LAWS CONTROLLING CRYSTALLIZATION, RECRYSTALLIZATION AND MELTING IN BULK POLYMERS
Experiments carried out during the last decade revealed several laws which control polymer crystallization and melting in bulk 1: (1)The crystal thickness dc is inversely proportional to the distance to a temperature Tc∝ which is located above the equilibrium melting point Tf∝. (2)Recrystallization processes result in crystal thicknesses which are also inversely proportional to the distance to Tc∝ (3) The lamellar crystallites are composed of blocks with a lateral size proportional to dc. (4) The temperature dependence of the growth rateu can be described by the equation The first exponential factor refers to the segmental mobility in the melt as described by the VogelFulcher law. The second exponential factor which controls the growth rate at high temperatures implies the existence of a temperature dependent activation barrier which diverges at the zero growth temperature Tzg. Hence, polymer crystallization and melting is controlled by 3 characteristic temperatures, Tc∝, Tf∝,Tzg, rather than the equilibrium melting temperature (Tf∝) only.
Gert Strobl
Physikalisches Institut,University Freiburg,79104 Freiburg,Germany
国际会议
International Symposium on Polymer Physics(2008年国际高分子物理学术会议PP2008)
厦门
英文
21-22
2008-06-08（万方平台首次上网日期，不代表论文的发表时间）