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ASTM D882 - Thin Plastic Film Tensile Testing Fixture

Universal Grip ASTM D882 pneumatic grip for universal testing machines

Downloads: Standard Test Method for Tensile Properties of Thin Plastic Sheeting - PDF · ASTM D882 Pneumatic Grip – Universal Grip Data Sheet (PDF)

Written by Chris Thomas, Universal Grip Company · Reviewed by Frank Bertini · Updated October 17, 2026

ASTM D882 is the standard test method for tensile properties of thin plastic sheeting and film, meaning anything under 1.0 mm thick; thicker material goes to ASTM D638. A strip is pulled in a tensile tester at a speed set by its expected elongation, and the test reports tensile strength, elongation, modulus, breaking factor and tensile energy to break. It is the property test that packaging, label, battery separator, capacitor film, agricultural film and medical film producers run every shift, and the one most often run badly, because film is thin, slippery and tears from the smallest edge nick.

This guide prints the full Table 1 of grip separations, crosshead speeds and strain rates (no ranking competitor page does), the specimen width, length, edge and thickness rules, how to choose line-contact, rubber-faced pneumatic or roller grips for a given film and how to tell slippage from stretch, when a video extensometer is required and when crosshead displacement is allowed, how to size a load cell for forces of 10 to 250 N, worked examples for strength, modulus and tensile energy to break, and a comparison with ISO 527-3. It is current to D882-26a and ends with the grips, extensometers and testers Universal Grip supplies for the test.

In this guide: What ASTM D882 Measures · Specimens: Width, Length, Edges and Thickness · Conditioning · Table 1: Grip Separation, Speed and Strain Rate · Grips: Line-Contact, Pneumatic Flat and Roller · Strain Measurement: Crosshead vs Extensometer · Load Cell Sizing · Step-by-Step Procedure · Calculations and Worked Examples · Common Errors · ASTM D882 vs ISO 527-3 · Equipment for ASTM D882 · FAQ

What ASTM D882 Measures

D882 covers the tensile properties of plastic sheeting and film less than 1.0 mm (0.04 in) thick, with film defined (per ASTM D883) as material 0.25 mm and thinner. The properties are those of D638 adapted to a thin strip without a dumbbell shape:

  • Tensile strength: maximum force divided by the original minimum cross-section, in MPa.

  • Tensile strength at break and percent elongation at break, from the force and extension at rupture.

  • Yield strength and elongation at yield, for films that show a zero-slope point before break.

  • Breaking factor: maximum force per unit of original width, in N/m or lbf/in, used where thickness is hard to measure or where the film is sold by width (tapes, labels).

  • Modulus of elasticity: the slope of the initial linear portion of the stress-strain curve after toe compensation; a secant modulus at a stated strain for films without a linear region.

  • Tensile energy to break (TEB): the area under the stress-strain curve to rupture, in MJ/m³, which is the film's toughness per unit volume and the best single number for predicting how a film survives handling.

Extension may be measured from grip separation, from an extensometer, or from gauge marks; D882 is unusual among plastics standards in permitting crosshead-based strain for strength and elongation, which is what makes it practical on thin films that a contacting extensometer would damage. The modulus, however, is tied to a specific grip separation and strain rate, and the result at any other rate is not comparable. The film puncture companion is ASTM F1306, tear is ASTM D1938, friction ASTM D1894 and seal strength ASTM F88; the plastics testing page covers the full film set.

Specimens: Width, Length, Edges and Thickness

  • Shape: a uniform strip, not a dumbbell. Width 5.0 to 25.4 mm (0.20 to 1.0 in); 25.4 mm is the most common width for films and 15 mm for thin PET and separator films.

  • Length: at least 50 mm (2 in) longer than the grip separation, so a modulus specimen at 250 mm separation is at least 300 mm long, and a high-elongation specimen at 50 mm separation at least 100 mm.

  • Width-to-thickness ratio: at least 8, so a 25 µm film may be as narrow as 0.2 mm in principle, and the rule only bites on sheet near 1 mm.

  • Edges: parallel to within 5 % of the width over the gauge region, and cut clean. D882 refers to ASTM D6287 for cutting: a razor-blade strip cutter with two parallel blades is preferred for any material that elongates more than 10 to 20 %, and the standard specifically does not recommend punch presses or single-blade templates for such films, because a nick or a crushed edge starts a tear long before the film reaches its true strength.

  • Thickness uniformity: within 10 % over the gauge region for film 0.25 mm and thinner, within 5 % for sheet from 0.25 to 1.0 mm.

