It has been shown that the free volume fraction at Tg is not a universal parameter for linear polymers of different molecular structure. The reason is that the volume expansion at Tg is partially contributed from the change of the numbers of conformations of isolated molecular chains due to internal rotation. In this paper
glassy transformation was connected with internal rotation of isolated molecular chains
and the relationship between free volume fraction of polymers at Tg and energy e of rotational isomerization of isolated molecular chains was formulated
e=-k·Tg·1n(Δa·Tg/1-Δa·Tg).The values of calculated from the above formula are in good agreement with those published in the literatures.Thus
the method described in this paper can be used to estimate a parameter for the flexibility of isolated molecular chains.7
Abstract
It has been shown that the free volume fraction at Tg is not a universal parameter for linear polymers of different molecular structure. The reason is that the volume expansion at Tg is partially contributed from the change of the numbers of conformations of isolated molecular chains due to internal rotation. In this paper
glassy transformation was connected with internal rotation of isolated molecular chains
and the relationship between free volume fraction of polymers at Tg and energy e of rotational isomerization of isolated molecular chains was formulated
e=-k·Tg·1n(Δa·Tg/1-Δa·Tg).The values of calculated from the above formula are in good agreement with those published in the literatures.Thus
the method described in this paper can be used to estimate a parameter for the flexibility of isolated molecular chains.7
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