Radiation‐induced copolymerization of ethylene and sulfur dioxide in the liquid and gas phases

Abstract

The radiation‐induced copolymerization of ethylene and sulfur dioxide has been studied in the liquid and gas phases. In the liquid phase, the copolymer composition remained equimolar over a temperature range of 20–160°C. and ethylene pressures of 50–680 atm. The rate of copolymerization in the liquid phase at 680 atm. increased with temperature to a maximum value at ∼80°C. Above this temperature the rate steadily decreased to zero at 157°C. because of temperature‐dependent depropagation reactions. In the gas phase, copolymers were formed that contained from 9 to 46 mole‐% sulfur dioxide. Under constant conditions of temperature, pressure, and radiation intensity, the copolymerization rate in the gas phase increased with increasing sulfur dioxide in the initial gas mixture. The propagating species for the liquid‐phase experiments is considered to consist of an equimolar complex molecule of ethylene and sulfur dioxide. For gas mixtures containing an excess molar concentration of ethylene, the propagating species are ethylene and the complex molecule. Infrared spectra show polysulfone structures. Calorimetric and x‐ray diffraction analyses indicate crystalline structures for copolymers in the range 9–50 mole‐% sulfur dioxide, although a melt transition temperature could not be observed for copolymer containing >31 mole‐% sulfur dioxide. Clear uniform film was obtained with copolymers containing up to 31 mole‐% SO2.

NMR Determination of the Microstructure of Poly(vinyl chloride sulfone). I. 1H Spectra

“…The S,S (R,R):S,R (R,S) ratio increased with copolymerization temperature and was 2.3 at -78 °C, 3.6 at -45 °C, and 5.8 at 0 °C. 5. "Across-SCV' diad placements with respect to the asymmetric center to the right for the SVS methine proton were not equally probable in the copolymer with ñ = 1.1.…”

“…This is in contrast to poly(olefin sulfone)'s, which have regularly alternating structures with = 1.0,4 with the exception of polyethylene sulfone) prepared in the gas phase. 5 The relationship between copolymer and comonomer compositions does not obey first-order Markoff statistics (Lewis-Mayo copolymerization model) at any temperature above -78 °C. 6 The copolymerization therefore follows a more complex mechanism, which may include participation of comonomer complexes, depropagation, or penultimate unit effects.…”

“…Figure5. Resonances of -sulfonyl methine protons in poly(vinylß,ß-di chloride sulfone)'s with ñ = 1.13 and1.4.…”

Polysulfones for conservation in the ethylene polymer industry. Progress report No. 7, October 1979-March 1980

“…The objectives of this program are: (1) prepare polysulfone copolymers by the partial substitution of S02 for ethylene and (2) determine their usefulness in industry as a means of substituting a low-cost polluting energy-conserving material in the ethylene polymer and copolymer market. The copolymerization of Et-S02 was studied in both liquid and gas phases at 10-13°C to determine the effect of pressure, S02 concentration, and radiation intensity on the polymerization rate and.…”