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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 15: Poster Session I
CPP 15.56: Poster
Montag, 17. März 2025, 19:00–21:00, P4
The effect of the intracrystalline chain diffusion on the non-linear mechanical behavior of semicrystalline polymers — •Rose Mary Michell, Albrecht Petzold, and Thomas Thurn-Albrecht — Martin Luther University Halle Wittenberg, Institute of Physics, D-06099 Halle, Germany.
This work studies the influence of intracrystalline chain diffusion (ICD) on the mechanical properties of semicrystalline polymers by comparing PEO with fast ICD and PCL with slow ICD. Mechanical tests were performed under plane strain compression at temperatures from -10 to 55 ∘C and true strain rates from 0.005 to 10 min−1. At large deformations, the PCL always shows a strain hardening effect, while PEO shows softening when the rate decreases, temperature increases, and molecular weight decreases. The data corresponding to the strain hardening part, which describes the network forces, was fitted using the Gaussian model. The stress-strain curve for PCL showed higher stress than the Gaussian chain model predicted. In contrast, PEO had lower stress values; this difference could be attributed to an effect linked to chain mobility. For slow ICD, the crystals act as physical crosslinking points. Otherwise, the chains can be pulled from the crystals and soften the network. In conclusion, we found systematic differences in non-linear mechanical behavior between crystal-fixed and crystal-mobile polymers. This suggests that the competition between ICD and deformation determines the non-linear mechanical behavior at large deformations of semicrystalline polymers.
Keywords: Plane Strain compression; Semicrystalline polymers; αc relaxation