SNIC
SUPR
SNIC SUPR
Coarse Grained Molecular Dynamics Simulations of Semicrystalline Polymers with focus on Crystallization, Mechanical Behavior and Electrical Properties
Dnr:

SNIC 2018/3-65

Type:

SNAC Medium

Principal Investigator:

Ulf Gedde

Affiliation:

Kungliga Tekniska högskolan

Start Date:

2018-01-30

End Date:

2019-02-01

Primary Classification:

10407: Theoretical Chemistry

Secondary Classification:

10406: Polymer Chemistry

Tertiary Classification:

20403: Polymer Technologies

Allocation

Abstract

Polyethylene (PE) with bimodal molecular weight distributions (i.e. both long and short chains) often have improved mechanical as well as electrical properties as compared to unimodal PE [1]. It is known that the fraction of tie-chains and entanglements bridging the PE crystal lamellae influences the properties of pure PE [2,3], but a significant part of the underlying physics needs further study. An increased knowledge in this field is crucial for the development of the more sustainable PE-based products. We are intending to use large scale atomistic and coarse-grained simulations techniques (including both Molecular Dynamics Monte-Carlo simulations) for explaining why the properties of PE are affected by the bimodality of the molar mass distribution. The gained knowledge is important for the process of tailor-making the polymer to obtain optimum properties for the given application. Coarse Graining codes will be used to obtain coarse-grained potentials based on atomistic Molecular Dynamics (MD) and Monte Carlo (MC) simulations. Having the coarse grained potentials, MD/MC simulations will be performed for predicting morphology and structure/property relationships for semicrystalline polymers and polymeric nanocomposites. Electrical and mechanical properties as well as transport properties (diffusion/solubility) will also be examined. The mechanical and electrical performance of bimodal polyethylene systems is a very urgent area, which will provide extremely important information towards further development of important products, e.g. high pressure pipes, high voltage direct current cables, etc., to be used in the green development of our energy systems. We have a long tradition in this type of research. Prof. Ulf Gedde was one of the principal scientist to provide this way of thinking in the 1980s which finally lead to the Borstar material group (Borealis, Sweden). We have published probably of the order of 50 scientific papers, mostly experimental. The very novel type of modelling here proposed is in the absolute research frontier. [1] M. Andersson et al, ACS Macro Letters 6(2):78, 2017 [2] A. Moyassari et al. The Journal of Chemical Physics 146 (20), 204901, 2017 [3] F Nilsson et al. Polymer 53 (16), 3594-­‐3601, 2012