Molecular Dynamics of High-Density Polyethylene Composites: Effects of Welding Temperature
The polyethylene pipes have always played an extremely significant role in gas and water distribution networks because of their numerous advantages [1]. For tightly joining two polyethylene pipe components, thermal butt-fusion welding processes are always the preferred method [2, 3, 4]. The nature of this welding method is to generate temperature-induced physical changes in the welding region of polyethylene, leading it to transition into glassy, rubbery, and viscous states, respectively at various temperatures, respectively [5]. The quality of welding joints is one of the most crucial factors considered, which is typically determined by the heating temperature, heating pressure, and heating time.
The purpose of this study was to investigate the effect of temperature on the quality of welding joints of high-density polyethylene at the molecular level. In this study, the welding system (HDPE polymer model) of MD simulation consists of two parallel molecular chains, each composed of 30 monomers, with a parallel distance of 5Å. The MD (Molecular Dynamics) [6] simulations of energy distribution, geometry optimization, molecular dynamics, and mechanical properties were performed with varying temperature, fixed pressure, and fixed time based on COMPASSâ…˘ Forcite in Material Studio 2023. The temperature range investigated spanned from 200°C to 350°C in increments of 30°C, with a fixed pressure of 0.2 MPa and a fixed total simulation time of 150 ps.
This study primarily took the interfacial energy, mean-squared displacement (MSD), radial distribution functions (RDFs) into consideration across different temperatures. By analyzing these results from the MD simulations, the study aims to gain a comprehensive understanding of the effect of temperature on the quality of welding joints of high-density polyethylene from the molecular perspective. Furthermore, research results of this study can also provide certain guidance for high-speed welding of polymers.
Polyethylene pipe, molecular dynamics, interfacial energy, mean-squared displacement (MSD), radial distribution functions (RDFs), temperature
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