Process for preparing copolymers of tetrafluoroethylene
ABS>Tetrafluoroethylene copolymers are prepared by a process which comprises copolymerizing tetrafluoroethylene, ethylene and fluoroolefines excluding tetrafluoroethylene in the presence of polymerization initiators so that the fluorine content may be 49% or more by weight in the product. The process improves the molding characteristics without affecting the heat resistance. When hexafluoropropylene, vinylidene fluoride, vinyl fluoride, and the like in the proportion of molecular ratio 30 to 70 C/sub 2/F/sub 4// 70 to 30 C/sub 2/H/sub 4/ and 1 C/sub 2/F/sub 4//0.1 to 1 fluoroolefines are cop olymerized, the product copolymers have the excellent molding characteristics as well as good heat resistance. The polymerization initiators may be peroxy- compounds, azo-compounds, ultraviolet radiations or ionizing radiations, preferably high energy ionizing radiations, usually gamma-rays from /sup 60/Co source delivering a dose 10/sup 3/ to 10/sup 7/ rad at a dose rate of 10/sup 2/ to 10/sup 9/ rad/hr. In one of the examples, 0.96 moles of tetrafluoroethylene, 1.35 moles of ethylene, 0.23 moles of hexafluoropropylene and 2.48 moles of trichloromonofluoromethane, wherein the molecular ratio of hexafluoropropylene/ tetrafluoroethylene is 0.25 and monomer/ solvent is 1.0, are charged into a 500 ml reactor and copolymerized at -30 deg C by irradiation with gamma-rays from the /sup 60/Co source at a dose rate of 6 x 10/sup 4/ rad/hr for 8.5 hours. The degree of copolymerization is 78%. The product has melting point at 248 deg C, pour point at 233 deg C, decomposition point at 305 deg C, space velocity 3.2 mm/ sup 3//sec, and excellent molding characteristics in extrusion and injection molding. (auth)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-29-026686
- OSTI ID:
- 4347405
- Report Number(s):
- JP 7325415 -
- Country of Publication:
- Japan
- Language:
- English
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Related Subjects
*FLUORINATED ALIPHATIC HYDROCARBONS-- RADIATION CHEMISTRY
*TEFLON-- RADIATION CHEMISTRY
ADDITIVES
ALKENES
CHEMICAL PREPARATION
COPOLYMERIZATION
DOSE RATES
EFFICIENCY
GAMMA RADIATION
IRRADIATION
N40300* --Chemistry--Radiation Chemistry
ORGANIC FLUORINE COMPOUNDS
ORGANIC SOLVENTS
ULTRAVIOLET RADIATION