Citation:
FU Tieyuan, QI Yuchen, WU Suyun, CHEN Donglin. EQUILIBRIUM HEAT OF FUSION OF POLYTETRAFLUOROETHYLENE*[J]. Chinese Journal of Polymer Science,
1985, 3(4): 324-331.
EQUILIBRIUM HEAT OF FUSION OF POLYTETRAFLUOROETHYLENE*
摘要:
The reliability of the values of equilibrium heat of fusion, △Hm, of polytetrafluoroethylene (PTFE)reported in the literature and the inadequacy of the generally accepted value of 13 .7 or 14.6 cal/gwere discussed. Through extrapolating linear plot of △Hm vs. Vsp of the thermally aged PTFE virginas-polymerized samples prepared in accord with ASTM D 1457-81a, △Hmo=79.6J/g (19.0 cal/g)and Vsp (specific volume of amorphous PTFE at 23℃)=0.480 cm3/g (or ρa=2 .08g/cm3) were ob-tained. The heats of fusion,△Hm,of the thermally aged and γ-irradiated samples are different irrespective of the same Vsp value for both samples.A qualitative explanation of this phenomenon was given based on the HV patterns of SALS and Kawai's model.
English
EQUILIBRIUM HEAT OF FUSION OF POLYTETRAFLUOROETHYLENE*
Abstract:
The reliability of the values of equilibrium heat of fusion, △Hm, of polytetrafluoroethylene (PTFE)reported in the literature and the inadequacy of the generally accepted value of 13 .7 or 14.6 cal/gwere discussed. Through extrapolating linear plot of △Hm vs. Vsp of the thermally aged PTFE virginas-polymerized samples prepared in accord with ASTM D 1457-81a, △Hmo=79.6J/g (19.0 cal/g)and Vsp (specific volume of amorphous PTFE at 23℃)=0.480 cm3/g (or ρa=2 .08g/cm3) were ob-tained. The heats of fusion,△Hm,of the thermally aged and γ-irradiated samples are different irrespective of the same Vsp value for both samples.A qualitative explanation of this phenomenon was given based on the HV patterns of SALS and Kawai's model.
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