Plastic & Polymer Testing Methods

What it determines

elemental and metal content, including trace catalysts that accelerate polymer degradation

Engineering question

Are harmful elements present, and does the material meet elemental limits?

Evidentiary use

Documents contamination or specification non-conformance.

What it determines

the polymer's chemical fingerprint, confirming resin identity and detecting absorbed contaminants or chemical degradation

Engineering question

Wrong resin, contaminated lot, or chemical attack on the surface?

Evidentiary use

Identifies the root-cause material and helps assign supplier or molder responsibility.

What it determines

the full formulation, reverse-engineering and quantifying the polymer, additives, and fillers

Engineering question

What is this made of, and did the formulation change?

Evidentiary use

Proves material substitution against a qualified specification.

What it determines

internal defects through optical, cross-sectional, CT, and metallographic imaging, often without destroying the evidence

Engineering question

Where and how did the defect initiate?

Evidentiary use

Preserves evidence non-destructively before any destructive testing.

What it determines

fracture-surface morphology (brittle versus ductile) and the elemental makeup of particles at the failure origin

Engineering question

How did it break, and what foreign material started the crack?

Evidentiary use

Establishes the failure mechanism and rules out alternative causes with jury-ready imagery.

What it determines

volatile organic compounds released by the material.

Engineering question

Is the material releasing volatiles that cause odor, fogging, corrosion of adjacent components, or a failure to meet an emissions limit?

Evidentiary use

Documents emissions against a contractual or regulatory limit and ties odor, residue, or corrosion complaints to one specific component rather than the assembly as a whole. PEG runs this to ASTM D3530, ASTM D6420, ASTM D4526, and to its own standard protocol where no consensus method applies.

What it determines

the specific organic contaminants, plasticizers, and chemical agents behind environmental stress cracking, separated and identified individually

Engineering question

What chemical contaminated or attacked this part?

Evidentiary use

Links a specific product or supplier to the damage.

What it determines

crystalline phase and filler identification.

Engineering question

Is the inorganic filler, or the crystalline form of the polymer, what the specification actually calls for?

Evidentiary use

Identifies mineral fillers and crystalline phases that infrared spectroscopy cannot distinguish on its own, corroborating a substitution finding with an independent method. PEG runs this to ASTM D5380, and to its own standard protocol where no consensus method applies.

What it determines

extractable additives, oils, and residues for identification.

Engineering question

What soluble additives, oils, or processing residues are present, and at what loading?

Evidentiary use

Isolates the extractable fraction so it can be identified and quantified by GC-MS or FTIR, which is the step that converts a suspicion of formulation change into a measured result. PEG runs this to its own standard protocol; no consensus standard is claimed.

What it determines

molecular structure and copolymer ratios for definitive identification.

Engineering question

What is the precise molecular structure, and what is the true comonomer ratio?

Evidentiary use

Provides definitive structural identification when infrared results are ambiguous or contested, which makes it the method of last resort in a disputed resin-identity case. PEG runs this to its own standard protocol; no consensus standard is claimed.

What it determines

Measures the length and length distribution of the polymer chains in a plastic material

Engineering question

Have the polymer chains been shortened by degradation in service, or was the resin the wrong molecular weight when it was supplied?

Evidentiary use

Separates in-service degradation from an out-of-specification starting resin, which is often the line between supplier liability and service-condition liability. PEG runs this to ASTM D6474, ASTM D5296, ISO 16014.

What it determines

plasticizer type and loading.

Engineering question

Which plasticizer was used, at what loading, and has it migrated out of the part?

Evidentiary use

Explains embrittlement and shrinkage caused by plasticizer loss, and documents the substitution or presence of a restricted plasticizer. PEG runs this to ASTM D1045.

What it determines

filler, flame-retardant, and moisture content through controlled weight loss

Engineering question

Does the composition meet specification?

Evidentiary use

Supports spec non-conformance and regulatory-compliance findings.

