PVC latex

Electroultrafiltration (EUF) combines forced-flow electrophoresis (see Electroseparations,electrophoresis) with ultrafiltration to control or eliminate the gel-polarization layer (45—47). Suspended colloidal particles have electrophoretic mobilities measured by a zeta potential (see Colloids Elotation). Most naturally occurring suspensoids (eg, clay, PVC latex, and biological systems), emulsions, and protein solutes are negatively charged. Placing an electric field across an ultrafiltration membrane faciUtates transport of retained species away from the membrane surface. Thus, the retention of partially rejected solutes can be dramatically improved (see Electrodialysis). 

Blends with PVC. Nitrile mbber may be blended with poly(vinyl chloride) (PVC) by the polymer producer by two different techniques (1) blending of NBR latex with PVC latex followed by co-coagulation and drying, or (2) physically mixing the soHd NBR and PVC powder in mixing equipment such as an internal mixer. NBR—PVC polymer blends are well known for the good ozone resistance that is imparted by the PVC. 

Liegeois (71), using 400.0 ml of water, 280.0 gr of VCM, 280.0 mgr of potassium persulphate initiator and 2.5 gr of sodium lauryl sulphate emulsifier at 50°C, measured by electron microscopy PVC latex particle diameters close to 190 A for a conversion level of 24%. The model predicted an average particle diameter equal to 200 A for the same conversion level and for the same experimental conditions. 

In this test, one VAE, the acrylic, and the plasticized PVC latexes failed with all of the retardants. 

Chemical Type Viton Butyl Rubber PVA Neoprene Nitrile PVC Latex... 

The first work was carried out by radiochemical polymerization of a mixture of dienic and acrylic monomers on a PVC latex. A parallel study by chemical means leads to equivalent products and the development of a reinforcing resin which satisfied the requirements listed above. At present a resin of this type is manufactured and sold by Pechiney-Saint Gobain under the name Lucovyl H 4010 (10). 

Lucovyl H 4010 is a copolymer obtained by chemical polymerization of a mixture of (principally) butadiene and acrylonitrile on a PVC latex. The mean particle diameter of the resin obtained is very small (less than 0.1 pm). Its refractive index is close to that of PVC, and its compatibility with PVC is excellent. This polymer disperses well in the PVC matrix to give a two-phase system as shown on the electron micrograph in Fig-... 

During this work we have studied the structure of products obtained from the polymerization of a mixture of butadiene and an acrylic monomer on a PVC latex. More particularly we have studied polymers by fractionation in solution and we describe this here for the specific case of systems of PVC-butadiene acrylonitrile. 

Preparation of Samples. PVC Latex. Polymerization was performed using chemical initiation (persulfate-metabisulfite) and radiochemical initiation (y-irradiation from 60Co mean dose rate 10,000 rads/hour). Emulsifier was potassium stearate. 

Particle size distribution of a seeded PVC latex (bimodal distribution)... 

Figure 3. Fractogram of PVC latex with superimposed particle diameter scale. Field = 82.6 g, flow = 226 ml/hr, V° = 2.0 ml, sample = 40 pi of 6% PVC. Reproduced with permission from Ref. 20. Copyright 1980 John Wiley.

Experiment A—Initial Seed Latexes for Growth Experiments. Four different PVC latexes were prepared for use as seeds in growth experiments according the well-known batch procedure. The properties of these seeds are given in Table I. 

PVC latex particles consisting of two size populations can be generated in a miniemulsion polymerization. The mechanism for the formation of two discrete particle families relies upon polymerization of two distinct kinds of droplets [74]. 

FIGURE 12.16 Shear thickening found by Hoffman [47] for 1.25 pm diameter polyvinyl chloride (PVC) latex particles in di-2-ethylhexyl phtiialate with the discontinuous dependence of viscosity on shear rate. Redrawn fi m Hofhnan [49]. 

The adsorption isoterms of SDS on polyvinyl chloride (PVC) latex particles in the presence of various concentrations of sodium ions in the bulk solution, have been determined by Bibeau and Matijevic (2 ). In the latices which were examined by us, the surface concentration of emulsifier was confined to the region well below the saturation level. Under these circumstances only a negligible fraction of the total amount of emulsifier will be dissolved in the aqueous phase. 

Bibeau and Matijevic studied the stability of a PVC latex by addition of electrolytes. They also found surface ion concentrations derived by electrophoresis to be poor indicators of latex stability. Their stability results were found to compare favorably with DLVO theory predictions, using the actual surface concentration of potential-determining species as the basis for interpretation. That means taking into account both fixed charges and adsorbed emulsifier. 

