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Nynas employed MALDI-TOF analysis as a direct approach to determining the molecular mass and gaining a higher understanding of the molecular structure of mineral oils.
While for most chemical products molecular weight is one of the most important material characteristics, in the oil industry it is far more common to use the viscosity instead. There are a few different reasons for this, but perhaps the most compelling is that there is no single representative molecule in a given oil fraction, but a distribution of more or less similar chemical structures and molecular sizes (mass) within the population of molecules in the oil. A more detailed insight into the oil’s molecular size and chemical structure is important for an improved understanding of its behavior in certain areas, such as migration and swelling potential of rubber materials.
The most common method to determine a mineral oil’s molecular weight (Mw) is by applying the standard method ASTM D 2502. While this method has its merits, it is also a fact that it is an indirect method which gives the Mw of an oil based on a calculation model. As a consequence, the calculated Mw of any mineral oil which is not exactly the same as those used in the original model will deviate from the “true” value.
In order to use a more direct approach to measure – rather than calculate – the molecular mass of mineral oils, Nynas applied MALDI-TOF* analysis to the assessment of the oil molecular mass.
“The MALDI-TOF technology makes it possible for us to make a direct measurement on the oil in question which ultimately results in a higher accuracy in the determination of the molecular weight. Mineral oils contain a variety of structures, and until now these differences have not been taken into account for the Mw assessment of the oil,” says Dr. Kamyar Alavi, Senior Technical Advisor, Tyre & Rubber Industries.
"Besides, it is important to know the Mw since some regulations specify certain Mw requirements which adds another weight to the question. The Mw is also an important factor for determining the risk of migration," adds Professor Thomas Norrby, Technical Manager Tyre & Rubber Industries.
* Matrix Assisted Laser Desorption Ionization – Time of Flight
2020 was a year like no other. Beyond the face masks, social distancing and working from home, the economy took a dive. These unprecedented events coincided with an ongoing restructuring of the refining industry, which will have a lasting effect on the production of tyres and rubber.Read more about Plasticizing rubber after Covid-19
Don’t miss Nynas senior specialst Dr Kamyar Alavi’s talk at Tire Technology Virtual “Live” 2021 on 8 June.Read more about Virtual presentation: Increased sustainability: tyre rubbers with raw materials from renewable resources