Ash Content
(ASTM D2584, D5630, ISO 3451)
Scope:
The Ash Content test is used to determine the amount of fillers
in a specimen after the polymer has been burned off.
Test Procedure:
Generally, a 2g sample is weighed out and placed into a dried
crucible. The sample is then burned in a muffle furnace at 600°C
until the entire polymer has been burned off. The crucibles are
then placed into desiccators to cool. The ash that is left in
the crucibles is then weighed to give the ash content of the
specimen.
Bulk Density (ASTM D1895B)
Scope:
Bulk density is defined as the weight per unit volume of
material. Bulk density is primarily used for powders or pellets.
Test Procedure:
A funnel is suspended above a measuring cylinder. The funnel is
filled with the sample and allowed to freely flow into the
measuring cylinder. The excess material on top of the measuring
cylinder is scraped off with a straight edge. The sample and the
cylinder is then weighed and the weight / volume (Bulk Density)
is determined.
Compression Set under Constant Deflection (ASTM D395 B)
Scope:
Compression set testing is used to determine the ability of
elastomeric materials to maintain elastic properties after
prolonged compressive stress.
Test Procedure:
The thickness of the original specimen is measured. The specimen
is then placed between spacers and in the compression device.
The specimen is compressed to 25% of its original height, using
spacers to accurately measure the compression. Within two hours
of assembly, the compression device is placed in an oven at a
specified temperature for the suggested time periods of 22 hours
and 70 hours. After removing the sample from the oven, the
specimen is allowed to cool for 30 minutes before measuring the
final thickness.
Compressive Properties (ASTM D695, ISO 604)
Scope:
Compressive properties describe the behavior of a material when
it is subjected to a compressive load. Loading is at a
relatively low and uniform rate.
Test Procedure:
The specimen is placed between compressive plates parallel to
the surface. The specimen is then compressed at a uniform rate.
The maximum load is recorded along with stress-strain data.
Charpy Impact (IS0-179)
Scope:
Charpy Impact is a single point test that measures a materials
resistance to impact from a swinging pendulum. Charpy impact is
defined as the kinetic energy needed to initiate fracture and
continue the fracture until the specimen is broken.
Test procedure:
The specimen is mounted horizontally and supported unclamped at
both ends. The hammer is released and allowed to strike through
the specimen. If breakage does not occur, a heavier hammer is
used until failure occurs.
Carbon Black In Olefin Plastics (ASTM D1603)
Scope:
Determination of carbon black content in Olefin materials like
polyethylene or polypropylene that do not contain nonvolatile
additives or fillers.
Test Procedure:
A sample of known weight is placed into a weighed combustion
boat. The sample is then placed into a 600°C tube furnace under
a dry oxygen free Nitrogen purge. After a set time the
combustion boat with the burn residue is cooled under the
nitrogen purge and weighed. The combustion boat is then placed
into a 600°C muffle furnace to oxidize the carbon residue. When
the carbon is completely oxidized the combustion boat is cooled
and weighed.
Coefficient of Friction (ASTM D1894)
Scope:
The test is used to determine the kinetic (moving) and static
(starting) resistance of one surface being dragged across
another.
Test Procedure:
A specimen is attached to a sled of specified weight. The sled
is pulled across a second surface at a speed of 150 mm/minute.
The force to get the sled started (static) and to maintain
motion (kinetic) is measured.
Deflection Temperature under Load (DTUL or HDT) ASTM D648,
ISO75
Scope:
Heat deflection temp. is defined as the temperature at which a
standard test bar deflects a specified distance under a load.
Test Procedure:
The bars are placed under the deflection measuring device. A
load of 0.45 MPa or 1.80 MPa is placed on each specimen. The
specimens are then lowered into a silicone oil bath where the
temperature is raised at 2° C per minute until they deflect 0.25
mm for ASTM, 0.32 mm for ISO flatwise, and 0.34 mm for ISO
edgewise.
