You want to study the crystallinity of a polymer in accordance with the ISO 11357-7 standard
What are polymers?
Polymers are materials made up of long linear carbon chains that may contain side chains called branches.
If the organisation of these chains has no long-range order, polymers are described as amorphous materials and can be represented schematically by a statistical ball of chains.
They are then characterised by a glass transition temperature Tg corresponding to the change of state between so-called rubbery materials (soft and viscous if T > Tg) and so-called glassy materials (hard and brittle if T < Tg).
Furthermore, if the chains adopt a regular conformation, the polymers exhibit long-range order and are described as crystalline.
Understanding the crystallinity of a polymer: a performance issue
Crystallinity is a key property of polymer materials: it has a direct influence on their mechanical strength, temperature resistance, transparency and ageing behaviour.
In an industrial context, mastering this property makes it possible to :
- Validate a choice of material
- Check the quality of a production batch
- Optimise a shaping process
- Compare formulations or monitor changes over time
A method standardised by ISO 11357-7
ISO 11357-7 defines a method for measuring the crystallinity of semi-crystalline polymers using differential scanning calorimetry (DSC). It is based on the determination of the heat of fusion measured during a controlled thermal cycle.
The data obtained can be used to :
- calculate the percentage of crystallinity in relation to a 100% crystalline reference polymer
- distinguish between amorphous and crystalline phases
- monitor the influence of successive heat treatments or recycles
The FILAB laboratory can help you study the crystallinity of a polymer in accordance with the ISO 11357-7 standard
Why choose FILAB to study polymer crystallinity according to ISO 11357-7?
With significant experience in materials characterization, FILAB can help you with your polymer characterization needs. Every day, our teams of engineers and PhDs work with manufacturers faced with problems relating to the structure, formulation or performance of their polymers.
To find out more about polymers
Calorimetric analysis
Study of morphology (porosity)
Study of thermal properties by DSC, ATG, ATG-FTIR
Determination of the cross-linking rate
Determination of molecular weight by GPC
FAQ
Crystallinity represents the ordered (crystalline) part of a polymer as opposed to its amorphous (disorganised) part.
It has a direct influence on the material's mechanical, thermal, optical and processing properties.
The study of crystallinity can be used to :
- Check material quality (raw materials or finished products)
- Validate the conformity of a supplier
- Understand a product deviation (change in behaviour, brittleness, opacity, etc.)
- Monitor the evolution of a polymer during ageing, recycling or heat treatment
This is an international standard which describes the methodology for calculating the crystallinity rate from data obtained by DSC (differential scanning calorimetry) analysis.
It provides a reliable quantitative assessment, based on the measurement of the heat of fusion.
ISO 11357-7 recommends the use of DSC (Differential Scanning Calorimetry).
This thermal technique is used to :
- identify thermal transitions (melting, crystallisation, Tg, etc.)
- calculate the heat of fusion and deduce the percentage of crystallinity
All types of semi-crystalline polymers, in various forms:
- granules
- films
- plates, injected or machined parts
- oatings or powders
Full DSC curve
Characteristic temperatures (melting, crystallisation)
Measured heat of fusion
Calculated crystallinity (%)
Yes, it's a frequent occurrence:
- comparison of two suppliers
- comparison of a compliant vs non-compliant batch
- monitoring changes between two processing cycles
Absolutely. Depending on your needs, we can couple DSC with :
- SEM to observe surface structure
- GPC to analyse molar mass
- FTIR to identify the chemical structure
- TGA to assess mass loss or thermal stability
