1.3- Butadiene-sulfur dioxide copolymer

The pyrolysis products of 1,3-diene-sulfur dioxide copolymers were analyzed in a field-ion mass spectrometer and the fragmentation results suggest an alternating 1 1 copolymer for poly(butadiene sulfone), poly(isoprene sulfone) and poly(2,3-dimethylbutadiene sulfone) [48]. 

The intermediate case where a complex is formed but opening occurs spontaneously to only a limited extent is illustrated by the reaction of butadiene or other conjugated dienes with sulfur dioxide (16). When the two components react, a cyclic adduct and a linear alternating copolymer are produced simultaneously. 

A free radical polymerization reaction in the presence of a peroxide or hydroperoxide can take place between an olefin and SO2. The resulting poly(olefin sulfone) may have a variable composition (variable content of SO2), but poIy(ethylene-a/f-sulfur dioxide), CAS 110711-58-5, or poly(ethylene sulfone) can be obtained. Different olefins can be used in the reaction, as well as butadiene. Poly(sulfur dioxide-co-alkenes) may have a variable composition from 1.1 mole ratio (a/t copolymer) to various other monomer ratios. 

Marvel reported that propylene and cyclohexene react with sulfiir dioxide to form alternating copolymers of olefin and sulfiir dioxide in a head-to-tail arrangement [2,4], Staudinger reported that 1,3-butadiene reacts with sulfur dioxide to form a cyclic sulfone and an amorphouse linear polysulfone [3,3a, 5]. 

Copolymers have also been prepared using mixtures of olefins with sulfur dioxide. Olefin pairs studied were butene with propylene [22-22b], butene with pentene [13], butene with isobutene [13b], butene with acrylonitrile [13,23], butene with vinyl acetate [24], butene with methacrylate esters [25], butene with acrylic esters [25], and butene with butadiene [24]. 

Matthews and Strange [42] reported a similar reaction of isoprene with sulfur dioxide in the presence of hydrogen chloride. Seyer and King [Id] reported that 1,3-cyclohexadiene reacted with sulfur dioxide to give a white amorphous compound, as earlier reported by Hofmann and Damm [43]. 2-Methyl- and 4-methyl-1,3-pentadiene were reported by Morris and Van Winkle [44] to react with sulfur dioxide to yield a cyclic sulfone and some hydrocarbon polymer. Starkweather [45] in 1945 reported that chloroprene (2-chloro-l,3-butadiene) reacted with sulfur dioxide in an emulsion system to give a copolymer. Poly-sulfone is the major product when radical initiators are used. Cyclic products predominate when radical inhibitors (hydroquinone) or temperatures in excess of the ceiling temperature are used. For example ... 

On the other hand, the joint polymerization of a series of electron-accepting and electron-donating monomers leads to alternating copolymers, mostly as a mixture with the head-to-head cycloaddition products. Electron-accepting maleic anhydride, fumaric ester, sulfur dioxide, or carbon dioxide in combination with electron-donating butadiene, isobutylene, vinyl ether, and p-dioxene or vinyl acetate belong to this series. 

The concentration of (Z)-configuration varies indirectly proportional with the polymerization temperatnre whereas the other three configurations vary directly proportional with the polymerization temperature. The total amoimt of E-, 1,2-, and 3,4- configurations vary from 5% at —40°C to 30% of the total polymer backbone at 100°C polymerization temperatures. Other structvu-al studies have involved 2,3-dichloro- butadiene homopolymer (52), the free-radical random copolymer with methyl methacrylate (53) with chloroprene, and the alternating copolymer of sulfur dioxide with chloroprene (54). Petiaud and Pham studied the thermodynamics of the various modes of imit addition (55). 

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