Styrene vinyl organometallic

Pittman built on the premise that vinyl organometallic monomers might be styrene-like. Special metal-containing vinyl monomers were developed. Thus, acrylates and methacrylates of ferrocene were prepared and their homo- and copolymerizations... 

A number of methods such as ultrasonics (137), radiation (138), and chemical techniques (139—141), including die use of polymer radicals, polymer ions, and organometallic initiators, have been used to prepare acrylonitrile block copolymers (142). Block comonomers include styrene, methyl acrylate, methyl methacrylate, vinyl chloride, vinyl acetate, 4-vinylpytidine, acrylic acid, and //-butyl isocyanate. 

The attachment of cymantrene groups to polymers has attracted interest for other reasons. Studies have shown, for example, that adherent, abrasion-resistant coatings are formed on metals when thin films of the Mn-containing polymer are subjected to irradiation with UV light. The polymerization of styrene tricarbonylchromium 47 has also been studied.This species is available from the reaction of styrene with Cr(CO)3(NH3)3. Although the Cr monomer 47 resisted attempts at homopolymerization, co-polymerizations with styrene, methyl acrylate, as well as with 41 to yield bimetallic polymers 48 were possible (Equation (17)). In addition, co-polymerization with vinyl-ferrocene afforded co-polymers of low molecular weight (Mn = ca. 4,000). A variety of other organometallic vinyl momomers 49 has been successfully polymerized to yield polymers 50 that contain pendant Gr, W, and Ir carbonyl moieties (Equation (18)). ... 

The use of organometallic compounds as chain-transfer catalysts in free-radical polymerization has been widely studied. One objective is the production of polymers with terminal vinyl groups and lower molecular weight components compared with polymerization in the absence of chain-transfer catalysts. Gomplexes of cobalt(ii) have been used as effective catalysts, but the instability of the intermediate cobalt hydride does not permit firm establishment of the reaction mechanism. To address this issue, several chromium compounds have been applied as catalysts for the polymerization of methylmethacrylate (MMA) and styrene. The temperature dependence of the rate constant for free-radical polymerization of MMA for catalyzed chain transfer by (GsPh5)Gr(GO)3 has been determined using the Mayo equation. ... 

Other Onium Salts and Organometallic Photoinitiators. The success of the iodonium and sulfonium salts as photoinitiators has led to the investigation of a number of analogous onium salts based on the halides and the Group VIA atoms however, these alternative initiators have not been widely used for various reasons. For example, chloronium and bromonium salts were prepared (57,58) and they were also found to function as cationic photoinitiators, but these salts are difficult to prepare and they have low thermal stability. Similarly, triarylselenon-ium salts have also been investigated and foimd to function as cationic initiators (59) however their preparation has been foimd to be expensive (60). Other onium salts such as phosphonium and arsonium salts, developed by Abu-Abdoun and co-workers for the photopolymerization ofp-methylstyrene and styrene, have also been reported (61-63) as successful cationic photoinitiators. Photopolymerization of carbazolyloxiranes with sulfonium and tropylium salts has been reported (64). Dialkylphenacyl sulfonium photoinitiator (65-67) has been reported with excellent solubility in both polar and nonpolar monomers. Pyridinium and isoquino-linium salts have also been reported and they were found useful for polymerizing both the epoxide and vinyl ether monomers (68). 

---