Density and Specific Gravity (ASTM D792, ISO 1183)
Scope:
Density is the mass per unit volume of a material. Specific
gravity is a measure of the ratio of mass of a given volume of
material at 23°C to the same volume of deionized water
Test Procedure:
There are two basic test procedures, Method A and Method B. The
more common being Method A, can be used with sheet, rod, tube
and molded articles. For Method A, the specimen is weighed in
air then weighed when immersed in distilled water at 23°C using
a sinker and wire to hold the specimen completely submerged as
required. Density and Specific Gravity are calculated.
Durometer Hardness, Shore Hardness (ASTM D 2240)
Scope:
Durometer Hardness is used to determine the relative hardness of
soft materials, usually plastic or rubber. The test measures the
penetration of a specified indentor into the material under
specified conditions of force and time.
Procedure:
The specimen is first placed on a hard flat surface. The
indentor for the instrument is then pressed into the specimen
making sure that it is parallel to the surface. The hardness is
read within one second (or as specified by the customer) of firm
contact with the specimen.
DSC (Differential Scanning Calorimeter) (ASTM D3417 /D3418
/ E1356, ISO 11357)
Scope:
Using a DSC (differential scanning calorimeter) the following
are commonly found:
Tg = Glass Transition Temperature = The temperature (°C) at
which an amorphous polymer or an amorphous part of a crystalline
polymer goes from a hard, brittle state to a soft, rubbery
state.
Tm = Melting point = The temperature (°C) at which a crystalline
polymer melts.
D Hm = The amount of energy in (joules/gram) a sample absorbs
while melting.
Tc = Crystallization point = is the temperature at which a
polymer crystallizes upon heating.
D Hc = The amount of energy (joules/gram) a sample releases
while crystallizing.
The data can be used to identify materials, differentiate
homopolymers from copolymers or to characterize materials for
their thermal performance.
Test Procedure:
A sample of 10 to 20 mg. in an aluminum sample pan is placed
into the differential scanning calorimeter. The sample is heated
at a controlled rate (usually 10°/min) and a plot of heat flow
versus temperature is produced. The resulting thermogram is then
analyzed.
Dielectric Constant and Dissipation Factor (ASTM D150,IEC
60250)
Scope:
Dielectric Constant is used to determine the ability of an
insulator to store electrical energy. The dielectric constant is
the ratio of the capacitance induced by two metallic plates with
an insulator between them to the capacitance of the same plates
with air or a vacuum between them. Dissipation factor is defined
as the reciprocal of the ratio between the insulating materials
capacitive reactance to its resistance at a specified frequency.
It measures the inefficiency of an insulating material. If a
material were to be used for strictly insulating purposes, it
would be better to have a lower dielectric constant.
Test Procedure:
A sample is placed between two metallic plates and capacitance
is measured. A second run is made without the specimen between
the two electrodes. The ratio of these two values is the
dielectric constant.
Flexural Properties (ASTM D790, ISO 178)
Scope:
The Flexural test measures the force required to bend a beam
under 3 point loading conditions. The data is often used to
select materials for parts that will support loads without
flexing. Flexural modulus is used as an indication of a
material’s stiffness when flexed. Since the physical properties
of many materials (especially thermoplastics) can vary depending
on ambient temperature, it is sometimes appropriate to test
materials at temperatures that simulate the intended end use
environment.
Test Procedure:
Most commonly the specimen lies on a support span and the load
is applied to the center by the loading nose producing three
point bending at a specified rate. The parameters for this test
are the support span; the speed of the loading; and the maximum
deflection for the test. These parameters are based on the test
specimen thickness, and are defined differently by ASTM and ISO.
Flammability (UL94, ASTM D635)
Scope:
The flammability test is used to determine the relative rate of
burning of self-supporting plastics. This test is mainly used
for quality control, production control and material
comparisons. It cannot be used as a criterion for fire hazard.
Test procedure:
The various flammability tests are all similar in that they (1)
orient a test sample either horizontally or vertically and place
it in a test chamber; (2) apply a flame from a Bunsen Burner for
a specified time; and (3) measure the time or distance that the
flame propagates.
FTIR (Fourier Transform Infrared Spectrometry) (ASTM
E1252)
Scope:
FTIR is used for material identification of polymer. It can also
be used to examine contaminants and some fillers within the
polymers.
