Rubber Terminology


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Abrasion     Loss of surface particles due to frictional forces.

Accuracy     The closeness of a measurement to its true value.

ACN     Acrylonitrile
A chemical CH2CHCN, also known as vinyl cyanide, manufactured from propylene and copolymerized with butadiene to produce butadiene/acrylonitrile elastomers.

Acrylate Rubber     General term used to describe a class of elastomers based on acrylate esters.

Adhesion     The state in which two surfaces are held together by interfacial forces which may consist of molecular forces or interlocking action or both.

API     Active Pharmaceutical Ingredient
The substance or substances in a drug product which is responsible for the indicated use.

Arrhenius Techniques     Research techniques utilizing the Arrhenius equation.
k = Ae -Ea/RT

ASTM     American Society for Testing and Materials Standards

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Biaxial Tension     Biaxial tension is produced through deforming a specimen simultaneously in two directions.

Butyl     ASTM designation IIR, for isobutylene-isoprene rubber. Butyl rubber is the common name for such materials.

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Calender     A precision machine equipped with three or more heavy, internally heated or cooled rolls, revolving in opposite directions, which is used for the highly accurate continuous sheeting or plying up of rubber compounds and fractioning or coating of fabric with rubber compounds.

Calendering     Material is passed through a series of rollers; the resulting surface depends on the pressure exerted by the rollers or their temperature, composition, and surface designs, also on the type of coating or glaze previously applied to the material to be calendered.

Carbon Black     Carbon black is a material, today usually produced by the incomplete combustion of petroleum products. Carbon black is a form of amorphous carbon that has an extremely high surface area to volume ratio and therefore was one of the first nanomaterials to find common use. It is similar to soot but with a much higher surface area to volume ratio. Carbon black is often used as a pigment and reinforcement in rubber and plastic products.

Carbon NMR     Subset of NMR. Analysis of carbon atom environments in a molecule to determine structure.

cGMP     Current Good Manufacturing Processes 
The guidelines to ensure the safety, purity and effectiveness of manufactured pharmaceuticals. The FDA is responsible for the enforcement of these guidelines.

Chemotherapy Drug     Treatment of a disease (usually cancer) by a combination of chemical substances or drugs, that kill or impair disease-producing organisms in the body.

Chromatogram     Data obtained from a chromatography experiment. Typically plotted as intensity as a function of retention time.

Chromatography     A field of Analytical Science in which materials are separated for later identification or quantitation.

CMC     Chemical Manufacturing and Controls 
The description of drug product composition and manufacturer submitted in an IND.

Coefficient     In mathematics, a coefficient is a constant multiplicative factor of a certain object.

Coefficient of Friction     Between rubber and dry surfaces, it is the ratio of the force required to move one surface over the other or the force pressing two surfaces together.

Composite     A homogeneous material created by the synthetic assembly of two or more materials (a selected filler or reinforcing elements and compatible matrix binder) to obtain specific characteristics and properties.

Compression Set     The residual deformation of material after removal of the compressive stress. Generally obtained after stress was applied for a given length of time at a specified temperature.

Compression Stress Relaxation (CSR)    Measurement of the sealing force exerted by a seal or O-ring under compression, between two plates. Compression Stress Relaxation (CSR) provides the definitive information for the prediction of the service life of materials by measuring the sealing force decay of a sample as a function of time, temperature and environment.

Compressive Stress     The time-dependent force necessary to maintain a constant compressive strain, divided by the original cross-sectional area over which the force is applied.

Cure     Similar to cross-linking and vulcanization, except that vulcanization refers specifically to sulfur cross-linking, while cure covers all types (sulfur, peroxide, radiation, etc.)

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Deformulation     Analysis of a product to determine chemical components and percentages.

Degradation     Decomposition of a compound by stages, exhibiting well-defined intermediate products.

Dispersion     1. The act of causing particles of matter to separate and become evenly distributed throughout a medium. 
2. A system of matter in which finely divided particles of one or more phases (components) are uniformly scattered throughout another phase or medium (a plastisol).

