High density polyethylene absorbance

Small areas Ventilate to remove the vapors. If condensation is present, decontaminate with copious amounts of a decontamination solution as described in Section 1.6.1. Collect and place into containers lined with high-density polyethylene. Wash the area with copious amounts of soap and water. Collect and containerize the rinseate. Removal of porous material, including painted surfaces, maybe required because the nerve agent that has been absorbed into these materials can migrate back to the surface posing both a contact and vapor hazard. 

Solution polymerizafion. Highly exothermic reactions can be handled by this process. The reaction is carried out in an excess of solvent that absorbs and disperses the heat of reaction. The excess solvent also prevents the formation of slush or sludge, which sometimes happens in the bulk process when the polymer volume overtakes the monomer. The solution process is particularly useful when the polymer is to be used in the solvent, say like a coating. Some of the snags with this process its difficult to remove residual traces of solvent, if that s necessary the same is true of catalyst if any is used. This process is used in one version of a low-pressure process for high-density polyethylene and for polypropylene. 

Parabens are approved for use in oral solution and suspensions at a concentration of 0.015% to 0.2% w/v. Due to their low solubility, the sodium salts of parabens are often used in aqueous formulations. The parabens are most effective in the pH range of 2 to 6, and their antimicrobial activity decreases with increasing pH. Additionally, they are very unstable at pH 8 or above in solution. Methyl paraben has also demonstrated incompatibility with sorbitol and may show some discoloration in the presence of iron. The absorption of methylparaben by plastics has been reported with the amount absorbed being dependent upon the type of plastic and vehicle. However, no absorption has been reported for low density polyethylene (LDPE) or high density polyethylene (HDPE) containers. Certain coloring agents such as yellow iron oxide, ultramarine blue, and aluminum silicate can extensively absorb ethyl paraben in simple aqueous systems, thus reducing its preservative efficacy. 

Focusing collectors are usually cast acrylic Fresnel lenses, or mirrors of aluminized polyester film in frames of aluminum. These reflectors are either enclosed in a bubble of poly(vinyl fluoride) film, or under polycarbonate glazing, which may be covered with a fluorocarbon film to reduce the reflectivity. The absorbers for active systems are copper or aluminum since the temperatures are too high (325—370°C) for plastics. The frames, however, can be molded ABS, high density polyethylene or polyurethane, either solid or structural foam. Polybutylene or chlorinated PVC can be used for piping hot water, and tanks can be made of either reinforced polyester or blow- or rotational-molded, high density polyethylene (12—15). 

Table 8. Changes of molecular mass of high-density polyethylene with the amount of oxygen absorbed at 100 °C...

High density polyethylene—commonly used in sample containers but can absorb trace metals if the sample is not acidified... 

Solids The most common solid oral dosage forms are capsules and tablets. A typical solid oral dosage forms container closure system is a plastic, usually high-density polyethylene (HDPE), bottle with a screw-on or snap-off closure and a flexible packaging system such as a pouch or a blister package. A typical closure consists of a cap, often with a liner, frequently with an inner seal. If used, fillers, desiccants, and other absorbent materials are considered primary packaging components. 

Absorption of methylparaben by plastics has also been reported the amount absorbed is dependent upon the type of plastic and the vehicle. It has been claimed that low-density and high-density polyethylene bottles do not absorb methylpar-aben. ... 

Small Areas Puddles of liquid must be contained by covering with vermiculite, diatomaceous earth, clay, fine sand, sponges, or towels. Place the absorbed material into containers with a high-density polyethylene liner. Decontaminate the area with copious amounts of aqueous sodium hydroxide solution (a minimum of 10 percent by weight). If sodium hydroxide solution is not available, then sodium carbonate may be used. Removal of porous material, including painted surfaces, that may have absorbed Nerve Agent liquid may be required as these materials could continue to re-release liquid and/or vapor after exposure has ceased. 

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