ASTM D883-24

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D883 − 24
Standard Terminology Relating to
Plastics
This standard is issued under the fixed designation D883; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* conflict between Terminology E176 and ISO 13943, the defi-
nitions given in Terminology E176 shall prevail.
1.1 This terminology covers definitions of technical terms
1.6.4 For terms relating to precision and bias and associated
used in the plastics industry. Terms that are generally under-
issues, the applicable definitions are contained in Terminology
stood or adequately defined in other readily available sources
E456.
are not included.
1.6.5 For terms related to plastic piping systems, the appli-
1.2 When a term is used in an ASTM document for which
cable definitions are contained in Terminology F412.
Committee D20 is responsible it is included only when judged,
1.7 This international standard was developed in accor-
after review, by Subcommittee D20.92 to be a generally usable
dance with internationally recognized principles on standard-
term.
ization established in the Decision on Principles for the
1.3 Definitions that are identical to those published by
Development of International Standards, Guides and Recom-
another standards body are identified with the abbreviation of
mendations issued by the World Trade Organization Technical
the name of the organization; for example, IUPAC is the
Barriers to Trade (TBT) Committee.
International Union of Pure and Applied Chemistry.
2. Referenced Documents
1.4 A definition is a descriptive phrase or a single sentence
with additional information included in discussion notes. 2.1 ASTM Standards:
C162 Terminology of Glass and Glass Products
NOTE 1—It is recommended that definitions be reviewed periodically.
C168 Terminology Relating to Thermal Insulation
1.4.1 When a new definition is added to this terminology
D638 Test Method for Tensile Properties of Plastics
standard, or the wording of a definition is revised, the date of
D747 Test Method for Apparent Bending Modulus of Plas-
the change shall be appended to the new or revised definition.
tics by Means of a Cantilever Beam (Withdrawn 2019)
1.5 For literature related to plastics terminology, see Appen- D790 Test Methods for Flexural Properties of Unreinforced
dix X1. and Reinforced Plastics and Electrical Insulating Materi-
als
1.6 Subsections 1.6.1 – 1.6.5 contain references to specific
D882 Test Method for Tensile Properties of Thin Plastic
terminology standards that are relevant to specific plastic
Sheeting
products or applications. In case of conflict between a defini-
D907 Terminology of Adhesives
tion contained in Terminology D883 and one contained in
D1003 Test Method for Haze and Luminous Transmittance
another standard, the definition given in Terminology D883
of Transparent Plastics
shall prevail.
D1711 Terminology Relating to Electrical Insulation
1.6.1 For terms related to thermal insulation, the applicable
D4703 Practice for Compression Molding Thermoplastic
definitions are contained in Terminology C168.
Materials into Test Specimens, Plaques, or Sheets
1.6.2 For terms related to electrical or electronic insulating
E176 Terminology of Fire Standards
materials, the applicable definitions are contained in Terminol-
E308 Practice for Computing the Colors of Objects by Using
ogy D1711.
the CIE System
1.6.3 For terms relating to fire, the applicable definitions are
E456 Terminology Relating to Quality and Statistics
contained in Terminology E176 and ISO 13943. In case of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This terminology is under the jurisdiction of ASTM Committee D20 on Plastics contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and is the direct responsibility of Subcommittee D20.92 on Terminology. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Feb. 1, 2024. Published February 2024. Originally the ASTM website.
approved in 1946. Last previous edition approved in 2023 as D883 - 23. DOI: The last approved version of this historical standard is referenced on
10.1520/D0883-24. www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D883 − 24
F412 Terminology Relating to Plastic Piping Systems aromatic polyester, n—a polyester derived from monomers in
which all the hydroxyl and carboxyl groups are linked
2.2 ISO Standards:
4 directly to aromatic nuclei. (1986)
ISO 13943 Fire Safety—Vocabulary (2023)
artificial weathering, n—exposure to laboratory conditions,
3. Terminology
which may be cyclic, involving changes in temperature,
relative humidity, radiant energy, and any other elements
3.1 Definitions:
found in the atmosphere in various geographical areas.
A-stage, n—an early stage in the preparation of certain
DISCUSSION—The laboratory exposure conditions are usually inten-
thermosetting resins in which the material is still soluble in
sified beyond those encountered in actual outdoor exposure in an
certain liquids, and may be liquid or capable of becoming
attempt to achieve an accelerated effect. (1980)
liquid upon heating.