  • Direction: anisotropic films (any oriented or blown film) are tested in two sets, machine direction and transverse direction, and reported separately.

  • Number: at least five specimens for an isotropic material and at least ten (five per direction) for an anisotropic one. A reduced set of three (or six) is allowed by agreement, in which case no standard deviation is reported. Specimens that break at an obvious flaw or outside the gauge region are discarded and replaced; a jaw break may be kept only if it is shown to give the same result as in-gauge breaks.

Measuring the cross-section

Thickness dominates the error in a film tensile result. The standard requires the cross-section at three places (the centre and about 13 mm from each end of the gauge region), width to 0.25 mm, and thickness to 0.0025 mm (0.0001 in) for film under 0.25 mm or to 1 % for thicker sheet, measured with a dead-weight micrometer per ASTM D5947 or D6988. On a 12 µm film a 1 µm error is an 8 % error in every stress value, so the gauge, its pressure foot and its zero matter more than the testing machine. Use the minimum cross-section for strength.

Conditioning

Condition per ASTM D618 Procedure A: at least 40 hours at 23 ± 2 °C and 50 ± 10 % relative humidity, and test in the same atmosphere. Moisture-sensitive films (polyamide, cellulose, PVOH and EVOH-based laminates) change strength and elongation by tens of percent with humidity, so for those the full 40 hours is not a formality. Non-ambient tests are run inside an environmental chamber with grips and specimen at temperature and reported as a variation.

Table 1: Grip Separation, Speed and Strain Rate

D882 sets the crosshead speed from the initial strain rate and the initial grip separation: speed A = separation B × strain rate C. The class is chosen by the expected elongation at break, and the standard's Table 1 is:

  • Modulus of elasticity: grip separation 250 mm (10 in), crosshead speed 25 mm/min (1.0 in/min), initial strain rate 0.1 mm/mm/min. A 100 mm (4 in) separation at 10 mm/min is permitted for routine work if it is shown not to change the result; 250 mm is mandatory for referee tests.

  • Elongation at break under 20 %: separation 125 mm (5 in), speed 12.5 mm/min (0.5 in/min), strain rate 0.1 mm/mm/min.

  • Elongation at break 20 to 100 %: separation 100 mm (4 in), speed 50 mm/min (2.0 in/min), strain rate 0.5 mm/mm/min.

  • Elongation at break over 100 %: separation 50 mm (2 in), speed 500 mm/min (20 in/min), strain rate 10 mm/mm/min.

Three rules go with the table. If the elongation of a material straddles two classes, use the lower strain rate. Results obtained at different strain rates are not comparable, so report the rate with the result and never mix classes in one comparison. And the modulus specimen is separate from the strength specimens: a specimen run at 25 mm/min on a 250 mm separation for modulus is not then run to break for strength, because the rate is wrong for that class. A stiff 12 µm PET film (elongation about 100 to 150 %) is therefore tested at 250 mm / 25 mm/min for modulus and at 50 mm / 500 mm/min for strength and elongation; a 25 µm polyethylene film (elongation 400 to 700 %) uses 50 mm / 500 mm/min; a brittle oriented polystyrene or a filled film with 5 % elongation uses 125 mm / 12.5 mm/min.

A 500 mm/min test on a 50 mm separation to 600 % elongation needs 300 mm of crosshead travel plus the grip stroke, which rules out short-column testers; a frame with at least 500 mm of travel is the practical minimum for polyolefin films. The Mark-10 tensile testers and the benchtop universal testing machines are available with extended columns for this reason.

Grips: Line-Contact, Pneumatic Flat and Roller

D882 names two gripping arrangements. Line grips concentrate the gripping force along a line, usually a flat jaw face opposed by a half-round face, so that the specimen is held at a defined line and the gauge length is unambiguous; they are the reference grip for stiff films. Flat grips hold the strip between flat faces lined with rubber, crocus or emery cloth, or pressure-sensitive tape, and are the usual choice for soft films. The standard asks that grips minimise slippage and uneven stress, recommends air-actuated (pneumatic) grips for materials that neck, and requires the jaw faces to be at least as wide as the specimen.

  • Pneumatic grips with rubber-faced or line-contact jaws: the first choice for a film lab. Constant air pressure holds a film that thins and necks without the clamping force relaxing, parallel-closing jaws insert the strip square, and 25 to 50 mm jaw widths cover every D882 strip. Set the pressure high enough to stop slip and low enough not to crush the film at the jaw edge; a line-contact face at modest pressure usually beats a flat face at high pressure on stiff PET and BOPP.

