Adhesive and adsorption properties of a cationic amphiphilic block copolymer for use as compatibilizer in (bio)-composites
2011 (English)In: EUPOC 2011, Biobased Polymers and Related Biomaterials, 2011Conference paper (Refereed)
The awareness of our need for a sustainable society has encouraged the search for renewable, high quality materials that can replace oil-based products. This has stimulated a lot of research where cellulosic fibres are combined with different types of polymer matrices to obtain more environmentally friendly composite materials. However, the compatibility between the different components in a composite, which is of decisive importance for its final properties, is a large problem in many systems today. In this work, the objective was to create a novel type of compatibilizer that can physically adsorb onto fibres to enhance the interaction between fibres and non-polar polymer matrices in fibre-reinforced composites, both by addressing surface energies and by introducing polymer entanglements at the interface. This physical route is much more convenient compared to covalent attachment since it can be performed in water under mild conditions and therefore does not require any use of organic solvents for the attachment of the compatibilizer. To achieve this, an amphiphilic block copolymer with one high molecular weight hydrophobic block (polystyrene, PS) and one cationic block (poly(dimethylamino)ethyl methacrylate, PDMAEMA) was synthesized. Due to the cationic charges, the polymers adsorb to oppositely charged surfaces resulting in a measured contact angle close to that of many non-polar polymer matrices. The adhesion, (measured with atomic force microscopy, AFM, using the colloidal probe technique), of the surface with compatibilizer towards a non-polar PS-probe increased with increasing contact time, most probably due to polymer entanglements between the non-polar blocks at the treated surface and the probe. This demonstrates that the use of this type of novel amphiphilic block copolymer is a promising route to improve the compatibility between charged reinforcing materials such as cellulose-based fibres but also glass-fibres, nanoclay, nanofibrillated cellulose and other charged reinforcing materials, and hydrophobic matrices in composite materials. Limitations when designing new materials due to a lack in compatibility could in this way be addressed in an easy but effective way resulting in more environmentally friendly materials with improved mechanical properties.
Place, publisher, year, edition, pages
IdentifiersURN: urn:nbn:se:kth:diva-84392OAI: oai:DiVA.org:kth-84392DiVA: diva2:499345
EUPOC 2011, Biobased Polymers and Related Biomaterials, Gargnano, Italy, May 29-Jun 3
QC 201203302012-02-132012-02-132012-03-30Bibliographically approved