a variable-speed motor; the measured torque exerted on an inner cylinder is a function of the viscosity of the test fluid. It is suitable for non-Newtonian suspensions.

Macromolecule Very large molecule, generally of polymer.

Master Batch Blend of several minor ingredients that is used later in the compounding of a product.

Master Viscometer Glass viscometer (capillary) with a liquid driving head of 400 mm or better, designed to minimize errors due to surface tension, kinetic energy, and capillary end effects.

Maximization Concerted effort to increase the efficiency of a process through the most appropriate combination of instruments and techniques.

Maxwellian Fluid Viscous fluid in which the stress-strain relationship includes the relaxation effect (time of relaxation of elastic stresses set up by sudden deformation).

Mayonnaise Technique Emulsification procedure in which the ingredients are added alternately.

Micron Unit of length, equals 1 micrometer or 0.001 mm.

Milling Final "polishing" operation (prior to packaging) to improve the stability of a grease by modifying its gel structure.

Miscella Solvent-oil solution obtained in the extraction of certain oil seed and containing mucilaginous materials that may be difficult to separate.

Micelle Small aggregation of surfactant molecules in a suspension. If water is the dispersing medium, the molecules are orientated with the hydrophilic end toward the water phase and the lipophilic ends together.

Mixture Material composed of two or more substances, each of which retains its own characteristic properties.

Modifier Additive that changes the nature of a product or the process by which it is produced.

Modulus of Elasticity Ratio of stress to strain in a material that is elastically deformed.

Molar Volume Molecular weight of a substance divided by its density.

Molecule The smallest theoretical quantity of a material that retains the properties exhibited by the material.

Molecular Association Aggregation of single molecules into complexes containing two or more molecules.

Molecular weight Sum of the atomic weights of all atoms in a molecule.

Mole Mass numerically equal to the sum of the atomic weights of all the atoms in a molecule.

Monomer Simple form of a compound that is the building block of a polymer.

Multiple Emulsion Emulsion in which the disperse phase contains globules of the continuous phase.

N

Natural Gums Plant (usually tree) exudations such as gum arabic, gum tragacanth, gum karaya, and guar that are high-polymer saccharides.

NF National Formulary.

Neutralization Number mg of KOH required to neutralize the acid in 1 g of oil.

Newton Viscometer Instrument that measure the resistance of a fluid to motion between two parallel sliding plates. A Newton viscometer is often used on high-viscosity materials.

Newtonian Fluids Fluids whose viscosity is independent of the rate of shear. Pure liquids, true solutions, and dilute suspensions are generally Newtonian.

Newton’s Law of Similarity Material systems are dynamically similar when the ratio of forces acting upon corresponding mass elements at corresponding times is constant. Such forces include pressure, inertia, gravity, viscosity, elasticity, and surface tension.

Nip Distance between rolls in mill or calender.

Nonelectrolyte Substance whose water solution will not noticeably conduct an electric current.

Nonionic Surfactants Covalent emulsifying agent that will not ionize in solution; they include alkyl ethers, alkylar ethers, thio-ethers, esters, and amides.

Non-Newtonian Suspensions In viscous flow, the viscosity of a non- Newtonian suspension is a function of the rate of shear and duration of the shear. Non-Newtonian classes of materials include Bingham plastics, pseudoplastics, dilatants, thixotrop, and rheopectics.

Nonpolar Liquids Liquids whose molecules possess little or no dipole moment.

Normal Hydrocarbons Hydrocarbons with straight, not branched, molecular chains.

O

Oil Common shorthand in emulsion technology referring to the water-insoluble phase of an emulsion. The oil phase may be a fluorocarbon, silicone, or wax, in addition to or instead of a conventional oil.

Organosol Colloidal suspension in which the continuous phase is an organic compound.

Osmosis Diffusion between two miscible fluids separated by a permeable wall.

