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 |  موضوع: كتاب Fatigue and Tribological Properties of Plastics and Elastomers السبت 30 سبتمبر 2023, 2:23 am | |
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أحضرت لكم كتاب
Fatigue and Tribological Properties of Plastics and Elastomers
Laurence W. McKeen
و المحتوى كما يلي :
Table of contents
1. Introduction to fatigue
2. Introduction to the Tribology of Plastics and Elastomers
3. Introduction to Plastics and Polymers
4. Styrenics
5. Polyethers
6. Polyesters
7. Polyimides
8. Polyamides
9. Polyolefins And Acrylics
10. Thermoplastic Elastomers
11. Fluoropolymers
12. High Temperature Plastics
Appendices
Abbreviations
Tradenames
Conversion Factors
Glossary of Terms
abrasion factor See wearfactor.
Abrasive Index A measure of the abrasion resistance of a test
vulcanized rubber relative to that of a standard vulcanized rubber
as tested in an NBS (National Bureau of Standards) Abrasion
Tester under the same specified conditions. The Abrasive Index
is calculated as the percent ratio between the number of
revolutions required to abrade 2.5 mm of the specimen and that
of the reference sample. In the NBS Abrasion Tester, stationary
specimen pressed by weighted arm of the specimen holders
against a rotating drum wrapped in abrasive paper. The Tester is
equipped with dual thickness gauges that measure the extent of
the lowering of the arms as specimen thickness decreases due to
wear. The gauges are in contact with the arms directly over the
specimens. Also called NBS Abrasion Index.
ABS See acrylonitrile butadiene styrene polymer.
ABS nylon alloy See acrylonitrile butadiene styrene polymer nylon
alloy.
ABS PC alloy See acrylonitrile butadiene styrene polymer
polycarbonate alloy.
ABS resin See acrylonitrile butadiene styrene polymer.
accelerant See accelerator.
accelerator A chemical substance that accelerates chemical,
photochemical, biochemical, etc. reaction or process, such as
crosslinking or degradation of polymers, that is triggered andor
sustained by another substance, such as a curing agent or
catalyst, or environmental factor, such as heat, radiation or a
microorganism. Also called accelerant, promoter, cocatalyst.
acetal resins Thermoplastics prepared by polymerization of
formaldehyde or its trioxane trimer. Acetals have high impact
strength and stiffness, low friction coefficient and permeability,
good dimensional stability and dielectric properties, and high
fatigue strength and thermal stability. Acetals have poor acid
and UV resistance and are flammable. Processed by injection
and blow molding and extrusion. Used in mechanical parts such
as gears and bearings, automotive components, appliances, and
plumbing and electronic applications. Also called acetals.
acetals See acetal resins.
acrylate styrene acrylonitrile polymer Acrylic rubber-modified
thermoplastic with high weatherability. ASA has good heat and
chemical resistance, toughness, rigidity, and antistatic properties.
Processed by extrusion, thermoforming, and molding. Used in
construction, leisure, and automotive applications such as siding,
exterior auto trim, and outdoor furniture. Also called ASA.
acrylic resins Thermoplastic polymers of alkyl acrylates such as
methyl methacrylates. Acrylic resins have good optical clarity,
weatherability, surface hardness, chemical resistance, rigidity,
impact strength, and dimensional stability. They ' have poor
solvent resistance, resistance to stress cracking, flexibility, and
thermal stability. Processed by casting, extrusion, injection
molding, and thermoforming. Used in transparent parts, auto
trim, household items, light fixtures, and medical devices. Also
called polyacrylates.
acrylonitrile butadiene styrene polymer ABS resins are
thermoplastics comprised of a mixture of styrene-acrylonitrile
copolymer (SAN) and SAN-grafted butadiene rubber. They have
high impact resistance, toughness, rigidity and processability, but
low dielectric strength, continuous service temperature, and
elongation. Outdoor use requires protective coatings in some
cases. Plating grades provide excellent adhesion to metals.
Processed by extrusion, blow molding, thermoforming,
calendering and injection molding. Used in household
appliances, tools, nonfood packaging, business machinery,
interior automotive parts, extruded sheet, pipe and pipe fittings.
Also called ABS, ABS resin, acrylonitrile-butadiene-styrene
polymer.
acrylonitrile butadiene styrene polymer nylon alloy A
thermoplastic processed by injection molding, with properties
similar to ABS but higher elongation at yield. Also called ABS
nylon alloy.
acrylonitrile butadlene styrene polymer polycarbonate alloy
A thermoplastic processed by injection molding and extrusion,
with properties similar to ABS. Used in automotive applications.
Also called ABS PC alloy.
acrylonltrile copolymer A thermoplastic prepared by
copolymerization of acrylonitrile with small amounts of other
unsaturated monomers. Has good gas barrier properties and
chemical resistance. Processed by extrusion, injection molding,
and thermoforming. Used in food packaging.
acrylonitrile-butadiene-styrene polymer See acrylonitrile
butadiene styrene polymer.
activation energy An excess energy that must be added to an
atomic or molecular system to allow a process, such as diffusion
or chemical reaction, to proceed.
alkylated See alkylated compounds.
alkylated compounds Chemical compounds treated to incorporate
in their molecules one or more covalently bonded alkyl groups, a
paraffinic hydrocarbon group [CnH(2n+l)] which may be
derived from an alkane by eliminating one hydrogen. Also called
alkylated.
amorphous nylon Transparent aromatic polyamide thermoplastics.
Produced by condensation of hexamethylene diamine, isophthalic
and terephthalic acid.