  • Roller grips (self-tightening): for high-elongation polyethylene and elastomeric films that pull out of flat jaws as they draw down. The strip wraps a roller that tightens as the load rises, there is no sharp jaw edge, and jaw breaks almost disappear. The gauge length is less sharply defined, which matters for modulus but not for strength or elongation at 500 mm/min.

  • Vise grips with rubber faces: adequate for routine QA on stiff films at low force, with the caveat that the clamping force is operator-dependent and slip is more common.

Slippage and jaw breaks

Slippage looks like extra elongation and a lower modulus, with a load trace that stalls or steps instead of rising smoothly. Detect it with an ink line across the strip at each jaw edge (it must not move), by comparing crosshead displacement with a video extensometer's strain, or by watching the first 5 % of the curve for a step. Fixes, in order: increase air pressure, change to a line-contact or roller face, or shorten the free length between jaw and gauge mark. Jaw breaks (fracture at or within a millimetre of the jaw) mean the jaw edge is cutting the film: round or rubber-faced jaws, lower pressure, and square insertion cure most of them, and the standard allows a jaw break to be counted only if it can be shown to give the same strength as a mid-gauge break. Tear failures, where a nick at the edge propagates slowly across the strip and the curve shows a long tail, are not valid and point back to the cutter.

Strain Measurement: Crosshead vs Extensometer

For elongation at break of 20 % and over, the standard allows extension to be taken from grip separation, with an accuracy requirement of ± 10 % on the extension measurement, which crosshead displacement meets if slip is controlled. For modulus and for elongation under 20 % the extension must be accurate to ± 1 %, which is ASTM E83 Class C; that is why the modulus test uses the long 250 mm separation, so that grip effects are a small fraction of the extension, and why an extensometer is the better instrument. A contacting clip-on extensometer cannot be used on a 12 to 25 µm film: its mass and knife edges tear the specimen or start the failure. A video extensometer tracks two ink marks on the film without contact, meets the ± 1 % requirement for modulus, follows a polyethylene film to 600 % elongation, and records the whole curve, which is also the easiest way to prove that the grips did not slip. For routine strength and elongation at 500 mm/min, crosshead displacement is what most labs use and what the standard permits; for modulus, use the extensometer or make the 250 mm separation non-negotiable.

Toe compensation (Annex A1 of the standard) removes the initial curved region of the curve caused by seating and slack. Software does it by extending the linear portion back to zero stress and moving the strain origin to that intercept; without it a modulus read from the raw curve is low and an elongation is high. Do not apply toe compensation if the curvature is real material behaviour, which a video extensometer trace makes obvious.

Load Cell Sizing

Film forces are small, and the standard requires that the failure load fall in the upper two-thirds of the load range in use. That rules out the 1 to 5 kN cells that come with general-purpose frames for almost every film:

  • 25 µm LLDPE, 25.4 mm wide: breaks at about 12 N; use a 25 N or 50 N cell.

  • 12 µm PET, 15 mm wide: about 35 N; use a 50 N cell.

  • 50 µm BOPP or 100 µm PP, 25.4 mm wide: 60 to 100 N; use a 100 N or 250 N cell.

  • 0.5 to 1.0 mm sheet, 25.4 mm wide: 250 N to 1.5 kN; a 500 N or 2 kN cell.

A 100 lb (445 N) Mark-10 frame with a 50 N or 100 N cell covers packaging films; a 300 lb frame with a 250 N cell covers heavier laminates; a 2.5 kN benchtop UTM with interchangeable 100 N and 1 kN cells covers films and sheet together. The force channel must be accurate to ± 1 % per ASTM E4 in the range used, which for a 10 N result on a 50 N cell means a cell with good low-end linearity, not merely a large one with a small reading.

Step-by-Step Procedure

  • 1. Cut strips with a two-blade razor cutter in the machine and transverse directions, 25.4 mm (or the chosen width) and at least 50 mm longer than the grip separation; inspect edges under light and discard any with nicks.

  • 2. Measure width to 0.25 mm and thickness to 0.0025 mm at three places; record the minimum cross-section.

  • 3. Choose the class from the expected elongation and set grip separation and speed from Table 1; set the load range so failure falls in its upper two-thirds.

  • 4. Mark gauge lines with ink or wax crayon if a video extensometer or gauge-mark method is used; never scratch the film.

  • 5. Clamp the strip square, aligned with the grip axis, with equal insertion top and bottom and no slack or pre-tension; zero force and extension.