DISCUSSION—Sometimes referred to as Resol. (See also B-stage and average injection velocity, n—the mean value of the velocity
C-stage.) (1978)
of the molten plastic flow front within a cavity during the
injection time that is calculated from the shot volume and
acetal plastics, n—plastics based on polymers having a pre-
injection time.
dominance of acetal linkages in the main chain. (See also
DISCUSSION—The average injection velocity is calculated as follows:
polyoxymethylene.) (1985)
V
s
V 5
av
acrylic plastics, n—plastics based on polymers made with
t × A × n
i c
acrylic acid or a structural derivative of acrylic acid. (1982)
addition polymerization—polymerization in which mono-
where:
mers are linked together without the splitting off of water or
V = average injection velocity, mm/s,
av
other simple molecules. (1983) V = shot volume, mm ,
s
t = injection time, s,
i
A = cross section of the cavity, mm , and
adiabatic extrusion—a method of extrusion in which, after c
n = number of cavities.
the extrusion apparatus has been heated sufficiently by
This calculation is valid for molds containing a single cavity or those
conventional means to plastify the material, the extrusion
containing identical multi-specimen cavities only and not for family molds.
process can be continued with the sole source of heat being
the conversion of the drive energy, through viscous resis-
tance of the plastic mass in the extruder. (1978)
B-stage, n—an intermediate stage in the reaction of certain
thermosetting resins in which the material swells when in
aging, n—(1) the effect on materials of exposure to an
contact with certain liquids and softens when heated, but
environment for an interval of time. (2) the process of
may not entirely dissolve or fuse.
exposing materials to an environment for an interval of time.
DISCUSSION—The resin in an uncured thermosetting molding com-
(1973)
pound is usually, in this stage, sometimes referred to as Resitol. (See
alkyd plastics, n—plastics based on alkyd resins. (1980) also A-stage and C-stage.) (1978)
bag molding, n—a method of molding or laminating which
alkyd resin, n—a polyester convertible into a crosslinked
involves the application of fluid pressure, usually by means
form; requiring a reactant of functionality higher than two,
of air, steam, water or vacuum, to a flexible barrier material
or having double bonds. (1982)
which transmits the pressure to the material being molded or
alloy, n—(in plastics), two or more immiscible polymers
bonded.
united, usually by another component, to form a plastic resin
DISCUSSION—The process is usually employed for forming shapes
having enhanced performance properties.
from preformed laminates comprising a fibrous sheet impregnated with
an A-stage or a B-stage thermosetting resin. (1986)
allyl plastics, n—plastics based on allyl resins. (1978)
binder, n—in a reinforced plastic, the continuous phase which
allyl resin, n—a resin made by polymerization of chemical
holds together the reinforcement.
compounds containing the allyl group. (1978)
DISCUSSION—During fabrication, the binder, which may be either
thermoplastic or thermoset, usually undergoes a change in state. (1978)
amino plastics, n—plastics based on amino resins. (1978)
biodegradable plastic, n—See degradable plastic.
amino resin, n—a resin made by polycondensation of a
blister, n—an imperfection, a rounded elevation of the surface
compound containing amino groups, such as urea or
of a plastic, with boundaries that may be more or less sharply
melamine, with an aldehyde, such as formaldehyde, or an
defined, somewhat resembling in shape a blister on the
aldehyde-yielding material. (1985)
human skin. (1983)
apparent density—See density, apparent.
block copolymer, n—an essentially linear copolymer in which
there are repeated sequences of polymeric segments of
different chemical structure. (1982)
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
blocking, n—unintentional adhesion between plastic films or
4th Floor, New York, NY 10036, http://www.ansi.org.
Date indicates year of introduction or latest review or revision. between a film and another surface. (1983)
D883 − 24
bloom, n—a visible exudation or efflorescence on the surface cellular plastic, n—a plastic containing numerous cells, inten-
of a material. (1972) tionally introduced, interconnecting or not, distributed
throughout the mass. (See also syntactic cellular plastics.)
blowing agent, n—a compounding ingredient used to produce
(1983)
gas by chemical or thermal action, or both, in manufacture of
cellular striation, n—a condition characterized by a layer
hollow or cellular articles. (1983)
within a cellular material that differs greatly from the
blow molding, n—a method of fabrication in which a heated
characteristic cell structure.
parison is forced into the shape of a mold cavity by internal
cellulosic plastics, n—plastics based on cellulose compounds,
gas pressure. (1985)
such as esters (cellulose acetate) and ethers (ethyl cellulose).
branched polyethylene plastics, n—those containing signifi-
(1985)
cant amounts of both short-chain and long-chain branching
chalking, n—(plastics), a powdery residue on the surface of a
and having densities in the 0.910 to 0.940 g/cm range.
material resulting from degradation or migration of an
DISCUSSION—These plastics, usually produced commercially by free
radical polymerization, are subcategorized by density level; low density
ingredient, or both.
polyethylene plastic and medium density polyethylene plastic.
DISCUSSION—Chalking may be designed-in characteristic. (1980)
bulk density, n—the weight per unit volume of a loosely
chemically foamed polymeric material, n—a cellular mate-
packed material, such as a molding powder or pellets.
rial in which the cells are formed by gases generated from
DISCUSSION—This term should not be used synonymously with
thermal decomposition or other chemical reaction. (1982)
apparent density.
chlorinated poly(vinyl chloride), n—a poly(vinyl chloride)
bulk factor, n—the ratio of the volume of a given mass of
(PVC) polymer modified by additional chlorination. (2000)
molding material to its volume in the molded form.
chlorinated poly(vinyl chloride) plastics, n—plastics based
DISCUSSION—The bulk factor is also equal to the ratio of the density
of the material to its apparent density in the unmolded form. (ISO) on chlorinated poly(vinyl chloride) in which the chlorinated
(1982)
poly(vinyl chloride) is in the greatest amount by weight.
