Browsing by Subject "polyethylene"

Now showing 1 - 3 of 3

Access status: Open Access ,
Considering semi-crystallinity in molecular simulations of mechanical polymer properties - using nanoindentation of polyethylene as an example
(Wydawnictwa AGH, 2021) Fritz, Susanne
Molecular dynamic (MD) simulations have been used to investigate the response of semi-crystalline polymers in nanoindentation tests, using polyethylene (PE) as an example. To that purpose, semi-crystalline simulation boxes of linear PE with various chain lengths up to C2000 were created by homogeneous nucleation during the non-isothermal cooling of melts. The final crystallinity depended on the chain length and the cooling rate used and could be estimated using various parameters like density, fraction of bonds in trans conformation, and energy terms. The simulation boxes were transferred into surface models and subjected to nanoindentation tests using non equilibrium MD. This allowed the deformation behaviour of the material to be analysed directly. Strong dependencies on the crystallinity of the PE were found, which underlines the importance of considering crystallinity when investigating the mechanical properties of semi-crystalline polymers by means of simulations.
Access status: Restricted ,
Izolacja, identyfikacja i zastosowanie mikroorganizmów glebowych w utylizacji produktów polietylenowych
(Data obrony: 2012-10-05) Kowalczyk, Anna
Wydział Geologii, Geofizyki i Ochrony Środowiska
Disposal of waste is now one of the most important contemporary environmental issues and the increasing amount of waste tends to seek new methods of disposal, in addition to burning and costly recycling. Particularly troublesome are the environmental waste polymers, including polyethylene material resistant to degradation. The present study sought to lead to degradation of the chemical structure of polyethylene with the participation of microorganisms. The biological material was isolated from the soil, and the substance has been degraded high density polyethylene (HDPE) in the form of foil. Disinfected samples were subjected to the action of microorganisms suspended in a liquid medium Davis Minimal Broth for 44 days. The medium was a modified chemical composition, so that the main carbon source for the microorganisms was polyethylene. During the breeding experiments the development of microorganisms population was controlled by making measurements of the optical density OD650. The microorganisms were identified as Achromobacter xylosoxidans and the film samples FTIR research showed degradation structure of HDPE.
Access status: Restricted ,
Pyrolysis of plastic using montmorillonite-based catalysts
(Data obrony: 2015-12-18) Ligenzowska, Dorota
Wydział Energetyki i Paliw