What it determines

melt temperature, crystallinity, glass transition, and oxidative induction time, verifying grade and detecting thermal abuse

Engineering question

Is it the right grade, thermally degraded, or embrittled?

Evidentiary use

Supports grade verification and processing-defect findings.

What it determines

melt viscosity as a quick grade and degradation indicator.

Engineering question

Is this the grade that was specified, and did it degrade during processing?

Evidentiary use

Gives a fast, universally accepted screen for grade substitution and thermal damage, which is why it is often the first number both sides can agree on. PEG runs this to ISO 1133-1, ASTM D1238, ISO 1133, ASTM D3364.

What it determines

the antioxidant protection remaining in a polyolefin (ASTM D3895)

Engineering question

Has the stabilizer package been depleted?

Evidentiary use

Supports premature oxidative-degradation causation.

What it determines

intrinsic or relative viscosity as a molecular-weight proxy.

Engineering question

Has molecular weight dropped through hydrolysis or thermal degradation?

Evidentiary use

Quantifies molecular-weight loss in condensation polymers such as PET and nylon, where hydrolytic degradation during drying or processing is a common and provable root cause. PEG runs this to ASTM D789, ISO 307, ASTM D4878, ASTM D4603.

What it determines

coefficient of thermal expansion and dimensional change with temperature.

Engineering question

Will thermal movement exceed what the joint, fastener, or surrounding assembly was designed to absorb?

Evidentiary use

Supports findings that a design failed to allow for differential expansion between dissimilar materials, a recurring cause of joint and fitting failure. PEG runs this to ISO 11359, ASTM D696, ASTM E831.

What it determines

viscoelastic behavior and transitions versus temperature.

Engineering question

How do stiffness and damping change across the actual service temperature range?

Evidentiary use

Locates the glass transition precisely and shows whether the material was already softening at its service temperature, which is evidence a datasheet value measured at room temperature cannot provide. PEG runs this to ASTM D4440, ASTM D4065.

What it determines

resistance to thermal decomposition.

Engineering question

Did the material see temperatures beyond what it can withstand, whether in processing or in service?

Evidentiary use

Establishes a measured decomposition onset that can be compared directly against documented process records or service conditions. PEG runs this to ASTM D3012.

What it determines

the temperature at which a polymer softens under load.

Engineering question

Will the part hold its shape under load at the temperature it actually operates at?

Evidentiary use

Compares a measured softening temperature against the real service condition, which frequently shows a material was specified for an application it was never rated for. PEG runs this to ASTM D648, ASTM D1525, ISO 75, ISO 306.

What it determines

strength, modulus, elongation, and toughness against datasheet values (ASTM D638)

Engineering question

Does it meet published values, or is it the wrong grade?

Evidentiary use

Confirms or disputes specification compliance and grade substitution.

What it determines

flexural strength and modulus (ASTM D790).

Engineering question

Does the part meet the published stiffness and bending strength it was sold on?

Evidentiary use

Documents a shortfall in bending performance, which is the loading mode most parts actually fail in. PEG runs this to ASTM D7264/D7264M, ISO 178:2001, ASTM D790, ASTM D7249, ASTM D7264, ASTM D6272, ISO 178.

What it determines

surface hardness (Shore, Barcol, IRHD, Rockwell).

Engineering question

Is the material the specified hardness, and has it hardened or softened in service?

Evidentiary use

Provides a rapid and effectively non-destructive indicator of cure state, aging, or grade substitution, often on parts too small or too valuable to cut up. PEG runs this to ASTM D2583, ASTM D2240, AS 1683.15.2, AS 1683.15.1, ASTM D1415, ISO 7619.

What it determines

impact strength and toughness, notched and unnotched

Engineering question

Is the part unexpectedly brittle?

Evidentiary use

Quantifies embrittlement for causation and damages.

What it determines

compressive strength and compression set.

