Polyvinyl acetate comonomers

Synonyms 2-Methyl-2-propene-1-sulfonic acid sodium salt Empiricai C4H7NaO S Formuia H2C=C(CH3)CH2S03Na Properties M.w. 158.15 m.p. > 300 C anionic Uses Dye improver reactive comonomer for acrylic fibers polymerization dyeable polyacrylonitrile/polyvinyl acetate comonomer reactive emulsifier or coemulsifier Manuf./Distrib. Aldrich http //www.sigma-aidrich.com, Monomer-Polymer Dajac Labs Trade Name Synonyms Geropon MLS/A [Rhodia HPCII http //www.rhodia-hpcii.com]... 

Vinyl Acetate, Homo- and Copolymer Latexes Vinyl Acetate Comonomer (butyl acrylate, ethylene, vinyl ester of versatic add) Partially Hydrolyzed Polyvinyl Alcohol Sodium Bicarbonate Hydrogen Peroxide (35%) Sodium Formaldehyde Sulfoxylate Water 70.0-100.0 0.0-30.0 6.0 0.3 0.7 0.5 80.0... 

Multifunctionality can be introduced not only through copolymerization but also by polymer analogous reactions in a postpolymerization modification step, often in combination with the introduction of additional comonomers during the polymerization process. Well-known technical examples are copolymers of polyvinyl alcohol and polyvinyl acetate with different amounts of vinyl acetate (see Section 3.1.3), which all derive from homopoly(vinyl acetate) and are the result of acetate hydrolysis to a different extent. The content of remaining vinyl acetate groups defines the hydrophilicity/hydrophobicity of the copolymer and thus the amphiphilic and stabilizing character of the material. 

Polyethylene (PE) is inherently less sensitive to oxidative attack than PP, but stabilization of PE is also mandatory for outdoor use. The stability varies with the type of polyethylene and manufacturing process. Linear low-density polyethylene (LLDPE) (1-octene comonomer) is significantly less sensitive to photooxidation than low-density polyethylene (LDPE) with comparable density and molecular weight [20, 21]. Generally, LDPE is less susceptible to photooxidation than high-density polyethylene (HDPE). The most fundamental difference between polyethylene homopolymers and polypropylene is the behavior of hydroperoxides toward photolysis. On photooxidation, hydroperoxides accumulate in PP, but decrease rapidly on UV exposure of PE. In copolymers of polyethylene with vinyl acetate, the stabihty depends on the content of vinyl acetate. The higher the content, the more the copolymers act like polyvinyl acetate, which is more susceptible to photooxidative degradation than polyethylene. 

It is the monomer for polyvinyl acetate, and a comonomer and intermediate for many members of the vinyl plastics family. 

Polyvinyl acetate (PVAc) emulsion polymers are used for adhesives, sealants, and paints. PVAc homopolymer is too brittle for most end uses, so much of fte PVAc used in the paint industry is internally plasticized through the incorporation of comonomers into the polymer backbone. However, there are some uses of externally plasticized PVAc in adhesives. The most common plasticizers used with adhesives are a variety of benzoate esters, although dibutyl terephthalate is now being promoted for this application. 

When a polyvinyl acetate emulsion is flexi-bilized internally with a comonomer, the plasticization is permanent and nonmigratory. This is because the comonomers are part of the main polymer chain, often with bulky side groups, increasing the freedom of rotation of the chain. The resulting softening and polymer mobility allows better adhesion to plastic surfaces. 

Fig. 1. Comonomer levels required to plasticize polyvinyl acetate.

The polyvinyl acetate emulsion is made by adding water to the reaction vessel together with emulsifiers, smfactants, or colloids as stabilizers. Vinyl acetate is added under shear and emulsified. An initiator or catalyst may be added together with the comonomer. 

As already mentioned, ethylene vinyl acetate copolymers can be synthesized in every ratio of the comonomers. The resulting polymers exhibit the complete scale of properties from thermoplastic material to elastomers. Polyethylene is a well-known thermoplastic with a very low glass transition temperature at about — 120°C and very high crystallinity of 40%-60%. Polyvinyl acetate is also a thermoplastic, but with a glass transition temperature of 28°C and completely amorphous stmcture. 

Studies of the dynamic vulcanization of polyolefins and NR have been reported in the literatures. Polyolefin NR blends prepared by this selective crosslinking could replace the vulcanized rubber in end products where high resilience and strength is not essential but low-temperature performance is required. They could also replace various flexible plastics such as plasticized polyvinyl chloride (PVC), ethylene vinyl acetate (EVA) and polypropylene comonomers. ... 

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