Armstron abrasion test An abrasion resistance test for vulcanized
rubber that uses Armstrong tape abrader. Samples are mounted
on flat holding plates affixed onto a continuous belt rotated with
the speed V1 by a pair of pulleys. The samples periodically come
in contact with an abrasive tape moved in the opposite direction
by a system of tape supply and take-up drums and guiding and
pressing rollers at the speed V2 Note: V1 so as to provide a
specified total rate of slip. The contact area is relatively small
and the speeds and pressure can be adjusted. Also called tape
abrasion test, MIL-T-5438.
aromatic polyester estercarbonate A thermoplastic block
copolymer of an aromatic polyester with polycarbonate. Has
higher heat distortion temperature than regular polycarbonate. 496
aromatic polyesters Engineering thermoplastics prepared by
polymerization of aromatic polyol with aromatic dicarboxylic
anhydride. They are tough with somewhat low chemical
resistance. Processed by injection and blow molding, extrusion,
and thermoforming. Drying is required. Used in automotive
housings and trim, electrical wire jacketing, printed circuit
boards, and appliance enclosures.
ASA See ucrylate styrene ucrylnnitrile polymer
ASTM D256 An American Society for Testing of Materials (ASTM)
standard method for determination of the resistance to breakage
by flexural shock of plastics and electrical insulating materials,
as indicated by the energy extracted from standard pendulum-
type hammers in breaking standard specimens with one
pendulum swing. The hammers are mounted on standard
machines of either Izod or Charpy type. Note: Impact properties
determined include Izod or Charpy impact energy normalized per
width of the specimen. Also called ASTM method D256-84.
See also impact energy.
ASTM D395 An American Society for Testing of Materials (ASTM)
standard method for testing the capacity of rubber to recover
from compressive stress in air or liquid media. The specimen is
subjected to compression by a specified force for a definite time
at a specified temperature. The difference between the original
and the final specimen thickness or compression set is calculated
as a percentage of the original thickness by measuring the final
thickness 30 minute after stress removal.
ASTM D412 An American Society for Testing of Materials (ASTM)
standard methods for determining tensile strength, tensile stress,
ultimate elongation, tensile set and set after break of rubber at
low, ambient and elevated temperatures using straight, dumbbell
and cut-ring specimens.
ASTM D638 An American Society for Testing of Materials (ASTM)
standard method for determining tensile strength, elongation and
modulus of elasticity of reinforced or unreinforced plastics in the
form of sheet, plate, moldings, rigid tubes and rods. Five (I-V)
types, depending on dimensions, of dumbbell-shaped specimens
with thickness not exceeding 14 mm are specified. Specified
speed of testing varies depending on the specimen type and
plastic rigidity. Note: Tensile properties determined include
tensile stress (strength) at yield and at break, percentage
elongation at yield or at break and modulus of elasticity. Also
called ASTM method D638-84. See also fensile strength.
ASTM D638, type IV See ASTM 0638.
ASTM D671 An American Society for Testing of Materials (ASTM)
standard test method for determination of the flexural fatigue
strength of rigid plastics subjected to repeated flexural stress of
the same magnitude in a fixed-cantilever type testing machine,
designed to produce a constant-amplitude-of-force on the test
specimen each cycle. The test results are presented as a plot (S-N
curve) of applied stress vs. number of stress cycles required to
produce specimen failure by fracture, softening, or reduction in
stiffness by heating caused by internal friction (damping). The
stress corresponding to the point when the plot becomes clearly
asymptotic to a horizontal (constant-stress) line is reported as
fatigue strength in pascals, along with corresponding number of
cycles. Also called ASTM D671-71B.
ASTM D671-71 B See ASTM 0671,
ASTM D746 An American Society for Testing of Materials (ASTM)
standard method for determining brittleness temperature of
plastics and elastomers by impact. The brittleness temperature is
the temperature at which 50% of cantilever beam specimens fail
on impact of a striking edge moving at a linear speed of 1.8-2.1
m/s and striking the specimen at a specified distance from the
clamp. The temperature of the specimen is controlled by placing
it in a heat-transfer medium, the temperature of which (usually
subfreezing) is controlled by a thermocouple.
ASTM D785 An American Society for Testing of Materials (ASTM)
standard test method for determination of indentation hardness of
plastics by a Rockwell tester. The hardness number is derived
from the net increase in the depth of impression as the load on a
ball indenter is increased from a fixed minor load (10 kgf) to a
major load and then returned to the minor load. This number
consists of the number of scale divisions (each corresponding to
0.002 mm vertical movement of the indentor) and scale symbol.
Rockwell scales, designated by a single capital letter of English
alphabet, vary depending on the diameter of the indentor and the
major load.
ASTM 0813 An American Society for Testing of Materials (ASTM)
standard test method for determination of resistance to crack
growth in vulcanized rubber subjected to repeated bend flexing.
Specimen cracking is initiated by making a pierced groove and
continued by flexing on De Mattia-type machine along the axis
parallel to the groove. The sample is mounted vertically, one end
in a fixed grip and another in a moving grip. The latter grip is
moving in a reciprocating fashion, bending the specimen. An
array of grips are used to test several specimens simultaneously.
The crack growth data are reported as the number of cycles
required to reach a specified crack length, the average rate of
crack growth over entire test period, or as the rate of cracking in
mm per kilocycle during a portion of the test.
ASTM D1004 An American Society for Testing of Materials (ASTM)
standard test method for determination of the initial tear
resistance of flexible plastic films and sheeting. The test is
preformed at very low rates of loading, e.g., 51 mdmin, to
measure the force required to initiate tearing. The specimen
geometry in this test produces a stress concentration in a small
area of the specimen. The maximum stress, usually found near
the onset of tearing, is recorded in newtons or pounds-force.
ASTM D1044 An American Society for Testing of Materials (ASTM)
standard test method for determination of resistance of
transparent plastics to surface abrasion by measurement of its
optical effects. The specimen is subjected to abrasion using
Taber abraser with CS-1OF disk for specified number of cycles
under specified load (usually 100 and 500 g, respectively).The
results are reported as a percentage of transmitted light scattered
by the abraded specimen.
