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  • A

    • Abrasion Resistance
      The ability of a material to withstand surface wear due to rubbing against another surface.
    • Adherence
      The measure of the bond between a coating and a substrate.
    • Adhesion
      Adhesion is the molecular attraction exerted between bodies in contact.
    • Adhesiveness
      Defined by Adhesive stress. A = F/S where F is the force perpendicular to the bond and S is the surface area of the bond.
    • Amorphous Polymer
      A polymer with an irregular molecular chain and no crystallinity.
    • Apparent Bending Modulus
      Used for material that are too flexible for a standard bending test. The sample is supported on a cantilever beam and deflected by a set angle. Deflection, angle and specimen dimensions are used for calculations.
    • Apparent Shear Rate
      Calculated by 4Q/p R3 where Q is the volumetric flow rate (m3/s) and R is the radius (m) of the capillary.
    • Apparent Viscosity
      The viscosity of a fluid, measured at a given shear rate at a fixed temperature.
    • Axial Strain
      Strain in the direction in which the force is applied, ie; on the same axis.
  • B

    • Bending Modulus
      The modulus of elasticity applicable to the bending of a sample; defined as Stress / Strain.
    • Bending Stress
      Force per cm² acting on point on the sample length when a force is applied at that point.
    • Bending Test
      A sample is supported at both ends and a compressive force is applied to the middle of the sample.
    • Blend
      A combination of two or more polymer chains having different features, that are not bonded to each other.
    • Bond Strength
      A measure of the stress required to separate a layer of material from the base to which it is bonded.
    • Break Detector
      Used to define the parameter that determines if a sample has broken. Two categories of sharp break, where the force drops quickly or a gradual break where the force reduces gradually.
    • Break Force
      Force at which a break is defined.
    • Break Load
      Load at which a break is defined.
    • Break Strength
      Force at which a break is defined divided by sample width.
    • Brittleness
      A material which has a tendency to fracture without appreciable deformation.
    • Bulk Modulus
      An elastic constant relating mean stress to volumetric strain.
    • Burst Strength
      The ability of a material to resist rupture by pressure, sample dimensions and probe dimensions are required.
  • C

    • Capillary Viscometer
      Measures the time of flow of a measured volume of solution through a capillary tube under the force of gravity is compared with the time taken for the same volume of pure solvent, or of another liquid of known viscosity to flow through the same capillary.
    • Chord
      A chord of a curve is a geometric line segment whose end points both lie on the curve. A secant or a secant line is the line extension of a chord.
    • Chord Modulus
      The chord modulus is the slope of the chord drawn between any two specified points on the stress-strain curve.
    • Cleavage Strength
      Tensile load divided by sample width required to cause separation of an adhesive bond.
    • Climbing Drum Peel
      Fixture designed to peel bond between sandwich type material usually having one rigid and one flexible surface.
    • Coefficient of Elasticity
      An alternative term for modulus of elasticity.
    • Coefficient of Kinetic Friction
      The ratio of friction force to normal force once slippage has begun between two objects in contact.
    • Cofficient of Static Friction
      A ratio measure of how much force is required before an inert object, of a given material, at rest on another known substance, can be put into motion.
    • Cohesive Strength
      Measure of force / area of two substances that stick to each other.
    • Cohesiveness
    • Compressibility
      The ability to be compressed.
    • Compression
      Application of a force to reduce a samples height.
    • Compression Set
      Deformation which remains in a sample after has been subjected to and released from a specific compress stress for a definite period of time at a prescribed temperature.
    • Compressive Deflection
      The distance that a sample is compressed.
    • Compressive Deformation
      Extent to which a material deforms under a crushing load.
    • Compressive Strength
      The measured resistance of a specimen to axial loading when expressed as force per unit area.
    • Compressive Yield
      The stress at which a material deforms found from the stress / strain curve.
    • Conventional Stress
      Conventional stress, as applied to tension and compression tests, is force divided by the original gauge length or height.
    • Creep
      Strain caused by stress that occurs over time.
    • Creep Distance
      Measurement of the distance a sample changes due to creep.
    • Creep Rate
      Rate of change of a sample due to creep.
    • Creep Recovery
      Measurement of the distance a sample returns to its original size after a creep test.
    • Crush Test
      Alternative name for a compression test, usually to fracture or break.
    • Crystalline
      Sample where the molecules are arranged in an irregular order.
    • Curing Strength
      Point at which a sample that requires time to cure achieves its maximum strength.
    • Cycling
      Exercising a sample between limits for a duration of fixed number times.
  • D

