Regensburg 2002 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 3: Poster: Kristalline Polymere

CPP 3.6: Poster

Monday, March 11, 2002, 13:30–15:00, B

The Tensile Deformation Behaviour of Isotactic Poly(1-butene) — •Mahmoud Al-Hussein and Gert Strobl — Fakultät für Physik, Albert-Ludwigs-Universität, Hermann-Herder-Str. 3
79104 Freiburg, Germany

We present the results of a study concerning the tensile deformation behaviour of P1b. The results showed that along a true stress-strain curve, three different characteristic points can be seen that mark the transition between three different regimes. This includes a Hookean elastic regime, a strain-softening regime and a strain-hardening regime at increasing strain. This general behaviour has also been shown by a series of semicrystalline polymers in previous studies that carried out in our group. This has led to a better understanding of the deformation mechanisms of semicrystalline polymers. A semicrystalline polymer can be considered as a combination of two interpenetrating networks. The first is set up by some crystalline blocks forming the crystallites, and the other is set up by the entangled fluid regions. Consequently, both of these networks will contribute to any imposed deformation. However, the extent of each contribution varies during the course of deformation. At low strains, the crystalline network contribution dominates through changing the coupling and invoking some coarse slips of the crystalline blocks. As the strain is increased, the entangled fluid regions becomes increasingly strained. This carries on until a critical strain is reached where the force generated from entangled fluid regions reaches a critical value that would be able to destroy the crystallites. At this stage the dominant mechanism becomes the disaggregation of the crystallites.