Bending force of LLDPE monofilaments at high temperatures measured in DMA (Dynamic Mechanical Analyzer)

The bending force of monofilaments used as pile layer in artificial turf football fields is a very important property due to the strong relation with the performance of the entire system being the force that mostly influences the deformation of monofilaments. The existing test methods for measuring this force can only be used to perform tests at room temperature. Nowadays, artificial turf surfaces are being installed worldwide, even in regions with very high values of air temperature, leading to the need of evaluating the performance of monofilaments and thus, of testing their bending force at elevated temperatures. The aim of this paper is to use the DMA's advantage of testing at high temperatures, by using a new test method developed for measuring the bending force of monofilaments at room temperature and to evaluate the results obtained. For this purpose, six different LLDPE (Low Linear Density Polyethylene) monofilaments are tested at temperatures 25 degrees C, 50 degrees C and 80 degrees C and the bending force is measured. The DMA is used successfully on performing tests at high temperatures. Considering the results, an analysis of the bending behavior of LLDPE monofilaments depending on the temperature is done. All fibers show the same trends regarding this influence, with decreasing of the bending force while increasing the temperature

Właściwości charakteryzujące zginanie monofilamentów LLDPE w zależności od stopnia zimnego rozciągu i składu polimeru

The behaviour of the pile layer of artificial turf is an important element for the performance of artificial turf. As a top layer, it is constantly under deformation, with the most possible being bending . The bending behaviour of monofilaments of linear low density polyethylene (LLDPE) is strongly influenced by the processing parameters, the type of polymer, and geometrical factors, which in combination with each other seem to have a strong influence on the behaviour of the final product. From the results obtained, the use of octene instead of hexene as a monomer yields better results for resilience due to a higher concentration of intrafibrillar tie molecules for the same degree of DSC crystallinity of the LLDPEs. The increase in the final cross section of monofilaments based on the same LLPDPEs resulted in a decrease in the intrafibrillar tie molecules due to a slower cooling after melt extrusion.Badania dotyczyły obróbki wykańczalniczej jedwabiu naturalnego. Mikrostruktura jedwabiu była badana za pomocą skaningowej mikroroskopii elektronowej, a właściwości mechaniczne testowane były klasyczną zrywarką firmy Instron, podczas gdy strukturę krystaliczną analizowano za pomocą spektroskopii w podczerwieni (FTIR) oraz rozproszenia promieniowania rentgenowskiego. Wyniki pozwoliły wytypować najlepszą w danych warunkach metodę obróbki