    • Deformation
      A change in dimensions of a material.
    • Delamination Force
      Force required to separate two bonded materials by a peeling action.
    • Delamination Strength
      Force required to separate two bonded materials by a peeling action divided by the sample width.
    • Denier
      Measurement of yarn size.
    • Density Column
      Device for measuring the density of plastic at 23 C.
    • Die Swell
      Die swell is a memory effect in which the polymer tries to return to its former shape after extrusion through a die.
    • Draw Down
      The effect of thinning of a extruded polymer when it leaves the die caused by the effect of gravity on the extruded polymer after the die.
    • Ductile
      Can be easily formed or shaped (opposite of brittle).
    • Ductility
      The ability of a material to deform plastically without fracturing.
    • Dumbbell
      Preformed sample specimen for tensile testing, enabling the sample to be gripped easily and have a section of the sample formed to high tolerance dimensions.
    • Dynamic Friction
      Resistance to relative movement of two bodies that are already in motion.
  • E

    • Edge Tear
      In determining the edge tear resistance of a paper sample, a strip of paper is simultaneously torn at opposite edges of the strip by means of a thin, V-notch beam held in a stirrup. A tearing force is applied at a constant rate of elongation until the paper begins to tear.
    • Elastic Limit
      The point beyond which the deformation of a structure or material are no longer purely elastic.
    • Elastic Modulus
      The ratio of stress, within the proportional limit, to the corresponding strain.
    • Elastic Strength
      The force at the elastic limit dived by sample width.
    • Elasticity
      Tendency of a material to return to its original shape after it has been stretched or compressed.
    • Elongation
      Extension of a specimen which has been stretched in a test. The percentage elongation is an indication of ductility.
    • Elongation at Fracture
      Extension of a specimen reported at break.
    • Elongation at Yield
      The extension of a specimen reported at the yield point.
    • Energy
      Work required or work done during a test. The area under a force curve divided by the change in extension.
    • Engineering Stress
      Force divided by the original sample area.
    • Events
      Points placed on a graph which may be used to report load, stress, strain, time or extension.
    • Extension
      Measurement of movement of the testing machine.
    • Extension Compensation
      Ability to tear out an extension before the main test starts.
    • Extensometer
      Device to measure accurately the movement of a sample either by contacting directly on the sample or a non-contacting optical method.
    • Extraction
      Removal of one component from another as in "Insertion / Extraction test.
  • F

    • Falling Dart
      Device for measuring the force required to break a thin film material by puncturing. Uses free falling masses.
    • Fatigue
      Fatigue is a process by which a material is weakened by cyclic loading.
    • Fatigue Duration
      Effects of fatigue on a sample experienced over time.
    • Fatigue Limit
      Point at which a sample fractures or reaches a defined point during cycling.
    • Flexural Bond
      Strength of an adhesive bond between two materials determined by a flexing motion.
    • Flexural Modulus
      The ratio, within the elastic limit, of the applied stress on a test specimen in flexure to the corresponding strain.
    • Flexural Resistance
      Flexural resistance is a measurement of a material and corresponds to the maximum stress per unit area that a specimen can withstand without breaking when subjected to a bending force.
    • Flexural Rigidity
      Measurement of force required to permanently deform a sample by bending.
    • Flexural Strength
      Maximum stress developed in a specimen just before it cracks or breaks in a flexure test.
    • Flexural Test
      A bending test.
    • Fractional Melt Index
      Term used to describe polymers that have a Melt Index of less than 1.
    • Fracturability
      Food testing, a load peak or fall in the first compression cycle (bite) indicating the sample has crumbled or fractured but has not completely broken.
    • Fracture
      A break in the sample.
    • Fracture Mode
      Direction applied to a crack to open it. Open, forward or transverse shear.
    • Fracture Test
      Test ending in a sample fracture, user defined.
  • G

