Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 29: Poster: Crystallization, Nucleation, Self Assembly
CPP 29.3: Poster
Dienstag, 8. März 2016, 18:15–21:00, Poster B2
Isothermal and non-isothermal crystallization of polyethylene at large undercooling — •Evgeny Zhuravlev1, Vadlamudi Madhavi2, René Androsch3, and Christoph Schick1 — 1University of Rostock, Institute of Physics, Wismarsche Str. 43-45, 18051 Rostock, Germany — 2ExxonMobil Research & Engineering Company, 1545 Route 22 East, LD 152, Annandale, New Jersey 08801, USA — 3Martin-Luther-University Halle-Wittenberg, Center for Engineering Sciences, 06099 Halle/S., Germany
The crystallization kinetics of high-density polyethylene and random copolymers of ethylene with up to 16 mol% 1-octene was studied by ultra-fast scanning calorimetry. In order to account for the inherently high crystallization rate of polyethylenes, in non-isothermal and isothermal crystallization experiments cooling rates up to 1,000,000 K/s and crystallization times as short as 10−6 s, respectively, were employed. It was possible to supercool the melt of high-density polyethylene down to 57 ∘C, and the melt of a copolymer with 16 mol% 1-octene down to -33 ∘C, without prior crystallization. At these temperatures, the characteristic time of the primary crystallization process is of the order of magnitude of 100−6 s. Complete vitrification of the liquid would require cooling even faster than 1,000,000 K/s. Compared to the homopolymer, the cooling-rate dependence of the crystallization temperatures and the temperature dependence of the characteristic time of primary crystallization of copolymers both are essentially parallel shifted to lower temperatures, which is suggested being caused by the depression of the equilibrium melting temperature.