O/W Emulsion Oil-in-water emulsion; oil is the internal phase, water the external phase. An O/W emulsion is dispersible (dilutable) in water, but not in oil.

P

Parasitic Reaction Side reaction that may interfere with a process and reduce its yield.

Partial Pressure Portion of the total pressure of a system that is the pressure contribution of a specific component of the gas mixture.

Penetrant Surface-active agent used in the textile industry to aid dyeing and sizing operations.

Penetrometer Instrument for determining the consistency of high- viscosity materials such as asphalts, greases, waxes.

Peptization Dispersion of a substance into particles of colloidal size, caused by addition of a peptizing agent.

Peptizing Agent A protective colloid.

Percolation Extraction process, usually of a liquid acting upon a solid.

Perfect Fluid Fluid of zero viscosity.

Permanent Emulsion Emulsion in which the droplets of the dispersed phase do not coalesce or coagulate in time: a stable emulsion.

Phase Interface Boundary surface between two phases or films.

Phase Rule For a heterogeneous system in equilibrium, the sum of the number of phases plus the number of degrees of freedom equals the number of components plus two.

pH Value Negative logarithm of the hydrogen ion concentration and hence the acidity or alkalinity of a solution. The scale ranges from 1 (highly acidic) through 7 (neutral) to 14 (highly basic).

Phase-Volume Ratio Ratio of the volume of the internal phase to that of the external phase in an emulsion.

Photomicrograph Photograph of the emulsion that is used for particle size determinations or other visual observations of the emulsion. Agglomeration can be seen if the particles are stabilized by the addition of a thickener, e.g. gelatin, to the continuous phase.

Physical Change Change in which the identifying chemical properties of a substance remain unchanged.

Pigment Finely divided insoluble substance that imparts color to the material to which it is added.

Pipeline Mixer Device for continuous mixing and/or homogenizing within a transfer pipe.

Pitting Spot corrosion that is caused by chemical or galvanic effects.

Plastic Deformation Change in the dimensions of a material load that is not recovered when the load is removed.

Plasticizer Chemical agent added to plastics to make them softer and more flexible.

Plastisol Suspension of resin(s) in plasticizer(s).

Plastic Solid Substance that does not deform under a shearing stress until the stress attains the yield stress, at which point the solid deforms permanently.

Plug Flow Flow characterized by an almost square velocity profile. Under certain pressure conditions prevailing in closed tubes, mass in the middle of the pipe moves like a solid plug, with laminar flow along the wall.

Poise Unit of viscosity, equivalent to 1 dyne/sec/cm2.

Poiseuille’s Equation Relation between liquid flow through a tube pressure, and length and cross-section of path, assuming uniform streamline flow.

Poiseuille Viscometer Instrument to measure viscosity based on outflow measurement of fluids. Commercial Poiseuille viscometers include Engler, Barbey, Redwood, and Saybolt units.

Polar Bond Essentially covalent chemical bond that results from the unequal sharing of valence electrons between atoms.

Polar Compound Substance that possesses a permanent electric moment.

Polar Liquids Liquids whose molecules possess a dipole moment such as alcohols, acids, aldehydes, etc.

Polydisperse Systems Systems that consist of various size particles droplets.

Polymer Compound formed by polymerization, characterized by high molecular weight (usually over 1000) and a repeating chemical structure.

Polymerization Formation of large molecules from smaller or (monomers).

Polyphase Emulsion Mixed, multiple, or dual emulsion that has well-defined internal and external phases; each phase contains droplets of the other phase.

Pour Point Lowest temperature at which an oil will pour.

Precipitate Substance separated from a solution, suspension, dispersion, or emulsion as a result of chemical or physical change.

Pressure Drop Difference in force on unit areas on the two sides of barrier.

Protective Agent Colloidal substance that stabilizes the suspension of the particles when adsorbed on suspended particles.

Protective Colloid Material that stabilizes a particular disperse system against coagulation or coalescence. It is usually a lyophilic colloid that forms a protective film (by adsorption) around each particle.