    • Gauge Length
      Unit of length which is used to calculate strain, the original sample length, height or grip separation.
    • Gel Bloom
      Test to BS757.
    • Glass Transition
      Change in an amorphous polymer from viscous to hard and relatively brittle.
    • Green Strength
      Term used to describe the strength of a polyurethane or rubber compound in the early stages of cure.
    • Gumminess
      The property of cohesiveness and stickiness.
  • H

    • Hardness
      Resistance to permanent deformation.
    • Hooke's Law
      The amount by which a material body is deformed (the strain) is linearly related to the force causing the deformation (the stress).
    • Hysteresis
      The mechanical energy loss that always occurs under loading and unloading, proportional to the area between the loading and unloading load-deflection curves within the elastic range.
  • I

    • Impact
      The striking of one body against another.
    • Impact Energy
      The energy dissipated during an impact.
    • Impact Strength
      The force / sample dimension in an impact test.
    • Insertionn
      Pushing or forcing one body in to another, as in insertion / extraction test.
    • Intrinsic Viscosity
      A measure of the capability of a polymer in solution to enhance the viscosity of the solution.
  • K

    • Knot Strength
      Measurement of the degradation of a material when a knot is formed due to compressive and tensile forces.
  • L

    • Lap Shear
      Shear stress that acts on a overlapped joint.
    • Limit of Proportionality
      Shear stress that acts on a overlapped joint.
    • Linear Density
      Mass per unit length.
    • Linear Portion
      Section of the stress / strain curve where increase in load is proportional to extension.
    • Load at Yield
      The load reported at point at which a specified deviation from proportionality of stress and strain occurs.
    • Lower Yield
      A lower yield is defined as being the first minima to occur after the upper yield.
    • Lower Yield Strength
      Force / area reported at a point of lower yield.
  • M

    • Markers
      Points placed on a graph to report load, extension, stress, strain. May be moved to recalculate values.
    • Maximum Bending Strain
      Change in length / original length and requires the span of the supports and the radius of the bend.
    • Maximum Bending Stress
      Force per unit area acting at a point along the length of a sample resulting from the bending moment applied at that point.
    • Mean Stress
      Algebraic difference between maximum and minimum stress.
    • Melt Flow Rate
      Defined as the weight of polymer in grams flowing through an aperture of specific diameter and length, with defined pressure over a 10 minute period. Also know as Melt Index.
    • Melt Strength
      A measure of the extensional viscosity of polymer melts.
    • Melt Viscosity
      A measure of the extensional viscosity of polymer melts.
    • Melt Volume Rate
      Defined as the volume of polymer in cm³ flowing through an aperture of specific diameter and length, with defined pressure over a 10 minute period.
    • Melting Point
      The temperature at which the structure of a crystalline polymer is destroyed to yield a liquid.
    • Modulus
      The physical measurement of stiffness in a material, equaling the ratio of applied load to the resultant deformation of the material.
    • Modulus of Bending
      The modulus of elasticity applicable to the bending of a beam; defined as Stress / Strain.
    • Modulus of Elasticity
      Rate of change of strain as a function of stress. The slope of the straight line portion of a stress-strain diagram.
    • Modulus of Rigidity
      Rate of change of strain as a function of stress in a specimen subjected to shear or torsion loading.
    • Modulus of Rupture
      In bending, the modulus of rupture is the bending moment at fracture divided by the section modulus.
    • Modulus of Toughness
      Work done on a unit volume of material as a simple tensile force is gradually increased from zero to the value causing rupture is defined as the Modulus of Toughness. This may be calculated as the entire area under the stress-strain curve from the origin to rupture.