Molecular simulations of strain-induced crystallization in multiblock copolymers

Semicrystalline thermoplastic elastomers such as polyurethanes, polyether-b-polyamide (or -polyester) and olefin block copolymers could be regarded as multiblock copolymers holding alternatingly crystallizable and noncrystallizable blocks. They are commonly processed by a basically strain-induced crystallization process in such as plastic molding, film stretching, fiber spinning and substrate casting. We studied three physical effects of the noncrystallizable components, i.e. dilution, microphase separation and contrast block rigidity, on the size diversity of crystalline microdomains yielded in strain-induced crystallization. The size diversity is considered as a vital factor in the high toughness of the materials, while the crystalline microdomains play the role of physical crosslinks in the high elasticity of the materials. Understanding these effects will facilitate our better understanding of chemical compositions and processing parameters of semicrystalline thermoplastic elastomers.