论文部分内容阅读
Precise control of viscous and elastic properties is considerably important for good processability at various processing operations for conventional polymer melts.In this presentation, new methods to improve the elastic nature of linear polymers including biomass-based polyesters are shown, which will be applicable to the processing operations requiring high melt elasticity such as foaming and blow-molding.One is to add a weak gel just beyond sol-gel transition point.When chain segments of a weak gel are miscible with matrix polymer chains strain-hardening behavior in elongational viscosity is enhanced to a great extent by a small amount of the gel, whereas the shear viscosity increases slightly.The other method is to add flexible nanofibers.Interdigitation of nanofibers provides long time relaxation mechanism.Furthermore, the elastic deformation of the network composed of the interdigitated fibers, which is presumably owing to bending energy of deformed fibers, is responsible for marked elastic properties such as normal stress difference, drawdown force, and Barus effect.The shear viscosity for the blend with flexible nanofibers is not greatly changed.