New materials based on polybutene-1: Effect of low amount of propylene on crystallization, polymorphism and properties

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Isotactic polybutene-1 belongs to the group of crystallizable polyolefins with special application-relevant properties like high heat distortion temperature, low creep, or high stress cracking resistance. A major disadvantage of polybutene-1 is a phase transition from an unstable mesophase into a metastable crystal which occurs in the solid state immediately after processing or solidification of the melt on cooling, covering a period up to several days. This phase transition is connected with volume shrinkage and distinct change of materials properties. The kinetics of the mesophase- crystal phase transition can advantageous be changed by random incorporation of low amount of co-units into the butene-1 macromolecule. This includes the insertion of propylene co-units into polybutene-1 with the crystallization behavior and the particular mesophase/crystal polymorphism not investigated yet. Therefore, it is the aim of this project to establish a correlation between the concentration of propylene co-units in random butene-1/propylene copolymers and the kinetics of the mesophase-crystal phase transition including the analysis of dependence of mechanical properties as a function of time during the phase transition. The research to be performed will include the evaluation of the effect of the primary condition of the solidification on the polymorphism focusing on conditions as are evident in real polybutene-1 processing schemes. The project will contribute to the development of new polymeric materials based on polybutene-1 and will provide further knowledge about structure formation of this important polymer at conditions relevant in real processing.