Engineering question

Will the seal or component recover after load, or has it taken a permanent set?

Evidentiary use

Explains gasket and seal leakage caused by loss of recovery rather than by installation error, which is a common point of dispute. PEG runs this to ASTM D6454, ASTM D1621, ISO 604, ASTM D695, ASTM D395, ASTM D575, ISO 815.

What it determines

shear strength and modulus.

Engineering question

Can the joint or section carry the shear load it sees in service?

Evidentiary use

Quantifies shear capacity where a fastener, weld, or bonded joint failed, allowing measured capacity to be set against calculated service load. PEG runs this to ISO 4587, ASTM D3164, ASTM D5868, ASTM D3163.

What it determines

bond and coating adhesion strength.

Engineering question

Was the bond or coating ever capable of holding, or did it fail because of the substrate beneath it?

Evidentiary use

Distinguishes adhesive failure at the interface from cohesive failure within the material, which is the distinction that decides whether the adhesive supplier or the substrate is responsible. PEG runs this to ASTM D1002, ISO 11339, ASTM D429.

What it determines

pipe stiffness and ring flexibility.

Engineering question

Does the pipe meet its required stiffness class, and will it deflect beyond the allowable limit under burial and traffic load?

Evidentiary use

Supports findings of under-specified or out-of-specification pipe in buried applications, where excessive deflection is both the failure and the proof of it. PEG runs this to ASTM D6575, AS/NZS 1462.22, AS/NZS 1462.23.

What it determines

the elastic Poisson's ratio.

Engineering question

How does the material deform laterally under load, and is that what the design calculation assumed?

Evidentiary use

Supplies a measured input for stress analysis and finite-element modeling, so that an opposing model built on handbook assumptions can be tested against the actual material. PEG runs this to ISO 527, ASTM D638.

What it determines

low-temperature flexibility and cracking resistance.

Engineering question

Will the material crack when flexed or handled at low service temperature?

Evidentiary use

Establishes the brittleness onset temperature, which is decisive where a product failed during cold-weather installation or a winter service excursion. PEG runs this to UL 1581-580.

What it determines

compatibility with service chemicals and susceptibility to environmental stress cracking (ASTM D543)

Engineering question

Will the chemical environment attack the material?

Evidentiary use

Establishes the chemical cause of a failure.

What it determines

an estimated service life via the Q10 protocol and Arrhenius extrapolation

Engineering question

Will the product last its rated service life?

Evidentiary use

Supports service-life disputes and warranty-fraud claims.

What it determines

UV and weathering resistance, tracking color, chalking, and strength loss

Engineering question

Will an outdoor product meet its weatherability warranty?

Evidentiary use

Validates or refutes weatherability warranty claims.

What it determines

rubber resistance to oil, ozone, and heat aging.

Engineering question

Will the elastomer survive its actual service environment for the design life?

Evidentiary use

Links field cracking, swelling, or hardening to a defined and reproducible exposure, which converts an observation into a tested mechanism. PEG runs this to ASTM D471-12, ASTM D1149, ASTM D573-04.

What it determines

the extent of oxidative degradation.

Engineering question

How far has oxidation progressed, and is it concentrated at the surface exposed to the aggressive medium?

Evidentiary use

Quantifies oxidative degradation from the infrared spectrum, comparing the ketone carbonyl absorbance near 1715 to 1720 per centimeter against a reference band such as methylene bending near 1460 per centimeter. Taken as a depth profile it shows the direction of attack, which distinguishes degradation driven by the pipe contents from degradation driven by the outside environment. PEG runs this to ASTM F2102.

What it determines

limiting oxygen index and flammability behavior.

Engineering question

Does the material actually meet the flammability class it was specified and certified to?

Evidentiary use

Documents conformance or shortfall against a code-referenced flammability requirement, which in building and transport cases is often the requirement the entire claim turns on. PEG runs this to UL 94 and ASTM D2863.

