Peroxides cyclic monomers

One of the so far not very numerous group of cyclic monomers able to polymerize and to copolymerize with styrene, methyl methacrylate, etc. under the effect of peroxides is spiroorthocarbonate [307],... 

This group of compounds includes those monomers with one or more carbon atoms carrying a hydroperoxy or peroxy group, and also singly bonded to an oxygen atom present as hydroxyl, ether or cyclic ether functions. While the group of compounds is, in general, moderately stable, the lower 1-hydroxy and 1,T-dihydroxy-alkyl peroxides or hydroperoxides are explosive. Individually indexed compounds are ... 

Free Radical Peroxides (monomers cyclic ketene acetals)... 

The most common method of preparation of PMTFPS is through the base-catalyzed ring-opening polymerization of the corresponding cyclic trimer.61-62 Details are in Section 2.11.1. A specific cure site for peroxide curing is developed by incorporating 0.2 mol% of methylvinyl siloxane.63 Typically, fluorosilicone elastomers are copolymers of 90 mol% of trifluoropropylsiloxy and 10 mol% of dimethylsiloxy monomers, but the fluorosilicone content in commercial products ranges from 40 to 90 mol%.63... 

Scheme 7.38 Free radical copolymerization of various alicyclic monomers initiated by (1) azoisobutyronitrile (AIBN) in THF, and (2) di-tert-butyl peroxide (DTBP) in propylene glycol monomethylether acetate, and used in the synthesis of the alicyclic polymer resist materials for ArF lithography, pioneered at the University of Texas at Austin in 1995. Note that although only 2,3-enchainment of the cyclic olefins is shown above the scheme, 2,7-enchainement is also possible, as reported by Gaylord and co-workers. ...

Cyclic acetone peroxides are an important class of home-made explosives, being easily prepared from household materials, but also highly unstable. An experimental and DFT investigation of the uncatalysed reaction of acetone and hydrogen peroxide has identified key steps (i) formation of the monomer, 2-hydroperoxipropan-2-ol, HO-CMe2-0-0-H (ii) polymerization and (iii) cyclization. DFT-generated reaction profiles match well with GC-MS, Raman and NMR observations over time. 

Several other oxidants have been used for the oxidation of olefins, such as organic hydroperoxides or hydrogen peroxide [107], which have limitations in their market volume not comparable with that of cyclic carbonates if the latter have to be used as monomers for polymers or in other large scale uses. The goal must be the direct use of dioxygen (or even better air) under controlled conditions which may block the radical reactions involving O2 and olefins. 

Radical ring-opening polymerization has been essentially developed by Bailey et al. in the mid-80s. ° With appropriate monomers such as cyclic ketene acetals, the method leads to polyesters, while keeping all the advantages of a free-radical polymerization process. With NMP, however, results are very scarce and only TEMPO was used so far in the polymerization of 2-methylene-1,3-dioxepane initiated by di-tert-butyl peroxide at 125... 

The cyclic structure of the polymers [31] was substantiated by infrared and chemical evidence. The fact that they were soluble (acetone, methyl ethyl ketone, acetic acid, dioxane) confirms their linear character. The polymerizations were also initiated by other radical initiators [peroxides, azobis(iso-butyronitrile)]. Carbinols with aliphatic, cycloaliphatic, and aromatic substituents were polymerized (104,106,109, 111, 113,119-121). Cyclic polymers are also obtained from their acetates and ethers (107, 113). Nuclear magnetic resonance has been employed to study transitions in these polymers (75, 76). Polymers possessing molecular weights of over 1,000,000 resulted in some cases. The kinetics of polymerization (11-14) were studied (111, 112). Copolymerization with vinyl monomers (108, 145) yielded linear, soluble polymers that contained cyclic structures derived from the vinylethynyl carbinol. 

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