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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 48: Poster: Polymer Crystallization, Nucleation and Selfassembly

CPP 48.5: Poster

Mittwoch, 22. März 2017, 18:30–21:00, P2-OG1

Separated lamellae of HDPE solidified from melt by slow cooling. — •Heinz H.W. Preuss — Hameln

The poster shows a representative selection of TEM photographs of mechanically separated lamellae of HDPE by H. Preuss (1). The specimen was heated in an oven and held for 20 minutes at 200 degrees centigrade, cooled down to 100 degrees centigrade in 30 minutes (3 K/min). The free surface was covered with a thin layer of gold (20 nm) by evaporation in vacuum. The gold layer was thickened with Cu by galvanization (0,1 mm). The metal sheet was torn off and the surface covered with C by evaporation in vacuum under an angle of nearly 30o. Then the copper was resolved with nitric acid and the gold after addition of hydrochloric acid. The C layer was put in the TEM on a grid woven with bronze wire. In the TEM one could see lamellae of polyethylene attached at the C layer showing the relief of the fracture surface by shadowing. The orientation of the molecular chains perpendicular to the plane of lamellae cold be confirmed by electron diffraction. Thus the chain folding model of A. Keller (2) cold be confirmed for HDPE solidified from the melt. 1. H.H.W.Preuss, physica status solidi Nr. 3 1963, 109 K ff; Plaste und Kautschuk 22. Jg. Heft 12/1975, 258 f. 2. 2. A. Keller, Kolloidzeitschrift, 165, 3 (1959)