Vinyl acetate , 413 Table

Functionality determination is useful for the elucidation of reaction mechanisms. The fact that Fn < 2 [vinyl acetate (Table 2.2)] means that termination by disproportionation is more important than coupling (Fn = 2). In most cases, the obtained results show the hydroxytelechelic character of the polymer, even if transfer reactions introduce functional groups different from those expected according to the initiation mechanism. 

In consequence, Pd-Au silica-supported catalysts promoted with KOAc were also studied. The results obtained showed that addition of Au to Pd catalysts significantly improves productivity [237,238,243], whilst also improving the intrinsic selectivity to vinyl acetate (Table 6.2) [237,244] ... 

Table 13. Ethylene-Vinyl Acetate Table 14. Styrenic Block Copolymers.

Thermoplastic based binders are by far the most widely used. These forms of binder usually contain a wax as a major component and a thermoplastic as the minor component. Additives are usually added for lubrication, viscosity control, wetting and improving powder-binder interaction. Debinding of such binders is normally achieved via thermal degradation, wicking, solvent extraction or even photo-degradation. Thermoplastics commonly used include polyethylene, polystyrene, polypropylene and ethylene vinyl acetate. Table 2 highlights some of the common thermoplastics used in PIM or MIM processes. 

Note that this inquiry into copolymer propagation rates also increases our understanding of the differences in free-radical homopolymerization rates. It will be recalled that in Sec. 6.1 a discussion of this aspect of homopolymerization was deferred until copolymerization was introduced. The trends under consideration enable us to make some sense out of the rate constants for propagation in free-radical homopolymerization as well. For example, in Table 6.4 we see that kp values at 60°C for vinyl acetate and styrene are 2300 and 165 liter mol sec respectively. The relative magnitude of these constants can be understod in terms of the sequence above. 

Tables 7 and 8 give properties of some diaHyl esters. DimethaHyl phthalate [5085-00-7] has been copolymerized with vinyl acetate and benzoyl peroxide, and reactivity ratios have been reported (75).

In studies of the polymerization kinetics of triaUyl citrate [6299-73-6] the cyclization constant was found to be intermediate between that of diaUyl succinate and DAP (86). Copolymerization reactivity ratios with vinyl monomers have been reported (87). At 60°C with benzoyl peroxide as initiator, triaUyl citrate retards polymerization of styrene, acrylonitrile, vinyl choloride, and vinyl acetate. Properties of polyfunctional aUyl esters are given in Table 7 some of these esters have sharp odors and cause skin irritation. 

Vinyl acetate is a colorless, flammable Hquid having an initially pleasant odor which quickly becomes sharp and irritating. Table 1 Hsts the physical properties of the monomer. Information on properties, safety, and handling of vinyl acetate has been pubUshed (5—9). The vapor pressure, heat of vaporization, vapor heat capacity, Hquid heat capacity, Hquid density, vapor viscosity, Hquid viscosity, surface tension, vapor thermal conductivity, and Hquid thermal conductivity profile over temperature ranges have also been pubHshed (10). Table 2 (11) Hsts the solubiHty information for vinyl acetate. Unlike monomers such as styrene, vinyl acetate has a significant level of solubiHty in water which contributes to unique polymerization behavior. Vinyl acetate forms azeotropic mixtures (Table 3) (12). 

Table 4. Copolymerization Parameters of Vinyl Acetate (M ) and Comonomers (M2)...

Table 6. Typical Manufacturers Specifications for Vinyl Acetate...

Table 7. Physical Constants for Poly(vinyl acetate)...

Growth in PVAc consumption is illustrated in Eigure 3. The emulsions continue to dominate the adhesives and paint markets. It also shows the distribution of PVAc and copolymer usage by market. The companies Hsted in Table 10 are among the principal suppHers of poly(vinyl acetate)s and vinyl acetate copolymers, but there are numerous other suppHers. Many other companies produce these polymers and consume them internally in the formulation of products. 

Table 11. Poly(vinyl acetate) Emulsion Specifications...

Table 4. Thermal Decomposition Products of Vinyl Alcohol—Vinyl Acetate Copolymers, %...

Poly(Vinylpyrrolidinone-CO Vinyl Acetate). The first commercially successful class of VP copolymers, poly(vinylpyrroHdinone-co-vinyl acetate) is currently manufactured in sizeable quantities by both ISP and BASF. A wide variety of compositions and molecular weights are available as powders or as solutions in ethanol, isopropanol, or water (if soluble). Properties of some examples of this class of copolymers are Hsted in Table 15. 

Vinyl neodecanoate [26544-09-2] is prepared by the reaction of neodecanoic acid and acetjiene in the presence of a catalyst such as zinc neodecanoate. Physical properties of the commercially available material, VeoVa 10 from Shell, are given in Table 4. The material is a mobile Hquid with a typical mild ester odor used in a number of areas, primarily in coatings, but also in constmction, adhesives, cosmetics, and a number of misceUaneous areas. Copolymerization of vinyl neodecanoate with vinyl acetate gives coating materials with exceUent performance on alkaline substrates and in exterior weathering conditions. 

Some comparative data for a VLDPE copolymer based on ethylene and oct-1-ene and an EVA material (91% ethylene, 9% vinyl acetate) are given in Table 10.7. 

Table I4.P shows the influence of these variables on some properties. The residual hydroxyl content is expressed in terms of poly(vinyl alcohol) content and residual acetate in terms of poly(vinyl acetate) content.

Table 2. Some Examples of SN2 Reactions of Vinyloxiranes and Vinyl Acetals 1...

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