MECHANISM OF DISCOLORATION OF IRRADIATED POLYVINYL CHLORIDE
The radiation chemical process in polyvinyl chloride was studied by means of electron spin resonance, optical spectroscopy, and measurement of gas evolution. The chief technique was to irradiate sampies at - 196 deg C and then follow the change or changes with rising temperature. primary radicals, such as -- CH/sub 2/--CH--CH/sub 2/-- and -- CHCl -- CH-- CHCl--, were produced. Among them some m crosslinks during irradiation even at -- 196 deg C. A mechanism for the discoloration of PVC, based upon results obtained by the three different methods, was postulated. Discoloration is caused by the formation of polyenyl radicals or polyene molecuies of considerable conjugation lengths, some as long as 9 conjugated double bonds. Polyenyl radicals are produced as a result of a thermally induced secondary reaction of the -- CHCl-- CH-- CHCl-- radical, above - - 70 deg C, thereby accompanied by hydrogen chloride detachment following the so- called zipper mechanism. An equation relating the pressure of evolved RCl to the reaction temperature was derived by a simple kinetic treatment of the zipper reaction. Some effect of heat treatment and increasing dose on discoloration is discussed. (P.C.H.)
- Research Organization:
- Japanese Assn. for Radiation Research on Polymers, Osaka, Japan
- NSA Number:
- NSA-17-011281
- OSTI ID:
- 4710802
- Journal Information:
- J. Appl. Polymer Sci., Journal Name: J. Appl. Polymer Sci. Vol. Vol: 6
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
ELECTRON SPIN RESONANCE STUDIES OF POLYVINYL CHLORIDE IRRADIATED IN HN$sub 3$ GAS
Radiation Chemistry of Polyvinyl Chloride
Related Subjects
COLOR
ELECTRONS
EQUATIONS
GASES
HEAT TREATMENTS
HYDROCHLORIC ACID
HYDROGEN CHLORIDES
IRRADIATION
LOW TEMPERATURE
MEASURED VALUES
METALS, CERAMICS, AND OTHER MATERIALS
MOLECULES
OPTICAL SYSTEMS
POLYMERIZATION
POLYVINYLS
PRESSURE
RADIATION EFFECTS
REACTION KINETICS
RESONANCE
SPECTROSCOPY
SPIN