Emulsifier-free emulsion polymerization of tetrafluoroethylene by radiation. II. Effects of reaction conditions on polymer particle size and number. [. gamma. radiation]

Journal Article · Mon Jan 01 04:00:00 EST 1979 · J. Polym. Sci., Polym. Chem. Ed.; (United States)

DOI:https://doi.org/10.1002/pol.1979.170170111· OSTI ID:6115673

Suwa, T; Watanabe, T; Seguchi, T; Okamoto, J; Machi, S

The size, distribution, and number of PTFE particles formed by radiation-induced emulsifier-free polymerization were measured by electron microscope and automatic particle analyzer (centrifugation method). From the electron micrographs we found that the particles are formed within 5 min. The change in the number of polymer particles (n/sub p/) with reaction time (t) depends on the relative concentration of growing polymer chains to stabilizing species produced by the radiolysis of water and monomer; that is, it was governed by TFE pressure/dose rate ratio and classified into three cases: case I, dn/sub p//dt = 0 (e.g., at 3 x 10/sup 4/ rad/hr and 20 kg/cm/sup 2/); case II, dn/sub p//dt < 0 (e.g., at dose rate below 1.9 x 10/sup 4/ rad/hr and 20 kg/cm/sup 2/); case III, dn/sub p//dt > 0 (e.g., at 3 x 10/sup 4/ rad/hr and 2 kg/cm/sup 2/). The polymer molecular weight above 10/sup 6/ is almost independent of the particle size. The polymerization loci are mainly on the surface of polymer particles dispersed in the aqueous phase in cases I and II except in the initial stage. In case III new particles are formed successively during polymerization. Therefore the polymerization loci are mainly in the aqueous phase. Especially in case I, we concluded that after the generation of particles the propagation proceeds mainly on the surface of polymer particles like the core shell model proposed by Granico and Williams. 10 figures, 3 tables.

• Research Organization: Japan Atomic Energy Research Inst., Takasaki
• OSTI ID: 6115673
• Journal Information: J. Polym. Sci., Polym. Chem. Ed.; (United States), Journal Name: J. Polym. Sci., Polym. Chem. Ed.; (United States) Vol. 17:1; ISSN JPLCA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHEMISTRY
COLLOIDS
COMPARATIVE EVALUATIONS
DATA
DATA FORMS
DISPERSIONS
DOSE RATES
ELASTOMERS
ELECTROMAGNETIC RADIATION
EMULSIONS
EXPERIMENTAL DATA
FLUORINATED ALIPHATIC HYDROCARBONS
GAMMA RADIATION
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN COMPOUNDS
INFORMATION
IONIZING RADIATIONS
ISOLATED VALUES
KINETICS
LATEX
MEDIUM TEMPERATURE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC POLYMERS
OXYGEN COMPOUNDS
PARTICLE SIZE
POLYETHYLENES
POLYMERIZATION
POLYMERS
POLYOLEFINS
POLYTETRAFLUOROETHYLENE
PRESSURE DEPENDENCE
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
REACTION KINETICS
RUBBERS
SIZE
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
WATER
YIELDS