(1978)
bulk molding compound (BMC), n—a putty-like mixture of
any thermosetting resin containing fillers, fiber
chlorofluorocarbon plastics, n—plastics based on polymers
reinforcements, catalysts and thickening agents, or thermo-
made with monomers composed of chlorine, fluorine, and
plastic polymers, often extruded into logs or ropes.
carbon only. (ISO) (1983)
DISCUSSION—BMC is suitable for molding by any one of three
chlorofluorohydrocarbon plastics, n—plastics based on poly-
matched-metal-mold processes—compression molding, transfer
molding, or injection molding. (1983) mers made with monomers composed of chlorine, fluorine,
hydrogen, and carbon only. (ISO) (1982)
butylene plastics, n—plastics based on resins made by the
polymerization of butene or copolymerization of butene with circuit, n—in filament winding, the winding produced by a
one or more unsaturated compounds, the butene being in single revolution of mandrel or form. (1978)
greatest amount by weight. (1975)
closed-cell cellular plastics, n—cellular plastics in which
almost all the cells are noninterconnecting. (1983)
C-stage, n—the final stage in the reaction of certain thermo-
setting materials in which they have become practically
cold flow, n—See creep. (1983)
insoluble and infusible.
cold molding, n—a special process of compression molding in
DISCUSSION—The resin in a fully cured thermoset molding is, in this
which the molding is formed at room temperature and
stage, sometimes referred to as Resite. (See also A-stage and B-stage.)
subsequently baked at elevated temperatures. (1982)
(1986)
collapse, n—inadvertent densification of cellular material dur-
cast film, n—a film made by depositing a layer of plastic, either
ing manufacture resulting from breakdown of cell structure.
molten, in solution, or in a dispersion, onto a surface,
(1982)
solidifying and removing the film from the surface. (1982)
composite, n—a solid product consisting of two or more
cavity, n—in specimen preparation, the part of the hollow
distinct phases, including a binding material (matrix) and a
space of a mold that forms one specimen.
particulate or fibrous material.
cell, n—a small cavity surrounded partially or completely by
DISCUSSION—Examples are moulding material containing reinforcing
walls. (1983)
fibers, particulate fillers, or hollow spheres. (1991)
cell, closed, n—a cell totally enclosed by its walls and hence compost, n—the product of composting.
not interconnecting with other cells. (ISO) (See cell and cell,
compostable plastic, n—a plastic that undergoes biological
open.) (1983)
degradation during composting to yield carbon dioxide,
cell, open, n—a cell not totally enclosed by its walls and hence water, inorganic compounds, and biomass at a rate consistent
interconnecting with other cells. (See cell and cell, closed.) with other known compostable materials and leaves no
(1983) visually distinguishable or toxic residues. (1996)
D883 − 24
compound, n—an intimate admixture of (a) polymer(s) with cycle time, n—in molding, the total time used to carry out a
all the materials necessary for the finished product. (1983) complete sequence of operations making up the molding
cycle.
compression molding, n—the method of molding a material
already in a confined cavity by applying pressure and usually degradable plastic, n—a plastic designed to undergo a signifi-
heat. (1986) cant change in its chemical structure under specific environ-
mental conditions resulting in a loss of properties as mea-
condensation polymer, n—a polymer made by condensation
sured by standard test methods appropriate to the plastic and
polymerization. (1983)
the application in a period of time that determines its
classification. (1991)
condensation polymerization, n—polymerization in which
monomers are linked together with the splitting off of water
biodegradable plastic, n—a degradable plastic in which the
or other simple molecules. (1983)
degradation results from the action of naturally-occurring
contact pressure molding, n—a method of molding or lami- micro-organisms such as bacteria, fungi, and algae.
DISCUSSION—The level of biodegradability may be indicated as
nating in which the pressure, usually less than 70 kPa (10
shown in subordinate definitions for biodegradable plastics. (1991)
psi), is only slightly more than necessary to hold the
materials together during the molding operation. (1985)
hydrolytically degradable plastic, n—a degradable plastic in
which the degradation results from hydrolysis.
cooling time, n—in molding, the time interval from the start of
DISCUSSION—The level of hydrolytic degradability may be indicated
forward screw movement until the mold starts to open.
as shown in subordinate definitions for hydrolytically degradable
copolymer, n—See polymer. (1983) plastic. (1991)
copolymerization, n—See polymerization. (1983)
oxidatively degradable plastic, n—a degradable plastic in
crater, n—a small, shallow surface imperfection. (1978)
which the degradation results from oxidation.
