Melting and annealing of oriented single crystal aggregates of trans-polydodecenamer

Abstract

The annealing behaviour of single crystal aggregates of two samples of trans-polydodecenamer with a trans double bond content of 96 and 75% is examined. Quantities such as density, long spacing, apparent enthalpy of fusion and crystallinity are measured. Two different mechanisms of thickening of crystallites, are involved in the annealing process, corresponding to two different regions of temperature and long-spacing. The temperature and the long-spacing at which the transition occurs are dependent upon the configurational purity of the polymer increasing with the percentage of trans double bonds ( T A⋍63° C , L⋍111 A ̊ ; T A⋍67° C , L⋍137 A ̊ for samples having trans double bond content of 75 and 96% respectively). The equilibrium melting points T° m and the surface free energy σ e of the crystallites of the two samples of trans-polydodecenamer have been calculated thermodynamically by using the slope method. Values of 88 and 80°C for the thermodynamic temperature and of 20 and 19 erg/cm 2 for the end surface free energy are found for the two samples of trans-polydodecenamer with high and low trans double bond content respectively.