  • 6. Run to break at the Table 1 speed, recording force against extension at 50 Hz or faster for the 500 mm/min class.

  • 7. Check the break: mid-gauge is valid; jaw breaks and tear failures are discarded unless shown equivalent; note slip evidence.

  • 8. Repeat for five specimens per direction (modulus specimens separately at 250 mm / 25 mm/min), then calculate and report means and standard deviations.

Calculations and Worked Examples

  • Tensile strength: σ = F max ÷ A 0, with A 0 the original minimum cross-section (width × thickness).

  • Breaking factor: F max ÷ original width, in N/m (or lbf/in).

  • Elongation: (extension ÷ initial grip separation or gauge length) × 100, at yield and at break.

  • Modulus: slope of the initial linear portion of the toe-compensated stress-strain curve, in MPa; a secant modulus is the stress at a designated strain divided by that strain.

  • Tensile energy to break: the area under the stress-strain curve to break, in MJ/m³; from a force-extension integrator, TEB = area ÷ (width × thickness × initial grip separation).

Example 1: strength and elongation of a polyethylene film. A 25 µm LLDPE strip 25.4 mm wide, tested at 50 mm grip separation and 500 mm/min (over-100 % class), breaks at a maximum force of 11.8 N after 280 mm of extension. Cross-section A 0 = 25.4 × 0.025 = 0.635 mm². Tensile strength = 11.8 ÷ 0.635 = 18.6 MPa. Breaking factor = 11.8 N ÷ 0.0254 m = 465 N/m (2.65 lbf/in). Elongation at break = 280 ÷ 50 × 100 = 560 %. The integrated area under the force-extension curve is 2.24 J, so TEB = 2.24 J ÷ (25.4 × 0.025 × 50 mm³ = 31.75 mm³) = 0.0706 J/mm³ = 70.6 MJ/m³.

Example 2: modulus of a PET film. A 12 µm PET strip 15 mm wide is tested at 250 mm separation and 25 mm/min with a video extensometer on 100 mm gauge marks. A 0 = 15 × 0.012 = 0.180 mm². After toe compensation the force at 0.5 % strain is 3.6 N, so the stress is 3.6 ÷ 0.180 = 20.0 MPa and the modulus is 20.0 ÷ 0.005 = 4,000 MPa = 4.0 GPa. Five specimens giving 4.0, 3.9, 4.1, 4.0 and 4.0 GPa are reported as 4.0 GPa with a standard deviation of 0.07 GPa, at a strain rate of 0.1 mm/mm/min on a 250 mm separation. Note that the same film tested at 100 mm separation without an extensometer typically reads 10 to 20 % lower, because grip compliance and seating are a larger share of a shorter extension; that is the reason the 250 mm separation is mandatory for referee results.

Typical values: LLDPE 15 to 30 MPa and 400 to 800 % elongation; HDPE 25 to 45 MPa; cast PP 30 to 45 MPa; BOPP 120 to 200 MPa in the machine direction with 100 to 200 % elongation; PET 150 to 250 MPa and 3.5 to 5 GPa modulus; nylon 6 film 150 to 300 MPa, strongly moisture-dependent. MD and TD values of an oriented film can differ by a factor of two, so direction must always be reported.

Common Errors

  • Wrong Table 1 class: running a sub-20 % film at 100 mm / 50 mm/min, or the 100 mm separation at the <20 % class speed; the correct <20 % row is 125 mm at 12.5 mm/min.

  • Modulus taken from a strength test at 500 mm/min, or from crosshead displacement at a short separation.

  • Edge nicks from a die or a dull single blade, giving tear failures and low strength.

  • Thickness from a nominal value or a single reading; 1 µm on a 12 µm film is 8 %.

  • Slipping grips mistaken for elongation; jaw breaks counted without checking equivalence.

  • Load cell too large (failure below the upper two-thirds of range).

  • Mixing machine and transverse direction specimens in one data set.

  • No toe compensation, or toe compensation applied to real curvature.

  • Insufficient crosshead travel for the >100 % class, ending the test before break.

  • Comparing D882 with ISO 527-3 values, or with D638 values on thicker sheet.

  • Citing D882-18; the current edition is D882-26a.

ASTM D882 vs ISO 527-3

ISO 527-3 is the international film tensile method, and ASTM notes that D882 is similar but not technically equivalent:

  • Specimens: ISO 527-3 uses a type 2 strip 10 to 25 mm wide and at least 150 mm long, and also allows type 4 and type 5 dumbbells; D882 uses strips only, 5 to 25.4 mm wide.

