Polar Vinyl Monomers

Uses. Magnesium alkyls are used as polymerization catalysts for alpha-alkenes and dienes, such as the polymerization of ethylene (qv), and in combination with aluminum alkyls and the transition-metal haUdes (16—18). Magnesium alkyls have been used in conjunction with other compounds in the polymerization of alkene oxides, alkene sulfides, acrylonitrile (qv), and polar vinyl monomers (19—22). Magnesium alkyls can be used as a Hquid detergents (23). Also, magnesium alkyls have been used as fuel additives and for the suppression of soot in combustion of residual furnace oil (24). 

Some polar vinyl monomers such as MMA can be polymerized. 

Rare Earth Metal-Initiated Polymerization of Polar Vinyl Monomers... 

Butler, K., P. R. Thomas, andG. J. Tyler Stereospecifle Pol5rmerizations of Some Polar Vinyl Monomers. J. Polymer Sci. 48, 357 (1960). 

Flexible polyurethane foam pre-irradiated with ionizing radiation in the presence of air can be readily grafted with vinyl monomers. Relatively low radiation doses (3 to 10 megarads) are required to graft various polar vinyl monomers. Grafting of as little as 2% by weight of acrylamide, methacrylamide, or acrylic acid converts the normally hydro-phobic polyurethane foam into a water-wettable sjjonge. 

This paper describes a method for improving hydrophilicity by using radiation-induced grafting of flexible polyurethane (polyether) foam with polar vinyl monomers. By this procedure, the normally hydrophobic material can be converted into a remarkably water-wettable sponge. 

Neutral organolanthanide metallocenes [532 536] and cationic zirconocene organic derivatives [537] appear to be effective catalysts for the polymerisation of polar vinyl monomers in which the heteroatom is conjugated with the double bond, such as acrylates [CH2=CH—C(0R)=0] and methacrylates [CH2= C(Me)-C(0R)=0]. 

Kuran, W., Polar Vinyl Monomer Polymerization and Copolymerization with Olefins Promoted by Organometallic Catalysts , Polimery, 42, 604-609 (1997). 

Name and characterise methods for obtaining a-olefin copolymers with polar vinyl monomers in the presence of coordination catalysts. 

Catalysts of the Ziegler-Natta type are applied widely to the anionic polymerization of olefins and dienes. Polar monomers deactivate the system and cannot be copolymerized with olefins. J. L. Jezl and coworkers discovered that the living chains from an anionic polymerization can be converted to free radicals by the reaction with organic peroxides and thus permit the formation of block copolymers with polar vinyl monomers. In this novel technique of combined anionic-free radical polymerization, they are able to produce block copolymers of most olefins, such as alkylene, propylene, styrene, or butadiene with polar vinyl monomers, such as acrylonitrile or vinyl pyridine. 

Modified Surfaces. It is frequently desirable to change the surface of a polymer. Nonpolar surfaces of plastics are characterized by static electricity buildup, non-wetting, poor adhesion, low printability, and poor dyeing. These disadvantages can be overcome by grafting polar vinyl monomers upon the surface by irradiation. A. S. Hoffman describes radiation grafting of polyelectrolytes upon nonpolar surfaces, and A. Chapiro and co-workers discuss radiation grafting of acrylic acid and vinyl pyridene upon Teflon films. 

This group has been best investigated theoretically, and is the most used in large-scale production. The basic members are ethylene and its derivatives. According to the type of substituent, the group contains two subgroups, alkenes (olefins) and polar vinyl monomers. 

These monomers usually polymerize by classical methods, i.e. radical or ionic, more readily than ethylene. On the other hand, they are too good as electron donors in coordination polymerizations they act as catalytic poisons. The group of polar vinyl monomers is very large. Mostly these compounds are of only theoretical interest. Many of them are, however, technically and socially important, and the exploitation of others is anticipated. 

A typical acrylic adhesive is a copolymer of acrylic alkyl esters and polar vinyl monomers. Acrylic alkyl ester, whose homopolymer T is lower than — 40°C,... 

Acrylic alkyl ester (Tg) Polar vinyl monomer (Tg)... 

The high polar group tolerance of co-catalyst-free ylide nickel catalysts makes them interesting candidates for fhe polymerization of polar monomers. In fact, quite a number of polar vinyl monomers can be homo- and copolymerized quite effectively. The mechanisms of initiation and chain propagation have not been elucidated yet. Especially, acrylic monomers are well suited. It is fhus possible to produce, for example, poly(methyl methacrylate), poly(efhyl acrylate) and poly-(butyl acrylate) in high yield [Eq. (15)]. 

What is fhe implication of our work wifh respect to the metal-catalyzed polymerization of polar vinyl monomers FirsL for fhe late metal compounds, fhe polar vinyl monomers can clearly outcompete efhene and simple 1-alkenes wifh respect to insertion. However, fhe ground-state destabilization of the alkene complex that favors the migratory insertion of fhe polar vinyl monomers is a two-edged sword because it biases the alkene coordination towards ethene and l-alkenes. Indeed, we have observed fhe near quantitative displacement of vinyl bromide by propene to form 7 from 3 (Scheme 9.1). Thus, the extent of incorporation of fhe polar vinyl monomer in fhe polymer will depend on the opposing trends in alkene coordination and migratory insertion. The above discussion does not take into account the problem of functional group coordination for acrylates or halide abstraction for vinyl hahdes. 

During the past 20 years, there has been much interest in understanding the grafting of polar vinyl monomers to polyolefins (PO). The grafting process can be performed in an inert solvent or in a PO melt. A direct grafting of a monomer to chains in molten PO that follows the free-radical mechanism appears more preferable, and it has been studied more widely. It is most often done by means of reactive extrusion (RE), where an extruder is used as a reactor of continuous action. This technology permits the production of a variety of functionalized PO (1-8). 

This chapter describes the coordination polymerization of acyclic and cyclic vinylic monomers, conjugated dienes, and polar vinylic monomers with the most important catalytic systems known in this area. A chronological classitication for the development of the main coordination catalyst types is outlined, as well as polymerization kinetics and mechanisms and applications of polymers obtained through different metallic complexes. 

Polar Vinyl Monomers The anionic polymerization of polar vinyl monomers is often complicated by side reactions of the monomer with both anionic initiators and growing carbanionic chain ends, as well as chain termination and chain transfer reactions. However, synthesis of polymers with well-defined structures can be effected under carefully controlled conditions. The anionic polymerizations of alkyl methacrylates and 2-vinylpyridine exhibit the characteristics of living polymerizations under carefully controlled reaction conditions and low polymerization temperatures to minimize or eliminate chain termination and transfer reactions [118, 119]. Proper choice of initiator for anionic polymerization of polar vinyl monomers is of critical importance to obtain polymers with predictable, well-defined structures. As an example of an initiator that is too reactive, the reaction of methyl methacrylate (MMA)... 

R 118 M. Kang, A. Sen, L. Zakharov and A.L. Rheingold, Trends in Alkene Insertion in Late- and Early-Transition Metal Compounds Relevance to Transition Metal-Catalysed Polymerization of Polar Vinyl Monomers , p. 143... 

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