DMA     Dynamic Mechanical Analysis. 
A technique used to study and characterize materials. It is most useful for observing the viscoelastic nature of polymers. An oscillating force is applied to a sample of material and the resulting displacement of the sample is measured. From this the stiffness of the sample can be determined, and the sample modulus can be calculated. By measuring the time lag in the displacement compared to the applied force, it is possible to determine the damping properties of the material.

DMTA     Dynamic Mechanical Thermal Analysis
see DMA.

DSC     Differential Scanning Calorimetry
Analysis of heat flow in and out of a material as a function of temperature.

Dye     Organic based material soluble in water or solvents.

Dynamic     Characterized by constant change, activity or progress.

Dynamic Properties     Mechanical properties exhibited under repeated cyclic deformations.

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EDAX    Energy Dispersive X-Ray Analysis
Technique used to determine semi-quantitative elemental composition of solid material.

Efficacy     The effectiveness of a drug for a specific indication.

Elastomer     A polymeric material which, at room temperature, is capable of recovering substantially in shape and size after removal of a deforming force. This generally refers to a synthetic polymer as opposed to rubber which preferably indicates the natural products.

Element     Atomic material such as carbon or nickel.

ESCA     Electron Spectroscopy for Chemical Analysis (same as XPS)
Surface analysis technique used to determine elemental and some chemical information.

Excipient     The filler portion of the final drug product, often an inert substance so as not to interact with the API.

Extract     To obtain from a substance by chemical or mechanical action as by pressure, distillation or evaporation.

Extractable     A chemical that is forcefully extracted from a container.

Extraction     The process of removing one or more components of a homogeneous mixture by treating the mixture with a liquid (solvent) in which the components to be removed are soluble but not the mixture as a whole.

Extrudability     Able to be extruded.

Extrusion     Process in which metal or other material is forced through a series of dies to create desired shapes.

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Failure Analysis     Root cause of product failure.

Fatigue Testing     Applying cyclic loading to your test specimen to understand how it will perform under similar conditions in actual use.

FDA     Food and Drug Administration 
Regulatory body ensuring the safety and efficacy of drugs for the Public.

FEA     Finite Element Analysis 
A computer simulation technique used in engineering analysis.

Filler     Additive often used to lower cost of a material and can be added to impart specific properties (such as calcium carbonate in a plastic).

Foam Rubber     Cellular rubber formed by whipping latex to a froth and then vulcanizing.

Force Decay     The decrease in stress that occurs after a specified time-interval during the application of a constant deformation. It is expressed as a percentage of the stress at the commencement of that time-interval. 

Formulation     The recipe for a product – the components and the procedure for combining the components.

FTIR     Fourier Transform Infrared Spectroscopy
Technique for obtaining vibrational spectrum of a material. Often used for identifying or fingerprinting materials. Obtained spectra can be compared to reference spectra.

Functional Group     The chemical characteristics of molecules such as alcohol, acid or ester.

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GC     Gas Chromatography 
Technique for separating chemicals that are volatile. Chemicals can then be identified or quantitated.

GC/MS     Gas Chromatography/Mass Spectrometry 
Technique for separating chemicals that are volatile and then obtaining a mass spectrum of that chemical. Mass spectrum can then be compared to reference materials for identification.

Geometrical Analysis     Displaying and testing for random distribution of directional data.

GLP     Good Laboratory Practices 
Non clinical guidelines to insure the integrity of research data.

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Headspace Analysis     The analysis of gasses evolved from a solid or liquid.

Heating Block     An insulation compound with unique heat absorbing properties which insulate against heat transfer during welding, soldering, brazing or other heat treatments.

HPLC     High Performance Liquid Chromatography
Technique for separating chemicals that are non-volatile. Chemicals can then be identified or quantitated.

Hydrocarbon     A chemical containing only carbon and hydrogen. Petroleum based chemicals are typically hydrocarbons.