Pseudoplasticity Property of a fluid whose consistency decreases constantly with increasing rate of shear.

Pseudostable State of a material that causes a change of its physical properties over a period of time.

Q

Quiescent Flow Condition existing when the degree of turbulence is less than that indicated by the Reynolds number.

R

Random Distribution Arrangement of particles in a mixture so that the probability of a single particle being at any one location is the same as that of its being at any other location.

Rao Birefringence Viscometer Couette-type viscometer that is used for low-viscosity fluids.

Relative Viscosity Viscosity of a liquid in terms of the viscosity of some standard liquid, such as water at 20˚C.

Relative Volatility Volatility of one component divided by volatility of the other components; the pressure ration for components following Raoult’s law.

Resolving Power Ability of a microscope to produce separate images of particles very close together.

Reynolds Number (Re, dimensionless) Measure of the degree of turbulence of a fluid flowing in a pipe; diameter times velocity times density and divided by absolute viscosity.

Rhe Unit of fluidity; 1 rhe=1 poise-1

Rheological Properties Flow properties of a system, e.g. plastic flow, thixotropy, and pseudoplasticity.

Rheology Study of the deformation and flow of matter.

Rheopectic Pertaining to a fluid whose apparent viscosity increases with time to some maximum value at any constant rate of shear.

Rigidity Reciprocal of mobility.

River-Water Die-Away Test Proposed test to determine the biodegradability of surface-active agents.

Roller Mill Two or more rolls, usually revolving at different speeds, between which the materials to be mixed are passed.

Rotational Flow Flow that exhibits appreciable vorticity.

ROV (Refined Oil Viscosity) Viscosity of lamp oils and napthas as measured by a Saybolt Thermo-viscometer.

Rupture Stress Shear stress.

S

Salting Out Precipitation of a material from its dispersion.

Saponification The process of hydrolysis of fats or oils by an alkali of a fluid to form soap.

Saybolt Universal Seconds (SUS) Kinematic viscosity of a fluid as determined by the time in seconds required for 60 cm3 of liquid to flow through a standard orifice.

Saybolt Viscometer Transpiration type of viscometer primarily used to determine viscosity of petroleum products.

Scattering Deflection of light rays by particles of suspended matter.

Sedimentation Spontaneous separation of two or more materials (liquids, solids or gases).

Segregation Separation of the constituents of a mixture, e.g. by electrostatic charges.

Seizing Metallic freezing together of materials under load.

Shake Flask Test Screening test for the determination of biodegradability, proposed by the Soap and Detergent Association.

Shear Stability Ability of a grease to withstand repeated working with minimum change in structure or consistency.

Shear Viscometer Instrument for measuring viscosities of complex fluids at different shear rates.

Shelf Life Period of time during which an undisturbed emulsion retains its type and essential properties.

Shock Chilling Addition of a cold fluid to a hot fluid in order to obtain rapid cooling of the blend to a given temperature.

Sil Viscometer Instrument used for the determination of viscosities of Newtonian fluids in the 0.6-10,000 cS range.

Simple Liquid Liquid in which the rate of shear is proportional to the shearing stress. The constant ratio of shearing stress to rate of shear of a simple liquid is the viscosity of the liquid.

Soap Metallic salt of a fatty acid.

Slip Displacement loss in a pump that is affected by the viscosity of the liquid being pumped and the pressure differential.

Solid Substance that undergoes permanent deformation only when subjected to shearing stress in excess of some finite value characteristic of the substance (yield stress).

Solids Active ingredients of a mixture. In the emulsion the "solids" includes the internal phase and the emulsifiers, stabilizers etc., all of the system except the continuous phase or solvent.

Solubility of an Emulsion Dispersibility of an emulsion as determined by the nature of the continuous phase.

Solute Substance that is dissolved in a solvent; the substance in lesser concentration in a solution.

