I am trying to bond aluminum surface with plexiglass with superglue. Both of my substrates will be under load. That's why I am trying to find a glue that will hold these two surfaces under stress. Superglue seems to work better than others so far. I was wondering what kind of bond forms between the polymerized cyanoacrylates and aluminum surface as well as cyanoacrylates and PMMA surface? Thanks.
The surface of aluminium actually is aluminium oxide with a layer of adsorbed sustances, mainly water but also hydrocarbons. Cleaning the surface can remove the organics as their re-adsoption usually takes a while. Water, however, is re-adsorbed quickly. An adhesive has to deal with this situation and form interaction with the actual surface.
There is no covalent bond formed between the Al2O3 and the cyano acrylate. Lewis acid base interactions can be numerous and relatively strong. They can give a good adhesion.
If you want to improve it use an appropriate siloxane primer. They can for covalent bonds with the Al2O3 surface and the adhesive.
A surface treatment of the PMMA would also be beneficial.
Dear Touhid Bin Anwar, the adhesion mechanisms are poorely understood as many possible interactions at the interface may be involved. The adsorbed water on the metal surface contributes positively to the formation of the adhesive since cyanoacrylates polymerize by water initiation. Please check the following document. My Regards
https://doi.org/10.1016/0584-8539(82)80183-9
Thank you Dr. Andreas Holländer and Dr. Abdelkader BOUAZIZ for your answers.
I will check the reference and get back to you if I have any question. Thanks.