Plastics, container material

The surface of the sample container may interact with the analyte. The surfaces can provide catalysts (e.g., metals) for reactions or just sites for irreversible adsorption. For example, metals can adsorb irreversibly on glass surfaces, so plastic containers are chosen for holding water samples to be analyzed for their metal content. These samples are also acidified with HNO3 to help keep the metal ions in solution. Organic molecules may also interact with polymeric container materials. Plasticizers such as phthalate esters can diffuse from the plastic into the sample, and the plastic can serve as a sorbent (or a membrane) for the organic molecules. Consequently, glass containers are suitable for organic analytes. Bottle caps should have Teflon liners to preclude contamination from the plastic caps. 

Epoxy resin adhesives, polyepoxy compounds in combination with amines, polyami-doamines, or dicarboxylic acid anhydrides. Uses metals, silicate-containing materials, plastics. 

Material Tests. Material tests measure some property of the polymer or plastic as opposed to measuriag the flammabiUty of the final product which contains the plastic. 

Increasingly, plastics are being used as parenteral packaging (qv) materials. Plastics such as poly(vinyl chloride), polyethylene, and polypropylene are employed. However, plastics may contain various additives that could leach into the product, such as plasticizers (qv) and antioxidants. PermeabiUty of plastics to oxygen, carbon dioxide, and water vapor must be tested in the selection of plastic containers. Furthermore, the plastic should withstand sterilization. Flaking of plastic particles should not occur and clarity necessary for inspection should be present. 

Container Insulation Tanks containing materials above atmospheric temperature may require insulation to reduce loss of heat. Almost any of the commonly used insulating materials can be employed. Calcium silicate, glass fiber, mineral wool, cellular glass, and plastic foams are among those used. Tanks exposed to weather must have jackets or protective coatings, usually asphalt, to keep water out of the insulation. 

Although inhibitors are deliberately added to the silicone formulation to control cure rate, unwanted cure inhibition can be caused by other species that react to form strong complexes with the platinum catalyst. Most notable of these undesired inhibitors include organotin and other organometallic compounds, sulfur, polysulfides, polysulfones or other sulfur-containing materials, amines, urethanes or amine-containing materials, unsaturated hydrocarbons in plasticizers, and some solder flux residues. 

IX lists the results of some of these experiments, comparing the nitrile materials with polyethylene, the most widely used plastic container material, and poly (vinyl chloride), which is being used for a number of food packaging applications. Note that in all instances there is an order of magnitude difference between the Lopac container and the other two. For flavorants, which are usually present in very low concentrations, this dilute solution test is probably more significant than a standard permeability test which only measures weight losses of the pure ingredient. 

MSWIs can accept virtually any mixed waste stream as long as it falls within its calorific window of 9-13 MJ/kg (hence including material containing regular plastics and PVC content). Furthermore, the heavy metal content should not be excessive (since this can make the quality of the slag not suitable for re-use) and the material should be destructible at the rather low incineration temperature of MSWIs (850 °C). Some waste will not be efficiently destroyed. 

MATERIALS Container, thermate, plastic explosive, nonelectric blasting cap, safety fuse, primacord (optional),... 

The important influence that sample container materials can have on seawater sample composition is illustrated next by two examples one concerning the storage of metal solutions in glass and plastic bottles, the other concerning the storage of solutions of phthalic acid esters and polychlorinated biphenyls in glass and plastic. 

An important number of these substances have an industrial origin. Some of them, like the pesticides, arrive intentionally in the environment and their use and release should be theoretically controlled. However, many of them have not been purposely produced as bioactive substances but more as components or additives of certain materials. Their significant growth in the chemical industry has not only been produced as a consequence of the discovery of new active principles in the pharmaceutical or pesticide area, but also because of the expansion of new technologies (electronics, containers, textiles, plastics, resins, foams, etc.), that require the development of new materials and substances with particular features. Most of these substances enter or are discharged to water and air sources without regulated controls. Wastewater treatment plants (WWTPs) are often not yet adapted to completely remove them, and therefore these new compounds can be found to some extent in wastewater effluents as well as in soil and sludge. 

Packaging waste is normally recovered from one of two sources. The first is the waste which is not used by the converter (i.e. the maker of the package) and the second is from the packages which are discarded at the point of sale. The former is relatively free of contaminates whereas the latter may contain adhesives, plastics, staples and other contraries . Many countries, including the UK, have developed very efficient collection and recovery systems for packaging material from wholesale and retail outlets. For example in 1991, the Japanese were recovering almost 70% of corrugated containers from this source. 

Reduction of polymer flammability is of broad interest for applications ranging from plastics to textiles. For polyesters, given their inherent instability towards water at elevated temperatures, and the high temperatures of manufacture, many classes of flame-retardant (FR) agents, including most halogen-containing materials, are impractical. Phosphate esters, capable of incorporation into the polymer backbone, were pioneered by Hoechst AG, and continue to be the materials of choice [84, 85],... 

PVC can also contain phthalates, plasticizers that make materials flexible. Phthalates have been linked to cancer, kidney damage, and problems with the reproductive system. 

The contractor should place any material that is removed and any debris from the work in sealed, leak-proof, properly labeled, plastic bags (6 mm thick) and should dispose of them in a proper land-fill. The contractor should comply with Health Department instructions about how to dispose of asbestos-containing material. 

This section includes the most important container materials glass, plastic, and elastomers and addresses the contamination issues for injectable formulations. 

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