Free radical polymerization allylic

Allyl polymers are made by free-radical polymerization of diaHyl compounds, most frequently diallyl dimethyl ammonium chloride (DADMAC) [7398-69-8] forming a chain containing a five-membered ring (28) poly(DADMAC) [26062-79-3]. 

Treatment of 2-methylthiirane with t-butyl hydroperoxide at 150 °C in a sealed vessel gave very low yields of allyl disulfide, 2-propenethiol and thioacetone. The allyl derivatives may be derived from abstraction of a hydrogen atom from the methyl group followed by ring opening to the allylthio radical. Percarbonate derivatives of 2-hydroxymethylthiirane decompose via a free radical pathway to tar. Acrylate esters of 2-hydroxymethylthiirane undergo free radical polymerization through the double bond. 

Additionally, it should be observed that the thermal oxidability and oxidative polymerization of the unsaturated fatty acids follows the trend linolenic > linoleic > oleic > > palmitoleic (Martinenghi, 1963). The oxidation involves, as first step, the abstraction of a hydrogen atom in allylic position to the double bonds. Certainly, this process is favoured in the case of fatty acids with two or more unconjugated double bonds where the formation of a free radical by allylic hydrogen abstraction leads quite necessarily to double bonds slippage with formation of conjugated double bonds ... 

As already mentioned allyl unsaturation is not very reactive as far as free-radical polymerizations are concerned... 

It has been suggested that free-radical polymerization would be a useful way to react an equimolar mixture of allyl acetate and methyl methacrylate. Is this a good idea (Allyl acetate e — —1.07, Q = 0.24 methyl methacrylate e = 0.40, Q = 0.78). 

Polymerization Catalysed by Acids and Bases. Carbonium ions and carbanions respectively are carriers of the chain transfer in cationic and anionic polymerizations respectively. Ionic polymerization mechanism was exploited for the synthesis of polymeric stabilizers in comparison with the free-radical polymerization only exceptionally. The cationic process was used for the synthesis of copolymers of 2,6-di-tert-butyl-4-vinylphenol with cyclopentadiene and/or for terpolymers with cyclopentadiene and isobutylene [109]. System SnCWEtsAlCla was used as an initiator. Poly(lO-vinylphenothiazin) was prepared by means of catalysis with titanium chlorides [110]. Polymers of 4-[a-(2-hydroxy-3,5-dimethylphenyl)ethyl]-vinylbenzene [111] and 3-allyl-2-hydroxyacetophenone [112] were also prepared under conditions of cationic polymerization. 

We have investigated the free-radical polymerization of a variety of diallyl dicarboxylates extensively, especially DAP, DAI, and DAT, in terms of allyl polymerization, cyclopolymerization, and gelation [38]. The cyclopolymerization resulted in cyclization constants Kc of 7.5, 1.6, and 0.6 mol/L at 60 °C for DAP, DAI, and DAT, respectively. In this coimection, it should be noted that in the polymerizations of DAP, DAI, and DAT, two different modes of intramolecular cyclization should be considered. The cyclization reaction of DAP... 

UnsaCuraCed Aromatic Compounds. Although they do not ordinarily do so in free-radical polymerization, aromatic compounds with allyl or vinyl side chains should be capable, under certain conditions, of undergoing reaction not only in the side chains but also at the ring. This has... 

Problem 6.28 Suggest a kinetic scheme to account for the following characteristics of free-radical polymerization of allylic monomers ... 

The free-radical polymerization process with allyl esters resembles that of vinyl and acrylic esters in that there are similar initiation, propagation, and... 

The free-radical polymerization of allyl esters exhibits several unique characteristics. In this respect they differ materially from the polymerization characteristics of vinyl esters. 

The kinetic chain length of a free-radical polymerization process is the ratio of kp/kr, where kp is the rate of propagation and ky is the rate of termination. Since allylic hydrogens are not involved in the propagation step, substitution of deuterium for these hydrogens was expected to affect the termination process. When this indeed was found to be the case, as evinced by the increase in the kinetic chain length and the MW of the polymer, it was considered reasonable evidence that the allylic hydrogens were the cause of the characteristic behavior of allyl esters [15]. 

A graft copolymer of styrene and 1,3-butadiene is called high-impact polystyrene and is used, for example, in laptop computer cases. It is prepared by free-radical polymerization of styrene in the presence of poly( 1,3-butadiene). Instead of reacting with styrene, the free-radical initiator abstracts an allylic hydrogen from poly( 1,3-butadiene). 

The preparation of ligand monomers requires the inclusion of one or more polymerizable substituents. Most imprinted metal ion complexants are made using free radical polymerization, thus requiring that the ligands have a vinyl or allyl... 

What is allylic polymerization If allyl alcohol does not polymerize to a high molecular polymer by free-radical polymerization, why does triallyl cyanurate form a high molecular weigh network structure by the same mechanism ... 

The great number of possible elementary reactions in free radical polymerizations explains why only a fraction of the many thermodynamically polymerizable groups can be converted free radically to un-cross-linked high-molar-mass polymers. Vinyl, vinylidene, and acrylic compounds, as well as some strained saturated rings, belong to this fraction. Allyl compounds only polymerize to branched oligomers, but diallyl and triallyl compounds produce high-molar-mass cross-linked networks. 

Most vinyl and acrylic compounds more or less obey ideal polymerization kinetics during free radical polymerization. Drastic deviations, however, occur for allyl polymerizations since a chain termination by monomer dominates in this case [see Equation (20-41)]. For this case, the formation of polymer free radicals is given analogously to Equation (20-51) as... 

An alternative method to the step polymerization of a mixture of phenols with methanal to form a copolymerized network is the free radical polymerization of substituted aromatics containing polymerizable, double bonds to produce products with improved properties. In this way, a highly crosslinked network is obtained by copolymerization of allyl Xylok with 4,4 -bismaleimidodiphenyl methane in presence of diisopropylbenzyl peroxide and imidazole (Scheme 25). 

End functionalization can be achieved by the addition of allyl bromide to form the corresponding vinyl-functionalized polymer. Allyl bromide acts as a chain transfer agent (CTA) in free-radical polymerizations and can be used to prepare chain-end-functionalized polymer via controlled free-radical polymerizations. The functionalization reaction proceeds via addition followed by fragmentation (i.e., elimination of a bromine radical). When ATRP is quenched with allyl bromide, a bromine radical is eliminated resulting in the formation of a Cu (II) species. The Cu(II) drives the equilibrium to the deactivated species, reducing the propensity of the chain end to add to allyl bromide. In order to overcome this, Cu(0) needs to be added to... 

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