Investigation of the influence of compatibilisation of PA6/ABS blends on melt processing, micro-structure and mechanical properties and their mutual interactions.
Blending of polymers is a technologically important procedure in polymer processing and a powerful tool in order to improve the end use properties of polymeric materials. The understanding of relevant micro-structural mechanisms during melt processing and of deformation on morphology in the solid state is essential in order to optimise the blending of polymers with respect to processability and performance. For example, it is often necessary to prepare a two phase polymer blend with a co-continuous morphology during extrusion. Therefore it is crucial to understand quantitatively the deformation of the phases and the processes leading to the break-up or the coalescence of micro-structures during mixing. Compatibilisation of the constituents generally improves the mechanical properties of the blend. In this context, the degree of compatibilisation, the mobility of the compatibiliser at the interface and in the bulk and its influence on interfacial tension and coalescence of droplets are important properties, which determine the final blend morphology and the mechanical performance. In the past, the relevant physical phenomena in complex multiphase blends (e.g., the industrially important PA 6/ABS blends) have only been partially explored. Especially, melt elongational properties, their influence on morphology and melt stability during processing were not the focus of previous studies.
This project aims to clear up those physical mechanisms in compatibilised PA 6/ABS blends, which are relevant to melt processing and to mechanical performance. The degree and the effect of compatibilisation as well as the formation of the morphology as a function of the overall composition of the blend will be investigated and their influences on the flow and the mechanical properties will be elucidated. Particularly, the deformation of the morphology during elongation in the solid and in the molten state will be investigated. The materials will be supplied by BASF AG (Ludwigshafen, Germany). The preparation of blends of selected composition ratios, including reactive compatibilisation, will be done by melt mixing in a twin-screw extruder. The melt processing properties will be investigated by performing elongational and shear rheometry. The mechanical properties of compatibilised PA 6/ABS blends will be evaluated by determining fracture mechanical quantities like the critical value of the stress field and the critical value of the energy release rate (fracture toughness). In addition, dynamic-mechanical analysis, fatigue crack growth tests, impact tests and micromechanical tests will be performed. The morphology of the blends will be investigated by microscopic (e.g. AFM and TEM) and scattering methods (SAXS / WAXS).
The morphological, mechanical and rheological properties of PA 6/ABS-blends were investigated in detail. Micromechanical tests on reactively compatibilized PA 6/ABS and PA 6/SAN blends are reported in Refs. 1 and 2. In these works, in situ-micromechanical investigations were carried out. The influence of compatibilizer concentration on rheological and mechanical properties (including fatigue crack propagation) of PA 6/ABS blends with a disperse morphology is the subject of Ref. 3. The correlation between blend composition, morphology and processing/end-use properties of reactively compatibilized PA 6/ABS blends is discussed in this article. In summary, a broad analysis of morphological, mechanical and rheological properties has been carried out within this IUPAC project.
1. U.A. Handge, C. Sailer, H. Steininger, M. Weber, St. Scholtyssek, V. Seydewitz, G.H. Michler, Micromechanical Processes and Failure Phenomena in Reactively Compatibilized Blends of Polyamide 6 and Styrenic Polymers: Part I: PA 6/ABS Blends, J. Appl. Polym. Sci. 112, 1658-1669 (2009). (https://dx.doi.org/10.1002/app.29566)
2. U.A. Handge, C. Sailer, H. Steininger, M. Weber, St. Scholtyssek, V. Seydewitz, G.H. Michler, Micromechanical Processes and Failure Phenomena in Reactively Compatibilized Blends of Polyamide 6 and Styrenic Polymers: Part II: PA 6/SAN Blends, J. Appl. Polym. Sci. 115, 2529-2539 (2010). (https://dx.doi.org/10.1002/app.31270)
3. U.A. Handge, A. Galeski, S.C. Kim, D.J. Dijkstra, C. Gotz, F. Fischer, G.T. Lim, V. Altstaedt, C. Gabriel, M. Weber, H. Steininger, Melt Processing, Mechanical and Fatigue Crack Propagation Properties of Reactively Compatibilized Blends of Polyamide 6 and an Acrylonitrile-Butadiene-Styrene Copolymer, J. Appl. Polym. Sci. 124, 740-754 (2012). (https://dx.doi.org/10.1002/app.35055)
Project completed – page last updated 6 Jan 2015