A thermodynamic multiphase scheme treating polymer crystallization and melting |
| |
Authors: | Email author" target="_blank">G?StroblEmail author |
| |
Institution: | 1.Physikalisches Institut, Albert-Ludwigs-Universit?t Freiburg,Freiburg,Germany |
| |
Abstract: | A comparison of transition and melting temperatures of n-alkanes
with experimentally determined ticknesses and melting points of
polyethylene lamellae shows that the variation of the thickness
with the crystallization temperature virtually agrees with the
chain length dependence of the crystalline-mesomorphic phase
transition in n-alkanes. Mesomorphic polyethylene layers are
stable objects up to the thickness set by this phase transition.
The findings lend further support to the view that polymer
crystallization generally uses a route which includes a passage
via a mesomorphic phase. We construct a thermodynamic scheme
dealing with the transitions between melt, mesomorphic layers and
lamellar crystallites, assuming for the latter ones that they
exist both in an initial “native” and a final “stabilized” form. Application of the scheme in a reconsideration
and quantitative evaluation of SAXS and DSC results previously
obtained for PE, sPP, iPS and P(epsilonCL) yields the
equilibrium transition temperatures between the various phases,
latent heats of transition and surface free energies. According to
the results the mesomorphic phases are not liquid-like, but have
thermodynamic properties which place them truly intermediate
between melt and crystals. |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|