DISCUSSION—The level of oxidative degradability may be indicated
crazing, n—apparent fine cracks at or under the surface of a
as shown in subordinate definitions for oxidatively degradable plastic.
plastic.
(1991)
DISCUSSION—The crazed areas are composed of polymeric material
of lower density than the surrounding matrix. (1978)
photodegradable plastic, n—a degradable plastic in which the
degradation results from the action of natural daylight.
creep, n—the time-dependent part of strain resulting from
DISCUSSION—The level of photodegradability may be indicated as
stress. (1983)
shown in subordinate definitions for photodegradable plastic. (1991)
cross laminate, n—a laminate in which some of the layers of
degradation, n—a deleterious change in the chemical
material are oriented approximately at right angles to the
structure, physical properties, or appearance of a plastic.
remaining layers with respect to the grain or strongest
(1980)
direction in tension. (See also parallel laminate). (1982)
delamination, n—the separation of the layers of material in a
crosslinking, n—the formation of a three dimensional polymer
laminate. (1978)
by means of interchain reactions resulting in changes in
physical properties. (1983)
density, apparent, n—the weight in air of a unit volume of a
material.
cross section of the cavity, n—in a mold for test specimens,
DISCUSSION—This term is sometimes used synonymously with bulk
the area of a planar section perpendicular to the flow pattern
density. (1973)
during filling of the mold that forms the critical portion of
the test specimen.
density, bulk, n—the weight per unit volume of a material
including voids inherent in material as tested.
cure, v—to change the properties of a polymeric system into a
DISCUSSION—This term is commonly used for material such as
more stable, usable condition by the use of heat, radiation, or
molding powder. (1973)
reaction with chemical additives.
DISCUSSION—Cure may be accomplished, for example, by removal of
depth, n—in the case of a beam, the dimension parallel to the
solvent or by crosslinking. (ISO) (1983)
direction in which the load is applied. (1978)
cure cycle, n—the schedule of time periods, at specified
dome, n—in reinforced plastics, an end of a filament-wound
conditions, to which a reacting thermosetting material is
cylindrical container. (1985)
subjected to reach a specified property level. (1983)
dry-blend, n—a dry compound prepared without fluxing or
cure time, n—the period of time that a reacting thermosetting
addition of solvent (also called powder blend). (1983)
material is exposed to specific conditions to reach a specified
dry-spot, n—an imperfection in reinforced plastics, an area of
property level. (1983)
incomplete surface film where the reinforcement has not
cut-layers, n—as applied to laminated plastics, a condition of
been wetted with resin. (1983)
the surface of machined or ground rods and tubes and of
sanded sheets in which cut edges of the surface layer or durometer, n—an instrument for measuring indentation hard-
lower laminations are revealed. (1978) ness.
D883 − 24
DISCUSSION—When the monomer is essentially tetrafluoroethylene,
elastomer, n—a macromolecular material that at room tem-
the prefix TFE is sometimes used to designate these materials. It is
perature returns rapidly to approximately its initial dimen-
preferable to use the accepted abbreviation, PTFE. TFE should not be
sions and shape after substantial deformation by a weak
used by itself to mean PTFE. When the resins are copolymers of
stress and release of the stress. (1985)
tetrafluoroethylene and hexafluoropropylene, the resins may be desig-
nated with the prefix FEP. Other prefixes may be adopted to designate
engineered plastic, n—a material that has been made by
other fluorocarbon plastics. (ISO) (1983)
specific design and through use of particular monomers and
monomer sequences to produce a plastic with desired fluorohydrocarbon plastics, n—plastics based on polymers
properties, possibly for a specific application. (1991) made with monomers composed of fluorine, hydrogen, and
carbon only. (ISO) (1982)
engineering plastics, n—those plastics and polymeric compo-
fluoroplastic, n—a plastic based on polymers made from
sitions for which well-defined properties are available such
monomers containing one or more atoms of fluorine, or
that engineering rather than empirical methods can be used
copolymers of such monomers with other monomers, the
for the design and manufacture of products that require
fluorine-containing monomer(s) being in greatest amount by
definite and predictable performance in structural applica-
mass.
tions over a substantial temperature range.
DISCUSSION—For specific examples of fluoroplastic see fluorocarbon
epoxy plastics, n—thermoplastic or thermosetting plastics
plastic, chlorofluorocarbon plastics, fluorohydrocarbon plastics,
containing ether or hydroxyalkyl repeating units, or both,
and chlorofluorohydrocarbon plastics. (1983)
resulting from the ring-opening reactions of lower molecular
foamed plastics, n—See cellular plastics (the preferred ter-
weight polyfunctional oxirane resins, or compounds, with
minology). (1983)
catalysts or with various polyfunctional acidic or basic
forming, n—a process in which the shape of plastic pieces
coreactants.
such as sheets, rods, or tubes is changed to a desired
DISCUSSION—Epoxy plastics often are modified by the incorporation
configuration.
of diluents, plasticizers, fillers, thixotropic agents, or other materials.
