Ml-02 Polymer Nanotechnology Applied to Polymer Alloys and Composites
Year: 2009
Type: conference-abstract
Abstract: Significant adhesion enhancement of various surfacefinishing materials to chemically inert automotive polyolefin blends can be attained through surface grafted connector molecules reactive with oxidized substrate surface. The effectiveness of adhesion improvement through such tethered interfaces is shown to depend on the mode of interaction with the adjacent medium: interpenetration or chemical reaction, as well as surface density and length of grafted molecules. We have frequently observed that some systems, such as painted or otherwise decoratively coated products, fail through the delamination of the coating from the substrate surface at the stress levels well below the anticipated loadbearing capacity of the tethered interface. Two hypotheses have been formulated to explain the observed phenomenon: (i) The chain scission in surface oxidized polyolefins takes place not only in the uppermost polymer surface, but may propagate into the sub-surface region, thus creating a weak boundary layer which fails cohesively through its bulk, (ii) In order to increase the load-bearing capacity of the interphase, the sub-surface region of the substrate needs to be reinforced by short-chain molecules penetrating into and subsequently providing effective crosslinks between individual fragments of excessively oxidized and hence, weaker sub-surface part of the interphase. In this paper we fully verify the above hypotheses. The oxidized sub-surface layer reinforced by polyethyleneimine becomes an integral part of the effective interphase in addition to the tethered interface and the interpenetrated network of connector molecules and the paint. Possibility of lignin application in rubber blends based on NR and SBR was studied. Seven types of lignin powder were tested as fillers for rubber blends before and after modification. Influence of lignin on vulcanisation process, mechanical properties, morphological structure as well as dynamical-mechanical properties was investigated. The significant positive effect of modified lignin on properties of model rubber blends was found.
Source: Chemické listy
Language: Czech
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W2185409666