  • Grip separation and gauge: ISO 527-3 uses a 100 mm grip separation with a 50 mm gauge length for strips; D882 uses 250, 125, 100 or 50 mm by elongation class with strain from grip separation allowed.

  • Speed: ISO 527-3 takes speeds from the ISO 527-1 list (typically 1 mm/min for modulus and 50 to 500 mm/min to break); D882 fixes them by strain-rate class.

  • Strain measurement: ISO 527-3 requires an extensometer or gauge marks; D882 permits grip separation for elongation of 20 % and above.

  • Modulus: ISO reports a chord modulus between 0.05 % and 0.25 % strain; D882 a tangent (or secant) modulus after toe compensation.

A lab serving both markets normally runs ISO 527-3 with a video extensometer and D882 to Table 1, and reports each to its own standard; one number does not serve both. For films thicker than 1 mm the ASTM method is D638 and the ISO method ISO 527-2.

Equipment for ASTM D882

See the tensile testing applications page and the tensile grips overview for grip and jaw options across film, sheet and laminate.

ASTM D882 FAQ

What is ASTM D882?

The ASTM standard test method for tensile properties of thin plastic sheeting and film under 1.0 mm thick. Strips are pulled at a speed set by their elongation class to determine tensile strength, elongation, modulus, breaking factor and tensile energy to break.

What is the ASTM D882 specimen size?

A uniform strip 5.0 to 25.4 mm wide and at least 50 mm longer than the grip separation, with a width-to-thickness ratio of at least 8, edges parallel within 5 % and thickness uniform within 10 % (film) or 5 % (sheet).

What are the ASTM D882 test speeds?

From Table 1: modulus at 250 mm grip separation and 25 mm/min; elongation under 20 % at 125 mm and 12.5 mm/min; 20 to 100 % at 100 mm and 50 mm/min; over 100 % at 50 mm and 500 mm/min. Speed equals grip separation times the initial strain rate (0.1, 0.1, 0.5 and 10 mm/mm/min).

How many specimens does ASTM D882 require?

At least five for an isotropic film and at least ten (five in each direction) for an anisotropic one. A reduced set of three or six is allowed by agreement without reporting a standard deviation.

What grips are used for ASTM D882?

Line grips (a flat face against a half-round face) or flat grips faced with rubber, emery cloth or tape, at least as wide as the specimen. Pneumatic grips are recommended for films that neck, and roller grips are used for high-elongation films that slip from flat jaws.

Can I use crosshead displacement for elongation in ASTM D882?

Yes for elongation at break of 20 % and over, where ± 10 % extension accuracy is required. For modulus and for elongation under 20 % the extension must be accurate to ± 1 %, which calls for a non-contact video extensometer or the full 250 mm grip separation.

How is tensile strength calculated in ASTM D882?

Maximum force divided by the original minimum cross-section (width × thickness), in MPa. Breaking factor is maximum force divided by width, in N/m.

What is tensile energy to break (TEB)?

The area under the stress-strain curve to rupture, in MJ/m³, which is the energy absorbed per unit volume of film. From a force-extension integrator it is the area divided by width × thickness × initial grip separation.

What load cell do I need for ASTM D882?

One whose range puts the breaking load in its upper two-thirds: 25 to 50 N for thin polyethylene films (about 12 N), 50 to 100 N for PET and BOPP (35 to 100 N), 250 N to 2 kN for sheet. General-purpose 1 to 5 kN cells are unsuitable for film.

What conditioning does ASTM D882 require?

At least 40 hours at 23 ± 2 °C and 50 ± 10 % relative humidity per ASTM D618 Procedure A, with testing in the same atmosphere.

What is the difference between ASTM D882 and ASTM D638?

D882 covers sheeting and film under 1.0 mm thick using uniform strips with speeds set by elongation class and strain from grip separation allowed; D638 covers thicker plastics using dumbbell specimens Types I to V with extensometer-based modulus.

Is ASTM D882 equivalent to ISO 527-3?

No. ISO 527-3 uses a 100 mm grip separation with a 50 mm gauge, allows dumbbell specimens, takes speeds from the ISO 527-1 list, requires an extensometer or gauge marks and reports a chord modulus; D882 fixes separations and speeds by strain-rate class and allows strain from grip separation. ASTM states the two are similar but not technically equivalent.

Need a fixture, grips or a complete system for ASTM D882? Contact Universal Grip with your specimen details, capacity and machine connection and we will quote the right setup.

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