DISCUSSION—The use of the term “forming” in plastics technology
(1985)
does not include such operations as molding, casting, or extrusion, in
which shapes or pieces are made from molding materials or liquids.
ethylene plastics, n—plastics based on polymers of ethylene or
(1982)
copolymers of ethylene with other monomers, the ethylene
being in greatest amount by mass. (ISO) (1982)
furan plastics, n—plastics based on furan resins. (ISO) (1982)
expandable plastic, n—a plastic in a form capable of being
furan resin, n—a resin in which the furan ring is an integral
made cellular by thermal, chemical, or mechanical means.
part of the polymer chain and represents the greatest amount
(1985)
by mass. (ISO) (1983)
gate, n—in an injection mold, a constriction in the flow channel
expanded plastics, n—See cellular plastic. (1985)
extrusion, n—a process in which heated or unheated plastic is between the runner and the mold cavity. (1983)
forced through a shaping orifice (a die) in one continuously
gel, n—
formed shape, as in film, sheet, rod, or tubing. (1983)
(1) a semisolid system consisting of a network of solid
aggregates in which liquid is held.
fabricating, n—the manufacture of plastic products from
(2) the initial jelly-like solid phase that develops during
molded parts, rods, tubes, sheeting, extrusions, or other
the formation of a resin from a liquid.
forms by appropriate operations such as punching, cutting,
(3) with respect to vinyl plastisols, gel is a state between
drilling, and tapping including fastening plastic parts to-
liquid and solid that occurs in the initial states of heating, or
gether or to other parts by mechanical devices, adhesives,
upon prolonged storage.
heat sealing, or other means. (1978)
DISCUSSION—All three types of gels have very low strengths and do
fiber show, n—strands or bundles of fibers not covered by resin
not flow like a liquid. They are soft, flexible, and may rupture under
which are at or above the surface of a reinforced plastic. their own weight unless supported externally. (1978)
(4) in plastic film and sheet, a nodule of plastic material composed
(1985)
of one or more of oxidized, high-molecular-weight, unmelted, non-
filler, n—a relatively inert material added to a plastic to modify
solvated, or cross-linked material of the same composition as the matrix
its strength, permanence, working properties, or other that, for a variety of reasons, has not blended with the matrix. See
fish-eye.
qualities, or to lower costs. (See also reinforced plastic.)
(1978)
DISCUSSION—Gel in the film or sheet is to be distinguished from
contamination such as particles of dirt, carbon, or lint. (1992)
film, n—in plastics, an optional term for sheeting having a
gel point, n—the stage at which a liquid begins to exhibit
nominal thickness not greater than 0.25 mm (0.01 in.).
pseudo-elastic properties.
(1985)
DISCUSSION—This stage may be detected as the inflection point on a
fish-eye, n—small globular mass that has not blended com-
viscosity-time plot. (See gel (2).) (1985)
pletely into the surrounding material. See gel. (1978)
gel time, n—the period of time from the initial mixing of the
fluorocarbon plastic, n—a plastic based on polymers made reactants of a liquid material composition to the time when
with perfluoromonomers. gelation occurs, as defined by a specific test method.
D883 − 24
DISCUSSION—For a material that must be processed by exposure to
halocarbon plastics, n—plastics based on resins made by the
some form of energy, the zero time is the start of exposure. (1983)
polymerization of monomers composed only of carbon and
a halogen or halogens. (1978)
glass, n—an inorganic product of fusion which has cooled to a
rigid condition without crystallizing.
haze, n—the cloudy or turbid aspect or appearance of an
DISCUSSION—Term not defined by Committee D20. Definition ap-
otherwise transparent specimen caused by light scattered
proved by Committee C14 on Glass and Glass Products. See Termi-
from within the specimen or from its surfaces.
nology C162.
DISCUSSION—For the purpose of Test Method D1003, haze is the
(a) Glass is typically hard and brittle and has a conchoidal
percentage of transmitted light which, in passing through the specimen,
fracture. It may be colorless or colored, and transparent to
deviates from the incident beam through forward scatter more than 2.5
opaque. Masses or bodies of glass may be made colored,
deg on the average. (1983)
translucent, or opaque by the presence of dissolved,
heat mark, n—extremely shallow depression or groove in the
amorphous, or crystalline material.