ASTM D1052 An American Society for Testing of Materials (ASTM)
standard test method for determination of resistance to cut
growth in vulcanized rubber subjected to repeated bending in
Ross flexing machine. A fixed pierced specimen is bent
repeatedly and freely at 90" angle over a 10-mm diameter rod in
pierced section by means of a holder arm. The resistance is
reported as the average number of cycles for each 100% increase
in cut growth above the initial pierce of 2.5 mm, up and
including 500%, where possible.
ASTM D1242 An American Society for Testing of Materials (ASTM)
standard test method for determination of resistance of plastics to
abrasion by loose abrasive (Method A) or by abrasive tape
(Method B) measured in terms of volume loss. In Method A,
Olsen-type wearometer is used wherein a fresh abrasive, such as
aluminum oxide, is fed on a rotating disk. The specimen is fixed
in a holder and pressed against the disk with a load of 10 lb. In
Method B, samples are mounted on flat holding plates affixed
onto a continuous belt rotated with the speed V1 by a pair of
pulleys. The samples periodically come in contact with an
abrasive tape moved in the opposite direction by a system of tape
supply and takeup drums and guiding and pressing rollers at the
speed V2 Note: V1 so as to provide a total rate of slip of about 497
100 in/min. The volume loss in cm’ is calculated after 1000
rotation or revolution cycles by measuring the weight of the
specimen before and after the test and dividing the difference by
its density. Also called ASTM D1242-56 (1981).
ASTM D1242-56 (1981) See ASTM 01242
ASTM D1708 An American Society for Testing of Materials (ASTM)
standard method for determining tensile properties of plastics
using microtensile specimens with maximum thickness 3.2 mm
and minimum length 38.1 mm, including thin films. Tensile
properties include yield strength, tensile strength, tensile strength
at break, elongation at break, etc. determined per ASTM D638.
ASTM D1709 An American Society for Testing of Materials (ASTM)
standard test method for determining resistance of polyethylene
film to impact by the free-falling dart. The impact resistance is
measured as the energy that causes 50%failure rate of the film.
The energy is calculated as the product of dart weight and
dropping height. There are 2 test methods (A and B) using darts
with different diameters of their hemispherical head and different
dropping heights.
ASTM D1894 An American Society for Testing of Materials (ASTM)
standard test method for determining coefficients of starting and
sliding friction (static and kinetic coefficients, respectively) of
plastic film and sheeting when sliding over itself or other
substances under specified conditions.
ASTM D1922 An American Society for Testing of Materials (ASTM)
standard test method for determining the resistance of flexible
plastic film or sheeting to tear propagation. The resistance is
measured as the average force, in grams, required to propagate
tearing from a precut slit through a specified length, using an
Elmendorf-type pendulum tester and 2 specimens, a rectangular
type and one with a constant radius testing length.
ASTM D2240 An American Society for Testing of Materials (ASTM)
standard method for determining the hardness of materials
ranging from soft rubbers to some rigid plastics by measuring the
penetration of a blunt (type A) or sharp (type D) indenter of a
durometer at a specified force. The blunt indenter is used for
softer materials and the sharp indenter - for more rigid materials.
ASTM D3702 An American Society for Testing of Materials (ASTM)
standard test method for assessing abrasive wear rate of self-
lubricating plastics intended for bearing applications in which
wear debris essentially remain in the contact zone. The specimen
of thrust washer configuration is mounted on a rotary upper
holder of a thrust washer tester and pressed against a steel washer
placed on a stationary lower holder. The specimen is rotated at a
speed of 36-900 rpm under 1-200 Ib load for a specified test
duration. The wear rate is calculated as an average specimen
thickness decrease rate in idh. Also called thrust washer friction
and wear test method.
ASTM D3841 An American Society for Testing of Materials (ASTM)
standard specification for glass fiber-reinforced polyester
construction panels. The specification covers classification,
inspection, certification, dimensions, weight, appearance, light
transmission, weatherability, expansion, impact resistance,
flammability and load-deflection properties of panels and their
methods of testing.
ASTM D4637 An American Society for Testing of Materials (ASTM)
standard specification for unreinforced or fabric-reinforced
vulcanized rubber sheet made from EPDM or chloroprene rubber
and used as single-ply roof membranes. The specification
specifies grades, dimensions, mechanical properties,
weatherability, resistance to ozone and heat aging, appearance,
and test methods. The mechanical properties tested include
tensile strength, set and elongation, seam strength, tear resistance
and tearing strength. The exposure tests include water
absorption. Also called ASTM DS D4637.
ASTM DS D4637 SeeASTM 04637.
atm See atmosphere.
bar A metric unit of measurement of pressure equal to 1.OE+06
dynes/cm* or 1.0E+05 pascals. It has a dimension of unit of
force per unit of areaused to denote the pressure of gases, vapors
and liquids.
bendingproperties Seepexural properties.
bending strength Seejlexural strength.
bendingstress Seeflexural stress.
bisphenol A diglycidyl ether The principal monomer used in the
preparation of epoxy resins, comprising two benzene rings linked
via isopropylidinebridge. Each ring is substituted with an epoxy
group in the para position. Highly reactive. Polymerizesto form
thermosetting epoxy resins. Also called diglycidyl ether of
bisphenol A, DGEBA.
bisphenolA polyester A thermoset unsaturated polyesterbased on
bisphenol A and fumaric acid.
blown film A plastic film produced by extrusion blowing, wherein
an extruded plastic tube is continuously inflated by internal air
pressure,cooled, collapsedby rolls and wound up. The thickness
of the film is controlled by air pressure and rate of extrusion.
breakingelongation See elongation.
C
CA See cellulose acetate.
