Polymers residue

MgCl2 obtained from magnesium alkyl haUdes (-P) = organic polymer residue present in MgCl2. 

Applications As the basic process of electron transfer at an electrode is a fundamental electrochemical principle, polarography can widely be applied. Polarography can be used to determine electroreductible substances such as monomers, organic peroxides, accelerators and antioxidants in solvent extracts of polymers. Residual amounts of monomers remain in manufactured batches of (co)polymers. For food-packaging applications, it is necessary to ensure that the content of such monomers is below regulated level. Polarography has been used for a variety of monomers (styrene, a-methylstyrene, acrylic acid, acrylamide, acrylonitrile, methylmethacrylate) in... 

This example (Kosanovich et al., 1995) builds on the previous example and illustrates how multivariate statistical techniques can be used in a variety of ways to understand and compare process behavior. The charge to the reactor is an aqueous solution that is first boiled in an evaporator until the water content is reduced to approximately 20% by weight. The evaporator s contents are then discharged into a reactor in which 10 to 20 pounds of polymer residue can be present from the processing of the previous batch. 

A liner containing glass wool was installed in the injection port of the GC to trap polymer residues. A solution containing a known amount of the carbamate in THF along with sulfolane as an internal standard was used to establish the concentration of carbamates in the PMMA and PPMA matrix. Quantum yields were then determined. Product ratios were calculated from UV difference spectra (taken on a Beckman DK-2A spectrometer) of films before and after photolysis. 

A jacketed polymerisation vessel had become coated internally by a build up of polymer residues, and the vessel was being cleaned by treatment with aqueous hydrogen peroxide. To 5000 1 of water in the vessel was added 150 kg of 27 wt% peroxide solution, and the vessel was heated by application of 10 bar steam (180°C) to the jacket. After a few minutes an explosion occurred, attributed to spontaneous ignition of a mixture of oxygen from the decomposing peroxide and monomer vapours produced by depolymerisation of the residue on the heated walls of the vessel. 

When the concentration (or, effective concentration in the case of polymer residues) is high, the formation of side products due to a second addition are observed ... 

The gray-scale has been inverted in Fig. 1 Id for clarity, i.e. pores completely filled with electrolyte are now dark. The PMMA web clearly stands out in Fig. lid. The pores in the upper row are well shaped, and they are completely filled by electrolyte. In contrast, the pores in the bottom row are well shaped as well but hold inclusions. The distinct gray-shades of the inclusions point to different chemical nature of the inclusions. In the original fully-colored image the inclusions exhibit totally different colors, which permit the assignment of the inclusions in the bottom left pore to an air lock, whereas the inclusion in the pore to the right is a polymer residue. It should be emphasized that the size of this polymer inclusion is too small to be laterally resolved in the FTIR image. 

It is important to note that not all dyestuffs behave the same when used in different applications or different polymers. Similarly, the hue of the dyestuff may change when the dyestuff is used in different plastics due to its solubility in that resin as well as factors created by the inherent color of the polymer. Residual volatile components in the polymer as well as catalysts and other additives have a distinct effect on the property of the dyestuff. Trace contaminants in the dyestuff can also have a profound effect on the dyestuff performance in different resins. 

Synthesis. Synthesis of the copolymers was performed by a hydrosilylation reaction of poly(dimethylsiloxane-co-methylhydrosiloxane) (Petrarch System, Inc.) and a-olefins of various lengths (Aldrich). A round-bottomed flask equipped with a magnetic stirring bar, condenser, and calcium chloride tube was charged with a 50% solution of the reactants (up to 10% molar excess of a-olefin) in dry toluene. A solution of hydrogen hexachloroplatinate(IV) in diglyme-isopropyl alcohol (150 ppm Pt) was then added to the reaction mixture. The reaction mixture was stirred at 60 °C for 3 h. At the end of this period, the mixture was refluxed with activated charcoal for 1 h and filtered while hot. Finally the solvent and excess a-olefins were removed under reduced pressure (67 Pa at 100 °C). The reaction proceeded to completion as evidenced by the absence of the Si-H absorption at 2130 cm" in the IR spectra. Residual a-olefin in the purified polymers was determined by gas-liquid chromatography. In all polymers, residual a-olefin was less than 1.5 wt %. 

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