Polyvinyl alkyl ethers

Several flexible polymers, such as natural rubber (NR) synthetic rubber (SR) polyalkyl acrylates copolymers of acrylonitrile, butadiene, and styrene, (ABS) and polyvinyl alkyl ethers, have been used to improve the impact resistance of PS and PVC. PS and copolymers of ethylene and propylene have been used to increase the ductility of polyphenylene oxide (PPO) and nylon 66, respectively. The mechanical properties of several other engineering plastics have been improved by blending them with thermoplastics. 

POLYVINYL ALKYL ETHERS. These products have properties which range from sticky resins to elastic solids. They are obtained by the low-temperature cationic polymerization of alkyl vinyl ethers having the general formula ROCH=CH-. These monomers are prepared by the addition of die selected alkanol to acetylene in the presence of sodium alkoxide or mercury(ll) catalyst, As shown by the following equations, the latter yields an acetal which must be thermally decomposed to produce the alkyl vinyl ether. 

Schell, W. J., Simha, R., Aklonis, J. J., Multiple transitions in polyvinyl alkyl ethers at low temperatures. Journal of Macromolecular Science-Chemistry, A3(7), pp. 1297-1313 (1969). 

Polyvinyl alkyl ether, monofunctional acrylate monomer, photoinitiator blends cured by UV. ... 

Crystalline polyvinyl alkyl ethers can also be prepared using Ziegler-type catalysts (Vandenberg, 1963). These catalysts are prepared by reacting an organometallic compound with a transi-... 

Mechanisms. Various mechanisms for homogeneous synthesis of stereoregular polyvinyl alkyl ethers have been proposed by Higashimura et al. (1959), Cram and Kopecky (1959), and Bawn... 

The results obtained with the cis- and traws-l-chloro-2-butoxy-ethylenes are consistent with a constant type of steric attack, together with a cis opening of the double bond. These results are also consistent with the mechanism proposed by Bawn and Led-with. Cram and Kopecky s postulate is not supported by the results because the mechanism does not require constant attack on one side of monomer. This is not to say that their mechanism does not apply to other examples, such as the polyvinyl alkyl ethers where only one asymmetric carbon per unit is involved. Natta s results may be consistent with Bawn and Ledwith s mechanism because of stereochemical influences of the chloro group. 

Polyvinyl alkyl ether adhesives (some are elastomers)... 

Several vinyl monomers are used to prepare thermoplastics that are useful in certain adhesive applications. The most important vinyl resins for adhesives are polyvinyl acetate, polyvinyl acetals (butyral and formal), and polyvinyl alkyl ethers. PVC and copolymers of both vinyl chloride... 

Adhesives recommended include epoxies, epoxy-phenolic, polyvinyl alkyl ether, and anaerobics (need a primer to activate the system). 

Adhesives recommended include casein glue, epoxies, polyvinyl alkyl ether, polyacrylate (carboxylic), SBR, and polyisohutylene. 

PVC epoxy, polyester-isocyanate, unsaturated polyester, vinyl chloride-acetate copolymer, polyvinyl acetate, polyvinyl alkyl ether, ethylene-vinyl acetate, nitrile rubber-phenolic, neoprene rubber, polyisobutylene rubber, polyurethane rubber, and polysulfide rubber. See discussion in Section 6.3.28 concerning migration of plasticizers in PVC. 

With a close resemblance in structure to the polyacrylates the polyvinyl alkyl ethers have also been examined as potential elastomers. It... 

GLASS TRANSITION TEMPERATURES OF POLYVINYL ALKYL ETHERS OF STRUCTURE +CH2—CH(ORH- (AFTER LAL AND TRICK... 

Although quite good elastomers may be obtained from several of the polyvinyl alkyl ethers they do not appear to possess any particularly outstanding property that will found them a place in the spectrum of commercial elastomers. The dynamic properties are of some interest and data on the relationship of the dynamic resilience at... 

Adhesives recommended include epoxies, vinyl alcohol—vinyl acetate copolymer, polyvinyl alkyl ether, polyacrylate (carboxylic), polyurethane (two-part), epoxy-phenolics, silicones, and cyanoacrylates. The high-strength thermoset and alloy adhesives are rarely justified for bonding lead. Even when other properties recommend these adhesives, the designer should check to see whether some low-cost or easier-to-use adhesive is also suitable. An exception is teme (lead-coated steel). This is a much stronger metal than lead, and lap-shear strengths exceeding 2.1 MPa are reported for adhesive joints with teme.° ... 

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