Crystallization of trans-1,4-polyisoprene*

Isothermal crystallization of TPI from its solutions and melt were both sudied to attain the kinetic parameters and polymorphic behaivor. The solubility curves of TPI in solvents and the conversion temperatures between isothermal and non-isothermal crystallization were supplied to propose the available concentrations and temperatures for TPI isothermal crystallization. In most cases, the kinetics of TPI crystallization was subject to the Avrami-equation though few deviations arising from the influence
of non-isothermal crystallization and transient nucleation were also observed under several special conditions. When TPI melt recrystalizaion was observed, β-TPI (metastable form) exhibited stronger melting memory effect than α-TPI. Irrespective of the pre-existed crystal modification, the reduced energy barrier for nucleation favored the formation of a-TPI. Furthermore, an increases in crystallinity was also observed if recrystallization occured at low temperatures.