Polythene coatings

Figure 2.6. Diaphragm diffusion cell after Dullien and Shemilt, 1961). A, light liquid compartment, B, heavy liquid compartment, C, stop-eoek D, E, capillaries, F, sintered glass diaphragm, G = polythene-coated iron stirrers, H, rotating magnets...

Sample (5.0 0.01 g) is transferred to a 250 ml Pyrex glass centrifuge bottle, and toluene (50 ml) is added. A polythene coated magnetic stirrer rotor is placed into the bottle which is stoppered with a cork (avoid rubber bungs). The bottle is placed on a magnetic stirrer and left for several hours until the sample has completely dissolved or dispersed in the solvent. Into the gently stirred contents of the bottle 50 ml of 0.6 M lithium chloride reagent is accurately pipetted. 

Dry A filter manufactured from cotton wool, glass-fiber fabric, pleated paper, foamed polyurethane, cellular polythene, or other suitable materials. As the name suggests, the filter is dry in nature and has no oil coating. 

The tapes are usually produced from polythene or polyvinylchloride films of 25 /im to 0-5 mm in thickness and the inner surface is coated with an adhesive, frequently rubber-based. The adhesive is usually between 25 and 100/im thick. 

Iron flake powder and polystyrene beads had been blended in a high-speed mixer. The mixture ignited and binned rapidly when discharged into a polythene bag. Rapid oxidation of the finely divided metal and/or static discharge may have initiated the fire. No ignition occurred when the iron powder was surface coated with stearic acid. 

Procedure. Wear PPE - rubber gloves, face shield and lab coat when handling the permanganate-buffer solution. Place the weighed sintered glass crucibles containing the ADF residue one at a time into a stainless steel or polythene tray containing 2-3 cm cold water (a 400 x 320 x 50 mm tray will hold 48... 

The prepared metal surface is coated with one or two coats of the primer, depending on the grade and the chemical and water resistance required. The coats must be applied at the recommended thickness. There is normally a minimum and maximum thickness. The aim is to fully wet the metal surface but not have too thick a layer. All the solvents in the primer must be evaporated before use. If the coated metal part is not used immediately, it must be carefully covered in polythene film to prevent surface contamination. 

A few grammes of 100 /im diameter polythene spheres are warm-pressed into a solid block. Describe the expected electrical characteristics of the block. In a separate experiment each sphere is first coated with a nanometre thick layer of aluminium prior to compaction. Describe how the electrical properties of the block would be modified and estimate the quantity of aluminium in the composite on the bases of volume and weight. Comment on the relevance of your finding to electroceramics research and development 30p.p.m. 90 p.p.m. 

Berg s divers for example, were hollow glass eontainers that contained mercury to give the desired density. The density was then adjusted to the desired value by etching with hydrofluoric acid. Various modified divers were later developed, the final ones, by Kaye and James [57], being metal coated polythene spheres which were located with search coils. 

We take the precaution of sealing the DNApolythene bags and storing them at -20 C. Plates coated with DNA modified with the alkylating agent melphalan, which induces unstable guanine N-7 adducts, are stable for at least one year when stored in this way. 

Next, crosslink the DNA to the protein by irradiating the plates with UV light (5) of about 254 nm wavelength such that each plate receives a total uniform exposure of about 8 min at about 800 pW/cm (seeNote 4). These plates can be stored until required. We store all DNA coated plates, sealed in polythene bags at-20°C, where they have been stable for at least one year. 

CH2=CH2 (ethene, ethylene) (CH2-CH2) Polyethylene, polythene, PE Squeeze bottles, food bags, dishes, insulation, coatings... 

About 75 years ago, the main material for cable sheathing was lead, protected from corrosion by asphalt-impregnated jute coating. Even then corrosion problems prevailed. Later on, extruded or drawn aluminum sheaths were in use, soon to compete with polythene. A large number of failures in the 1960s caused by water in the cable led to the development of sophisticated methods of sheathing involving coated aluminum and clad metals of copper adjacent to a number of steels (45). 

---