CAB See cellulose acetate butyrate.
carboxyl-terminated butadiene-acrylonitrile See carboxyl-
terminated butudiene-acrylonitrile copolymer.
carboxyl-terminated butadiene-acrylonitrile copolymer
Liquid nitrile rubber containing reactive carboxy end groups,
used as a toughener or impact modifier in plastics. It cures at
room or elevated temperatures to solid elastomeric block
copolymerswith of matrix resins. It improves crack resistance of
epoxy and polyester compositions and enhances fatigue
resistance of glass fiber-reinforced plastics. It has good electric
and wetting properties. Used in epoxy coatings and structural
adhesives, potting, encapsulation, and cable fillers. Can be
processed by rotomolding. Also called CTBN, carboxyl-
terminatedbutadiene-acrylonitrile.
cast film Film produced by pouring or spreading resin solution or
melt over a suitable temporary substrate, followed by curing via
solvent evaporation or melt cooling and removing the cured film
from the substrate. cellulose acetate Thermoplastic esters of cellulose with acetic acid.
Have good toughness, gloss, clarity, processability, stiffness,
hardness, and dielectric properties, but poor chemical, fire and
water resistance and compressive strength. Processed by
injection and blow molding and extrusion. Used for appliance
cases, steering wheels, pens, handles, containers, eyeglass frames,
brushes, and sheeting. Also called CA.
cellulose acetate butyrate Thermoplastic mixed esters of cellulose
with acetic and butyric acids. Have good toughness, gloss,
clarity, processability, dimensional stability, weatherability, and
dielectric properties, but poor chemical, fire and water resistance
and compressive strength. Processed by injection and blow
molding and extrusion. Used for appliance cases, steering
wheels, pens, handles, containers, eyeglass frames, brushes, and
sheeting. Also called CAB.
cellulose propionate Thermoplastic esters of cellulose with
propionic acid. Have good toughness, gloss, clarity,
processability, dimensional stability, weatherability, and
dielectric properties, but poor chemical, fire and water resistance
and compressive strength. Processed by injection and blow
molding and extrusion. Used for appliance cases, steering
wheels, pens, handles, containers, eyeglass frames, brushes, and
sheeting. Also called CP.
cellulosic plastics Thermoplastic cellulose esters and ethers. Have
good toughness, gloss, clarity, processability, and dielectric
properties, but poor chemical, fire and water resistance and
compressive strength. Processed by injection and blow molding
and extrusion. Used for appliance cases, steering wheels, pens,
handles, containers, eyeglass frames, brushes, and sheeting.
chlorendic polyester A chlorendic anhydride-based unsaturated
polyester.
chlorinated polyvinyl chloride Thermoplastic produced by
chlorination of polyvinyl chloride. Has increased glass transition
temperature, chemical and fire resistance, rigidity, tensile
strength, and weatherability as compared to PVC. Processed by
extrusion, injection molding, casting, and calendering. Used for
pipes, auto parts, waste disposal devices, and outdoor
applications. Also called CPVC.
chlorohydrins Halohydrins with chlorine as a halogen atom. One of
the most reactive of halohydrins. Dichlorohydrins are used in the
preparation of epichlorohydrins, important monomers in the
manufacture of epoxy resins. Most chlorohydrins are reactive
colorless liquids, soluble in polar solvents such as alcohols.
Note: Chlorohydrins are a class of organic compounds, not to be
mixed with a specific member of this class, l-chloropropane-2.3-
diol sometimes called chlorohydrin.
chlorosulfonated polyethylene rubber Thermosetting
elastomers containing 20- 40% chlorine. Have good
weatherability and heat and chemical resistance. Used for hoses,
tubes, sheets, footwear soles, and inflatable boats.
coefficient of friction See kinetic coefficient of,friction.
coefficient of friction See kinetic coejjicient offriction.
coefficient of friction, kinetic See kinetic coefficient offriction.
coeff lclent of friction, kinetic See kinetic coeficient offriction.
coefficient of friction, static See stutic coefficient qffriction.
coeff lcient of friction, static See static coejjicient offriction
conditioning Process of bringing the material or apparatus to a
certain condition, e.g., moisture content or temperature, prior to
further processing, treatment, etc. Also called conditioning
cycle.
conditioning cycle See conditioning.
covulcanization Simultaneous vulcanization of a blend of two or
more different rubbers to enhance their individual properties such
as ozone resistance. Rubbers are often modified to improve
covulcanization.
CP S e e cellulose propionate.
crack driving force See stress-intensify factor runge.
crack growth See fatigue crack growth.
crack growth rate Seefutigue crack growth rate.
crack propagation See futigue crack growth.
crack propagation rate See,fatigue crack growth rate.
cracking Appearance of external and/or internal cracks in the
material as a result of stress that exceeds the strength of the
material. The stress can be external and/or internal and can be
caused by a variety of adverse conditions: structural defects,
impact, aging, corrosion, etc. or a combination of thereof. Also
called cracks. See also processing defects.
cracks See cracking.
crazes See crazing.
crazing Appearance of thin cracks on the surface of the material or,
sometimes, minute frost-like internal cracks, as a result of stress
that exceeds the strength of the material, impact, temperature
changes, degradation, etc. Also called crazes.
crystal polystyrene See generul purpose polystyrene.
CTBN See carbo,xyl-terminated butadiene-acrylonitrile copolymer.
CTFE See polychlorotrijluoroethylene.
cycles to failure See futigue life.
dddN See fatigue crack growth rate.
DAP See diallyl phthalate resins.
degradation Loss or undesirable change in the properties, such as
color, of a material as a result of aging, chemical reaction, wear,
exposure, etc. See also smbility.
delta E See color difference.
delta K See stress-intensityjuctor range.
DGEBA See bisphenol A diglycidyl ether
diallyl phthalate resins Thermosets supplied as diallyl phthalate
prepolymer or monomer. Have high chemical, heat and water
resistance, dimensional stability, and strength, Shrink during peroxide curing. Processed by injection, compression and
transfer molding. Used in glass-reinforced tubing, auto parts,
and electrical components. Also called DAP.
diglycldyl ether of bisphenol A See bisphenol A diglycidyl ether.
