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Copolymerization of tetrafluoroethene (TFE) with ethene (E) in wateralcohol medium initiated by 2,2Ј-azo-bis-izobutyronitrile (AIBN) at 338 K and 4.2 MPa was conducted in an autoclave by employing a semiflow procedure to feed the comonomers. The thermal properties of the copolymers under both the static and dynamic conditions of thermal treatment in air (ageing) were studied. The most pronounced changes in the initial temperature of destruction were observed for the compositions containing more than 42 mol % TFE, which corresponded to the formation of alternating copolymers. The reaction of thermal degradation was found to follow the first order kinetic equation, with the activation energy 174 kJ ⅐ mol Ϫ1 . The higher thermal stability of the alternating TFE-E copolymers was proved by IR spectroscopy and DTA analysis. Both the melting and crystallization DSC scans of copolymers of various compositions were analyzed. Monomodal peak of melting (and respectively, crystallization) was observed in both scans for the alternating copolymer, whereas the second peak appeared for the copolymer fractions with the higher content of ethylene block fragments and 30 -40 mol % TFE units. The dynamic-mechanical analysis showed three relaxation transitions (␥, ␤ 1 and ␤ 2 , ␣) in the temperature interval from 173-433 K, related to the mobility of structural units of different type in the copolymers prepared.

SYNOPSISRadical copolymerization of tetrafluoroethylene (TFE) with ethylene (E) was initiated by 2,2'-azo-bis-isobutyronitrile in batch and semibatch operation. The effect of reaction conditions (temperature, pressure, stirring speed, molar ratio of monomers, etc.) on copolymerization rate and copolymer molecular weight was studied. The highest reaction rate was observed at TFE content over 70 mol % and was found to be proportional to initiator concentration and total monomer content by powers of 0.9 and 1.54, respectively. These dependencies were attributed to the heterophase character of the copolymerization.The monomer reactivity ratios and overall activation energy of the reaction were determined. The effect of the monomer composition on the distribution of monomer units in the copolymer chain was studied. Kinetic mechanism of the copolymerization was suggested.Some of the basic physical properties and chemical resistance of the alternating copolymers synthesized were also determined. 0 1995 John Wiley & Sons, Inc.

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SYNOPSISRadical copolymerization of tetrafluoroethylene (TFE) with ethylene (E) by azo-bis-isobutyronitrile in the temperature interval 333-363 K, monomer pressure from 3.0 to 7.0 MPa at TFE/E molar ratio from 77/23 to 23/77 in bulk was carried out. The effect of reaction conditions on the yield, molecular weight, and polymer composition of copolymer synthesized was studied. White powdery alternating copolymers were obtained at TFE content in the monomer mixture from 65 to 85 mol %. Copolymerization rate R was described by the equation R = kM[ln] [ C h411.3 which was related to the heterophase character of the reaction. The reactivity ratio of TFE and E (0.067 k 0.12 and 0.52 k 0.18, respectively) and apparent activation energy E. = 135 kJ/mol were found. The TFE and E block formation probabilities were calculated and compared with IR spectroscopy data. Melting point, entropy, and enthalpy of fusion of the entirely alternating copolymers were determined. Some of the basic properties of the alternating copolymers obtained were also studied. 0 1995