Copolymerization of vinyl monomers

The reactions of alkyl hydroperoxides with ferrous ion (eq. 11) generate alkoxy radicals. These free-radical initiator systems are used industrially for the emulsion polymerization and copolymerization of vinyl monomers, eg, butadiene—styrene. The use of hydroperoxides in the presence of transition-metal ions to synthesize a large variety of products has been reviewed (48,51). 

Graft Copolymerization of Vinyl Monomers Onto Macromolecules Having Active Pendant Group via Ceric Ion Redox or Photo-Induced Charge-Transfer Initiation... 

Recently, Li et al. [30], Yu et al. [31] reinvestigated the mechanism of graft copolymerization of vinyl monomers onto carbohydrates such as starch and cellulose initiated by the Ce(IV) ion with some new results as mentioned in Section II. Furthermore, they investigated the mechanism of model graft copolymerization of vinyl monomers onto chitosan [51]. They chose the compounds containing adjacent hydroxyl-amine structures, such as D-glucosamine, /mn5-2-amino-cyclohexanol, 2-... 

Therefore, the graft copolymerization of vinyl monomers onto macromolecules having active an pendant group can be achieved either by redox initiation with a Ce(IV) ion or by photo-induced charge-transfer initiation with BP, depending on the structure of the active groups. 

According to this scheme the fundamental difference in the mechanism of free-radical copolymerization of MA with TASM and of MA with alkyl acrylates is due to the fact that in the former copolymerization intermolecular coordination is involved. This coordination is similar to the effect of various complexing agents (ZnCl2, SnCft and A1C13) on free-radical homo- and copolymerization of vinyl monomers. This effect seems to favor the appearance of isotactic configurations along the main chain. 

Peracetic acid, formed in situ from acetic acid and hydrogen peroxide in acid aqueous solution, was found to initiate graft copolymerization of vinyl monomers, e.g. methyl methacrylate and 4-vinyl pyridine, onto wood and cellulosic fibers at a good rate (1-3 h time) at 60°C2. The initiati on reaction is not specific for grafting and considerable amounts of homopolymer is formed. 

Greenley, R. Z., Q and e Values for Free Radical Copolymerizations of Vinyl Monomers and Telogens, pp. 267-274 in Chap. II in Polymer Elandbook, 3rd ed., J. Brandrup and E. H. Immergut, eds., Wiley-Interscience, New York, 1989b. 

Because of these complications, data from copolymerizations should be used with caution. Nevertheless, it appears that, for the copolymerization of 1,6-anhydroaldopyranoses, the major premises are met (as well as for radical copolymerization of vinyl monomers). 

GRAFT COPOLYMERIZATION OF VINYL MONOMERS ONTO POLYMERS CONTAINING STYRENE... 

Chemical processes are far more varied and may involve either the formation of radicals or ions along a polymeric backbone. Both cationic processes3 as well as radical processes have been widely used for graft copolymerization of vinyl monomers onto various polymers. Radical graft copolymerization has been reported for many polymers including styrene-butadiene block copolymers, and acrylonitrile-butadiene-styrene terpolymer, ABS.3 7 9... 

Zilkha, A., B. A. Feit, and A. Bar-Nun Anionic graft copolymerization of vinyl monomers on natural polyhydroxy compounds, their derivatives, and on synthetic polyhydroxy polymers. Israeli Pat. 15 962, Oct. 1962 C. A. 58, 5803 (1963). 

Chirality induction can be achieved in homo- and copolymerization of vinyl monomers based on chiral monomer structure [1,3,8,9]. The first example of this type of polymerization was the copolymerization of (S)-a-methylbenzyl methacrylate with maleic anhydride the polymerization product showed [a]D +23° after removal of the chiral side group [73]. For another example, the copolymerization of an optically active styrene derivative (39) with N-phenylmaleimide (17, R = -Ph) followed by removal of the optically active side group and deboronation gave an optically active N-phenylmaleimide-styrene copolymer [74]. 

Grafting can also be obtained by addition copolymerization of vinyl monomers with unsaturated polymers. The unsaturation may be located either in the side groups or in the backbone. 

Graft Copolymerization of Vinyl Monomers onto Cellulosic Fibers... 

The low effect of the structure of oligomer alkyl radicals on the rate constant of their reaction with oxygen also follows from the review article on the copolymerization of vinyl monomers with oxygen in the liquid phase. 

Fullerenes and their water soluble derivatives are of great deal interest for scientific research due to their biological activity [1]. Therefor, the problems of modification and functionalization of nanomaterials to obtain their water soluble derivatives are very challenging task. In present work we have investigated low-temperature y -induced copolymerization of vinyl monomers such as acrylamide and acrylic acid with fullerene C6o to obtain their water soluble polymers containing fullerene. 

In contrast to the above situations, parylene polymer deposition has very poor adhesion to a smooth surface substrate but can penetrate deep into small cavities. para-Xylylene prefers to react with another para-xylylene or its derivatives. Although it has the feature of difunctional free radical, it is rather stable and does not initiate polymerization of other monomers for conventional free radical polymerization. In spite of numerous attempts, the polymerization of various vinyl monomers initiated by para-xylylene or copolymerization of vinyl monomers with /7ura-xylylene has been elusive. 

In 1985, Rizzardo et al.27 filed a patent for the use of alkoxyamines (Scheme 12) as regulating initiators for the living radical polymerization and block copolymerization of vinyl monomers. R is a group that upon dissociation (Scheme 10) forms a radical that adds to the monomer. The mechanism was disclosed shortly thereafter and involves the reversible dissociations shown in Scheme 11, with the nitroxide radical taking the role of X.28 In a later simulation, the group also revealed the reason for the remarkable absence of the usual terminations and rediscovered the principles of the persistent radical effect 29 As chains undergo termination transient radicals are removed from the system and the concentration of persistent species builds . Further, the authors noted correctly that, in contrast to normal radical polymer-... 

Some typical values of reactivity ratios for monomers that will copolymerize via a free-radical route are shown in Table 1.15 (Tirrell, 1989, Allcock and Lampe, 1981). These have been selected in order to span the range of values shown in the preceding tables. It may be noted that the copolymerization of vinyl monomers with maleic anhydride will invariably lead to alternating copolymers since rj 2 0. The mechanism of alternating... 

Consider the copolymerization of vinyl monomer A with divinyl monomer BB where all of the vinyl groups (i.e., the A group and both B groups) have... 

On the other hand, for a reason why the intermolecular ht addition may be equilibrated, the electrostatic repulsion between the highly polar anhydride units may be considered similar to the well known case in the radical copolymerization of vinyl monomers carrying carbonyl(34) or nitrile group(35) in which the penultimate effect is involved. That is, the polymer(D) obtained via intramolecular hh and intermolecular tt additions in which five-membered anhydride units are separated by two methylene units is sterically and/or electrostatically favorable compared with the polymer(E) formed via intramolecular ht and intermolecular ht additions in which six-membered anhydride units are separated by only one methylene unit. 

Block Copolymerization of Vinyl Monomers from Living Polyacetals... 

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