DIN 53453 A German Standards Institute (DIN) standard specifying
conditions for the flexural impact testing of molded or laminated
plastics. The bar specimens are either unnotched or notched on
one side, mounted on two-point support and struck in the middle
(on the unnotched side for notched specimens) by a hammer of
the pendulum impact machine. Impact strength of the specimen
is calculated relative to the cross-sectional area of the specimen
as the energy required to break the specimen equal to the
difference between the energy in the pendulum at the instant of
impact and the energy remaining after complete fracture of the
specimen. Also called DIN 53453 impact test.
DIN 53453 impact test See DIN 53453.
DIN 53456 A German Standards Institute (Deutsches Institut fuer
Normen, DIN) standard test method for determining ball
indentation hardness of plastics. The indentor is forced into the
specimen under the action of the major load, the position of the
indentor having been fixed beforehand as a zero point by the
application of a minor load. The hardness is calculated as the
ratio of the major load to the area of indentation.
durometer A hardness See Shore hardness.
durometer hardness Indentation hardness of a material as
determined by either the depth of an indentation made with an
indentor under specified load or the indentor load required to
produced specified indentation depth. The tool used to measure
indentation hardness of polymeric materials is called durometer,
e.g., Shore-type durometer.
ECTFE See ethylene chlorotrifluoroethylene copolymer.
Elmendorf tear strength The resistance of flexible plastic film or
sheeting to tear propagation. It is measured, according to ASTM
D1922, as the average force, in grams, required to propagate
tearing from a pre-cut slit through a specified length, using an
Elmendorf-type pendulum tester and 2 specimens, a rectangular
type and one with a constant radius testing length.
elongation The increase in gauge length of a specimen in tension,
measured at or after the fracture, depending on the viscoelastic
properties of the material. Note: Elongation is usually expressed
as a percentage of the original gauge length. Also called tensile
elongation, elongation at break, ultimate elongation, breaking
elongation, elongation at rupture. See also tensile strain.
elongation at break See elongation.
elongation at rupture See elongation.
EMAC See ethylene methyl acrylate copolymer.
embrittlement A reduction or loss of ductility or toughness in
materials such as plastics resulting from chemical or physical
damage.
endurance limit The maximum stress below which a material can
endure an infinite number of loading-unloading cycles of
specified type without failure or, in practice, a very large number
of cycles. Also called fatigue endurance limit.
EPDM See EPDM rubber.
EPDM rubber Sulfur-vulcanizable thermosetting elastomers
produced from ethylene, propylene, and a small amount of
nonconjugated diene such as hexadiene. Have good
weatherability and chemical and heat resistance. Used as impact
modifiers and for weather stripping, auto parts, cable insulation,
conveyor belts, hoses, and tubing. Also called EPDM.
epoxides Organic compounds containing three-membered cyclic
group(s) in which two carbon atoms are linked with an oxygen
atom as in an ether. This group is called an epoxy group and is
quite reactive, allowing the use of epoxides as intermediates in
preparation of certain fluorocarbons and cellulose derivatives and
as monomers in preparation of epoxy resins. Also called epoxy
compounds.
epoxies See epoxy resins.
epoxy compounds See epoxides.
epoxy resins Thermosetting polyethers containing crosslinkable
glycidyl groups. Usually prepared by polymerization of bisphenol
A and epichlorohydrin or reacting phenolic novolaks with
epichlorohydrin. Can be made unsaturated by acrylation.
Unmodified varieties are cured at room or elevated temperatures
with polyamines or anhydrides. Bisphenol A epoxy resins have
excellent adhesion and very low shrinkage during curing. Cured
novolak epoxies have good UV stability and dielectric properties.
Cured acrylated epoxies have high strength and chemical
resistance. Processed by molding, casting, coating, and
lamination. Used as protective coatings, adhesives, potting
compounds, and binders in laminates and composites. Also
called epoxies.
epoxyethane See ethylene oxide.
EPR See ethylene propene rubber.
ETFE See ethylene tetrajluoroethylene copolymer.
ethylene acrylic rubber Copolymers of ethylene and acrylic esters.
Have good toughness, low temperature properties, and resistance
to heat, oil, and water. Used in auto and heavy equipment parts.
ethylene copolymers See ethylene polymers.
ethylene methyl acrylate copolymer Thermoplastic copolymers
of ethylene with <40% methyl acrylate. Have good dielectric
properties, toughness, thermal stability, stress crack resistance,
and compatibility with other polyolefins. Transparency decreases
with increasing content of acrylate. Processed by blown film
extrusion and blow and injection molding. Used in heat-sealable
films, disposable gloves, and packaging. Some grades are FDA-
approved for food packaging. Also called EMAC.
ethylene polymers Ethylene polymers include ethylene
homopolymers and copolymers with other unsaturated
monomers, most importantly olefins such as propylene and polar
substances such as vinyl acetate. The properties and uses of
ethylene polymers depend on the molecular structure and weight.
Also called ethylene copolymers.
ethylene propene rubber Stereospecific copolymers of ethylene
with propylene. Used as impact modifiers for plastics. Also
called EPR. ethylene tetrafluoroethylene copolymer Thermoplastic
alternating copolymer of ethylene and tetrafluoroethylene. Has
good impact strength, abrasion and chemical resistance,
weatherability, and dielectric properties. Processed by molding,
extrusion, and powder coating. Used in tubing, cables, pump
parts, and tower packing in a wide temperature range. Also
called ETFE.
ethylene vinyl alcohol copolymer Thermoplastics prepared by
hydrolysis of ethylene-vinyl acetate polymers. Have good barrier
properties, mechanical strength, gloss, elasticity, weatherability,
clarity, and abrasion resistance. Barrier properties and
processibility improve with increasing content of ethylene due to
lower absorption of moisture. Ethylene content of high banier
grades range from 32 40 44 mole %. Processed by extrusion,
coating, blow and blow film molding, and thermoforming. Used
as packaging films and container liners. Also called EVOH.
ethylene-acrylic acid copolymer A flexible thermoplastic with
water and chemical resistance and barrier properties similar to
those of low-density polyethylene and enhanced adhesion, optics,
toughness, and hot tack properties, compared to the latter.