What it determines

resistance to slow crack growth in pipe-grade polyolefins.

Engineering question

Will the pipe survive decades of sustained stress, or will a crack grow slowly and quietly to failure well inside the rated life?

Evidentiary use

The central durability evidence in pipe litigation, because it reproduces the brittle, low-stress cracking that causes real long-term field failures rather than the ductile overload that short-term burst testing produces. PEG runs this to AS/NZS 1462.25, ISO 13479, ASTM F1473.

What it determines

internal wall and joint anomalies in pipe and fusion joints without cutting out the line, using ultrasonic inspection

Engineering question

Where are the cold joints, voids, or crack initiation sites before we destructively sample?

Evidentiary use

Preserves the evidence in place and targets destructive sampling to the actual defect location.

What it determines

dimensions, wall thickness, and longitudinal reversion.

Engineering question

Was the part made to dimensional specification, and does reversion on heating reveal frozen-in processing stress?

Evidentiary use

Documents dimensional non-conformance directly, and uses reversion to expose residual extrusion stress that is invisible on the finished part but drives later cracking. PEG runs this to ASTM D6525, ASTM D1204, ISO 3167, AS/NZS 1462.4:2002, AS/NZS 1462.1, ISO 2505, ASTM D5796, ASTM D2122.

What it determines

density and specific gravity.

Engineering question

Is this the density grade that was specified, and is filler loading consistent between samples?

Evidentiary use

A simple, robust and inexpensive check for resin substitution and filler variation, which makes it a strong corroborating measurement precisely because it is hard to dispute. PEG runs this to ASTM C271, ASTM D792, ISO 1183, AS 1683 Part 4.

What it determines

degree of crosslinking (gel content) in PEX and HDPE.

Engineering question

Was the PEX crosslinked to the degree the standard requires?

Evidentiary use

Tests a stated pass or fail requirement rather than a matter of opinion, because ASTM F876 and F877 set a minimum gel content for PEX in hot-water service, typically 65 percent or greater depending on the crosslinking method. PEG runs this to ASTM D2765.

What it determines

mold shrinkage.

Engineering question

Was the dimensional error caused by the material, or by the mold and the process?

Evidentiary use

Separates inherent resin shrinkage behavior from tooling and process error, which is the question that decides whether the molder or the material supplier is responsible. PEG runs this to ISO 2577, ISO 294-4, ASTM D955.

What it determines

moisture and volatile content.

Engineering question

Was the resin dried properly before it was processed?

Evidentiary use

Supports hydrolytic degradation findings and explains splay, voids and bubbling that trace back to inadequate drying rather than to the resin itself. PEG runs this to ASTM D6869.

What it determines

inorganic residue after combustion, such as filler or glass content.

Engineering question

Is the filler or glass-fiber loading what the specification requires?

Evidentiary use

Quantifies inorganic content directly, supporting findings of reinforcement shortfall or filler substitution where a part failed below its rated strength. PEG runs this to ASTM D5630, ASTM D2584, ASTM E1131, ISO 3451.

What it determines

how much oxygen passes through a barrier material.

Engineering question

Does the barrier meet the oxygen-transmission limit its application requires?

Evidentiary use

Supports barrier-performance disputes, including ferrous corrosion in hydronic heating systems caused by oxygen ingress through non-barrier tubing, where the pipe itself never fails but the system does. PEG runs this to ASTM D3985, ASTM F1307, ISO 15105, ISO 2556, ASTM D1434, ASTM F1249.

What it determines

conformance to a named material or product specification.

Engineering question

Does this material or product actually meet the specification it was sold and certified under?

Evidentiary use

Consolidates individual test results into a single conformance conclusion against a named consensus standard, which is the form the question almost always takes in deposition and at trial. The governing specification is whichever one the purchase documents name. PEG runs this to ASTM F442, ASTM F1281, ISO 1872, ISO 1873, ASTM D2846/D2846M, ASTM F876.