Rutile titanium dioxide (special grade for high PVC latex paints) 300.00 81.0... 

If the feed is preconditioned properly, the UF flux is often quite stable. One thousand hours of continuous operation between cleanings is common. When flux decay does occur, detergent washing is usually sufficient to restore flux. In some cases, polymer solvents may be required. Proper selection of a solvent resistant membrane and/or solvents which will dissolve the latex but not affect the membrane is crucial. For PVC latex, the solvents of choice are methyl isobutyl ketone (MIBK) and methyl ethyl ketone (MEK). Styrene butadiene rubber will swell in MIBK, MEK or toluene. Polyvinyl acetate will dissolve in the low MW alcohols such as propyl alcohol. Generally, the membranes are first washed with water, then detergent, followed by another water flush. The system is then drained of all water since it will affect polymer solubility in MEK. Finally, a solvent rinse is employed. If the module is tubular, sponge balls will enhance cleaning. 

Neo Acids. Neo acids are actually not made by the 0x0 process but are products of Koch carbonylation. They are frequently included with the family of 0x0 chemicals because their end use products serve similar markets. For instance, pivaloyl chloride made from neo pentanoic acid is used as a precursor for several herbicides, pesticides, and pharmaceutical products. Neodecanoic acids are used as drying agents for paint and as a heat stabilizer for PVC. Latex paint additives are made from vinyl and glycidyl esters which are derived from neodecanoic acid. 

Starch utilization in plastic and rubber compositions began in the 60s and 70s, with oxidised starch in rubber and other polymers, such as urethane foams, poly(vinyl alcohol) and copolymers of poly(ethylene-co-acrylic acid) formulations, and as a filler in plasticized polyvinyl chloride (PVC) [37,39]. In another technique, gelatinized starch was mixed with PVC latex and the water was removed to give a PVC-starch composition, which was mixed with a PVC plasticizer such as dioctyl phthalate (DOP). 

The mixed sur ctant systems have found rather extensive use for industrial production of PVC latexes. A major advantage of the method is that a separate homogenization stq) is avoided. The relatively large size and the broad size distribution of the spontaneously formed monomer droplets are maintained in the final latex. Disadvantages of the process are the requirements made with respect to the structure of the fatty alcohol and ionic surfactant, and to the absolute amounts and the ratio between the two components. Also, the method only permits a limited variation of the size and size distribution of the final latex. 

Processing of PVC in the form of latex used to be commonplace in paper and textile industries. Now, water-based emulsion polymerizates are used the most frequently in water-based inks, lacquers, and adhesives. Past literature" covers information on formulation and compounding PVC latexes. 

Uses Primary or sec. emulsifier for emulsion polymerizafion, SBR, PVC latex stabilizer food pkg. adhesives defoamer in food-contact coatings defoamer in food-contact paper coatings food-contact paper/paperboard Regulatory FDA 21CFR 175.105,176.170,176.180,176.200 SARA... 

Chem. Descrip. Sodium lauryl sulfate CAS 151-21-3 EINECS/ELINCS 205-788-1 Uses Emulsifier for emulsion polymerization, emulsion and suspension PVC, latexes solubilizer foaming agent dispersant food pkg. adhesives, paper defoamer in food-contact paper/paperboard emulsifier in food-contact articles in resinous/polymeric food-contact coatings Features For use alone or with other surfactants exc. mech. stability... 

BIscumylphenyl trimellitate piastidzer, PVC film Dl (Cl-9 alkyl) adipate Palatinol AH Santicizer 97 Uniplex 125-A piastidzer, PVC food wraps Uniflex DBS pbstidzer, PVC latex Reofos 1884 piastidzer, PVC plastisols Benzoflex 2088 Butyl benzyl plthalalb, Di (Cl-9 alkyl) adipab, Phosflai 362 Phosilex 390 Sanlicizef 97 piastidzer, PVC resins 2-Etltyihexanoi piastidzer, PVC sealers Epimer 100... 

Emulsion small drops 0.5-10 pm of insoluble monomer suspended in water with water-soluble catalysts in micelles industrial polymers, synthetic rubbers, polybu-tadience, PVC, latex paints, adhesives, coatings, ABS, PV acetate, styrene butadiene batch STR 2-3 kW/m mixing 155-230 rpm shear number 9000-12 000 impeller diam./tank diam. = 0.25-0.3, 17 = 110 W/m K heat transfer area = 3.3 m /m. ... 

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