Regensburg 2004 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 13: SYMPOSIUM: Understanding and Controlling Complex Structures: From Synthetic Polymers to Biomaterials I

CPP 13.4: Talk

Tuesday, March 9, 2004, 10:45–11:00, H 37

A model describing the tensile deformation properties of semi-crystalline polymers exemplified for a sample of low density polyethylene — •Ke Hong, Ankur Rastogi, and Gert Strobl — Physikalisches Institut, Albert-Ludwigs-Universität, Hermann-Herder-Str.3, 79104 Freiburg, Germany

The tensile deformation behavior of a low density polyethylene was studied with the aim of understanding the different contributing forces and modelling the deformation properties of semicrystalline polymers. The sample PEVA12 which was used is capable of uniform deformation. In this way true stress-strain curves were obtained easily. Employing stress-relaxation measurement, the viscous force included in the stress was determined. The unrelaxable stress is quasi-stable and includes the network force and the crystal skeleton contribution. The results so obtained can be represented by means of a three components model in which a first component describes the crystal skeleton behavior with a spring combined with a finite-plastic element. Conventional Gaussian chain statistics are employed in a second component which deals with the stress arising from the entanglement network. A Hookean spring in series with a Eyring dashpot represents as the third component the relaxatory stress. Using this model experimental stress-strain curves, stress relaxation curves, creep curves and load-unload-cycle-tests can be well reproduced.
15 min. Pause