Molecular Weight Dependency of Crystallization Line, Recrystallization Line, and Melting Line of Polybutene-1

Abstract

Isothermal crystallization and subsequent melting processes in semicrystalline polymers can be described by several linear dependencies termed as crystallization line, recrystallization line, and melting line in a phase diagram of inversed crystalline lamellar thickness as a function of temperature. The crystallization line denotes the lamellar thickness dependency on crystallization temperature. Upon subsequent heating, the system either undergoes a process involving a continuous change in lamellar thickness following a recrystallization line or a direct melting at a constant thickness defining a melting line. The limiting temperatures of infinite lamellar thickness for crystallization line and recrystallization line coincide with each other and are higher than that of melting line. The above-mentioned experimental results are interpreted as a consequence of involvement of a mesomorphic phase during crystallization. In this work, the effect of molecular weight on the crystallization line, recrystallizati...