Hz     Hertz
Unit of frequency equal to one cycle per second.

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IC     Ion Chromatography
Technique for separating chemicals that are ionic. Chemicals can then be identified or quantitated. Typically used for inorganic anions such as sulfate, phosphate or chloride.

ICP     Inductively Coupled Plasma Spectroscopy 
Technique for quantitating elements, in particular, metals. Sample must be digested in acid.

Impact Strength     Measure of the toughness of a material – as the energy required to break a specimen with a single blow.

Impact Testing     An impact test is a test for determining the energy absorbed in fracturing a test piece at high velocity.

Impulse Testing     Hose assemblies, when tested at 100% of working pressure with 212°F (100°C) circulating test fluid, shall withstand a minimum of 200,000 impulse cycles without indication of leakage or failure (SAE J343).

Inorganic     Materials not containing carbon and hydrogen such as metals, ceramics, semi-conductors.

Instron Universal Testing     Name brand instrument associated with physical measurements of materials such as compression, elongation, and tensile.

IRM     Industry Reference Material 
Materials used on an industry-wide basis as reference materials.

ISO     International Organization for Standardization 
International standard for quality requirements in business relationships .

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LC     Liquid Chromatography 
see HPLC.

Leachable     Chemicals that migrate from a container closure system into a drug product.

Leco     LECO Corporation provides instrumentation for elemental determination in organic and inorganic materials.

Limit of Detection     Lowest level of a material that can be detected by technique – typically signal is three times baseline noise.

Limit of Quantitation     Lowest level of a material that can be quantitated by technique – typically signal is ten times baseline noise.

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Mass Spectrometry     Technique for obtaining mass spectrum of material. Mass spectrum can be used to determine chemical structure and identify materials.

Membrane     A thin layer that separates various cellular structures or organs.

Method Validation     A detailed investigation of an analytical method that confirms with a high degree of accuracy the effectiveness of the analytical method.

Microscopy     Any technique for producing visible images of structures or details too small to otherwise be seen by the human eye by using a microscope or other magnification tool.

Microscopy, Electron     The diffraction, reflection or refraction of radiation upon the subject of study and the subsequent collection of this scattered radiation in order to build up an image.

Molding     Molding is accomplished by forcing the material into a shape using heat and pressure. Rubber and elastomers can be molded by compression, transfer and injection methods.

Molecule     A finite, ordered set of atoms that are bonded together to make a new material.

MTS     MTS is a company providing instrumentation for static and dynamic testing.

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NMR     Nuclear Magnetic Resonance Spectroscopy 
Technique for determining chemical structure of materials. Typically used for organic materials.

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Organic     Materials containing carbon and hydrogen as well as other elements such as oxygen, nitrogen, phosphorus and sulfur.

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Particle     A very small piece or part; a tiny portion or speck.

Patent     A grant made by a government that confers upon the creator of an invention the sole right to make, use and sell that invention for a set period of time.

Permeability     1. The property or condition of being permeable. 
2. The rate of flow of a liquid or gas through a porous material.

Permeation     The movement of atoms, molecules or ions into or through a porous or permeable substance (such as zeolite or a membrane).

Physical Testing     Field of testing that measures physical parameters of materials such as viscosity, tensile strength and abrasion resistance.

Pigment     Typically an inorganic colorant that is insoluble in water or solvents.

Planar Shear     Shear that acts between two parallel planes.

Plastic     A polymeric material that can be formed by applying heat. Same as thermoplastic.

Plasticizer     Material added to a polymer to impart flexibility.

Polymer     A material composed of repeating atoms, molecules or functional groups that are linked together in sufficient amounts so that removal or addition of a few units does not substantially vary the properties of the polymer.

PPB     Parts Per Billion 
A unit of measurement. 100 ppb = 0.00001%.

PPM     Parts Per Million
A unit of measurement. 100 ppm = 0.01%.

