Thermal-insulation performance of low density polyethylene (LDPE) foams: Comparison between two radiation thermal conductivity models
Journal Title: Polyolefins Journal - Year 2019, Vol 6, Issue 1
Abstract
The loss of energy, especially in industrial and residential buildings is one of the main reasons of increased energy consumption. Improving the thermal insulation properties of materials is a fundamental method for reducing the energy losses. Polymeric foams are introduced as materials with excellent thermal insulation properties for this purpose. In the present study, a deep theoretical investigation is performed on the overall thermal conductivity of low-density polyethylene (LDPE) foams. The thermal conductivity by radiation is predicted using two different methods. The most appropriate model is selected through comparing results with experimental data. The results show that the theoretical model has an appropriate agreement with the experimental results. The effects of foam characteristics including foam density, cell size, and cell wall thickness on the overall thermal conductivity are investigated. The results indicate that by decreasing the cell size and increasing the cell wall thickness, the overall thermal conductivity is decreased signifcantly. Also, there is an optimum foam density in order to achieve the smallest thermal conductivity. The lowest overall thermal conductivity achieved in the studied range is 30 mW/ mK at a foam density of 37.5 kg.m-3, cell size of 100 μm, and cell wall thickness of 6 μm.
Authors and Affiliations
Rezgar Hasanzadeh, Taher Azdast, Ali Doniavi, Richard Eungkee Lee
Effect of NH3/methylaluminoxane/dodecylamine modifiednanoclay on morphology and properties of polyethylene/ clay nanocomposites prepared by in-situ polymerization
This study presents methods for treating a kind of nanoclay and investigates the effects of methylaluminoxane (MAO) exposure time and or dodecylamine (DDA) reflux time on in-situ polymerization of ethylene in the presenc...
Testing DFT ability to predict the stereoselectivity of group 4 metallocenes in propylene polymerization
In this study we have tested the ability of a standard DFT computational protocol to reproduce the experimentally obtained stereoselectivity of 26 different C2-symmetric zirconocene catalysts active in propylene polymeri...
Polymerization of propylene in a minireactor: Effect of polymerization conditions on particle morphology
Gas phase polymerization of propylene was carried out in a semi-batch minireactor using a commercially supported Ziegler–Natta (ZN) catalyst. The influence of variables including monomer partial pressure, external electr...
Introduction of titanium species into fluorine-modified SiO2- supported Cr-V bimetallic catalyst for ethylene polymerization and ethylene/1-hexene copolymerization
Chromium-vanadium (Cr-V) bimetallic catalysts are prepared by the introduction of vanadium into the Phillips catalyst which is one of the most significant industrial ethylene polymerization catalysts for tuning the Phill...
Storage time effect on dynamic structure of MgCl2.nEtOH adducts in heterogeneous Ziegler-Natta catalysts
Primary MgCl2.3.3EtOH adduct (PCT1) was prepared by melt quenching method and then submitted into a programmed thermal dealcoholation project using a fluidized bed reactor. During thermal dealcoholation program, differen...