Vinyl butyrate, polymerization

Water-soluble polymers eomprise a major elass of polymerie materials and are used in a wide variety of applieations. Synthetie water-soluble polymers inelude poly(vinyl aleohol), poly(aerylamide), poly(aerylie aeid), poly(ethylene oxide), poly(vinyl pyrrolidone), eellulosies, and many eopolymers of these types. Their end uses are quite varied and their applieations depend mainly on their viseosify-ing, rheologieal, and surfaee-aetive properties (1). For example, poly (vinyl aleohol) is used in adhesives, fibers, textile and paper sizing, paekaging, as a stabilizer for emulsion polymerization, and as a preeursor for the manufaeture of poly(vinyl butyral), whieh is used in automotive windshields. Poly(vinyl aleohol) is also the world s largest volume, eommodity, water-soluble polymer. 

Vinyl coatings are used primarily on metal surfaces. They provide excellent protection by their strong cohesive forces, although their adhesion to the metal is not good. Used with a phosphoric acid-containing primer to etch the metal surface, this adhesion is markedly improved. The primer also contains poly(vinyl butyral) and is approximately 0.2-0.3 mil thick (1 mil = 1/1000th inch). Poly(vinyl butyral) is made from polymerized vinyl acetate by hydrolysis and reaction with butyraldehyde. 

The main applications for PVA are in textile sizing, adhesives, polymerization stabilizers, paper coating, poly(vinyl butyial), and PVA fibers. In terms of percentage, and omitting the production of PVA not isolated prior to conversion into poly(vinyl butyral), the principal applications are textile sizes, at 30% adhesives, including use as a protective colloid, at 25% fibers, at 15% paper sizes, at 15%, poly(vinyl butyral), at 10% and others, at 5%, which include water-soluble films, nonwoven fabric binders, thickeners, slow-release binders for fertilizer, photoprinting plates, sponges for cosmetic, and health care applications. 

The most common polymer of a vinyl ester is poly(vinyl acetate), CAS 9003-20-7, with the formula [-CH2CH(OC(0)CH3)-]n. Other vinyl esters also are known, such as poly(vinyl butyrate), poly(vinyl benzoate) CAS 24991-32-0, and poly(vinyltrifluoroacetate), CAS 25748-85-0. Poly(vinyl acetate) is typically obtained from the monomer with radical initiators, either by emulsion or suspension polymerization. The polymer Is used in water-based emulsion paints, adhesives [22], gum base for chewing gum, etc. Also, poly(vinyl acetate) is used as a precursor for the preparation of other polymers such as poly(vinyl alcohol) or poly(vinyl acetals). Thermal decomposition of poly(vinyl acetate) starts at a relatively low temperature, around 200° C, some of the reports regarding its thermal decomposition being given in Table 6.5.8 [13]. The same table includes references for poly(vinyl butyrate) and poly(vinyl cinnamate), CAS 9050-06-0. 

Once the above observations have been made, questions naturally arise concerning the infiuence of the aromatic nuclei of such initiators as benzoyl peroxide on the polymerization process. Indeed chain transfer between benzoyl peroxide and poly(vinyl acetate) fiee radicals has been observed [41]. The copolymerization of benzoyloxy radicals with vinyl formate, vinyl propionate, vinyl butyrate, vinyl benzoate, and vinyl phenylacetate has been studied in considerable detail [42,43]. 

Poly (vinyl acetate) is the most widely used vinyl ester polymer. It is also the precursor or starting material for the production of two other polymers that cannot be prepared by direct polymerization because the starting monomer is unstable. These are poly(vinyl alcohol) and poly(vinyl acetal). The most important of the latter are poly(vinyl butyral) and poly(vinyl formal). 

Poly(vinyl formals) and poly(vinyl butyrals) are of importance in the coating industry. Commercial products differ in the degree of polymerization and acetalation, but especially in the residual polyfvinyl alcohol) content. 

There are different grades of each of these materials according to the overall molecular weight and the degree of substitution. These polymers are used as components of systems with unique adhesive properties for example, in the manufacture of safety glass laminates (poly(vinyl butyral) and mixed derivatives) and of metal-to-metal adhesive (poly(vinyl formal) cured with phenolics and other resins). Reactions of poly(vinyl alcohol) with acids or anhydrides occur as normal esterifications, a route used to synthesize polymers and copolymers that cannot be readily formed by conventional polymerization (e.g., when the reactivity ratios of the monomers are not suitable). 