Precision     The repeatability of an experiment. The standard deviation of a set of experiments.

Problem Solving     Higher-order cognitive process that requires the modulation and control of more routine or fundamental skills.

Proton NMR     Subset of NMR. Analysis of proton environments in a molecule to determine structure.

Pyroloysis     The chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents, except possibly steam.

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Rebound Testing     A method of determining the resilient properties of vulcanized rubber by measuring the rebound of a steel ball or pendulum falling from a definite height onto a rubber sample.

Resin     A hydrocarbon secretion of many plants, valued for its chemical constituents and uses. Also, synthetic substances with similar properties.

Resonance     The tendency of a system to oscillate at maximum amplitude at a certain frequency. This frequency is known as the system’s natural frequency of vibration, resonant frequency or eigenfrequency.

Reverse Engineering     See deformulation.

Rheometry     The experimental techniques used to determine the rheological properties of materials. The quantitative and qualitative relationships between deformations and stresses, respectively their derivatives.

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SBR     Styrene-Butadiene Rubber 
Rheologic Control Compound.

Sealing Force Decay     The magnitude by which the sealing force reduces over a period of time.

SEM     Scanning Electron Microscopy 
Technique for imaging a material at higher magnification than available with traditional optical microscopy.

Shelf Life     The time an unvulcanized stock can be stored without losing any of its processing or curing properties.

Specification     The specific set of requirements agreed to by the sponsor/user and the manufacturer/producer of a system.

Spectroscopy     A field of analytical science in which various energies of light (electromagnetic radiation) are used to study materials.

Spectrum     Data obtained from a spectroscopy experiment. Typically intensity plotted as a function of energy.

Sponge Rubber     A soft, porous rubber used in toys, cushions, gaskets and weather stripping. Can also be used as a vibration dampener.

Static Analysis     Tools to analyze the components and resources of an application without having to run the application.

Stearic Acid     A colorless, odorless, waxlike fatty acid, CH3(CH2)16COOH, occurring in natural animal and vegetable fats and used in making soaps, candles, lubricants and other products.

Stress Decay     Stress release due to creep.

Sulfur     A chemical element, S, atomic number 16. It is an abundant, tasteless, odorless, multivalent non-metal. Sulfur, in its native form, is a yellow crystalline solid. In nature, it can be found as the pure element or as sulfide and sulfate minerals. It is an essential element for life and is found in two amino acids, cysteine and methionine.

Surfactant     A class of chemicals that lower the surface energy of a system such as wetting agents, detergents.

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Test Plaque     Test specimen.

TGA     Thermo-Gravimetric Analysis 
Analysis of weight loss (or gain) as a function of temperature.

Thermal Analysis     A field of science that studies changes of materials as a function of temperature.

Thermoplastic     A polymer that can be formed and reformed with temperature such as polypropylene, polyamides.

Thermoset     A polymer that once it is formed is fixed in that position. Typically a chemical reaction takes place to form a thermoset such as epoxy, urethane.

TIC     Total Ion Chromatogram 
Chromatogram acquired by GC/MS.

TMA     Thermal Mechanical Analysis 
Analysis of dimensional changes of a material as a function of temperature.

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Uniaxial Compression     Compression produced through compacting a specimen in one direction only.

Uniaxial Tension     Tension produced through stretching a specimen in one direction only.

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Viscosity     The resistance of a material to flow either by gravity or under stress.

Volumetric Compression     A cylindrical specimen is constrained in a fixture and compressed to examine the specimens compressabilty.

Vulcanization     1. An irreversible process during which a rubber compound, through a change in its chemical structure (cross-linking), becomes less plastic and more elastic. It becomes more resistant to swelling by organic liquids. Elasticproperties are conserved, improved, or extended over a greater range of temperature. 
2. It often refers to the reaction of rubber, specifically with sulfur, while “curing” covers other methods of cross-linking.
Both terms are often used interchangeably.

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XPS     See ESCA

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