Contains 3-20% acrylic acid, with density and adhesion to polar
substrates increasing with increasing acrylic acid content. FDA-
approved for direct contact with food. Processed by extrusion,
blow and film methods and extrusion molding, and extrusion
coating. Used in rubberlike small parts like pipe caps, hoses,
gaskets, gloves, hospital sheeting, diaper liners, and packaging
film.
EVOH See ethylene vinyl alcohol copolymer.
extenders Relatively inexpensive resin, plasticizer or filler such as
carbonate used to reduce cost and/or to improve processing of
plastics, rubbers or nonmetallic coatings.
F
falling dart impact See,fulling weight impact energy.
falling dart impact energy See dart impact energy.
falling dart impact strength See falling weight impact energy.
falling sand abrasion test A test for determining abrasion
resistance of coatings by the amount of abrasive sand required to
wear through a unit thickness of the coating, when the sand falls
against it at a specified angle from a specified height through a
guide tube. Also called falling sand test method.
falling sand test method See,falling sand abrasion test,
falling weight impact See,falling weight impact energy.
falling weight impact energy The mean energy of a free-falling
dart or weight (tup) that will cause 50% failures after 50 tests to a
directly or indirectly stricken specimen. The energy is calculated
by multiplying dart mass. gravitational acceleration and drop
height. Also called falling weight impact strength, falling weight
impact, falling dart impact energy, falling dart impact strength,
falling dart impact, drop dart impact energy, drop dart impact
strength.
falling weight impact strength Seefalling weight impact energy.
fatigue crack growth Crack extension caused by constant-
amplitude fatigue loading of material specimen. The initial crack
is often introduced by artificial notching or cutting. Also called
fatigue crack propagation, crack growth, crack propagation.
fatigue crack growth rate The rate of crack extension caused by
constant-amplitude fatigue loading, expressed in terms of crack
extension per cycle. Also called crack propagation rate, da/dN,
crack growth rate.
fatigue crack propagation See fatigue crack growth.
fatigue endurance limit See endurance limit.
fatigue life Number of loading-unloading cycles of a specified type
that material specimen can endure before failing in a fatigue test.
Also called cycles to failure.
Faville-LeValley Falex 6 See thrust-washer testing machine.
FEP See fluorinated ethylene propylene copolymer.
flexural fatigue Progressive localized permanent structural change
occurring in a material subjected to cyclic flexural stress that may
culminatain cracks or complete fracture after a sufficient number
of cycles.
flexural properties Properties describing the reaction of physical
systems to flexural stress and strain. Also called bending
properties.
flexural strength The maximum stress in the extreme fiber of a
specimen loaded to failure in bending. Note: Flexural strength
is calculated as a function of load, support span and specimen
geometry. Also called modulus of rupture in bending, modulus
of rupture, bending strength.
flexural stress The maximum stress in the extreme fiber of a
specimen in bending. Note: Flexural stress is calculated as a
function of load at a given strain or at failure, support span and
specimen geometry. Also called bending stress.
fluorinated ethylene propylene copolymer Thermoplastic
copolymer of tetrafluoroethylene and hexafluoropropylene. Has
decreased tensile strength and wear and creep resistance, but
good weatherability, dielectric properties, fire and chemical
resistance, and friction. Decomposes above 204°C (400°F).
releasing toxic products. Processed by molding, extrusion, and
powder coating. Used in chemical apparatus liners, pipes,
containers, bearings, films, coatings, and cables. Also called
FEP.
fluoro rubber Seejluoroelastomers.
fluoroelastomers Fluorine-containing synthetic rubber with good
chemical and heat resistance. Used in underhood applications
such as fuel lines, oil and coolant seals, and fuel pumps, and as a
flow additive for polyolefins. Also called fluoro rubber.
fluoroplastics Seefluoropolymers.
fluoropolymers Polymers prepared from unsaturated fluorine-
containing hydrocarbons. Have good chemical resistance,
weatherability, thermal stability, antiadhesive properties and low
friction and flammability, but low creep resistance and strength
and poor processibility. The properties vary with the fluorine
content. Processed by extrusion and molding. Used as liners in
chemical apparatus, in bearings, films, coatings, and containers.
Also called fluoroplastics.
fluorosilicones Polymers with chains of alternating silicon and
oxygen atoms and trifluoropropyl pendant groups. Most are
rubbers. 501
FMQ See methy~luorosilicones.
fractional melt index resin Thermoplastics having a low melt
index of <1. These resins have higher molecular weights and are
harder to extrude because of lower rate and greater force
requirements compared to the lower molecular weight resins.
They are mainly used for heavy duty applications such as pipe.
fracture mechanics A method of fracture analysis that can
determine the stress required to induce fracture instability in a
structure containing a crack of known size and shape. Also
called linear elastic fracture mechanics.
general purpose polystyrene General purpose polystyrene is an
amorphous thermoplastic prepared by homopolymerization of
styrene. It has good tensile and flexural strengths, high light
transmission and adequate resistance to water, detergents and
inorganic chemicals. It is attached by hydrocarbons and has a
relatively low impact resistance. Processed by injection molding
and foam extrusion. Used to manufacture containers, health care
items such as pipettes, kitchen and bathroom housewares, stereo
and camera parts and foam sheets for food packaging. Also
called crystal polystyrene.
glycol modified polycyclohexylenedimethylene
terephthalate Thermoplastic polyester prepared from glycol,
cyclohexylenedimethanol, and terephthalic acid. Has good
impact strength and other mechanical properties, chemical
resistance, and clarity. Processed by injection molding and
extrusion. Can be blended with polycarbonate. Also called
PCTG.
