Viscoelastic properties of a butadiene-styrene block copolymer. A mechanical model
The manifestations of microheterogeneous structure in the viscoelastic properties of a butadiene-styrene copolymer of AB type with lamellar superstructure were investigated. The temperature dependences of the shear elasticity components, G′ and loss G″, were measured at 0·5 Hz. A mechanical model for the calculation of G∗(T) is presented. An interpretation of the “maximum smearing” effect in the G″(T) dependence between the glass temperatures of polybutadiene and polystyrene is proposed.
For a thick incompressible hyperelastic plate under biaxial thrust, flexural and constitutive (homogeneous) instabilities are considered. In the present study their interaction (coupling) is discussed, when the critical conditions coincide for both kinds of instabilities. With the help of branching theory, especially the Fredholm Alternative theorem, the interactive post-critical equilibrium configurations are defined.