Surface pretreatments solvent cleaning treatments

Polyethylene terephthalate cannot be solvent-cemented or heat-welded. Adhesives are the prime way of joining PET to itself and to other substrates. Only solvent cleaning of PET surfaces is recommended as a surface treatment. The linear film of polyethylene terephthalate (Mylar) provides a surface that can be pretreated by alkaline etching or plasma for maximum adhesion, but often a special treatment such as this is not necessary. An adhesive for linear polyester has been developed from a partially amidized acid from a secondary amine, reacted at less than stoichiometric with a DGEB A epoxy resin, and cured with a dihydrazide.72... 

Adhesion to plasticized PVC is often poorly effective because migrating plasticizer contaminates surfaces. In this case, pretreatment comprises cleaning with a ketone solvent such as acetone. Polystyrene, nylon, melamine-formaldehydes and polyesters can be pretreated by abrading with an emery cloth prior to cleaning with an alcohol. The effectiveness of all surface treatments decrease rapidly with time, so it is necessary to both modify and adhere within a short period. 

With thermal or solvent welding, snrface preparation is not as critical as with adhesive bonding. However, some form of surface pretreatment may still be necessary, although difficult chemical or physical treatments to increase the surface energy are not required. Certainly, the parts should be clean, and aU mold release and contaminants must be removed by standard cleaning procedures. 

Another similar pretreatment involves argon-ion sputtering for 45 min at 750 eV in the UHV using an argon gas pressure of 10 Torr (140). These conditions were selected to remove the adventitious carbon and surface hydroxides but not to cause extensive oxide reduction or lattice damage. Before either of these treatments, the samples should first be solvent cleaned as desalbed above. 

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