Patent GB-884999-A (GB)
Title: Improvements in or relating to polymerisation of trans-substituted ethylenes
IPC: C08F14/12
Filed: 1957-04-18
Abstract: High polymers of 1,2-dichloroethylene, having a softening point above 240 DEG  C. and decomposition temperature above 290 DEG  C., are obtained by treating trans-1,2-dichloroethylene with ionizing radiation at a temperature between -48 and +48 DEG  C., preferably 20 DEG  C.  The dose rate is preferably kept low, e.g. 200 roentgens/minute.  Higher dose rates, e.g. 6600 roentgens/minute, reduce the time required, but result in a higher proportion of liquid polymers.  The solid polymers produced are partially soluble in dimethyl formamide and tetrachloroethane, but are insoluble in most of the usual organic solvents.  Suitable radiations are gamma rays having a photon energy of at least 1MeV; high energy particles such as protons, electrons and helium ions; and the radiation from an atomic pile of similar energies.  The dichloroethylene is preferably in the liquid state and may be mixed with other substances, one or more of which may be copolymerizable therewith.  In an example, trans-1, 2-dichloroethylene was placed in an annular glass vessel placed round a source comprising 70 curies of cobalt-60 emitting gamma radiations of 1,33 and 1,17 MeV.  The irradiation lasted 95 hours at 200 roentgens/minute, i.e. a dose of 1,1X106 roentgens.  In a comparative example, the cis-isomer yielded substantially only liquid polymers after 15 days irradiation under p  the same conditions, 69% of the total product being accounted for by the dimer, trimer and tetramer compared with 12% from the trans isomer. Specification 517,195 is referred to.ALSO:High polymers of 1,2-dichloroethylene having a softening point above 240 DEG C. and decomposition temperature above 290 DEG C. are obtained by treating trans-1,2-dichloroethylene with ionising radiation at a temperature between -48 DEG C. and +48 DEG C., preferably 20 DEG C.  The dose rate is preferably kept low, e.g. 200 roentgens/minute.  Higher dose rates, e.g. 6600 roentgens/minute reduce the time required but results in a higher proportion of liquid polymers.  The solid polymers produced are partially soluble in dimethyl formamide and tetrachloroethane but are insoluble in most of the usual organic solvents.  Suitable radiations are gamma rays having a photon energy of at least 1 MeV; high energy particles such as protons, electrons and helium ions, and the radiation from an atomic pile of similar energies. The dichloroethylene is preferably in the liquid state and may be mixed with other substances one or more of which may be copolymerisable therewith.  In an example trans-1,2-dichlorethylene was placed in an annular glass vessel placed round a source comprising 70 curies of cobalt-60 emitting gamma radiations of 1.33 and 1.17 MeV.  The irradiation lasted 95 hours at 200 roentgens/minute, i.e. a dose of 1.1+106 roentgens.  In a comparative example the cis-isomer yielded substantially only liquid polymers after 15 days irradiation under the same conditions, 69% of the total product being accounted for by the dimer, trimer and tetramer compared with 12% from the trans-isomer.  Specification 517,195 is referred to.