KINETICS OF GAS EVOLUTION IN THE LOW-TEMPERATURE RADIOLYSIS OF PARAFFIN AND POLYETHYLENE

Journal Article · Wed Sep 11 04:00:00 EDT 1963 · Doklady Akademii Nauk SSSR (U.S.S.R.) English translation currently published in a number of subject-oriented journals

OSTI ID:4693972

Vasil'ev, G K; Skurat, V E; Tal'roze, V L

Samples of paraffin and high-density polyethylene in the form of disks 0.1 to 0.8 mm thick and weighing 0.03 to 0.2 g were irradiated with 1.8-Mev electrons at liquid-nitrogen temperatures. The glass ampule was evacuated to 10/ sup -2/ mm Hg std, and the gas pressure was measured during irradiation with a U- shaped oil manometer. Pressure readings were taken by remote control on a television camera. The hydrogen concentration was measured by a mass spectrometer. The absorbed dose was calculated from the electron beam passing through the sample. The amount of gas evolved was plotted as a function of the irradiation dose at --175 deg C. The rate of hydrogen evolution increased with increasing dose in paraffin, but did not increase in polyethylene up to a dose of 2000 M rad. The apparent radiation yield for the evolution of hydrogen from polyethylene was 0.21 at a dose of 4500 to 6200 M rad. On heating the samples, additional hydrogen was evolved, and the kinetics of hydrogen evolution can be described by the following equation: lnSTA1 - (Q(t)/Q/sub o/! = - ( pi /sup 2/Dt/ 41/sup 2/). Here Q(t) is the amou nt of hydrogen evolved at time t: Q/sub o/ is the total amount of trapped hydrogen; D is the diffusion coefficient for hydrogen, and 1 is the half-thickness of the sample. A plot of -ln alpha = -- ln( pi D/sup 2//41/sup 2/) versus 10/sup 3//T (reciprocal of the temperature) gave a straight line for the paraffin sample with an activation energy E = 3.4 plus or minus 0.5 kcal/mol for the diffusion coefficient D. Polyethylene did not give a straight-line plot. The volume ratio of trapped hydrogen in cma under normal conditions to sample weight was 10 for paraffin at a dose >250 M rad, 100 for polyethylene at a dose of 2000 M rad, 260 for polyethylene at a dose of 4550, and 285 for polyethylene at a dose of 6250 M rad. (TTT)

• Research Organization: Inst. of Chemical Physics, Academy of Sciences, USSR
• NSA Number: NSA-17-040866
• OSTI ID: 4693972
• Journal Information: Doklady Akademii Nauk SSSR (U.S.S.R.) English translation currently published in a number of subject-oriented journals, Journal Name: Doklady Akademii Nauk SSSR (U.S.S.R.) English translation currently published in a number of subject-oriented journals Vol. Vol: 152; ISSN DANKA
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

ABSORPTION
ACTIVATION ENERGY
CHEMISTRY
CONCENTRATION
DECOMPOSITION
DIFFUSION
EFFICIENCY
ELECTRON BEAMS
ENERGY RANGE
EQUATIONS
EXCITATION
GASES
GLASS
HEATING
HYDROGEN
IRRADIATION
LOW TEMPERATURE
MANOMETERS
MASS SPECTROMETERS
MEASURED VALUES
MEV RANGE
OILS
PARAFFIN
PLATES
POLYETHYLENES
PRESSURE
QUANTITY RATIO
RADIATION CHEMISTRY
RADIATION DOSES
RADIOLYSIS
REACTION KINETICS
REMOTE CONTROL
TELEVISION
TEMPERATURE
THERMODYNAMICS
THICKNESS
TRAPS
VACUUM
VESSELS
WEIGHT