Sulfur dioxide olefin copolymers

Expandable Olefin-Sulfur Dioxide Copolymers from Suspension Polymerization... 

The olefin-sulfur dioxide copolymers are thermoplastic and colorless transparent coherent moldings can be prepared. The properties of the polymers vary from that of ethylene-sulfiir dioxide, which is very interactable, to 1-decene-sulfur dioxide, which is soft, rubbery, and soluble in many organic solvents. The... 

Although all the olefin-sulfur dioxide resins decompose by heating well above their softening points, they can be satisfactorily molded within a fairly wide temperature range [22a]. For example, propylene-sulfur dioxide copolymers can be molded at 180°-200°C. Some properties of the molded resins are shown in Table IV [9a]. Some other examples of olefin-sulfur dioxide copolymers and their polymerization conditions are shown in Tables V-IX. 

TABLE VI Preparation of Olefin-Sulfur Dioxide Copolymers Using O(,a -azobisisobutyronitrile Initiator (0.2 gm) ... 

This volume continues in the same format as the first edition with updates on the syntheses of various types of polymers, including olefin-sulfur dioxide copolymers, polythioesters, sulfide polymers, polyisocyanates, polyoxyalkyihydroxy compounds, polyvinyl carbazole, polyvinyl acetate, polyallyl esters, polyvinyl fluoride, and miscellaneous polymer preparations. The book should be useful to academic and industrial chemists who desire typical synthetic procedures for preparing the polymers described herein. In addition to reviewing the latest journals, we survey the patent literature and give numerous additional references. 

Tokura N. Olefin-sulfur dioxide copolymers. Encycl. Polym. Set Technol. l%8 9 460-485. 

NMR analysis has indicated [9b] that the olefin used does not isomerize during copolymerization. Various vinyl monomers copolymerize with SO2 such as vinyl chloride, styrene, acrylamide, and chloroprene. However, methyl methacrylate is reported [9b] to homopolymerize in SO2 when used as a solvent (cationially or radically) but not to form polysulfones (sulfur dioxide copolymers). 

The reaction of sulfur dioxide with olefins under free-radical-cataly2ed conditions produces copolymers which, ia most cases, are of an alternating 1 1 type (249,250) ... 

It has been shown by Barb and by Dainton and Ivin that a 1 1 complex formed from the unsaturated monomer (n-butene or styrene) and sulfur dioxide, and not the latter alone, figures as the comonomer reactant in vinyl monomer-sulfur dioxide polymerizations. Thus the copolymer composition may be interpreted by assuming that this complex copolymerizes with the olefin, or unsaturated monomer. The copolymerization of ethylene and carbon monoxide may similarly involve a 1 1 complex (Barb, 1953). 

Another class of "chain scission" positive resists is the poly(olefin sulfones). These polymers are alternating copolymers of an olefin and sulfur dioxide. The relatively weak C-S bond is readily cleaved upon irradiation and several sensitive resists have been developed based on this chemistry (49,50). One of these materials, poly(butene-l sulfone) (PBS) has been made commercially available for mask making. PBS exhibits an e-beam sensitivity of 1.6 pC cm-2 at 20 kV and 0.25 pm resolution. 

PBS (Figure 30) is an alternating copolymer of sulfur dioxide and 1-butene. It undergoes efficient main chain scission upon exposure to electron beam radiation to produce, as major scission products, sulfur dioxide and the olefin monomer. Exposure results first in scission of the main chain carbon-sulfur bond, followed by depolymerization of the radical (and cationic) fragments to an extent that is temperature dependent and results in evolution of the volatile monomers species. The mechanism of the radiochemical degradation of polyolefin sulfones has been the subject of detailed studies by O Donnell et. al. (.41). 

The other major class of positive resists is based on polyfolefin sulfones) which are alternating copolymers of sulfur dioxide and the respective olefin having the general structure. 

The interactions of a-olefins or styrene with sulfur dioxide (16) or a-olefins (24, 58, 78), frans-stilbene (64), styrene (1,63), p-dioxene (52), 2,2-dimethyl-l,3-dioxole (17), or alkyl vinyl ethers (1, 63) with maleic anhydride yield charge transfer complexes which are stable and generally readily detectable either visually or by their ultraviolet absorption spectra. However, under the influence of a sufficiently energetic attack in the form of heat or free radicals, the diradical complexes open, and alternating copolymers are formed. 

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]. 

Sulfur dioxide does not homopolymerize, but on reaction with olefins it yields copolymers.Terminal olefins react more readily than those with an internal double bond. The presence of various substituents affects the rate of polymerization. Conjugated dienes copolymerize with sulfur dioxide to give linear polymers containing residual double bonds. 

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]. 

Vinyl acetate in the presence of other olefins reacts with sulfur dioxide to give copolymers [24]. For example 20-30% vinyl acetate in the presence of propylene or butene reacts with sulfur dioxide. 

The same author prepared alternating copolymers of a-olefins with sulfur dioxide since here the possibility of a hydrogen shift is evidently eliminated. These processes usually were initiated spontaneously when the components were stirred in sealed pressure bottles at room temperature. Sluggishly initiating systems were accelerated by the addition of a few drops of cumene hydroperoxide. These processes were free-radical polymerizations. The effect of cumene hydroperoxide on the initiation is interesting in view of the very low half life of this reagent at room temperature. The products from these polymerizations were optically active. 

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