Crystallization of Polyethylene at Large Undercooling
| Autor: | Arnold Lustiger, Christoph Schick, René Androsch, Evgeny Zhuravlev, Vadlamudi Madhavi |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Ethylene Polymers and Plastics Organic Chemistry Thermodynamics 02 engineering and technology Calorimetry Polyethylene 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention Inorganic Chemistry chemistry.chemical_compound Crystallography chemistry law Materials Chemistry Copolymer Vitrification Crystallization 0210 nano-technology Supercooling Order of magnitude |
| Zdroj: | ACS Macro Letters. 5:365-370 |
| ISSN: | 2161-1653 |
| Popis: | Extremely fast crystallization of high-density polyethylene and random copolymers of ethylene with up to 16 mol % 1-octene was observed for the first time by ultrafast scanning calorimetry. In order to account for the inherently high crystallization rate of polyethylenes, in nonisothermal and isothermal crystallization experiments cooling rates up to 1 000 000 K/s and crystallization times as short as 10 μs, respectively, were employed. It was possible to supercool the melt of high-density polyethylene down to 57 °C and the melt of a random ethylene/1-octene 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 μs. 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 random ethylene/1-octene copolymers both are nearly parallel shifted to lower temperatures. Fast crystallization under conditions of reduced linear crystal growth rate is possibly caused by boosting homogeneous nuclei density up to 10 |
| Databáze: | OpenAIRE |
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