Abstract
AbstractMelts of a commercial poly(methyl methacrylate) product and a commercial polystyrene were elongated homogeneously up to Hencky strains of ε > 4 by means of the rotary clamp technique. For this purpose, certain modifications to the rheometer were necessary which are described in detail. Both polymer melts show strain hardening, i. e. the elongational viscosities are higher than the threefold of the linear viscoelastic limiting viscosity measured in shear. The degree of hardening is very different: For the poly(methyl methacrylate) product the hardening is only small, and so are the recoverable portions of the total strains, whereas for the polystyrene the opposite is true. This different behaviour is connected with a difference of the linear viscoelastic relaxation spectra at long relaxation times. The test results can be described efficiently by the Lodge‐Wagner rubberlike liquid constitutive equation.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call