PTG/e can be an extension of your in-house R&D. Whether it is contract research or simply the analysis of a material, you can count on us for professional support. We take a pragmatic approach, which translates into short communication lines internally and regular contact between our researchers and the customer. In this way we can monitor project progress and steer the process as needed.
Our services include organising postdoc-level open courses. And thanks to our large network of lecturers, we are also able to offer (in-house) courses tailored to your specific needs.
Research & innovation
Need an experienced partner to complement your in-house R&D from time to time? For example when you are short of capacity or do not have the necessary expertise in house?
PTG/e is fully equipped to take on a variety of tasks.
Also for shorter term projects PTG/e is your partner.
Comparison of raw materials, material identification or a quick literature scan – these are just a few of the services that PTG/e can perform for you.
With access to a wide network of (own) experts in many different areas, PTG/e is excellently placed to help you expand your knowledge of polymers. We are organizing customized company specific courses, as well as open PTN courses.
Especially for polymers: Size Matters!
Important properties of polymeric materials like tensile strength and viscosity critically depend on the size, or rather, the chain length of the macromolecules that they consist of. In other words, these properties are defined by the molecular weight distribution and the average molecular weight of the polymer.
Measuring the molecular weight of a polymer therefore provides crucial information for understanding many aspects related to the behaviour of polymeric materials.
Thus, chemically identical polymers can show different tensile properties as a result of differing molecular weight. Such differences frequently result from polymer degradation and are especially relevant in the context of recycling. Also in polymer production, the molecular weight is a key parameter in quality control. While often only the melt flow index (MFI) is measured, knowledge of the actual molecular weight (distribution) provides a more detailed picture. Finally, in the development of new polymer materials, assessment of the molecular weight is a key factor for optimizing synthesis conditions.
The molecular weight of many conventional polymers can conveniently be assessed by a technique called Size Exclusion Chromatography (SEC). This technique separates dissolved polymer molecules according to their size by passing them through a column packed with porous particles. While the larger molecules cannot enter the pores and therefore elute from the column relatively rapidly, the smaller ones do enter the pores of the column material and thus experience a net retardation. The final result is a chromatogram, showing the amount of material eluting from the column versus the elution time, with the elution time being inversely related to the molecular weight.
One key issue with SEC is the fact that polymeric materials need to be dissolved in a suitable solvent. However, not all polymers are the same and their solubility heavily depends on their chemical nature and molecular weight. While many common polymers (e.g. perspex or polystyrene) are easily dissolved in tetrahydrofuran (THF), more polar materials like polyamides or some polyesters, require hexafluoroisopropanol (HFIP) for complete dissolution. Even water (H2O) may be the only suitable solvent for certain polymers. On the other hand, the industrially important class of polyolefins (e.g. polyethylene, polypropylene) can only be dissolved in a chlorinated solvent and the complete SEC analysis is performed at 160 °C!
It is clear that every type of material needs specific measurement conditions to assess its molecular weight. At PTG/e, we have many years of experience with polymers of widely varying nature. Our state-of-the-art SEC equipment, running on different solvents, enables us to cover molecular weight determinations of almost any polymeric material, including those that are notoriously ‘difficult’ to dissolve.
Please contact us if you would like to find out whether molecular weight determination by SEC can provide a breakthrough insight into your material of interest!
Surface structure analysis by profilometry
The analysis of surface structures is of great importance in many industries, such as chip/sensor manufacturing, inkjet printing or membrane production. In these industries surface analyses are used for instance as quality control, checking surface roughness or finding the root cause of defects.
As an example, one of our customers had approached us to help solve an issue with a curable resin product. The application of this product requires a very flat surface. At first, the resin was cast on a Teflon film, in order to ‘copy’ the flat surface of these films onto the resin product. By the naked eye, such a film indeed appears very flat, but surface profiling revealed that the film has depth differences of 1-1,5 micrometers (see Figure 1). A silicon wafer, a known flat substrate material, shows depth differences of just 30 nanometers (see Figure 2). Using this silicon wafer as substrate for the curable resin did result in the desired smoothness of the final product. Therefore, surface profiling enabled our customer to choose the right substrate for their product.
Figure 1: Surface profile of Teflon foil.
Figure 2: Surface profile of the silicon (Si) wafer with a line profile analysis, indicated by the pink raster. The line profile is represented in the graph.
Another example below shows a microchip, which can be found in everyday devices like laptops or smartphones. A detailed image of its complex surface profile can be used to inspect the chip for any damages or incorrect assembly. The surface images in Figure 3 were obtained by an optical surface profiling technique.
Figure 3: Surface profile in 2D and 3D of a microchip in common electronics.
Using this technique, surfaces can be analysed quickly and accurately. Surface profiling can be done optically (optical profilometry), in which case light is used to illuminate a surface. The reflected light is detected and translated into a 2D/3D profile image. However, profiling can also be performed physically (stylus profilometry), where a stylus is used to probe a surface. Both techniques are extremely sensitive, capable of measuring depth differences of less than 1 nanometer. The choice of which technique is preferred mostly depends on the sample surface. For a very soft surface, you want to choose optical profilometry, so the surface is not changed as a result of the measurement. If a surface is absorbing (almost) all light, stylus profilometry is preferred.
At PTG/e, we offer both optical and stylus profilometry, as each technique has its pros and cons (which can often be compensated by the other technique). As such, we will always decide together with our customers which technique is best suited for their samples.
Interested in optical and physical surface profiling? Please contact us, it’s our pleasure to discuss the possibilities.
Bio-based aliphatic/aromatic poly(trimethylene furanoate/sebacate) random copolymers: Correlation between mechanical, gas barrier performances and compostability and copolymer
Agata Zubkiewicz, Anna Szymczyk, Rafaël J. Sablong, Michelina Soccio, Giulia Guidotti, Valentina Siracusa, Nadia Lotti
Polymer Degradation and Stability, 195,2022, 109800