Suchergebnisse

The contribution of Spanish scientists to the rheology involved in polymer processing during the last 25 years is investigated. It is shown that the performed research covers, at different levels, all industrial polymeric materials: thermoplastics, thermosets, adhesives, biopolymers, composites and nanocomposites, and polymer modified bitumen. Therefore, the rheological behaviour of these materials in processing methods such as extrusion, injection moulding, additive manufacturing, and others is discussed, based on the literature results. A detailed view of the most outstanding achievements, based on the rheological criteria of the authors, is offered ; This research was funded by Basque Government, IT1309-19. LS acknowledges the postdoctoral grant from Basque Government

The paving industry is currently demanding polymer modified bitumens (PMBs) with enhanced in-service performance and low enough viscosity at lower application temperatures. With this aim, this study focuses on the use of ethylene vinyl acetate (EVA) copolymers with low melting temperatures and explores the effect on the desired properties of the vinyl acetate (VA) content and Melt Flow Index (MFI). To that end, binders were prepared from EVA copolymers having varying VA contents from 7 to 33 wt.%, and MFI from 2 to 800. A comprehensive characterization based on viscous flow curves, dynamic shear temperature sweeps, standardized technological tests, differential scanning calorimetry (DSC) and optical microscopy analysis was conducted on EVA-binders with 5 and 7.5 wt.% EVA. Low VA contents proved to endow bitumen with improved performance at medium-high in-service temperatures. Interestingly, binder viscosity at 135ºC decreased with increasing the MFI, regardless the selected VA content. This means that tailored PMBs can be designed with both improved in-service performance at medium-high temperatures and reduced viscosity to facilitate polymer-bitumen mixing, mineral coating and asphalt mix laydown/compaction at lower temperatures. ; This research is a part of the Marie Curie Initial Training Network (ITN) action, FP7 - PEOPLE-2013-ITN. This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement number 607524.