FTIR | EUROLAB

What Is FTIR?

FTIR analysis is the determination of functional groups and polymer type by taking the absorption spectrum of the sample in the infrared region; It is an analysis method in which material identity is confirmed by library comparison.

Purpose of FTIR

The purpose is to verify the identity of the polymer or additive and identify impurities and degradation products.

Which Products Is FTIR Applied To?

Polymer authentication
Coatings and adhesives
Foreign matter and pollution analysis
Degradation and aging assessment

In Which Sectors Is FTIR Used?

PlasticsAutomotivePackagingConsumer Products

Standards Related to FTIR

ASTM E1252
ASTM D7844
ISO 10640
ASTM E1421 (device performance)

FTIR Conditions

Measurement mode: Transmission, attenuated total reflection (ATR) or reflection
Wave number range: Typically in the mid-infrared region
Resolution and number of scans: Defined in the standard or method
Library: Comparison with commercial and in-house spectrum libraries

Equipment for FTIR

FTIR spektrometresi
ATR accessory and crystal
FTIR with microscope coupling (for small particles)
Sample preparation (film press, KBr tableting)

Sample Requirements for FTIR

The sample surface must be clean; mold release agent residue distorts the spectrum
In ATR, the sample must be in full contact with the crystal
Matrix interference should be evaluated in filled samples
In contamination analysis, the sample must be protected from contamination

Duration of FTIR

Typically 1–3 days.

FTIR Procedure

1Device performance is verified and the background is taken.
2The sample is prepared in accordance with the measurement mode.
3The spectrum is collected.
4Characteristic bands are evaluated.
5Library comparison is made.
6The result is interpreted.

FTIR Acceptance Criteria

FTIR is a qualitative method; The acceptance criterion is usually agreement with the reference spectrum or the absence of a particular band.

Evaluation of Results

Library match percentage alone is not evidence; Polymers with similar structures give similar spectra. Fillers and additives can mask polymer bands. Calibration is required for quantitative results.

FTIR Report

Applied method and measurement mode
Device performance verification
Specimen preparation
Spectrum and characteristic bands
Library comparison and review

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

Material specifications
Food contact and restricted substance evaluations

Plastics Testing — What Does This Testing Field Cover?

The section below describes the field that the FTIR test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

Plastics testing determines the mechanical, thermal and burning behaviour of a polymer material. Unlike metals, plastics are VISCOELASTIC: their behaviour depends on loading rate, temperature and moisture. The same material therefore gives different results under different conditions, and the test conditions are an inseparable part of the result.

The practical consequence of viscoelasticity is this: a plastic part continues to deform over time under a constant load (creep) and the stress it carries at constant deformation falls over time (stress relaxation). A screwed joint loosens, a clamp loses its clamping force, a shelf sags over time. A short-term tensile test does not show this behaviour; a long-term test or an accelerated model is needed.

Thermal behaviour is the second main axis. Melt flow rate indicates the processability of the material and lot-to-lot consistency; heat deflection temperature and the Vicat softening point give a rough limit for service temperature. Thermal analysis (DSC, TGA, DMA) reveals the identity of the material: glass transition temperature, melting behaviour, crystallinity, filler content and decomposition temperature.

Burning behaviour is the third axis and ties directly into product standards. The UL 94 class and the limiting oxygen index are written into the material data sheet; a particular class is required for the housing of an electrical appliance, while a different classification system applies to a construction product.

Ageing is the most frequently skipped part of the field. Plastics degrade under UV, heat, moisture and oxygen: colour changes, the surface cracks, impact strength falls. For a part intended for outdoor use, what matters is not its values on day one but its values after ageing. Xenon arc and fluorescent UV equipment accelerate this degradation and allow comparison.

The output of this family is usually written into the material data sheet, and product standards refer to that sheet. But there can be a difference between the data sheet value and the behaviour of the actual part: orientation formed during moulding, weld lines and internal stresses make the part behave differently from the specimen.

The use of recycled content has added a new question to the field. Recycled resin varies from lot to lot; mechanical properties, colour and burning behaviour can shift between batches. For a manufacturer using recycled material, incoming material control is therefore not a choice but a necessity.

Method groups in this field

Mechanical
Tension, compression, bending, Charpy and Izod impact, hardness (Shore), creep and environmental stress cracking.
Thermal
Melt flow index (MFI), heat deflection temperature (HDT), Vicat softening temperature, linear thermal expansion.
Thermal analysis
Transition temperatures and crystallinity by DSC, composition and decomposition by TGA, dynamic mechanical behaviour by DMA.
Burning
UL 94 classification, limiting oxygen index (LOI), glow wire and needle flame tests.
Ageing
Accelerated ageing by xenon arc and fluorescent UV, hot air ageing, humidity and condensation.
Physical
Density, water absorption, ash content, gas and water vapour permeability of films and sheets.

Commonly confused in this field

A plastics result without a stated test rate and temperature cannot be interpreted; viscoelastic behaviour depends on these parameters.
A specimen result does not transfer directly to the actual part; moulding orientation and weld lines are decisive.
HDT and Vicat values are NOT service temperatures; they are a rough indication of an upper limit and do not apply under load.
The UL 94 class depends on thickness; a different wall thickness requires re-verification.
For moisture-absorbing polymers (such as polyamide), results are misleading unless conditioning is carried out.
ASTM D638 and ISO 527 results are not directly equivalent; the specimen geometries and rate definitions differ.

Which decisions these results support

Material selection and supplier approval
Meeting the flammability and thermal requirements of the product standard
Verifying the use of recycled content and lot control
Moulding process control and lot consistency
Demonstrating ageing resistance for outdoor use

Related Tests

Frequently Asked Questions About FTIR

According to which standard is FTIR made?

FTIR is executed in scope ASTM E1252, ASTM D7844, ISO 10640 and ASTM E1421 (device performance). The limit values and acceptance criteria to be applied are defined in the product standard; The version valid for your product is confirmed in writing at the offer stage.

Which products does FTIR apply to?

Mainly applied to Polymer authentication, Coatings and adhesives, Foreign matter and pollution analysis and Degradation and aging assessment. Whether your product is included in the scope is determined by examining its technical specifications and intended use.

Under what conditions is FTIR done?

The determining parameters are: Measurement mode — Transmission, attenuated total reflection (ATR) or reflection, Wave number range — Typically in the mid-infrared region and Resolution and number of scans — Defined in the standard or method. The full terms are in the "Test Conditions" section on the page and vary depending on the product standard.

What kind of sample is needed for FTIR?

The sample surface must be clean; mold release agent residue distorts the spectrum, In ATR, the sample must be in full contact with the crystal and Matrix interference should be evaluated in filled samples. The number of samples is determined according to the product standard and the scope to be reported.

How long does FTIR take?

Typically 1–3 days. This duration belongs to the experiment itself; sample preparation, queuing and reporting are also evaluated. A realistic schedule for your product is given in the offer.

What is the FTIR result called "appropriate"?

FTIR is a qualitative method; The acceptance criterion is usually agreement with the reference spectrum or the absence of a particular band.