Figure 1.15 shows polyisobutylene, a vinylidene polymer with symmetric substitution, and thus without stereoisomers. Cis and trans isomers are possible in butenylene polymers. Two examples are at the bottom of Fig. 1.15. They are not interconvertable by rotating of the molecule. Shown in the figures are the trans isomers (). In the cis isomers the backbone chain continues on the same side of the double bond ( /). In Figs. 1.16 and 1.17 a series of vinyl and vinylidene polymers are shown. The above-mentioned PTFE, poly(vinyl butyral), and poly (methyl methacrylate) are given, starting in Fig. 1.17. Polyoxides are drawn at the bottom of Fig. 1.17, and the top of Fig. 1.18. Poly(ethylene terephthalate) and two aliphatic polyamides (nylon 6,6 and nylon 6) round out Fig. 1.18. The 20 polymers just looked at should serve as an initial list that must be extended many-fold during the course of study of thermal analysis of polymeric materials.

Vinyl butyral Single Tg FTIR NMR Miscible when blend was prepared by in situ polymerization of oligomer linn Tripathy et al. (2003)... 

The decomposition of the polymeric binder in a ceramic green body is more complex than that of the pure binder. In the case of poly(vinyl butyral). Fig. 6.59 shows that oxide powders can catalyze the reaction, leading to a decrease in the decomposition temperature (89). Cerium oxide (Ce02), for example, reduces the temperature for the greatest weight loss by 200°C. Binders that normally burn out completely in the pure state may leave a small amount of residue that cannot be easily removed from the particle surfaces. For a given binder composition, the amount of residue depends on several factors, such as the powder composition, the gaseous atmosphere, and the structure and chemistty of the powder surface. 

Polyrn rS. Polymeric monolayers are formed either by spreading preformed polymers or by polymerizing reactive monomers on the water surface. A large variety of preformed polymers has been studied, including polyacrylates and polymethacrylates, poly(vinyl butyral), poly(vinyl methyl ether), poly(vinyl acetate), poly(vinyl fiuoride), poly(vinylidene fluoride), (12), silicone copolymers, maleic anhydride copolymers, and polypeptides (1). Monomers that have been successfully polymerized at the air-water interface include derivatives of aniline (13), vinyl alcohol (14), and styrene (15). In addition to the interesting chemistry and the two-dimensional structural control, polymer LB Aims are much more robust than films formed from straight-chain amphiphiles. 

The molecular weight of polymer when vinyl butyrate is polymerized in an inert solvent is 500,000. With all other conditions the same, addition of 5 g/liter of 1-dodecanethiol decreases the molecular weight to 150,000. 

Fig. 10.—Benzoyl peroxide-initiated polymerization of vinyl-i-j3-phenyl-butyrate in dioxane at 60°C plotted as a first-order reaction. [M]o and [M ] represent concentrations of monomer initially and at time t, respectively. In experiments 1, 2, and 3, respectively, [M]o = 2.4, 7.28, and 5.97 g. of monomer per 100 cc. of dioxane. (Results of Marvel, Dec, and Cooke obtained po-larimetrically.)...

Several different film-forming polymeric binders were used, including polar, water-soluble materials (PVA, poly(vinyl alcohol)) and organic materials of lower polarity (CAB, cellulose acetate/butyrate, and Elvamide , a polyamide polymer). Figure 6 illustrates the optical spectra obtained for films in CAB binder in the visible region. Note that substantial differences are obtained depending on the nature of the activator. 

Starting from a copolymer of vinyl acetate and silicone made by radical polymerization in solution, the saponification leads to a silicone-modified polyvinyl alcohol. This modified polyvinyl alcohol is dissolved in water and then acetalized with aldehydes (butyr- or acetaldehyde)... 

In the polymerization of vinyl esters of perfluorinated acids, ordinary organic solvents are not suitable because of the low solubility, particularly of the higher esters. Therefore, fluorinated solvents have been suggested. Methyl perfluoro-butyrate is considered satisfactory. While benzotrifluoride may be used, the polymers produced in this solvent are low molecular weight [91]. 

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