BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI - Universitatea ...

114 Birgit Kjærside Storm
The HSP can be measured for the different adhesives. In Fig. 7 the HSP plot
of the epoxy based adhesive DP 460 from 3M is shown and in Fig. 8 the HSP plot
of the polyurethane adhesive Sikaflex from Sika Industries is shown.
From comparing the HSP for an adhesive with the HSP for a surface –
aluminium or anodized aluminium – it can be foreseen if it can be possible to
wet the surface with the adhesive and if it can be possible to make a reaction
between the adhesive and the surface. Fig. 9 shows the HSP plot for an unsealed
anodized aluminium surface.
Fig. 9 - The HSP plot of an unsealed anodized aluminium.
The anodizing has been made in the laboratory
For an unsealed anodized surface it can with some polyurethane adhesives
and some epoxy adhesives be possible to make a chemical bonding in the
interphase. Such an adhesive can be used as a primer if it can be possible to find
another adhesive, which can give the strength of the bonding and can wet the
primer.
7. Results
For several systems combined with anodized aluminium and a structural
adhesive the strength and the flexibility has been measured. The adhesives used
in the experiments have been commercial adhesives and the anodizing process
has been carried out either in a laboratory or in a commercial system. For the
laboratory made anodizing the process has been made with parameters and
chemicals as near the commercial systems as possible.