Plastics surface preparation cleaning

S.3.3 Reinforced plastics. Adhesives that give satisfactory results on the resin matrix alone may also be used to bond reinforced plastics. Surface preparation of reinforced thermosetting plastics consists of abrasion and solvent cleaning. A degree of abrasion is desired so that the reinforcing material is exposed to the adhesive. 

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. 

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... 

Plastic films can be formed from a number of polymers two of the most common are collodion (nitrocellulose) and polyvinyl formal (Formvar). A number of other plastic materials can be used for thin films, some with specific advantages (101). Plastic films are usually prepared either by spreading a drop of solution of the plastic (in an appropriate solvent) onto a clean water surface, or by stripping off a film that has been coated onto a clean, flat surface (such as a glass slide) onto the surface of clean water. 

Surface preparation is most important for plastic parts that will be bonded with adhesives. Solvent and heat welding do not generally require chemical alteration of the surface however, they do require cleaning. Welding procedures are discussed in another section of this chapter. 

Besides residual tea stains, discolored plastic dishes often lead to consumer complaints. If, during food preparation or the cleaning process, plastic surfaces come into contact with hydrophobic stains such as ketchup, curry, or paprika, their coloring components are able to migrate into the plastic surface, leaving stubborn red or yellow spots that are extremely difficult to remove. Currently, only separately added boosters based on diacylperoxide chemistry are able to remove this type of stain effectively. 

Hot presses are expensive. 2 Often used without rigorous surface preparation. 3 Plastics and rubber parts not normally cleaned and never with chlorinated solvent. 4 Inexpensive heating techniques available. 5 May need pre-shaping curved surfaces difficult. 

There is increasing use of rigid plastics as substrates in place of metals. Plastic surfaces may be prepared by chemical cleaning and/or surface roughening with a mechanical blast. Flame treatment and corona treatment are also viable options. 

Electroless Plating n The deposition of metals on a catalytic surface from solution without an external source of current. The process is used as a preliminary step in preparing plastic articles for conventional electroplating. After cleaning or etching, the plastic surface is immersed in solutions that react to precipitate... 

Unlike composites, most plastics have chemistries that are not suitable as adhesives. They typically have low surface energy while adhesive materials have high surface energy. Consequently, the high-surface energy adhesives do not wet and bond to the plastic surface. Furthermore, most plastic surfaces contain low-molecular weight material and contaminants, such as lubricants or mold-release agents, from the fabrication process. Thus, surface preparation is needed to prepare a reproducible clean and activated surface that is suitable for... 

The surface preparation of plastics needs some care due to the manufacturing processes employed, some of which can leave a degree of surface contamination although the material might look clean. 

In IMS, supportive materials, whose surfaces are coated with conductive materials, are used in principal. In the simplest way, the tissue slices can be placed on a metal MALDI plate directly.9 In this case, however, the target plate must be cleaned carefully after the measurement is over. Currently, the method commonly used is that samples are prepared on a disposable plastic sheet or a glass slide coated with series of conductive materials. In particular, a plastic sheet (ITO sheet) or glass slide (ITO glass slide available from Bruker Daltonics K.K., Billerica, MA, or Sigma, St. Louis, MO) coated with ITO (indium-tin oxide) is useful because it has superior optical transparency... 

Almost any substrate that will be powder coated, whether it is metal, medium-density fiberboard (MDF), or some other material, requires some kind of surface freafmenf. Surface preparafion (prefreafmenf) of wood and more specifically, MDF preparation consist of sanding, removal of confami-nanfs, and board condifioning. MDF boards fhaf will be coafed by UV curable powders should have a moisture content of 49%. If is also a common practice fo preheaf MDF boards prior to application of fhe UV powder. Mefal surfaces are always cleaned by washing and usually freated by a phosphafe primer. Conductive plastics are washed and dried and then coated without any further treatment. Nonconductive plastics are made conductive by applying a primer coat or treated by plasma or flame. ... 

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