Synthesis, characterization and testing of emulsion. The emulsion in the first formulation had pva as protective colloid and protein b was added during polymerization. The emulsion polymerization of each of vinyl acetate and. Ewart equation is not applicable to the emulsion polymerization of vinyl acetate. Emulsion polymerization of vinyl acetate mohamed s. Improving the water sensitivity of polyvinyl acetate pvac films as well as pressure sensitivity, adhesion and washability of polybutyl acrylate were achieved by using bis 2ethylhexyl maleate behm.
Fast and exothermic discontinuous emulsion polymerization processes are particularly difficult to optimize from both safety and productivity point of view because of the occurrence of side undesired reactions e. Pdf in this study, the emulsion homopolymerization system containing vinyl acetate, potassium persulfate, a new cationic polymeric surfactant and. A kinetic study of the emulsion polymerization of vinyl acetate. This is considered to be due to two factors, namely, 1 the great solubility in water of vinyl acetate and 2 the fact that vinyl acetate is easily subject to the influences of retarders or chain transfer agents. The emulsion polymerization of vinyl acetate possesses the rather typical properties in comparison the emulsion polymerizations of the comonomers. Sandler and wolf karo, polymerization of vinyl acetate and other vinyl esters, polymer synthesis, 10. In this study, the influence of eight emulsion polymerization variables on the final psa properties of butyl acrylate vinyl acetate bavac emulsion based psas was investigated i. Celanese emulsion polymers is a global leader in vinyl acetateethylene vae emulsions.
Emulsion polymerization, latex, polymerization temperature, vinyl acetate butyl acrylate copolymer, i. The surfactantfree emulsion polymerization of vinyl acetate vac was achieved using raftmadixmediated polymerization induced selfassembly pisa process in water. In this study, the influence of eight emulsion polymerization variables on the final psa properties of butyl acrylatevinyl acetate bavac emulsionbased psas was investigated i. This colorless liquid is the precursor to polyvinyl acetate, an important industrial polymer. The industrial importance of vinyl acetate latexes makes the mechanism and kinetics of their emulsion polymerization of practical as well as scientific interest. Us2667473a vinyl acetatenvinylpyrrolidone copolymers. Emulsion polymerization of vinyl acetate springerlink. Emulsion polymerization of vinyl acetate in the presence of a. Particle size and molecular weight distributions author. Vam is a key ingredient in emulsion polymers, resins, and intermediates used in paints, adhesives, coatings, textiles, wire and cable polyethylene compounds, laminated safety glass, packaging.
Emulsion polymerization of vinyl acetate semicontinuous emulsion polymerizations of vac with polymeric surfactant were carried out in a 250 ml five neck glass reactor equipped with a condenser, a thermo meter, two dropping funnels, and a mechanical stirrer having a constant speed of 400 rpm and a reflux con. Apr 12, 2012 here, a novel watersoluble n,ndialkyl dithiocarbamate raft agent has been prepared and employed in the emulsion polymerization of vinyl acetate. Process these products are produced by emulsion polymerization using proprietary materials and processes. Celanese is a global leader in polyvinyl acetate homopolymer emulsions, often called pvac or occasionally pva homopolymers.
Raftmediated emulsion polymerization of vinyl acetate. Vinyl acetate emulsion polymerization and copolymerization with acrylic monomers provides a collection and logical organization of the published data much of it formerly found fragmented throughout various journals and little of it referenced in general emulsion polymerization books. May 15, 2014 the surfactantfree emulsion polymerization of vinyl acetate vac was achieved using raftmadixmediated polymerization induced selfassembly pisa process in water. First, welldefined hydrophilic macromolecular raft agents macroraft bearing a xanthate chain end were synthesized by raftmadix polymerization of nvinylpyrrolidone nvp and nacryloylmorpholine nam or by. First, welldefined hydrophilic macromolecular raft agents macroraft bearing a xanthate chain end were synthesized by raftmadix polymerization of nvinylpyrrolidone nvp and nacryloylmorpholine nam or by postmodification. The versatility of the emulsion copolymerization reaction and the ability to control the properties of the final latices have led to rapid expansion both in the quantity of polyvinylacetate and vinyl acetate acrylic copolymer latices and in their applications. H yildirim erbil, experimental determination of latex properties, vinyl acetate emulsion polymerization and copolymerization with acrylic monomers, 10. The emulsion with starch as protective colloid exhibited the largest particle size. The reported independence of the rate of polymerization from the monomer concentration in the emulsion polymerization of vinyl acetate has been investigated. The emulsion polymerization kinetics of vinyl acetate and butyl acrylate in presence of behm was studied. Effect of polyvinyl alcohol of different molecular weights as. Here, a batch emulsion polymerization system was studied and various particle stability aspects were investigated in an attempt to produce a stable latex with minimum coagulum content.
