Crystallization and Nucleation in a Polybutadiene-Isotactic Polypropylene Block Copolymer and the Corresponding Blend

摘要

The physical behavior of a block copolymer is related to its microphase separated morphology. In the case where one of the blocks is capable of crystalizing, the nucleation and growth of the crystallites may be influenced by the non-crystallizable regions of the chain. Thus, phase separation and properties of a semicrystalline block copolymer should be inter-related with the factors governing crystallization. This paper reports a study of the crystallization behavior and nucleation phenomena of a recently reported novel polybutadiene-isotatic polypropylene block copolymer and the corresponding homopolymer blend. In addition to presenting various crystallization and nucleation data, some qualitative insight is provided regarding the relationship between microphase separation in block copolymers (which requires that the block junction be at the interface) and the driving forces for crystallization (which involves surface free energy difference between the crystal and the melt as well as the difference in the interfacial energies between components in the melt).