Polyvinyl chloride color compounding

Cd and its compounds find applications in several industrial materials electrode materials in Ni-Cd batteries (about 70% of total produced Cd), pigments in ceramics, glasses, paper, plastics, artists colors (13%), stabilizers for polyvinyl chloride and related polymers (7%), coatings on steel, aluminium, and other nonferrous metals (8%), and specialized alloys (see Alloys) and others (2%). 

In vinyl compound polymerization of vinyl acetate, alcohol, bromide, chloride, or carbonate, ascorbic acid can be a component of the polymerization mixture (733-749). Activators for the polymerization have been acriflavine (734), other photosensitive dye compounds (737,738), hydrogen peroxides (740,741,742), potassium peroxydisulfate (743), ferrous sulfate, and acyl sulfonyl peroxides (747). Nagabhooshanam and Santappa (748) reported on dye sensitized photopolymerization of vinyl monomers in the presence of ascorbic acid-sodium hydrogen orthophosphate complex. Another combination is vinyl chloride with cyclo-hexanesulfonyl acetyl peroxide with ascorbic acid, iron sulfate, and an alcohol (749). Use of low temperature conditions in emulsion polymerization, with ascorbic acid, is mentioned (750,751). Clarity of color is important and impact-resistant, clear, moldable polyvinyl chloride can be prepared with ascorbic acid as an acid catalyst (752) in the formulation. 

CdS is used in the semiconductor industry (Bruce and O Hare 1996), and also extensively as a pigment. The available pigment colors are mostly yellow, orange, red to Bordeaux red as (Hg,Cd)S and Cd(S,Se), and are used in polystyrene, polyethene, polypro-pene, and polycarbonate. The pigments belong to the most brilliant inorganic compounds and are prepared from either Cd metal or metal salts they are insoluble in water (Bucher et al. 1984). Other important uses of Cd include plating (Cd-coated steel), batteries, and in polyvinyl chloride (as a stabilizer, especially in outdoor window frames). 

Polyvinyl chloride (pol-ee-VYE-nul KLOR-ide) is also known as PVC, vinyl, chlorethylene homopolymer, and chlor-ethene homopolymer. It is the third most commonly produced plastic in the United States, exceeded only hy polyethylene and polypropylene. It is offered commercially in a variety of formulations, usually as a white powder or colorless granules. The compound is resistant to moisture, weathering, most acids, fats and oils, many organic solvents, and attack by fungi. It is easily colored and manufactured in a variety of forms, including sheets, films, fibers, and foam. 

Sodium aluminum silicate has been found to be an effective extender of colorants, replacing up to 10 percent of Ti02 in a variety of compounds. The grades with higher structure also produce higher levels of reinforcement. In a polyvinyl chloride plastisol, for example, replacing 10 percent Ti02 increases tensile properties by about 25 percent. 

The process starts with the preparation of polymer solutions, for instance, polyvinyl alcohol (PVA), and metal compounds, for instance, 3d-metal chlorides. Afterwards, the solutions with a certain concentration are mixed in the ratio PVA-metal chloride equals to 20 1-1 5 (better 5 1). Then the prepared solutions are dried till they obtain gel-like colored films with further temperature elevation up to 100°C. The films obtained are controlled by spectral photometry, and also with help of transmission optical microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. When the film color changes to black, the films are heated in the furnace according to the following program 100-200-300-400°C. As a result, the dark porous semiproduct with many microcracks is formed, that is milled in spherical or jet mill. The nanopowder obtained is steamed and dispersed in hot water. After filtration, the powder is dried and tested with the help of Raman spectroscopy. X-ray photoelectron spectroscopy, transmission electron microscopy and electron microdiffraction. 

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