Solution Homogeneous mixture of two or more substances. It is characterized by an ionic or molecular-level subdivision of the components that will not become heterogeneous upon standing.

Solvation Adsorption of molecules of a dispersing liquid by the dispersed particles.

Solvent Constituent of a solution present in the larger amount.

Space Velocity Product of the feed rate times specific volume of feed divided by volume of vessel used in a converting operation, expressed in volume processed per unit time. It is the reciprocal of hypothetical retention time.

Specific Surface Surface area of a substance per unit volume.

Specific Viscosity Relative viscosity of a fluid.

Specific Volume Reciprocal of density; volume per unit mass, as cm3/g, ft3/1b, etc.

Speed Velocity see Space Velocity.

Spreading Coefficient (Harkins) Number describing the decrease in the total interfacial energy of an aqueous system by the addition of a specific surface substance.

Stable Emulsion Emulsion that retains its form and condition and in which the particles of the internal phase do not coalesce.

Stabilizer Ingredient that is added to a system to maintain the physical and chemical properties of the product throughout its processing and service life.

Stagnation Point Point at which the fluid velocity of a system is zero.

Standard Deviation Statistical measure of the scattering of data from the average; equal to the root mean square of the individual deviations from average.

Stem Diffuse Double Layer Presence of a sharp Helmholtz layer of i nic thickness at the interface followed by a Gouy exponential electrical potential drop into the bulk of the fluid. This effect is two-sided; it exists on both sides of the interface in an emulsion.

Stone Unit of kinematic viscosity, symbol S.

Stone’s Law A small sphere falling under the action of gravity through a viscous medium reaches a constant velocity that is a function of the radius of the sphere, its density, the density of the medium, and its viscosity coefficient.

Stormer Viscometer Viscometer is which the fluid is placed between two cylinders. The inner cylinder rotates by the action of a falling weight. The rotational speed is determined by measuring the time required for a definite number of revolutions of the inner cylinder. The torque is determined from the weight and radius of the pulley. The viscosity of the fluid is a function of the rotational speed and torque.

STP Standard Temperature and Pressure: 0˚C, 760 mm pressure.

Stran Deformation Change in the dimensions of a body under stress.

Stratification Formation of layers in a fluid mixture.

Streamline Line that gives the velocity direction of a fluid (number of particles) at each point along the line.

Streamline Flow Flow where fluid particles move along the streamlines.

Stress Internal force exerted by one part of a body upon an adjoining part.

Structural Color Color due to the physical structure of the mass and not dependent upon the electronic configuration of the substance.

Substance Any form of matter that is homogeneous throughout, i.e. solid, liquid, gas.

Supersaturated Solution One that contains more solute in solution than is present in a saturated solution of the same substance at the same temperature and pressure. A supersaturated solution is usually formed by reducing the temperature or removing some of the solvent from a saturated solution.

Surface-Active Agent Substance that affects the surface tension of a liquid. They include emulsifying agents, detergents, suspending agents, wetting agents, etc.

Surfactant Surface-active agent.

Suspensoid Colloidal suspension in which there is little attraction between the dispersed substance and the dispersing liquid; a lyophobic colloid.

Syneresis Exuding of small amounts of liquids from gels by contraction.

Thermoplastic Resin that can be readily softened and resoftened by heat.

T

Thickner Device that produces separation of solids from liquids by sedimentation; material that increases the viscosity of a fluid.

Thick Phase Increase in viscosity found in an emulsion before inversion. The close packing of the internal phase results in a high viscosity. The thick phase is often used to maximize the shear on an emulsion by mixing the emulsion into a thick phase or causing inversion by mixing the thick phase.

Thixotropy Reversible gel-sol-gel transition that is characterized by a reduction in viscosity upon the application of shearing stress.

Time-Measuring Viscometer Instrument measuring the time needed for efflux of a liquid through an opening, rise of an air bubble, fall of a steel ball, revolution of a paddle driven by a constant torque, or slide of a plate.