Ethylenevinyl acetate copolymers having a gel content of not more than 0. Emulsion polymerization is a complex process in which the radical addition polymerization proceeds in a heterogeneous system. Vinyl acetate emulsion polymerization odonnell 1958. Vinyl acetate polymers and vinyl acetate acrylic copolymers are used for a wide range of applications including paints, bond coats, binders, pigmented paper coatings, textiles, and nonwovens. Back to top product description4,6 vinyl acetate polymers and vinyl acetateacrylic copolymers are families of emulsion products manufactured by the dow chemical company. Emulsion polymerization is the complex process which radicals. Here, a novel watersoluble n,ndialkyl dithiocarbamate raft agent has been prepared and employed in the emulsion polymerization of vinyl acetate.
Due to the fact that the vinyl acetate is an esther, it presents the reactive properties of said group. Finally, a series of experiments on the emulsion polymerization of vinyl acetate has been carried out in an indirectly cooled semibatch reactor rc1, 1 l, mettler toledo to validate the model. Introduction bulk, solution, suspension and emulsion polymerization are the main polymerization processes which are used for manufacturing industrial polymers. The emulsion polymerization of vinyl acetate was investigated with the use of block copolymers of ethylene and propylene oxides commercially known as pluronic surfactants as emulsifying agents. The surfactantfree emulsion polymerization of vinyl acetate vac was achieved using raftmadixmediated polymerizationinduced selfassembly pisa process in water. Abstract an emulsion polymerization system with uniform continuous addition of vinyl acetate monomer, pluronic f68 surfactant, and persulfate initiator has. This process involves emulsification of the relatively hydrophobic monomer in water by an oilinwater emulsifier, followed by the initiation reaction with either a watersoluble or an oilsoluble free radical initiator. So in this present study the vinyl acetate is copolymerized with acryl amide monomer by. Rovace vinyl acetate polymers and vinyl acetate acrylic. Unlike styrene, vinyl acetate is easily affected by chain transfer agent or retarder in the process of emulsion polymerization. This is hardly surprising in view of the industrial importance of the polymer. The order of the polymerization reaction with respect to the behm in presence of each of.
The emulsion in the second formulation had hec as protective colloid. A kinetic study of the emulsion polymerization of vinyl acetate forskningscenter riso, roskilde publication date. Vinyl acetate is an organic compound with the formula ch 3 co 2 chch 2. Polyvinyl acetate is synthesized by the emulsion polymerization of vinyl acetate monomer vam. Vinyl acetate emulsion polymerization and copolymerization. Vinyl acetate monomer introduction quantum chemical corporation, usi division, is one of the largest manufacturers of vinyl acetate monomer vam in the united states. Because of its good adhesion to a number of substrates, and to some extent because of. Emulsion polymerization of vinyl acetate okamura 1962. To ensure good product properties and to optimize conversion and production rates, the polymerization reaction is carried out at 20002600 bar tubular 12002000 bar autoclave operating pressure and at 180280 c operating temperature. An example of such a process is the manufacture of polyvinyl alcohol by polymerization of vinyl acetate in the presence of methanol initiated by azobisisobutyronitrile aibn, followed by alkaline hydrolysis of the polyvinyl ester.
In agreement with the smith and ewart scheme for emulsion polymerizations, the polymerization rate was found to be independent of the total monomer amount present and. Pvac emulsions are best known for their use in wood glues or school glues due to their strong adhesion properties. Effect of polyvinyl alcohol of different molecular weights. Understanding vinyl acetate polymerization accidents. Poly vinyl acetate is to be hydrolyzed into polyvinyl alcohol for rendering it higher water soluble. The impact of gf31 on polyvinyl acetate pvac dispersion physicochemical and production parameters were determined.
There are many different types of emulsion polymerizations depending on. Effects of agitation in emulsion polymerization of vinyl acetate, ethylene, and nmethylol acrylamide initiator policies for batch emulsion polymerization of vinyl acetate a twoday symposium on emulsion polymerization of vinyl acetate, april 1011, 1980. The worldwide production capacity of vinyl acetate was estimated at 6,969,000 tonnesyear in 2007, with most capacity concentrated in the united states 1,585,000 all in texas. Persulfate metabisulfite initiated vinyl acetate vinyl. Xtxrwkrvritetpuhfffaoysan vinyl acetate chemical compound vinyl acetate vinyl acetatenvinylpyrrolidone copolymers us2667473a en. The kinetic results reveal that the polymerization nucleation mechanism changes from homogeneous to micellar and raftgenerated radicals can change the kinetic behavior from conventional emulsion. We manufacture these highperformance emulsions in all three major regions of the world at our facilities throughout north america, europe and asia. Process for the production of ethylenevinyl acetate. Effect of polyvinyl alcohol of different molecular weights as protective colloids on the kinetics of the emulsion polymerization of vinyl acetate k. So in this present study the vinyl acetate is copolymerized with acryl amide monomer by emulsion polymerization, to make. Emulsion polymerization of vinyl acetate wiley online library. Emulsion polymerization is one of the most widely used polymerization techniques in industry, and emulsion polymers are utilized in various fields, including coatings, paints, inks, adhesives, and rubbers. Towards a consistent mechanism of emulsion polymerizationnew.
