The Effect of Different Nanofillers on Properties and Mixing of Ethylene Propylene Diene Rubber
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Erilaisten nanotäyteaineiden vaikutus eteeni propeeni dieeni kumin ominaisuuksiin ja sekoittamiseen.
Polymer nanocomposites have intensively been studied in the recent years. The reason for this are the superior properties that can be obtained by the use of nanofillers compared to traditional ones in certain materials such as thermoplastics. However, the improvement in properties of rubber by using nanofillers has been difficult to demonstrate. The main problems which were experience in this study were the dispersion or agglomeration of the filler and the poor interaction between the matrix and the nanofiller.This study compares processing and properties of different kinds of commercial nanofillers with ethylene propylene diene rubber (EPDM). The fillers used are mainly clay based, but carbon nanotubes and calcium carbonate are also evaluated.The literature review focuses on the elastomer and the fillers used in this study, and the improvements in properties achieved so far. Properties of the rubber, of the nanofillers as well as modifications of the fillers are addressed. In the final part, the mixing process and different mixing techniques of filled rubber are discussed.In the practical part, six different nanofillers were tested in an EPDM matrix. Of these, the most interesting fillers were selected and tested in concentrations from 0,5 to 7,5 phr. Finally, one filler was selected for modification in order to investigate if the properties could be further enhanced.Testing of the materials included tensile properties, tear strength, hardness, compression set and bound rubber. In addition, curing behaviour and Mooney viscosity were analyzed. Scanning electron microspore was used to investigate the microstructure of the composites. Within this study, a significant improvement of the property profile of the materials by the addition of nanofillers was not observed. The most probable reason for this is an insufficient dispersion of the fillers, with the consequence that the material lacks the filler–filler and filler–polymer network necessary for a good reinforcing effect. The filler–polymer interactions are poor, despite the modifications used in some materials, which also negatively influences the properties. /Kir10