Titer The re-solidification point of the melted oil, fat, butter or wax.

Torr Unit of pressure, same as millimeter of mercury.

Turbidimeter Instrument that measures the reduction in light transmission caused by interposing a suspension between light source and observer.

Turbulence Flow caused by superimposing irregular currents on a uniform flow.

Turbulent Flow Motion of a fluid in which its velocity at a fixed point fluctuates randomly with time.

Tyndall Effect Light-scattering that is visible when a beam of coherent light passes through a colloidal system.

U

Ubbelohde Viscometer Suspended level instrument that determines kinematic viscosities of transparent Newtonian liquids in the 2-10,000 cS range.

Ultrasonic Emulsifer Machine that is used for the preparation of fine- particle-size emulsions. The emulsion is forced at high velocity against the edge of a blade. The acoustical waves of the vibration of the blade produce cavitation, which accomplishes the emulsification.

Unstable Emulsions Those emulsions that separate into two immiscible phases, or otherwise lose homogeneity.

USP United States Pharmacopeia.

V

Valence Number of electrons gained, lost, or shared by an atom in bonding to one or more other atoms.

Velocity of Approach Average velocity of fluid in a duct head of the point considered.

Vinyl Class of resins containing materials such as polyvinyl chloride, polyvinyl acetate, etc.

Viscometer (Viscosimeter) Instrument for measuring the viscosity of a fluid. Types of viscometers are: 1) Poiseuille, 2) Stokes, 3) Couette, 4) Newton, 5) Coulomb, according to the effect used to measure the viscosity.

Viscosity Breaking (Visbreaking) Thermal treatment (cracking) of petroleum fractions, with or without catalyst.

Viscosity Gravity Constant Correlation of specific gravity and viscosity: low for paraffinic, high for napththenic oils.

Viscosity Index Relationship between viscosity change of an oil with change in temperature; an empirical measure of the temperature coefficient of viscosity.

Viscosity Property of resistance offered by a fluid to relative motion of its parts.

Viscosity Range Ratio of viscosity of a fluid at its lowest temperature to that at its highest temperature, or lowest to highest shear.

Viscous Fluid Fluid having appreciable fluid friction.

Viscous Forces Tangential frictional forces. The action of such internal shear forces results in a conversion of mechanical energy into heat or unavailable thermal energy.

Volatility Relative tendency of a substance to evaporate. Controlled by vapor pressure for components in a homogeneous liquid obeying Raoult’s Law.

Vortex Swirl Rotation of a liquid as if it were a solid body; there is no interchange of position between particles.

W

Wax Distillates Neutral petroleum distillates that contain paraffin.

Weber Number Dimensionless parameter concerning surfaces or interfacional tension forces.

Wetting Agent Surface-active agent that is widely used in the textile industry to aid dyeing and sizing operations by making the textile absorbent and thus easier to "wet" with the dye or size.

W/O Emulsions Water-in-oil emulsion in which the water is the internal phase and the oil is the external or continuous phase. The W/O emulsion may be diluted by the addition of an oil and retain its homogeneity (see definition of Unstable Emulsions).

Y

Yield Strength Lowest stress at which a material undergoes plastic deformation. Below this stress the material is elastic; above it, viscous.

Yield Value of Plastic Minimum stress required to start flow.

Z

Zeitfuchs Crossarm Viscometer Instrument used to determine kinematic viscosities of transparent or opaque Newtonian liquids in the 0.3-10,000 cS range.

Zeitfuchs Viscometer Instrument used to determine kinematic viscosities of transparent Newtonian liquids in the 0.6-5,000 cS range.

Zeta Potential Measure of the speed with which charged oil droplets travel under the influence of a unit electrical field, or the potential difference from the surface of the droplet out into the bulk.

Zwitter Ions Molecular units containing groups that are ionized cationically and groups that are ionized anionically, both present in approximately the same numbers so that the molecule as a whole is electrically neutral.