Graves tear strength A force required to tear completely across a
specially designed nicked rubber test specimen, or right-angled
test specimen, by elongating it at a specified rate using a power-
driven tensile testing machine (Graves machine) as described in
the ASTM D624. Expressed in units of force per thickness of
specimen.
halogen compounds A class of organic compounds containing
halogen atoms such as chlorine. A simple example is halocarbons
but many other subclasses with various functional groups and of
different molecular structure exist as well.
halohydrins Halogen compounds that contain a halogen atom(s) and
a hydroxy (OH) group(s) attached to a carbon chin or ring. Can
be prepared by reaction of halogens with alkenes in the presence
of water or by reaction of halogens with triols. Halohydrins can
be easily dehydrochlorinated in the presence of a base to give an
epoxy compound.
HDPE See high density polyethylene.
HDT See heat dejlection temperature.
heat deflection point See heat dejlection temperature.
heat deflection temperature The temperature at which a material
specimen (standard bar) is deflected by a certain degree under
specified load. Also called heat distortion temperature, heat
distortion point, heat deflection point, deflection temperature
under load, tensile heat distortion temperature, HDT.
heat distortion point See heat dejlection temperature.
heat distortion temperature See heat deflection temperature.
heterocyclic See heterocyclic compounds.
heterocyclic compounds A class of cyclic compounds containing
rings with some carbon atoms replaced by other atoms such as
oxygen, sulfur and nitrogen. Also called heterocyclic.
high density polyethylene A linear polyethylene with density
0.94-0.97 g/cm3. Has good toughness at low temperatures,
chemical resistance, and dielectric properties and high softening
temperature, but poor weatherability. Processed by extrusion,
blow and injection molding, and powder coating. Used in
houseware, containers, food packaging, liners, cable insulation,
pipes, bottles, and toys. Also called HDPE.
high impact polystyrene See impact polystyrene.
high molecular weight low density polyethylene
Thermoplastic with improved abrasion and s*ss crack resistance
and impact strength, but poor processibility and reduced tensile
strength. Also called HMWLDPE.
HIPS See impact polystyrene.
HMWLDPE See high molecular weight low density polyethylene.
I
impact energy The energy required to break a specimen, equal to
the difference between the energy in the striking member of the
impact apparatus at the instant of impact and the energy
remaining after complete fracture of the specimen. Also called
impact strength. See also ASTM 0256, ASTM 03763.
impact polystyrene Impact polystyrene is a thermoplastic produced
by polymerizing styrene dissolved in butadiene rubber. Impact
polystyrene has good dimensional stability, high rigidity and
good low temperature impact strength, but poor barrier
properties, grease resistance and heat resistance. Processed by
extrusion, injection molding, thermoforming and structural foam
molding. Used in food packaging, kitchen housewares, toys,
small appliances, personal care items and audio products. Also
called IPS, high impact polystyrene, HIPS, impact PS.
impact property tests Names and designations of the methods for
impact testing of materials. Also called impact tests. See also
impact toughness.
impact PS See impact polystyrene.
impact strength See impact energy,
impact tests See impact property tests.
impact toughness Property of a material indicating its ability to
absorb energy of a high-speed impact by plastic deformation
rather than crack or fracture. See also impact property tests.
initial tear resistance The force required to initiate tearing of a
flexible plastic film or thin sheeting at very low rates of loading, 502
measured as maximum stress usually found at the onset of
tearing. Also called tear resistance, initial.
ionomers Thermoplastics containing a relatively small amount of
pendant ionized acid groups. Have good flexibility and impact
strength in a wide temperature range, puncture and chemical
resistance, adhesion, and dielectric properties, but poor
weatherability, fire resistance, and thermal stability. Processed
by injection, blow and rotational molding, blown film extrusion,
and extrusion coating. Used in food packaging, auto bumpers,
sporting goods, and foam sheets.
IPS See impact polystyrene
IS0 2039-2 An International Organization for Standardization (KO)
standard test method for determination of indentation hardness of
plastics by Rockwell tester using Rockwell M, L, and R hardness
scales. The hardness number is derived from the net increase in
the depth of impression as the load on a ball indenter is increased
from a fixed minor load (98.07 N) to a major load and then
returned to the minor load. This number consists of the number
of scale divisions (each corresponding to 0.002 mm vertical
movement of the indentor) and scale symbol. Rockwell scale
vary depending on the diameter of the indentor and the major
load. For example, scale R corresponds to the ball diameter 12.7
mm and major load 588.4 N. Also called IS0 2039-B.
IS0 2039-8 See I S 0 2039-2.
isophthalate polyester An unsaturated polyester based on
isophthalic acid.
lzod See Izod impact energy.
lzod impact See Izod impact energy.
lzod impact energy The energy required to break a specimen equal
to the difference between the energy in the striking member of
the Izod-type impact apparatus at the instant of impact and the
energy remaining after complete fracture of the specimen. Also
called Izod impact, Izod impact strength, Izod.
lzod impact strength See Izod impact energy
J
J Seejoule.
JIS P8116 A Japanese Standards Association (Nippon Kikaku
Kyokai) standard test for determining the resistance of flexible
plastic film or sheeting to tear propagation. The resistance is
measured as the average force, in grams, required to propagate
tearing from a precut slit through a specified length, using an
Elmendorf-type pendulum tester.
joule A unit of energy in SI system that is equal to the work done
when the point of application of a force of one newton (N) is
displaced through distance of one meter (m) in the direction of
the force. The dimension of joule is N m. Also called J.
K
K See wear factor.