Test Procedure:
The sample is inserted into a detector and the amount of
Infrared Light absorbed at each frequency is determined. A
spectrum is produced and matched to known spectra in a
computer-based library.
Impact Resistance of Plastic Film by the Free-Falling Dart
Method (ASTM D1709 ISO 7765-1)
Scope:
Falling dart impact is a traditional method for evaluating the
impact strength or toughness of a plastic film. This test uses a
single dart configuration and a single drop height, while
varying the weight of the dart. Test results can be used either
as a quality control evaluation or for end use comparisons.
Test Procedure:
The test specimen is clamped securely in a pneumatic ring at the
base of the drop tower. The mounting bracket is adjusted to the
appropriate drop height, and the dart is inserted into the
bracket. The dart is released to drop onto the center of the
test specimen. The drop weight and the test result (pass / fail)
are recorded.
Test method A specifies a dart with a 38 mm (1.5") diameter
dropped from 0.66 m (26")
Test method B specifies a dart with a 51 mm (2") diameter
dropped from 1.5 m (60")
Izod Impact Testing (Notched Izod) (ASTM D256 and ISO180)
Scope:
Notched Izod Impact is a single point test that measures a
materials resistance to impact from a swinging pendulum. Izod
impact is defined as the kinetic energy needed to initiate
fracture and continue the fracture until the specimen is broken.
Test procedure:
The specimen is clamped into the pendulum impact test fixture
with the notched side facing the striking edge of the pendulum.
The pendulum is released and allowed to strike through the
specimen. If breakage does not occur, a heavier hammer is used
until failure occurs.
Melt Flow Index (MFI), Melt Flow Rate (MFR) ASTM D1238
(Procedure A), D3364, ISO 1133
Scope:
Melt Flow Rate measures the rate of extrusion of thermoplastics
through an orifice at a prescribed temperature and load.
Test Procedure:
The material is loaded into the barrel of the melt flow
apparatus, which has been heated to a temperature specified for
the material. A weight specified for the material is applied to
a plunger and the molten material is forced through the die. A
timed extrudate is collected and weighed. MFR values are
calculated in g/10 min.
Oxygen Concentration to Support Candle-Like Combustion of
Plastics (ASTM D2863)
Scope:
To determine the minimum concentration of oxygen in an
oxygen/nitrogen mixture that will support a flaming burn in a
plastic specimen. There is no correlation to real end use
conditions.
Test Procedure:
The test sample is positioned vertically in a glass chimney, and
an oxygen/nitrogen environment is established with a flow from
the bottom of the chimney. The top edge of the test sample is
ignited, and the oxygen concentration in the flow is decreased
until the flame is no longer supported.
Peel Tests (ASTM D903, D1876, D3167)
Scope:
The Peel Test measures the strength required to pull apart a
bonded surface. It is useful in evaluating adhesives, adhesive
tapes, or other attachment methods.
Test Procedure:
The sample is measured for thickness, it is placed in a fixture
in a universal tester. The specimen is pulled at the specified
speed until either the part or the bond fails. Types of failure
are noted as cohesive, adhesive, or substrate failure.
QUV (Accelerated Weathering) (ASTM D4329, D4587, ISO 4892,
SAE J2020)
Scope:
Accelerated weathering simulates damaging effects of long term
outdoor exposure of materials and coatings by exposing test
samples to varying conditions of the most aggressive components
of weathering - ultraviolet radiation, moisture and heat. A QUV
test chamber uses fluorescent lamps to provide a radiation
spectrum centered in the ultraviolet wavelengths. Moisture is
provided by forced condensation, and temperature is controlled
by heaters.
Test Procedure:
Up to 20 test samples are mounted in the QUV and subjected to a
cycle of exposure to intense ultraviolet radiation followed by
moisture exposure by condensation. Various cycles are defined
depending upon the intended end use application e.g., a typical
cycle for automotive exterior applications would be 8 hours UV
exposure at 70° C followed by 4 hours of condensation at 50° C.
These cycles would be continued for extended periods of time -
up to thousands of hours - simulating even longer periods of
time in the real world.
