Polyvinyl acetate functional groups

The combined results of kinetic studies on condensation polymerization reactions and on the degradation of various polymers by reactions which bring about chain scission demonstrate quite clearly that the chemical reactivity of a functional group does not ordinarily depend on the size of the molecule to which it is attached. Exceptions occur only when the chain is so short as to allow the specific effect of one end group on the reactivity of the other to be appreciable. Evidence from a third type of polymer reaction, namely, that in which the lateral substituents of the polymer chain undergo reaction without alteration in the degree of polymerization, also support this conclusion. The velocity of saponification of polyvinyl acetate, for example, is very nearly the same as that for ethyl acetate under the same conditions. ... 

The assumption of forces of interaction between solvent and solute led to the century old principle that like dissolves like . In many cases the presence of similar functional groups in the molecules suffices. This rule of thumb has only limited validity since there are many examples of solutions of chemically dissimilar compounds. For example, for small molecules methanol and benzene, water and N,N-dimethylformamide, aniline and diethyl ether, and for macromolecules, polystyrene and chloroform, are completely miscible at room temperature. On the other hand, insolubility can occur in spite of similarity of the two partners. Thus, polyvinylal-cohol does not dissolve in ethanol, acetyl cellulose is insoluble in ethyl acetate, and polyacrylonitrile in acrylonitrile [12], Between these two extremes there is a whole range of possibilities where the two materials dissolve each other to a limited extent. 

The pyrazolone can be incorporated directly in the polymer by utilizing a polymer-forming derivative such as a 1 -(amino or hydroxy -phenyl)pyrazolone in a phenol (or aniline)-formaldehyde polymerization. Alternatively, the pyrazolone nucleus can be combined with a synthetic or natural polymer by reaction of a functional group in the pyrazolone with the polymer. Thus, a 1-formylphenyl type is used to form a polyvinyl acetal. A compilation of such reactions is given in Part 1, Chapter II, Section 14, pp. 108-110. 

Polyvinyl alcohol (PVA) was first prepared by Hermann and Haehnel [12] in 1924 by hydrolyzing polyvinyl acetate in ethanol with potassium hydroxide. PVA is produced commercially from polyvinyl acetate, usually by a continuous process. The acetate groups are hydrolyzed by ester interchange with methanol in the presence of anhydrous sodium methylate or aqueous sodium hydroxide. The physical characteristics and specific functional uses depend on the degree of polymerization and the... 

Here advantage is taken of modification by swelling and adsorption of chemically reactive modifiers and catalysts into the polymer to generate different functional groups. It has been shown that the pendant hydroxyl groups of polyvinyl alcohol (PVA) and poly-2-hydroxy propyl methacrylate can partially be reacted with acetic or benzoic anhydride or phenyl isocyanate to form new structures [44], to form side groups with ester linkages. As a result a copolymer of is produced ... 

In this section, we discuss the identification process and the chemical structures of polymers as obtained from their infrared and Raman spectra. Many polymers have common features, and it is convenient to segregate polymers into groups, such that the characterization of the polymers in a group can be discussed together. A popular method for classifying polymers is by their modes of application. For instance, some polymers, such as polyvinyl acetate, polystyrene, and nylons, are classified as thermoplastics, while urea, melamine, and epoxide resins are classified as thermosets or thermosetting resins. In this chapter we will use a different approach to classify the polymers, based on their similarity of chemical structure. This enables us to utilize the correlation between the functional groups of polymers and their characteristic infrared and Raman frequencies. 

Relatively little work has been dcnie with anion exchange membranes prepared by casting a polymer already containing functional groups (approach c ). Also in this approach polystyrene and polyethylene polymers are usually used however other less common backbones such as polyvinyl acetate and chitosan have also been used to prepare anion exchange membranes [9-11]. 

Polyvinyl acetate emulsions can be further modified by the incorporation of functional groups. These groups permit the design of polymers which have the ability to bond a wider spectrum of surfaces, including difficult-to-bond substrates. The addition of functional groups also permits crosslinkability of the polymer in order to achieve a high degree of water, solvent, or heat resistance. 

Work by Lee et aV used N-(benzylpolyvinyl)-N -methyl-4,4 -bipyridinium (PVBV ) with 41% of the benzyl groups having viologen functions, and polyvinyl-N-acetate-JV -methyl-4,4 -bipyridinium (PVAV " ) with 40% of the acetate groups having viologen functions. 

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