Plastics substrate preparation

Fortunately for the commonly used metals this controlled oxidation occurs naturally after grit blasting or acid etching. In the case of plastics, no such convenient oxidation process takes place. However, each material will have a unique surface layer containing potential sites for bonding  

The C(=0)0, ester group will partake in hydrogen bonding through both oxygen atoms, especially the activated carbonyl group. Some polyesters will be less easy to bond if steric hindrance is likely. Even PBT proves difficult to bond and often requires further treatment. 

In theory PU should be very active towards bonding, with an activated N-H and a carbonyl group, as described for polyamides. However PUs are never that easy to bond and could be due to surface oxidation and/or surface hydrolysis, it is normal to remove the surface, degrease and prime before the surface is too old. 

The sites for hydrogen bonding and chemical reaction are significant and polyureas are generally easy to bond. Being more oxidation resistant and hydrolysis resistant than the urethane group is significant. 

A regular repeating stable carbonyl group is available for polar attraction and hydrogen bonding. 

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TABLE F2 Surface Preparation Methods for Plastic Substrates... 

Solvent-resistant polymers are attractive for a variety of microanalytical applications. For chemical sensing, solvent-resistant polymers are important as supports for deposition of solvent-based polymeric sensing formulations.1 Otherwise, a solvent that is used for the preparation of the sensor formulation can attack a plastic substrate of choice forcing the use of either less attractive substrate materials or the use of a complicated sensor-assembly process.2 3 Solvent-resistant polymers also attract interest for microfluidic applications as an alternative to glass and silicon.43 Examples of solvent-resistant polymeric microfluidic systems include those for organic-phase synthesis,6 polymer synthesis,7 studies of polymeric and colloidal... 

Prior to the mid-1950s, all thermoplastic acrylics were classic solution polymers prepared in suitable organic solvents. They were employed in a variety of applications, including general industrial finishes and appliance enamels and coatings for a variety of wooden, metallic, and plastic substrates. 

ELECTRON MICROSCOPY. The samples were prepared for electron microscopy as follows. The test materials with the adsorbed protein were placed in a vacugm evaporator (2 ). The specimens were dehydrated in vacuo (10 Torr) for 60 min., shadowed with tungsten, and carbon coated. The plastic substrates were dissolved in an appropriate solvent, either 1,2-dichloroethane (EDC), or N,N-dimethylacetamide (DMAC). The carbon replica, mounted on an microscope grid, was examined in the electron microscope. For observation, we used a Philips 300 electron microscope operated at 80 kV with a 50 micron objective aperture. 

All of the plastics, rubbers and composites described previously for their use in the automobile industry may or may not show any health hazard, depending on their preparation and contents. In this context, certainly the ones that are used in interiors are of the utmost importance and should be considered and examined more critically. On the other hand, the ones used in exteriors, should also be considered, not for their health hazard considerations, but mainly on different grounds (i.e., the loss of light stabilisers by migration from automotive finishes, which can significantly reduce the durability of coatings on plastic substrates [14]). 

The plastic substrates employed in this study were injection-molded plaques (1.5 mm thick) or 125 )im thick extruded films prepared from unfilled Ultem polyetherimide (Ultem KXX)). In addition, plaques containing 10, 20, or 30 % glass-filler (Ultem 2112, Ultem 2212, or Ultem 2312, respectively) were used. All materials are available from GE Plastics. 

Nature of the Substrate and Substrate Preparation / surface energies, solubility parameters (plastic substrates). 

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