Resistance of Plastics to Chemical Reagents (ASTM D543)
Scope:
This test covers the evaluation of plastic materials for
resistance to chemical reagents, simulating performance in
potential end use environments. Chemical reagents can include
lubricants, cleaning agents, inks, foods, or anything else that
the test material may be expected to come in contact with. The
test includes provisions for reporting changes in weight,
dimensions, appearance and strength properties. Provisions are
made for various exposure times, strain conditions and elevated
temperatures.
Test Procedure:
Multiple specimens, at least 5, should be used for each
material/chemical/time/strain condition. Specimens can be
weighed and measured prior to contact with the chemical reagent.
To simulate end use stress in the test samples, strain jigs
designed for ASTM izod bars or ASTM Type I tensile bars are
used. Depending upon the type of contact anticipated for the
test sample, the exposure to the chemical agent could be
immersion, wipe, spray, or saturated gauze. The test samples are
then sealed in a container, and either left at room temperature
or placed in an oven. After the agreed upon period of time, the
specimens are removed and evaluated for desired properties such
as change in weight, appearance or tensile properties vs.
controls.
Shear Strength by Punch Tool (ASTM D732,A2LA)
Scope:
Shear strength testing is used to determine the load at which a
plastic or film will yield when sheared between two metal edges.
Shear strength results are important to designers of film and
sheet products that tend to be subjected to shear loads, or in
applications where applied crushing loads are a risk.
Test Procedure:
The test is performed by clamping a test sample attached to a
1-inch punch between two metal fixtures. A male punch is then
forced through the hole in the metal fixture causing shear along
the edge of the hole. A universal testing machine is used to
push the punch until shearing of the specimen occurs.
Surface Resistivity,Volume Resistivity (ASTM D257,
IEC60093)
Scope:
Surface resistivity is the resistance to leakage current along
the surface of an insulating material. Volume resistivity is the
resistance to leakage current through the body of an insulating
material. The higher the surface/volume resistivity, the lower
the leakage current and the less conductive the material is.
Test Procedure:
A standard size specimen is placed between two electrodes. For
sixty seconds, a voltage is applied and the resistance is
measured. Surface or volume resistivity is calculated, and
apparent value is given (60 seconds electrification time).
Tear Resistance of Plastic Film and Thin Sheeting by
Pendulum Method (Elmendorf Tear) (ASTM D1922)
Scope:
A pendulum impact tester is used to measure the force required
to propagate an existing slit a fixed distance to the edge of
the test sample. One use of these results would be for the
specification of material and thickness for plastic film used in
packaging.
Test Procedure:
Ten samples each are cut from the plastic film in the machine
direction and in the transverse direction. A sample is
positioned in the tester and clamped in place. A cutting knife
in the tester is used to create a slit in the sample which ends
43mm from the far edge of the sample. The pendulum is released
to propagate the slit through the remaining 43mm. The energy
loss by the pendulum is used to calculate an average tearing
force.
Tensile Testing of Plastics (ASTM D638, ISO 527)
Scope:
Tensile tests measure the force required to break a specimen and
the extent to which the specimen stretches or elongates to that
breaking point. Tensile tests produce a stress-strain diagram,
which is used to determine tensile modulus. The data is often
used to specify a material, to design parts to withstand
application force and as a quality control check of materials.
Test Procedure:
Specimens are placed in the grips of the Instron at a specified
grip separation and pulled until failure. For ASTM D638 the test
speed is determined by the material specification. For ISO 527
the test speed is typically 5 or 50mm/min for measuring strength
and elongation and 1mm/min for measuring modulus.
Tensile Tests of Rubber (ASTM D412)
Scope:
Tensile tests measure the force required to break a specimen and
the extent to which the specimen stretches or elongates to that
breaking point. The data is often used to specify material, to
design parts to withstand application forces and as a quality
control check of materials.
Test Procedure:
Place specimens in the grips of the Instron at a specified gage
length and pull until failure. The testing speed is determined
by the material specification. An extensometer can also be
attached to test specimen to determine elongation and tensile
modulus.
