This page shows (part of) the analysis equipment and techniques available at PTG/e including a brief description of the equipment or technique.
Confocal Raman Spectroscopy
The Confocal Raman Spectroscopy is a perfect analysis technique for material identification.
This analysis technique allows us to measure through a transparent glass and a polymer surface or is able to focus on tiny particles that are present underneath the surface. A spectrum is then recorded of the particle (or sample area) in focus, containing detailed chemical information, with which the material can be identified.
Raman spectroscopy is similar to infrared spectroscopy in a way that both techniques are used to identify unknown substances. Raman spectroscopy uses a laser to interact with an unknown substance. Confocal Raman microscopy combines the Raman spectroscopy with an optical microscope, which provides extra spatial (vertical and horizontal) resolution of samples. Therefore, this technique is especially useful for microscopic defect analysis. Analyses can be performed in 1D, 2D and 3D with spot sizes of less than 1,0 µm.
For this identification also an extensive Raman database is available.
TGA-IR-GC-MS ‘Hyphenation setup’
With this setup it is possible to combine analysis techniques for identifying complex and unknown materials.
With this setup, it is possible to combine the analysis techniques TGA, FT-IR and GC-MS via coupling of the devices.The TGA – IR – GC-MS ‘Hyphenation setup’ is a powerful analysis technique to identify complex and unknown materials. Some applications for this technique are:
- The identification of additives, like plasticizers, in plastics
- Determination of the primary components of a material
- Analysis of unknown contaminations in a material, like fragrances or solvents
To characterize a material, it is first placed in the oven of the TGA, where it is heated with a programmed heating rate. During heating, weight loss can occur due to thermal decomposition or solvent evaporation. The evolved gases from these events are transferred via a transfer line to a heated chamber of the FT-IR. There, the gas is exposed to an infrared beam. The functional groups in the measured gas each respond differently to infrared radiation, which helps to identify the molecules.
Following the FT-IR, the gas is transferred via another transfer line to be injected onto the column of the GC. Depending of the affinity of the injected gas with the column, the temperature of the column and the speed of the carrier gas, the injected gas has a certain retention time. Different components have a different retention time, which enables the GC to separate the individual components of the injected gas.
An mass spectrometer (MS) is located at the end of the column. In the MS, the separated components are ionized and brought into an electric field. This field will accelerate the ionized components to a certain speed, depending on their mass and charge. The MS uses this principle to create a spectrum, which, together with the retention time of the GC, is unique for each component. Combining the data from FT-IR and GC-MS, the individual components of the evolved gases from TGA can be characterized.
Aside from the fully hyphenated setup, it is also possible to use the individual analysis techniques, or a partially hyphenated setup, for example TGA – IR or TGA – GC-MS. The specific required setup will depend on what needs to be analyzed exactly.
Compounder (twin screw)
A compounder can be used to mix additives into a thermoplastic material or even to perform reactive extrusion.
The equipment used is a ThermoElectron Rheomex OS – PTW 16 twin-screw compounder with a range of heads, such as monofilament, tape (2 cm) and film (10 cm). The screw diameter is 16 mm, the screw structure and L/D ratio are variable (25 or 40) with a maximum temperature of 400 °C.
Once a good recipe has been developed, a sample batch can be compounded at kilogram scale, which can subsequently be broken down into granulate by means of the pelletiser. At the customer’s facility, this granulate can be tested for its suitability for a specific application.
Differential Scanning Calorimetry (DSC)
DSC is used to examine the thermal transitions in a polymeric material (e.g. melting point, Tg and crystallization).
Measurements are carried out with a TA Instruments Q2000, which has a temperature range of -80 to 300 °C. A material sample of as little as 3 mg is sufficient for a measurement.
The results of a DSC measurement can for example be used to determine if a material melts and if so, when. It can also be used to distinguish between a homopolymer, a copolymer and a blend.
Dynamic Mechanical Thermal Analysis (DMTA)
DMTA is a technique used to analyse the viscoelastic behaviour of a material as a function of temperature or frequency. This provides information on the stiffness of the material.
Measurements are carried out with a TA Instruments Q800 DMTA, with a temperature range of -100 to 300 °C. Clamps are available for measuring films (up to 2 mm thick) and a sample specimen (up to 4 mm thick); dual/single cantilever and 3-point bend clamps).
The DMTA measurement results are used for determining the glass transition temperature (Tg). A DMTA diagram shows the modulus of elasticity (E-modulus) as a function of temperature. The E-modulus is a measure of stiffness of a material.