Berlin 2001 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 18: Poster: Polymer Blends, Heterogeneous Systems, Colloids and Nanoparticles, Interfaces, Polyelectrolytes

CPP 18.25: Poster

Wednesday, April 4, 2001, 12:30–15:00, AT1

Influence of the transcrystallinity at interfaces on the mechanical properties of polymer composites — •Hans Kothe and Bernd Jungnickel — Deutsches-Kunststoff Institut, Schlossgartenstr. 6, 64289 Darmstadt

The mechanical properties of polymer composites depend decisively on the efficiency of the stress transfer between the polymer matrix and the composite material. Here, especially transcrystallinity at the composite surface should heavily influence those properties. The interface between both components should consequently be optimised in this respect if possibly at all.

We report on corresponding experiments on polypropylene/glass fibre and poly (ether ether ketone)/carbon fibre composites. Light microscopic, dynamic-mechanical, thermodynamic, and X-ray diffraction measurements were carried out. First, the conditions for the occurrence of strong transcrystallinity were investigated. The subsequent dynamic-mechanical measurements revealed then clear differences between several glass fibre/polypropylene composite systems of distinctly different transcristallinity. Especially above the glass temperature, the mechanical properties depend strongly on the extent of transcrystallinity. Upon existence of strong transcrystallinity, the lost in shear modulus between -50 C and 100 C is two times lower as in a system exhibiting only weak transcrystalline structure.