Polyvinyl acetate, PVAc

The determination of adsorption isotherms at liquid-solid interfaces involves a mass balance on the amount of polymer added to the dispersion, which requires the separation of the liquid phase from the particle phase. Centrifugation is often used for this separation, under the assumption that the adsorption-desorption equilibrium does not change during this process. Serum replacement (6) allows the separation of the liquid phase without assumptions as to the configuration of the adsorbed polymer molecules. This method has been used to determine the adsorption isotherms of anionic and nonionic emulsifiers on various types of latex particles (7,8). This paper describes the adsorption of fully and partially hydrolyzed PVA on different-size PS latex particles. PS latex was chosen over polyvinyl acetate (PVAc) latex because of its well-characterized surface PVAc latexes will be studied later. 

Vinyl chloride polymers and copolymers are often referred to as vinyl resins. PVC is the most important member of the vinyl resin family, which includes polyvinyl acetate (PVAC), polyvinyl alcohol (PVA), polyvinylidene chloride (PVdC) and polyvinyl acetal. Almost always the term PVC includes polymers of VCM as well as copolymers that are mostly VCM. 

Another attractive quality of the PVA is its outstanding chemical stability. Peter and Stefan ( ) investigated the chemical stability of PVA vis a vis a series of solvents and reagents and some of their results are summarized in Table I. This table presents a comparison between the chemical resistances of PVA, polyvinyl butyral(PVB), polyvinyl acetate(PVAc), and cellulose acetate(CA). It is evident from this table that the PVA is considerably more stable than the rest of the tested materials. 

Figure 17. Plot of log [ril vs. log M for a Branched Polyvinyl Acetate (PVAc) (Aldrich 18250-8 Lot 3).

Branching effects of polyvinyl acetate (PVAc) were... 

The effect of structural regularity on properties of polymers may be illustrated by the hydrolytic products of polyvinyl acetate (PVAc). PVAc is insoluble in water, but because of the presence of polar hydroxyl groups, partially hydrolyzed PVAc is soluble in water. 

Polyvinyl acetate (PVAc) loses acetic acid, and polybutyl methacrylate loses butene at high temperatures. Both PVC and polyvinylidene chloride (PVDC) lose chlorine as hydrogen chloride and other halogenated species when heated above 200 °C. 

Because of the presence of atactic acetyl groups, polyvinyl acetate (PVAc). whose repeating unit is as follows. 

Fig. 25. Guinier plot of the soft sphere model. The numbers denote the number of branching shells the filled and open circles are lightscattering results from polyvinyl acetate (PVAc) microgels in methanol at 20 °C at A0 = 546 nm and 436 nm, respectively. The dot-dash line corresponds to the Rayleigh-Gans behavior of hard spheres, i.e. no Mie scattering93)...

Polyvinyl acetate (PVAc) in the pure and solid form is colorless and transparent. It is somewhat brittle unless the degree of polymerization is low. Its softening temperature is between 40 and 90F (4 and 32C), depending on the molecular weight. It shows the phenomenon of cold flow. 

The newer type of colloidal catalysts have been prepared containing palladium (4), platinum (4), rhodium (5), and iridium (6). A variety of synthetic polymers has been applied. Among those tested were polyvinyl alcohol (PVA), polyvinyl acetate (PVAc), polymethyl methacrylate (PMMA), and polymethyl acrylate (PAMA). In general, polyvinyl alcohol (4a) has been found most satisfactory. 

Recently a spray-dried mixture of 8 parts of polyvinyl acetate (PVAc) and 2 parts of povidone K 30 can be found in the market. It is recommended as matrix for sustained-release tablets obtained by direct compression. In this product povidone has two functions to get a free-flowing polyvinyl acetate powder and to form pores in the tablets. 

Adimoll DO is a low-temperature-resistant plasticizer suitable for a large number of polymers, e.g. polyvinyl chloride (PVC), acrylonitrile-butadiene rubber (NBR), styrenebutadiene rubber (SBR) and polyvinyl acetate (PVAC). Commonly used in plastic wraps for food storage. 

In a later study, the ultrasonic degradation and copolymerization of partially hydrolyzed PAM and polyvinyl acetate (PVAc) in ethanol/water (55/45) was studied [32]. The degradation rate of PVAc follows Ovenall s equation approximately. Sonication of 0.50% aqueous mixture of PVAc and partially hydrolyzed PAM (1 1 by weight) at 25 °C using an 18.2-kHz probe for 10 min gave a yield of copolymer which amounted to 4.3%. 

Another commercially available blocky copolymer is partially hydrolysed polyvinyl acetate (PVAc), which is commercially referred to as polyvinyl alcohol. The molecule contains short blocks of PVAc which form the anchor chains to the hydrophobic surface, leaving several loops and tails of PVA chains which are strongly hydrated to give an effective steric barrier ... 

Polv (Stvrene-Aervlle Estert fSAEt Polyvinyl Acetate (PVAC)... 

Polyvinyl acetate (PVAc) (as adhesive), as well as cellulose acetate (CA) compounds and sheets, cellulose nitrate pigment binders and polyvinyl butyral (PVB) sheets (used mainly for safety glass interlayers) are the other main users of a range of different... 

Details A liquid and a monomer that are used for the production of polyvinyl acetate (PVAc) polymers and copolymers (such as ethylene-vinyl acetate). 

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