Techniques latex-based

Rogach AL, Kotov NA, Koktysh DS, Ostrander W, Ragoisha GA (2000) Electrophoretic deposition of latex-based 3D colloidal photonic crystals A technique for rapid production of high-quality opals. Chem Mater 12 2721-2726... 

The finished dry rubber and latex based rubber products can be vulcanized by several techniques depending on the type of rubber compound (dry rubber compound/latex compound), size of the finished product, and its shape and structure. Moulded rubber products are vulcanized by press curing using compression, transfer, or injection moulding presses. The vulcanization techniques other than moulding may be grouped into batch and continuous methods. The batch methods include the use of autoclaves, hot air/gas oven, and hot liquid/ water bath. Rubber products may be vulcanized at room temperature by cold curing either by immersion of rubber products in a carbon disulphide solution of sulphur chloride (SjCy, or by exposure to its vapour. 

This paper reports on the synthesis, characterisation, and applications of novel flame retardant dibromostyrene-based latexes. They are copolymers of dibromostyrene with butadiene, alkyl acrylates and methacrylates, vinyl acetate, styrene and unsaturated carboxylic acids, which form a wide variety of flame retardant latexes via an emulsion polymerisation technique. Choice of monomer or monomer blend is based upon the final glass transition temperature of the copolymer desired. Other criteria include desired physical properties and chemical resistance. Dibromostyrene-based butadiene and acryUc latexes are shown to possess the desired physical properties for use in coatings, adhesives and sealants, and the bromine content of the latexes has enabled the material to pass six different flammability requirements for the end uses such as textile backcoating, latex-based paint, contact adhesive, latex sealant, nonwoven binder, and carpet backing. 18 refs. 

Sucrose acetate-isobutyrate may be emulsified readily with a surfactant mixture having an HLB value of 14, Table IV. The ester is heated to about 70°C and an inversion technique is used to produce an oil-in-water-type emulsion having excellent stability. As interest increases in water-based coatings as a means of reducing air pollution, it is significant that SAIB emulsions may be used in latex-based coatings ( ). 

Use of seed polymers introduces a new degree of flexibility into the kind of product that may be produced. Within wide limitations, the seed polymer can be a latex based on any monomer—not only one based on vinyl chloride. For example, the seed may be a hexyl acrylate-based polymer or copolymer that may confer internal, permanent plasticization to the vinyl chloride polymer ultimately associated with it. Furthermore, as in many of these processes, the monomer added to the seed may consist of a mixture of several monomers to yield a large variety of copolymers that have significantly different properties from copolymers prepared without the use of a seed (co)polymer. Whether the products of such procedures are graft copolymers, intertwined chains within the latex particle, mixtures of latex particles of different chemical composition, or combinations of these probably varies with each system. Investigation of the fine structure of such latex systems is difficult. Therefore the technique itself is widely used. The physical properties of the system are related to the operations involved in the preparation rather than with the overall composition and conformation of the polymer chains. 

This technique is based on the density change that occurs when monomer is converted to polymer. This difference, which is obviously a maximum in bulk polymerization, allows emulsion polymerizations of relatively high solids content to be accurately monitored [137]. The main disadvantage of on-line densimetry is that, as for latex GC, a sample of the reaction medium must be introduced in the thermo-stated measurement cell and the system is liable to suffer clogging. A further dis-... 

Changes in the percolation threshold and critical exponent for composites prepared via a latex-based route using different processing techniques have been observed. Composites prepared with both a latex of high-Tg [PS) and low-Tg [poly[methyl acrylate) [PMA)) polymer, and SWCNTs and MWCNTs were compared, and the results are presented in the following sections. 

SWCNT/PS composites prepared using three processing techniques are addressed. For one series, the latex-based route, described in Chapter 2, was strictly followed. For two other series of composites, alternative processing techniques were used [see Table 4.2), namely, film casting/compression moulding and spin coating. 

SWCNT/PMA composites were prepared using two processing techniques. For one series, the latex-based route was strictly followed. For the second series of composites, the two-component SWCNT - latex colloidal mixture was allowed to slowly dry at room temperature. The ability of the latex to flow once the aqueous phase is removed, allowed the formation of a homogenous film. Table 4.4 lists the preparation techniques utilized. 

The percolation threshold for MWCNT/PMA composites, prepared using the conventional latex-based technique (S2-FD/CM), was compared to latex-cast composites [S2-LC). The results of the conductivity measurements are given in Figure 4.13 (/) along with the linear fittings of the equation given in Table 4.1. The determined percolation thresholds, ultimate conductivities, and critical exponent values are summarized in Table 4.5. 

Each painter had his own technique the binding medium was thus prepared using different additives, giving rise to a variety of recipes for each technique. For example, it is believed that fig latex (a white liquid exuded by the fig tree) was commonly added to the egg tempera, and that animal or plant resins were added to oil- and wax-based binders. On account of their adhesive properties, these materials were used not only as paint binders, but also as consolidants in restorations, as ingredients in varnishes used to finish paintings, and as ingredients of mordants to apply metallic leaf decorations. 

At Desoto, in Greensboro, N.C., wash solvent from each solvent-based paint batch is separately collected and stored. When the same type of paint is going to be produced, waste solvent from the previous batch is used in place of virgin solvent, reducing the volume of the wastestreams which can contain metals as well as other paint wastes and solvent. In 1981, Desoto produced 25,000 gallons of waste mineral spirits. In 1982, when the system was implemented, waste solvent production amounted to 400 gallons. This same technique is currently being applied to their latex paint production operation (Kohl 1984). 

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