(b) When a specific kind of glass is indicated, such surface of a plastic visible because of a sharply defined rim
or a roughened surface. (See also shrink mark.) (1978)
descriptive terms as flint glass, barium glass, and window glass
should be used following the basic definition, but the qualify-
high density polyethylene plastics, (HDPE), n—those linear
ing term is to be used as understood by trade custom.
polyethylene plastics, g. v., having a standard density of
(c) Objects made of glass are loosely and popularly re-
0.941 g/cm or greater.
ferred to as glass; such as glass for a tumbler, a barometer, a
DISCUSSION—These plastics are usually produced commercially by
window, a magnifier or a mirror. (1978)
processes not employing free radical polymerization. Standard density
refers to the density of the material molded to a thickness of 1.9 mm
glass finish, n—a material applied to the surface of glass fibers
(0.075 in.) using Procedure C of Annex A1 of Practice D4703.
used to reinforce plastics and intended to improve the
physical properties of such reinforced plastics over that
high-pressure molding, n—a method of molding or laminat-
obtained using glass reinforcement without finish. (1982)
ing in which the pressure used is greater than 1400 kPa (200
psi). (1985)
glass transition, n—the reversible change in an amorphous
polymer or in amorphous regions of a partially crystalline
hold pressure, n—in molding, the melt pressure during the
polymer from (or to) a viscous or rubbery condition to (or
hold time interval in injection molding.
from) a hard and relatively brittle one.
DISCUSSION—The glass transition generally occurs over a relatively
homopolymer, n—a polymer resulting from polymerization
narrow temperature region and is similar to the solidification of a liquid
involving a single monomer. (1983)
to a glassy state; it is not a phase transition. Not only do hardness and
brittleness undergo rapid changes in this temperature region but other
hydrocarbon plastics, n—plastics based on resins made by the
properties, such as thermal expansibility and specific heat also change
polymerization of monomers composed of carbon and hy-
rapidly. This phenomenon has been called second order transition,
drogen only. (1985)
rubber transition and rubbery transition. The word transformation has
also been used instead of transition. Where more than one amorphous
hydrolytically degradable plastics, n—See degradable plas-
transition occurs in a polymer, the one associated with segmental
tic.
motions of the polymer backbone chain or accompanied by the largest
inhibitor, n—a substance used in low concentration which
change in properties is usually considered to be the glass transition.
(1980) suppresses a chemical reaction.
DISCUSSION—Inhibitors, unlike catalysts, are consumed during the
glass transition temperature (Tg), n—the approximate mid-
reaction. (1983)
point of the temperature range over which the glass transi-
tion takes place. injection molding, n—the process of forming a material by
DISCUSSION—The glass transition temperature can be determined forcing it, in a fluid state and under pressure, through a
readily only by observing the temperature at which a significant change
runner system (sprue, runner, gate(s)) into the cavity of a
takes place in a specific electrical, mechanical, or other physical
closed mold.
property. Moreover, the observed temperature can vary significantly
DISCUSSION—Screw injection molding and reaction injection molding
depending on the specific property chosen for observation and on
are types of injection molding. (1983)
details of the experimental technique (for example, rate of heating,
frequency). Therefore, the observed Tg should be considered only an
injection time, n—the time interval from the beginning of
estimate. The most reliable estimates are normally obtained from the
screw forward movement until switching over to hold
loss peak observed in dynamic mechanical tests or from dialatometric
pressure. (1995)
data. (1978)
insert, n—a part consisting of metal or other material which
graft copolymer, n—a copolymer in which polymeric side
may be molded into position or may be pressed into the
chains have been attached to the main chain of a polymer of
molding after the completion of the molding operation.
different structure. (1973)
(ISO) (1978)
gusset, n—
(1) a piece used to give additional size or strength in a intumescence, n—the formation of a swelling/foaming sub-
particular location of an object. stance in response to heat that insulates the underlying
(2) the folded-in portion of flattened tubular film. (1972) substrate material. (2022)
D883 − 24
isotactic, adj—pertaining to a type of polymeric molecular linear polyethylene plastics, n—those containing insignificant
structure containing a sequence of regularly spaced asym- amounts of long-chain branching but which may contain
metric atoms arranged in like configuration in a polymer significant amounts, by design, of short-chain branching.
chain. (1985) DISCUSSION—These plastics, usually produced commercially by pro-
cesses not employing free radical polymerization, are subcategorized
knit-line, n—See weld-line (the preferred terminology).
by density level; linear low density polyethylene plastic, linear medium
(1983)
density polyethylene plastic, and high density polyethylene plastic. For
differentiation among high molecular versions of these plastics pro-
knuckle area, n—in reinforced plastics, the area of transition
duced commercially by stereo-specific catalysts, see extra-high mo-
between sections of different geometry in a filament-wound
lecular weight polyethylene plastic and ultra-high molecular weight
part. (1985)
polyethylene plastic.
laminate , n—a product made by bonding together two or
low density polyethylene plastics, (LDPE), n—those
more layers of material or materials. (See also cross lami-
branched polyethylene plastics, q. v., having a standard
nate and parallel laminate.) (ISO)
density of 0.910 to 0.925 g/cm .