K factor See weur,fuctor.
kinetic coefficient of friction The ratio of tangential force, which
is required to sustain motion without acceleration of one surface
with respect to another, to the normal force, which presses the
two surfaces together. Also called coefficient of friction,
coefficient of friction. kinetic.
kinetic strip test An ozone resistance test for rubbers that involves a
strip-shaped specimen stretched to 23% and relax to 0 at a rate of
30 cycles per minute, while subjected to ozone attack in the test
chamber. The results of the test are reported with 2 digits
separated with a virgule. The number before the virgule indicates
the number of quarters of the test strip which showed the cracks.
The number after the virgule indicates the size of the cracks in
length perpendicular to the length of the strip.
L
labile crack Crack in the process of growth or propagation.
Unstable crack that can readily begin to grow as a result of
internal or external processes in the material, such application of
stress.
LCP See liquid crystul polymers
LDPE See low density polyethylene.
limiting pressure-velocity value The value of the product
between the load applied to the specimen normal to its friction
surface and the sliding speed of this surface against a
countersurface in wear testing of plastics at which friction-
generated temperatures reach melting or softening points of a
plastic or at which the wear rate begins to increase rapidly.
Limiting PV is usually expressed in the unit of pressure or stress
such as kg(f)/cm2 times the unit of speed such as c d s . Also
called limiting PV, LPV, PV, PV limit.
limiting PV See limiting pressure-velocity value.
linear elastic fracture mechanics Seefracture mechanics
linear low density polyethylene Linear polyethylenes with
density 0.91-0.94 p/cm3. Has better tensile, tear, and impact
strength and crack resistance properties, but poorer haze and
gloss than branched low-density polyethylene. Processed by
extrusion at increased pressure and higher melt temperatures
compared to branched low-density polyethylene, and by molding.
Used to manufacture film, sheet, pipe, electrical insulation,
liners, bags and food wraps. Also called LLDPE, LLDPE resin.
linear polyethylenes Linear polyethylenes are polyolefins with
linear carbon chains. They are prepared by copolymerization of
ethylene with small amounts of higher alfa-olefins such as 1-
butene. Linear polyethylenes are stiff, tough and have good
resistance to environmental cracking and low temperatures.
Processed by extrusion and molding. Used to manufacture film,
bags, containers, liners, profiles and pipe.
liquid crystal polymers Thermoplastic aromatic copolyesters with
highly ordered structure. Have good tensile and flexural
properties at high temperatures, chemical, radiation and fre
resistance, and weatherability. Processed by sintering and
injection molding. Used to substitute ceramics and metals in
electrical components, electronics, chemical apparatus, and
aerospace and auto parts. Also called LCP.
LLDPE See linear low density polyethylene. 503
LLDPE resin See linear low density polyethylene.
low density polyethylene A branched-chain thermoplastic with
density 0.91-0.94 g/cm3. Has good impact strength, flexibility,
transparency, chemical resistance, dielectric properties, and low
water permeability and brittleness temperature, but poor heat,
stress cracking and fire resistance and weatherability. Processed
by extrusion coating, injection and blow molding, and film
extrusion. Can be crosslinked. Used in packaging and shrink
films, toys, bottle caps, cable insulation, and coatings. Also
called LDPE.
LPV See limiting pressure-velocity vulue.
macroscopic properties See thermodynumic properties.
mechanical properties Properties describing the reaction of
physical systems to stress and strain.
methylfluorosilicones Silicone rubbers containing pendant
fluorine and methyl groups. Have good chemical and heat
resistance. Used in gasoline lines, gaskets, and seals. Also called
FMQ.
methylphenylsilicones Silicone rubbers containing pendant
phenyl and methyl groups. Have good resistance to heat,
oxidation, and radiation, and compatibility with plastics.
methylsilicone Silicone rubbers containing pendant methyl groups.
Have good heat and oxidation resistance. Used in electrical
insulation and coatings. Also called MQ.
methylvinylfluorosilicone Silicone rubbers containing pendant
vinyl, methyl, and fluorine groups. Can be additionally
crosslinked via vinyl groups. Have good resistance to petroleum
products at elevated temperatures.
methylvinylsilicone Silicone rubbers containing pendant methyl
and vinyl groups. Can be additionally crosslinked via vinyl
groups. vulcanized to high degrees of crosslinking. Used in
sealants, adhesives, coatings, cables, gaskets, tubing, and
electrical tape.
micron A unit of length equal to 1E-6 meter. Its symbol is Greek
small letter mu or mum.
microtensile specimen A small specimen as specified in ASTM
D1708 for determining tensile properties of pldstics. It has
maximum thickness 3.2 mm and minimum length 38.1 mm.
Tensile properties determined with this specimen include yield
strength, tensile strength, tensile strength at break and elongation
at break.
MIL-T-5438 See Armstron ubrusion test
modified polyphenylene ether Thermoplastic polyphenylene
ether alloys with impact polystyrene. Have good impact strength,
resistance to heat and fire, but poor resistance to solvents.
Processed by injection and structural foam molding and
extrusion. Used in auto parts, appliances, and
telecommunication devices. Also called MPE, MPO, modified
polyphenylene oxide.
modified polyphenylene oxide See modified polyphenylene
ether.
modulus of rupture See,fZexurul strength.
modulus of rupture in bending Seejlexurul strength.
molecular weight The sum of the atomic weights of all atoms in a
molecule. Also called MW.
molybdenum disulfide Molybdenum disulfide (MoS,) is a
crystalline filler used as an external lubricant in plastics such as
polystyrene, nylons, and fluoropolymers to improve their wear
resistance.
MPE See modified polyphenylene ether.
MPO See modijied polyphenylene ether.
MQ See methylsilicone.
MW See moleculur weight
NBS Abrasion Index See Abrasive Index.
neoprene rubber Polychloroprene rubbers with good resistance to
petroleum products, heat, and ozone, weatherability, and
toughness.
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