TGA (Thermo gravimetric Analysis) (ASTM E1131, ISO 11358)
Scope:
In a Thermo-gravimetric Analysis, the percent weight loss of a
test sample is recorded while the sample is being heated at a
uniform rate in an appropriate environment. The loss in weight
over specific temperature ranges provides an indication of the
composition of the sample, including volatiles and inert filler,
as well as indications of thermal stability
Test Procedure:
Set the inert (usually N2) and oxidative (O2) gas flow rates to
provide the appropriate environments for the test. Place the
test material in the specimen holder and raise the furnace. Set
the initial weight reading to 100%, then initiate the heating
program. The gas environment is preselected for either a thermal
decomposition (inert - nitrogen gas), an oxidative decomposition
(air or oxygen), or a thermal-oxidative combination.
Vicat Softening Temperature (ASTM D1525, ISO 306, A2LA
Accredited)
Scope:
The Vicat softening temperature is the temperature at which a
flat-ended needle penetrates the specimen to the depth of 1 mm
under a specific load. The temperature reflects the point of
softening to be expected when a material is used in an elevated
temperature application.
Test Procedure:
A test specimen is placed in the testing apparatus so that the
penetrating needle rests on its surface at least 1 mm from the
edge. A load of 10N or 50N is applied to the specimen. The
specimen is then lowered into an oil bath at 23 degrees C. The
bath is raised at a rate of 50° or 120° C per hour until the
needle penetrates 1 mm.
Viscosity of Polymers (ASTM D2857, D4603) Inherent,
Intrinsic, Relative Viscosity
Scope:
Dilute Solution Viscosity is used as an indication of the
molecular weight of polymers. The results of the test are
expressed in Relative Viscosity, Inherent Viscosity, or
Intrinsic Viscosity. It is used for polymers that dissolve
completely without chemical reaction or degradation and can
provide an excellent determination of lot-to-lot consistency or
be used to compare molded parts to original resin for
determinations of degradation from molding.
Test Procedure:
The polymer is first weighed and then dissolved in an
appropriate solvent. The solution and viscometer are placed in a
constant temperature water bath. Thermal equilibrium is obtained
within the solution. The liquid is then brought above the upper
graduation mark on the viscometer. The time for the solution to
flow from the upper to lower graduation marks is recorded.
Water Absorption 24 Hour/Equilibrium (ASTM D570)
Scope:
Water absorption is used to determine the amount of water
absorbed under specified conditions. Factors affecting water
absorption include: type of plastic, additives used, temperature
and length of exposure. The data sheds light on the performance
of the materials in water or humid environments.
Test Procedure:
For the water absorption test, the specimens are dried in an
oven for a specified time and temperature and then placed in a
desiccator to cool. Immediately upon cooling, the specimens are
weighed. The material is then emerged in water at agreed upon
conditions, often 23°C for 24 hours or until equilibrium.
Specimens are removed, patted dry with a lint free cloth, and
weighed.
Xenon-Arc Exposure of Plastics Intended for Indoor or
Outdoor Applications (Weather-Ometer®) (ASTM D2565, D4459, G155,
SAE J1885, J2527, J1960)
Scope:
Accelerated weathering simulates the damaging effects of long
term outdoor exposure of materials and coatings by exposing test
samples to varying conditions of the most aggressive components
of weathering - light, moisture, and heat. A Weather-Ometer uses
a xenon arc light source to provide a radiation spectrum that
simulates natural sunlight. Glass filters around the xenon arc
modify the light spectrum to simulate the appropriate end use
conditions. Moisture is provided by a humidifier and direct
spray, and temperature is controlled by heaters. Microprocessors
monitor and precisely control the radiation applied to the test
samples.
No direct correlation can be made between accelerated weathering
duration and actual outdoor exposure duration. However,
performance comparisons under the controlled conditions of
accelerated weathering can be compared to documented performance
of materials and coatings that have experienced extended periods
of end use exposure.
Test Procedure:
Up to 60 test samples are mounted in the Xenon Arc and subjected
to a cycle of exposure to specified combinations of light,
humidity, temperature and water spray. Various cycles are
defined by the appropriate specifications depending upon the
intended end use application.
Polystyrene Lightfastness Standards are included among the test
samples to monitor and verify the performance of the equipment.
These cycles would be continued for extended periods of time -
up to thousands of hours - simulating even longer periods of
time in the real world.
