Kinetic Studies on the Radiation-Induced Solution Polymerization of Tetrafiuoroethyiene

Hisasue, Michio; Ukihashi, Hiroshi; Τabata, Yoneho

doi:10.1080/00222337308061173

Cited by 3 publications

References 4 publications

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Emulsifier‐free emulsion polymerization of tetrafluoroethylene by radiation. I. Effects of reaction conditions on the polymerization rate and polymer molecular weight

Suwa

Watanabe

Okamoto

et al. 1978

J. Polym. Sci. Polym. Chem. Ed.

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The radiation‐induced emulsifier‐free emulsion polymerization of tetrafluoroethylene was carried out at an initial pressure of 2–25 kg/cm2, temperature of 30–110°C, and under a dose rate of 0.57 × 104−3.0 × 104 rad/hr. The rate of polymerization was shown to be proportional to 1.0 and 1.3 powers of the dose rate and initial pressure, respectively, and is maximal at about 70°C. The molecular weight of polytetrafluoroethylene (PTFE) lies in the range of 105−106, increases with reaction time in the early stage of polymerization, and is maximal at 70°C but is almost independent of the dose rate. An interesting discovery is that PTFE, a hydrophobic polymer, forms as a stable latex in the absence of emulsifier. When PTFE latex coagulates during polymerization under certain conditions, the polymerization rate decreases, probably because polymerization proceeds mainly on the polymer particle surface. The observed rate acceleration and successive increase in polymer molecular weight may be due to slow termination of propagating radicals in the rigid PTFE particles.

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