Cyclic copolymerization

The monomers 3-allylcyclopentene and 3-allylcyclohexene produce soluble copolymers with MA. Copolymer composition studies show the materials to be 2 1 molar in MA and diene residues 45 and 46. As shown, a cyclic copolymerization mechanism is also advanced for the formation of the multicyclic repeating units [Eqs. (14) and (15)]. 

Aliphatic/aromatic. Copolymerization of aliphatic monomers (terpenes, cyclic C5, and acyclic C5) with the aromatic C9 petroleum stream is used to produce... 

Lustoh, J. and Vass, F. Anionic Copolymerization of Cyclic Ethers with Cyclic Anhydrides. Vol. 56, pp. 91 —133. 

Other ring-opening copolymerizations (of, for example, the cyclic allyl sulfide 19), also yield polymers with in-chain ester groups and copolymcrizc more readily (Section 4A2.2). 

Polymerization equilibria frequently observed in the polymerization of cyclic monomers may become important in copolymerization systems. The four propagation reactions assumed to be irreversible in the derivation of the Mayo-Lewis equation must be modified to include reversible processes. Lowry114,11S first derived a copolymer composition equation for the case in which some of the propagation reactions are reversible and it was applied to ring-opening copalymerization systems1 16, m. In the case of equilibrium copolymerization with complete reversibility, the following reactions must be considered. 

Cationic copolymerization of cyclic ethers, formals, esters and anhydrides has been thoroughly studied in recent years and sufficient information about it is now available. The propagating species involved in the cationic copolymerization of these oxacyclic monomers are believed to be the oxonium ions in most cases, but their detailed nature is dependent on monomer structure. From their copolymerization behavior, these monomers can be arranged in the following order of increasing car-bocationic character of the propagating species ... 

The propagating species involved in the polymerization of cyclic formal seem to resemble carbocations, and random copolymers are formed in the copolymerization of cyclic formals with styrene. For the copolymerization of DOL with styrene, the DOL-St cross-sequence was estimated, by NMR or by chemical methods, from the decrease of the formal unit in the copolymer and the formation of nearly random copolymer was confirmed132. ... 

Cationic copolymerization of other cyclic monomers has been studied less extensively. Such copolymerization between substituted 2-oxazolines has been reported198. ... 

Anionic copolymerization of cyclic monomers occurs only between similar monomer pairs. Random copolymers are not formed between vinyl monomers and epoxides or lactones198 because the propagating species are very different. Thus, the success of the copolymerization of cyclic disulfide and nitropropylene was an exceptional case... 

Anionic copolymerization of e-caprolactam and cj-caprylolactam was also reported212,213. Organosiloxane copolymers can be prepared from two different cyclics by using acid or base catalysts214. ... 

Because of the great differences in the properties between vinyl polymers and heterochain polymers, copolymerization of a vinyl monomer and a cyclic monomer seems very intersting. Yet, little success has been achieved in the formation of random copolymers because the reactivities are very different between vinyl monomers and cyclic monomers. However, recent progress in the field of organic chemistry has suggested many possibilities especially for the activation of monomers and for the modification of the reactivity of the propagating species. The probability of successful synthesis of random copolymers has thus greatly increased. 

Detailed information on the copolymerization of cyclic trifluoropropylmethyl-siloxane trimer and octamethylcyclotetrasiloxane is also very limited in the open literature26 27 . Recently, preparation of various amine terminated (dimethyl-tri-fluoropropyl,methyl)siloxane oligomers with varying molecular weights and backbone compositions has been reported 69115 ll7). Table 11 shows various properties of the oligomers produced as a function of composition. These types of modification play very important roles in determining the solubility characteristics and hence the compatibility of resultant polysiloxanes with other conventional organic monomers... 

Cyclosilazanes are found to be reluctant to polymerize by the ring-opening process, probably for thermodynamic reasons. On the other hand, six- and eight-membered silazoxane rings are able to undergo anionic polymerization under similar conditions to those which have been widely used for cyclosiloxane polymerization provided there is no more than two silazane units in the cyclic monomer. They can also copolymerize with cyclosiloxanes however, the chain length of the linear polymer formed is substantially decreased with increasing proportion of silazane units. 

The polymerization of dimethyl maleate and 1,6-hexanediol proceeded using lipase CA catalyst in toluene to give the polymer exhibiting exclusively cis structure [55]. During the polymerization, cyclic oligomers were formed. The cycles were semi-crystalline, whereas the linear polymer was amorphous. In the lipase CA-catalyzed copolymerization of dimethyl maleate and dimethyl fumarate with 1,6-hexanediol, the content of the cyclization was found to depend mainly on the configuration and concentration of the monomers [56]. 

Lipase CA catalyzed the polymerization of cyclic dicarbonates, cyclobis (hexamethylene carbonate) and cyclobis(diethylene glycol carbonate) to give the corresponding polycarbonates [105]. The enzymatic copolymerization of cyclobis(diethylene glycol carbonate) with DDL produced a random ester-carbonate copolymer. As to enzymatic synthesis of polycarbonates, reported were polycondensations of 1,3-propanediol divinyl dicarbonate with 1,3-propanediol [110], and of diphenyl carbonate with bisphenol-A [111]. 

More active zinc phenoxide initiators of the type [Zn(0Ar)2(Et20)2]956 were found to catalyze both the copolymerization of CHO with C02 and the terpolymerization of CHO, PO, and C02 attempts to copolymerize PO and C02 yielded predominantly cyclic carbonates. For example, (332) copolymerizes CHO and C02 at 80 °C and 800 psi to give a copolymer containing 91% syndiotactic polycarbonate linkages (and 9% polyether junctions due to the non-insertion of C02) with good activity (>350g polymer/g [Zn] in 69 h).957 However, the polymerization is not well-controlled (Mw/Mn>2.5). Variation of the phenoxide ligands revealed that (333) is 4 times... 

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