DISCUSSION—A single resin-impregnated sheet of paper, fabric, or
DISCUSSION—These plastics are usually produced commercially by
glass mat, for example, is not considered a laminate. Such a single-
processes employing free radical polymerization. Standard density
sheet construction may be called a “lamina.” (See also reinforced
refers to the density of the material molded to a thickness of 1.9 mm
plastic.) (1983)
(0.075 in.) using Procedure C of Annex A1 of Practice D4703.
lattice pattern, n—in reinforced plastics, a pattern of filament
low-pressure molding, n—a method of molding or laminating
winding with a fixed arrangement of open voids. (1985)
in which the pressure is 1400 kPa (200 psi) or less. (1985)
lay, n—
lubricant bloom, n—See bloom. (1982)
(1) the length of twist produced by stranding filaments,
luminous transmittance, n—the ratio of the luminous flux
such as fibers, wires, or roving;
transmitted by a body to the flux incident upon it.
(2) the angle that such filaments make with the axis of the
DISCUSSION—Parallel definitions apply to spectral and radiant trans-
strand during a stranding operation.
mittance. See Test Method E308 for a detailed discussion of terminol-
DISCUSSION—Length of twist of a filament is usually measured as the
ogy. (1982)
distance parallel to the axis of the strand between successive turns of
the filament. (1985)
mat, n—a fibrous material consisting of randomly oriented
lay up, n—in reinforced plastics, an assembly of layers of chopped or swirled filaments loosely held together with a
resin-impregnated material ready for processing. (1982) binder. (1982)
lay up, v—in reinforced plastics, to assemble layers of resin-
mechanically foamed plastic, n—a cellular plastic in which
impregnated material for processing. (1985)
the cells are formed by the physical incorporation of gases.
(1985)
let-go, n—an area in laminated glass over which an initial
adhesion between interlayer and glass has been lost. (1985)
medium density polyethylene plastics, (MDPE), n—those
branched polyethylene plastics, q. v., having a standard
lignin plastics, n—plastics based on lignin resins. (ISO) (1983)
density of 0.926 to 0.940 g/cm .
lignin resin, n—a resin made by heating lignin or by reaction DISCUSSION—These plastics are usually produced commercially by
processes employing free radical polymerization. Standard density
of lignin with chemicals or resins, the lignin being in greatest
refers to the density of the material molded to a thickness of 1.9 mm
amount by mass. (ISO) (1983)
(0.075 in.) using Procedure C of Annex A1 of Practice D4703.
linear low density polyethylene plastics, (LLDPE), n—those
melamine plastics, n—plastics based on resins made by the
linear polyethylene plastics, q.v., having a standard density
condensation of melamine and aldehydes. (1985)
of 0.919 to 0.925 g/cm .
DISCUSSION—These plastics are usually produced commercially by
melt pressure, n—the pressure applied to the plastic material
processes not employing free radical polymerization. Standard density
in front of the screw driving the injection molding process on
refers to the density of the material molded to a thickness of 1.9 mm
a reciprocating screw machine that is calculated based on the
(0.075 in.) using Procedure C of Annex A1 of Practice D4703.
hydraulic force acting axially on the screw.
linear medium density polyethylene plastics, (LMDPE),
DISCUSSION—Melt pressure is calculated as follows:
n—those linear polyethylene plastics, q. v., having a standard
4 × 10 × F
s
density of 0.926 to 0.940 g/cm .
P 5
π × D
DISCUSSION—These plastics are usually produced commercially by
processes not employing free radical polymerization. Standard density
where:
refers to the density of the material molded to a thickness of 1.9 mm
P = melt pressure, MPa,
(0.075 in.) using Procedure C of Annex A1 of Practice D4703.
F = hydraulic axial force, kN, and
s
D = screw diameter, mm. (1995)
melt temperature, n—the temperature of the molten plastic.
These definitions are identical with those appearing in Terminology D907,
which were prepared by ASTM Committee D14 on Adhesives. (1995)
D883 − 24
mold open time, n—the time interval from the instant the mold oligomerization, n—the process of converting a monomer or
begins to open until it is closed again. (1995) mixture of monomers into a oligomer. (1983)
open-cell cellular plastic, n—a cellular plastic in which there
mold temperature, n—the mean temperature of the mold
cavity surface measured after the system has obtained is a predominance of interconnected cells. (1985)
thermal equilibrium and immediately after opening the
organosol, n—a suspension of a finely divided polymer in a
mold. (1995)
plasticizer, together with a volatile organic liquid.
DISCUSSION—The volatile liquid evaporates at elevated temperatures,
molding, bag, n—See bag molding. (1985)
and the resulting residue is a homogeneous polymeric mass, provided
molding, blow, n—See blow molding. (1985)
the temperature is high enough to accomplish mutual solution of the
molding, compression, n—See compression molding. (1985)
polymer and plasticizer. (1985)
molding, contact pressure, n—See contact pressure mold-
oxidatively degradable plastic, n—See degradable plastic.
ing. (1985)
molding, high-pressure, n—See high-pressure molding.
