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Title: Emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. III. Simultaneous formation of hydrofluoric acid. [. gamma. radiation]

Abstract

Simultaneous formation of hydrofluoric acid (HF) in the radiation-induced polymerization of tetrafluoroethylene (TFE) was investigated. HF concentration in PTFE latex was determined mainly by conductometric titration with 0.01 and 0.001N NaOH. The amount of HF formed is almost independent of agitation speed and th amount of n-hexadecane added and is maximal at ca. 70/sup 0/C corresponding to the rate of polymerization. The rate of HF formation increases with the initial pressure of TFE monomer and dose rate and decreases with polymerization or TFE consumption. This fact suggests that HF is formed mainly by TFE reactions and not by the degradation of PTFE. The mechanism of HF formation in this reaction system in the absence of oxygen is shown in the following two schemes: scheme I is the reaction of TFE with primary radicals (OH-, H-, e/sup -//sub aq/) from the radiolysis of water; scheme II is the reaction of water with the species from the radiolysis of TFE. On the assumption that HF is formed only according to scheme I, the G value of HF formation G(HF)/sub calc/ can be calculated as 11.25. All observed G values G(HF)/sub obs/ are larger than G(HF)/sub calc/. When the polymerization is carried outmore » at 20 kg/cm/sup 2/ under various dose rates, G(HF)/sub obs/ increases with the dose rate. When the polymerization is carried out at 3.0 x 10/sup 4/ rad/hr under various pressures, G(HF)/sub obs/ decreases with the decrease in pressure from 20 to 2 kg/cm/sup 2/ and is fairly close to G(HG)/sub calc/ at 2 kg/cm/sup 2/. This indicates that HF formation is due mainly to scheme II at high pressure (in the presence of enough TFE) and to scheme I as the pressure is lowered. 5 figures, 7 tables.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Japan Atomic Energy Research Inst., Takasaki
OSTI Identifier:
6293991
Resource Type:
Journal Article
Journal Name:
J. Polym. Sci., Polym. Chem. Ed.; (United States)
Additional Journal Information:
Journal Volume: 17:1
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; FLUORINATED ALIPHATIC HYDROCARBONS; CHEMICAL RADIATION EFFECTS; HYDROFLUORIC ACID; CHEMICAL REACTION YIELD; POLYTETRAFLUOROETHYLENE; CHEMICAL REACTION KINETICS; CHEMICAL REACTIONS; DOSE RATES; ELECTRIC CONDUCTIVITY; EMULSIONS; EXPERIMENTAL DATA; GAMMA RADIATION; HEXADECANE; ISOLATED VALUES; LATEX; MEDIUM PRESSURE; MEDIUM TEMPERATURE; ORGANIC SOLVENTS; PH VALUE; POLYMERIZATION; PRESSURE DEPENDENCE; QUANTITATIVE CHEMICAL ANALYSIS; QUANTITY RATIO; RADICALS; SODIUM HYDROXIDES; TEMPERATURE DEPENDENCE; TIME DEPENDENCE; TITRATION; WATER; ALKALI METAL COMPOUNDS; ALKANES; CHEMICAL ANALYSIS; CHEMISTRY; COLLOIDS; DATA; DATA FORMS; DISPERSIONS; ELASTOMERS; ELECTRICAL PROPERTIES; ELECTROMAGNETIC RADIATION; HALOGENATED ALIPHATIC HYDROCARBONS; HYDROCARBONS; HYDROGEN COMPOUNDS; HYDROXIDES; INFORMATION; INORGANIC ACIDS; IONIZING RADIATIONS; KINETICS; NUMERICAL DATA; ORGANIC COMPOUNDS; ORGANIC FLUORINE COMPOUNDS; ORGANIC HALOGEN COMPOUNDS; ORGANIC POLYMERS; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; POLYETHYLENES; POLYMERS; POLYOLEFINS; RADIATION CHEMISTRY; RADIATION EFFECTS; RADIATIONS; REACTION KINETICS; RUBBERS; SODIUM COMPOUNDS; SOLVENTS; YIELDS; 400600* - Radiation Chemistry

Citation Formats

Suwa, T., Watanabe, T., Okamoto, J., and Machi, S. Emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. III. Simultaneous formation of hydrofluoric acid. [. gamma. radiation]. United States: N. p., 1979. Web. doi:10.1002/pol.1979.170170112.
Suwa, T., Watanabe, T., Okamoto, J., & Machi, S. Emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. III. Simultaneous formation of hydrofluoric acid. [. gamma. radiation]. United States. doi:10.1002/pol.1979.170170112.
Suwa, T., Watanabe, T., Okamoto, J., and Machi, S. Mon . "Emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. III. Simultaneous formation of hydrofluoric acid. [. gamma. radiation]". United States. doi:10.1002/pol.1979.170170112.
@article{osti_6293991,
title = {Emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. III. Simultaneous formation of hydrofluoric acid. [. gamma. radiation]},
author = {Suwa, T. and Watanabe, T. and Okamoto, J. and Machi, S.},
abstractNote = {Simultaneous formation of hydrofluoric acid (HF) in the radiation-induced polymerization of tetrafluoroethylene (TFE) was investigated. HF concentration in PTFE latex was determined mainly by conductometric titration with 0.01 and 0.001N NaOH. The amount of HF formed is almost independent of agitation speed and th amount of n-hexadecane added and is maximal at ca. 70/sup 0/C corresponding to the rate of polymerization. The rate of HF formation increases with the initial pressure of TFE monomer and dose rate and decreases with polymerization or TFE consumption. This fact suggests that HF is formed mainly by TFE reactions and not by the degradation of PTFE. The mechanism of HF formation in this reaction system in the absence of oxygen is shown in the following two schemes: scheme I is the reaction of TFE with primary radicals (OH-, H-, e/sup -//sub aq/) from the radiolysis of water; scheme II is the reaction of water with the species from the radiolysis of TFE. On the assumption that HF is formed only according to scheme I, the G value of HF formation G(HF)/sub calc/ can be calculated as 11.25. All observed G values G(HF)/sub obs/ are larger than G(HF)/sub calc/. When the polymerization is carried out at 20 kg/cm/sup 2/ under various dose rates, G(HF)/sub obs/ increases with the dose rate. When the polymerization is carried out at 3.0 x 10/sup 4/ rad/hr under various pressures, G(HF)/sub obs/ decreases with the decrease in pressure from 20 to 2 kg/cm/sup 2/ and is fairly close to G(HG)/sub calc/ at 2 kg/cm/sup 2/. This indicates that HF formation is due mainly to scheme II at high pressure (in the presence of enough TFE) and to scheme I as the pressure is lowered. 5 figures, 7 tables.},
doi = {10.1002/pol.1979.170170112},
journal = {J. Polym. Sci., Polym. Chem. Ed.; (United States)},
number = ,
volume = 17:1,
place = {United States},
year = {1979},
month = {1}
}