The Effect of Structural Parameters on the Cross-Linking of Various Grades of LLDPE

Document Type: Research Article

Authors

1 Department of Chemical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, I.R. IRAN

2 Department of Chemical Engineering, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, I.R. IRAN

3 Jam Petrochemical Company, Pars Special Economic Energy Zone (Assaluyeh), I.R. IRAN

Abstract

Polyethylene’s application for insulating is highly advanced but due to thermoplastic properties, its application confronts constraints such as the limited 70°C temperature of the conductor. Polyethylene thermosetting procedure in which molecules are knotted and a 3D-molecular-network formed is developed to conquer the mentioned problem and to raise the applicable temperature of the insulation. This paper reports the cross-linking of two cable grades of LLDPE by using DCP (Dicumyl Peroxide). DCP was chosen for its prevalence among various cross-linking agents. Structural parameters like molecular weight, melt flow index, viscosity and number of branches were obtained using relative tests as Gel Permeation Chromatography (GPC),Rheometry and Fourier Transform-InfraRed (FT-IR) spectrometer. After calculating the percentage of gel content, properties of the pure and cross-linked samples were compared by thermal and mechanical analysis with DSC, TGA, and DMTA. The effects of cross-linking like melting and decomposition temperatures, crystal formation, viscous and elastic modulus were discussed by using various structural parameters such as MFI, molecular weight, short chain branches. Studies declared that cross-linked polymer, unlike the pure one, had a solid state with thermal mechanical properties in the range of 110 to 120°C, so this assist overcomes the problem of using polyethylene in temperatures around the melting point.
 

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Main Subjects


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Volume 37, Issue 1 - Serial Number 87
January and February 2018
Pages 175-183