parallel laminate, n—a laminate in which all the layers of
(1985)
material are oriented approximately parallel with respect to
molding, injection, n—See injection molding. (1985)
the grain or strongest direction in tension. (See also cross
molding, low-pressure, n—See low-pressure molding. laminate.) (1985)
(1985)
parison, n—the shaped plastic mass, generally in the form of
molding, transfer, n—See transfer molding. (1985)
a tube, used in blow molding. (ISO) (1983)
molding pressure, compression, n—the calculated fluid pres-
sure applied to the material in the mold. (1985) phenolic plastics, n—plastics based on resins made by the
condensation of phenols, such as phenol or cresol, with
molding pressure, injection, n—the pressure applied to the
aldehydes. (1985)
cross-sectional area of the material cylinder. (1982)
phenolic resin compound, single-stage, n—a phenolic mate-
molding pressure, transfer, n—the pressure applied to the
rial in which the resin, because of its reactive groups, is
cross-sectional area of the material pot or cylinder. (1982)
capable of further polymerization by application of heat.
(See also phenolic resin compound, two-stage.) (1978)
monomer, n—a low-molecular-weight substance consisting of
molecules capable of reacting with like or unlike molecules
phenolic resin compound, two-stage, n—a phenolic material
to form a polymer. (1983)
in which the resin is essentially not reactive at normal
storage temperatures, but contains a reactive additive which
necking, n—the localized reduction in cross-section which
causes further polymerization upon the application of heat.
may occur in a material under tensile stress. (1982)
(1978)
nonrigid plastic, n—for purposes of general classification, a
photodegradable plastic, n—See degradable plastic.
plastic that has a modulus of elasticity either in flexure or in
tension of not over 70 MPa (10 000 psi) at 23°C and 50 %
pimple, n—an imperfection, a small, protuberance of varied
relative humidity when tested in accordance with Test
shape on the surface of a plastic product. (1983)
Methods D790, Test Method D747, Test Method D638, or
pit, n—an imperfection, a small crater in the surface of the
Test Methods D882. (1983)
plastic, with its width of approximately the same order of
novolac (or novolak), n—a phenolic-aldehyde resin which,
magnitude as its depth. (1983)
unless a source of methylene groups is added, remains
plastic(s), n—a material that contains as an essential ingredient
permanently thermoplastic. (See also resinoid and thermo-
one or more organic polymeric substances of large molecular
plastic.) (1977)
weight, is solid in its finished state, and, at some stage in its
nylon plastics, n—plastics based on resins composed princi-
manufacture or processing into finished articles, can be
pally of a long-chain synthetic polymeric amide which has
shaped by flow.
recurring amide groups as an integral part of the main
DISCUSSION—Rubber, textiles, adhesives, and paint, which may in
polymer chain. (1985)
some cases meet this definition, are not considered plastics. See ASTM
definitions of these terms.
olefin plastics, n—plastics based on polymers made by the
DISCUSSION—The above definition may be used as a separate mean-
polymerization of olefins or copolymerization of olefins with
ing from the definitions contained in the dictionary for the adjective
other monomers, the olefins being at least 50 mass %. (1983)
“plastic.”
oligomer, n—a substance composed of only a few nonomeric
DISCUSSION—The plural form may be used as an adjective to refer to
units repetitively linked to each other, such as a dimer,
two or more plastic materials, for example, plastics industry. However,
trimer, tetramer, etc., or their mixtures.
when the intent is to distinguish “plastic products” from “wood
DISCUSSION—The physical properties of an oligomer vary with the products” or “glass products,” the singular form should be used. As a
addition or removal of one or a few constitutional units from its general rule, if the adjective is to restrict the noun modified with respect
molecules. (1983) to the type of material, “plastic” should be used; if the adjective is to
D883 − 24
indicate that more than one type of plastic material is or may be
polybutylene plastics, n—plastics based on polymers made
involved, “plastics” is permissible. (1982)
with butene as essentially the sole monomer. (1985)
plastic composite, n—a material consisting of two or more
polycarbonate, n—a polyester polymer in which the repeating
distinct immiscible materials, at least one of which is a
structural unit in the chain is of the carbonate type. (1983)
plastic. (2019)
polycarbonate plastics, n—polyester plastics based on poly-
DISCUSSION—Codes identify plastic lumber and wood/plastic com-
posites as plastic composites, for application as materials for exterior mers in which the repeating structural units in the chains are
decking, stair treads, handrails and guardrails. Codes define plastic
essentially all of the carbonate type. (1983)
composite as “a generic designation that refers to wood/plastic com-
polycondensation, n—See condensation polymerization.
posites and plastic lumber.” Outside of code use, a wide variety of
plastic composites exist, which are used for many applications. Such
(1982)
plastic composites can contain multiple types of fibrous fillers other
polydicyclocpentadiene plastic, n—a crosslinked thermoset
than wood fibers (including glass reinforcements) or even contain no
polymer formed by the ring-opening metathesis polymeriza-
fibrous components. Plastic composites have in common only that they
tion of dicyclopentadiene.
are composed of two or more constituent materials, one of which is a
plastic.
polyester, n—a polymer in which the repeated structural unit
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