Therefore, both experimental studies and reaction simulations were performed. Emulsion polymerization, kinetics, nucleation, viscosity, calculations an extensive literature exists on the subject of the emulsion polymerization of vinyl acetate. Vinyl acetate from ethylene, acetic acid and oxygen. Characterization of grafting in the emulsion polymerization. Emulsion polymerization of vinyl acetate in the presence. Emulsion polymerization of vinyl acetate semicontinuous emulsion polymerizations of vac with polymeric surfactant were carried out in a 250 ml five neck glass reactor equipped with a condenser, a thermo meter, two dropping funnels, and a mechanical stirrer having a. Vinyl acetate has high water solubility, a high monomerpolymer swelling rati o, and a high chain tr ansfer constant. Synthesis of vinyl acetatecobutyl acrylate latexes. Dec 03, 2007 considering styrene emulsion polymerization 50 c with the propagation rate constant k p 237 l mol. Pdf emulsion polymerization of vinyl acetate in the presence of a. Emulsion polymerization of vinyl acetate with renewable raw materials as protective colloids hanna lange 8 2. Kinetics of vinyl acetate emulsion polymerization in a. For the emulsion polymerization process, the vinyl acetate certified acs grade, aldrich was distilled at atmospheric pressure at 72c using a raschig. The main objective of this work is to study the kinetics of vinyl acetate va emulsion polymerization reactions performed in this pspc.
Vinyl acetate has high water solubility, a high monomerpolymer swelling ratio, and a high chain transfer constant. More recently, emulsion polymers have been used as fine materials in chromatography, electron microscopy, drug delivery, and bio. Increasing pvac emulsion polymerization productivityan. Emulsion polymerization of vinyl acetate with renewable.
This booklet describes applica tions, specifications and properties for vinyl acetate monomer. Vinyl acetate emulsions stanchem polymers emulsion. A kinetic study of the emulsion polymerization of vinyl. Kinetics of vinyl acetate emulsion polymerization in a pulsed. Emulsion polymerization of vinyl acetate pdf free download. Persulfate initiated vinyl acetate vinyl versatate copolymer latex d. Semicontinuous vinyl acetate vac radical emulsion polymerization in water with 3methacryloxypropyltrimethoxysilane gf31 comonomer was performed using protective colloid pva and surfaceactive compound. To both of these emulsions, protein a was added after polymerization, as a filler, combined with crosslinking agent b as crosslinking agent before hot pressing. Emulsion polymerization of vinyl acetate in the presence of. Effects of polymerization variables on the prop erties of vinyl acetate ba sed emulsion polymers 37 rubber company, was the first to be granted a patent to produce a synthetic rubber in the presence of soap as emulsifying agent 4. Proprietary process technology eva ethylene vinylacetate. Emulsion polymerization of vinyl acetate with renewable raw. More importantly, our employees are experts in polymerization, process technology, manufacturing and. Vinyl acetate emulsion polymerization and copolymerization with acrylic monomers provides.
Introduction free radical emulsion polymerizations are very popular reactions used to manifacture a great variety of. Batch emulsion copolymerization of vinyl acetate and 2ethyl hexyl acrylate vac2eha 90. Our houston, texas, facility is the worlds largest single vam manufacturing plant. Pdf characterization of polyvinyl alcohol during the. Emulsion polymerization, latex, polymerization temperature, vinyl acetatebutyl acrylate copolymer, i. Thus more than 45 years after the first commercial production of vinyl acetate latexes, their use is still growing, both in actual quantities and different applications. This is the case for vinyl acetate recovered from polymerization processes where the conversion ratio is not 100%. Poly vinyl acetate latexes were the first synthetic polymer latexes to be made.
898 524 902 553 1558 1383 1007 619 778 77 1333 72 1050 1365 1248 486 1306 521 417 1148 1292 1345 301 1149 774 1438 1280 560 138 637 1336 140 1241 1483 477 1191