Cleaning plastic surfaces

The snrface condition of the part must be considered before any attempts are made for printing on plastic. Surface cleaning and treating methods described under the entry on adhesive bonding are applicable also for treating the surfaces before printing. 

Avseenko et al. (2001) immobilized antigens onto aluminum-coated Mylar films by electrospray (ES) deposition. Various surface modifications of the metallized films were studied to determine their abilities to enhance sensitivity. The plastic surfaces were firsf cleaned by plasma discharge treatment, followed by coating with proteins (BSA and casein) or polymers such as poly (methyl methacrylate) or oxidized dextran, or they were exposed to dichlorodimethyl silane to create hydrophobic surfaces. Protein antigen was prepared in 10-fold excess sucrose and sprayed onto the surfaces to form arrays with spot diameters between 7 and 15 pm containing 1 to 4 pg protein. 

Plugs for graphite bridge initiators are made by molding the plastic about a twisted pair of enameled wires, and thea grinding the surface clean, bis ieaves a plastic surface with two metal islands separated by twice the thickness of the enamel. A droplet of colloidal suspension of graphite in water is applied over the point of closest approach of these islands to dry. Since both resistance... 

Sn, Sb)02/Mica Sn(0,F)2/Mica electrically conductive conductive flooring, antistatic packaging materials, light colored primed plastic surfaces which can be electrostatically painted in further coating process, light colored conducting surfaces in clean room conditions for dust reduction [5.235]... 

A microwave oven equipped with Pello 3420 Load Cooler attachment is set at 25°C and full power. Two beakers, each filled with 500 ml of water, are placed in previously determined hot spots in the microwave oven (see pages 102-103). Grids containing the thin cryosections are floated (section side down) sequentially on small drops of 0.15% glycine and 1% BSA for 15 sec and 5 min, respectively. The reagent drops are placed on a clean disposable plastic surface which has been placed on the cold spot in the oven (an area between the two beakers of water). The local temperature is controlled using the microwave temperature probe immersed in a tube of water placed close to the grids. 

We have found solid pins the easiest to clean rapidly, and have observed no carryover between samples using such pins. In addition, we have found that solid pins also work well when printing directly onto glass or plastic surfaces (Fig. 7). 

As with metal substrates, the effects of plastic surface treatments decrease with time, so it is important to carry out the priming or bonding as soon as possible after surface preparation. The surface preparation methods suggested in App. F are recommended for conventional adhesive bonding. Greater care must be taken in cleaning thermoplastics than... 

As a general rule, samples should be collected in decontaminated flasks and even those considered metal-free should be pre-washed. Glass recipients should be avoided. A good procedure for cleaning plastic containers is keeping them at least 24 h in a 10% (v/v) ethanolic nitric acid solution. Aqueous solutions do not leach out the aluminum well, because water does not wet plastic surfaces better contact occurs when an alcoholic solution is used. It can be seen that all alcoholic solutions were more efficient than the aqueous solutions. Table 10 shows the aluminum extracted from polyethylene by the action of some washing solutions. Just before use, the containers should be abundantly washed with ultrapure water. The best option is to use the flasks just after rinsing them, however if they must be dried, they should not be placed in an oven, even with the open side on tissue paper (paper contains aluminum). The best way is let them dry under a laminar flow. The proper heat and air movement inside the hood will help to rapidly dry the flasks. 

Strain-proofing and self-cleaning effects can be enhanced through the highly hydrophilic function. As an example, a plastic surface smeared with oil cannot be cleaned unless one uses detergent. A highly hydrophilic surface,... 

Solvent cleaners are generally free of builder salts. The cleaning efficacy depends on solvent-type compounds, such as glycol ethers. Solvent cleaners are less effective on particulate soiling, such as mud on floors however, they are effective against oily soiling, particularly on modern plastic surfaces. 

Unlike their parent product, powder cleansers, the cream cleansers usually use the gentler calcite abrasive. This, combined with their liquid form, helps to convey the image of less harsh cleaning to the consumer. This is especially important to consumers who have softer, plastic surfaces in their bathrooms such as the fiberglass (polymethyl methacrylate) shower enclosures which are much more easily marred than the traditional vitreous materials [18]. 

The use of bundles of thin walled plastic tubes have been used in shell and tube heat exchangers. Apart from the resistance to deposit accumulation afforded by the polymeric material, the oscillation of the flexible tubes under the influence of the flows in the shell as well as within the tubes assists in keeping the surface clean. A recent innovation is the use of ceramic heat exchangers for handling corrosive fluids, e.g. heating corrosive gases to 580°C prior to incineration at 950°C and also as an acid condenser for sulphuric acid at 250°C [Redman 1989],... 

Adsorbance of hydrocarbon vapours can he minimized by storing the substrates in freshly oxidized aluminium containers, which preferentially absorb the hydrocarbons. A disadvantage of this technique is the extra steps involved in periodically stripping and reoxidizing the metal surface of the container. The ultraviolet/ozone technique, mentioned above, may also be used to keep oxidic surfaces clean in an ambient environment. In general, however, cleaned surfaces should at least be stored in clean glass or plastic containers. 

Regular and frequent interactions between hands and their surroundings suggests that transfer of contaminating virus can occur readily between the contact points. Such transfer of infectious virus to and from hands upon casual contact with objects or other animate or inanimate surfaces can be demonstrated to occur readily in experimental settings [4,6,7]. Several studies have shown that clean hands can readily become contaminated when objects or surfaces with infectious vims on them are touched or handled [6]. The reverse has also been shown to be true. Transfer of a rhinovirus was observed in 15 of 16 trials in which a plastic surface, contaminated 1-3 hours previously, was touched by a volunteer [8]. Individuals with acute rhinovims colds were shown to deposit in-... 

An effective solvent for plastics objects may be required as a component of an adhesion or repair treatment where the edges to be joined require etching or softening. By contrast, a poorly effective solvent for plastic may be sought as a component of a cleaning treatment where the soil is dissolved while the original plastic surface remains undamaged. In addition, selection of an effective and appropriate solvent may also depend on its evaporation rate, environmental or health and safety considerations. 

There are some occasions where it is necessary to apply solvents to plastics, for example removal of residues from adhesive labels or earlier repairs. Selection of liquids to clean plastics surfaces, which will not soften or dissolve them, may be achieved in two ways. The trial and error approach involves applying drops of cleaning agents to a test piece or a hidden area of the object and examining the results with time. A more systematic approach is to compare the polarity of the liquid with that of the plastic in order to avoid those liquids which are most likely to dissolve or soften the object. 

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