Studies on Electrical and Thermal Properties of Vinyloxyaminosilane Grafted Ethylene–Propylene–Diene Terpolymer/Linear Low Density Polyethylene Blends for Cable Applications

Abstract

ABSTRACT:A new terpolymer of vinyloxyaminosilane (VOS) grafted onto ethylene-propylene-diene terpolymer (EPDM) has been synthesised in a Haake Rheocord-90, torque rheometer. Vinyloxyaminosilane grafted ethylenepropylene-diene terpolymer/linear low density polyethylene (EPDM-g-VOS/LLDPE) blends with different compositions were prepared using a two roll mixing mill. The electrical properties such as surface and volume resistivities, dielectric strength and arc resistance are decreased and dielectric constant and dielectric loss are increased with increasing percentage composition of LLDPE in EPDM-g-VOS/LLDPE blends due to enhanced crosslink density. The incorporation of VOS moiety onto EPDM improves the inception decomposition and final decomposition temperatures due to stable three dimensional network and high bond energy of -Si-O-Si-linkage. The values of T g are increased with increasing concentration of LLDPE in the EPDM-g-VOS/LLDPE blends due to enhanced crystallinity and crosslink density. Thermal aging studies on mechanical properties show that the tensile strength, elongation at break and Young modulus are decreased due to disruption of crosslinking at LLDPE sites.KEY WORDS Vinyloxyaminosilane grafted Ethylene-Propylene-Diene Terpolymer/Linear Low Density Polyethylene (EPDM-g-VOS/LLDPE) Blends / Dielectric Strength / Arc Resistance / Dielectric Constant / Inception Decomposition / Thermal Ageing / Synthetic polymers find number of applications in the field of electrical insulation, as molded components and as extruded cables. Crosslinking of thermoplastic polymers with organic and/or other curing agents leads to a three dimensional network structure having adequate thermal endurance properties coupled with good dielectric and mechanical properties. A good combination of flexibility and strength is an essential requirement of cable insulant. A continuous effort is being made to improve mechanical and thermal endurance properties of cable insulant without significant loss of dielectric characteristics. The advent of a newer technique, involving the grafting of silanes onto the polymer chain followed by its subsequent condensation reaction in the presence of moisture and catalyst is more attractive due to various advantages. The service life of cable insulant materials suffers from thermooxidative aging and degradation. Thermal stability of these polymers depends upon the type and nature of cross-link system.The selection of polymeric insulating material for cable application depends upon various factors. 1-3 Different thermal and electrical testing techniques are applied for quality checkup for cable materials. [4][5][6] Cables for special applications areas such as resistance to oil, resistance to flame and fire requires specific characteristics. 7,8 Gartasegna 9 developed low-voltage and mediumvoltage cable insulant products using vinyltrimethoxysilane (VTMO) grafted and moisture crosslinked ethylene-propylene copolymer (EPR) and ethylenepropylene-diene terpolymer (EPDM) and charecterised. Tanida et al. 10...

An efficient strategy triggered crosslinking of polyethylene and its application in degassing‐free ultrahigh voltage power cables

“…Low-density polyethylene (LDPE) grade 2220H with an MFI of 2 g/10 min and a density of 0.920 g/cm 3 was supplied by BASF-YPC company, China. 4,4 0 -thiobis (6-tertbutyl-m-cresol) antioxidant with a density of 1.12 g/cm 3 was purchased from SI Group, Inc. Dicumyl peroxide with purity of 98% and a density of 1.02 g/cm 3 was provided by Nouryon Chemicals International B.V., China. 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane with a purity of 90% and density of 0.866 g/cm 3 was purchased from Shanghai SendChem Co., Ltd.…”

“…However, low thermal stability and breakdown strength of PE limit its industrial applicability, especially in the field of high-voltage (HV) and ultrahigh voltage (UHV) power cables. [2][3][4] Therefore, crosslinking of polyethylene (XLPE), which forms a three-dimensional network through intra-or intermolecular chemical bonding, is an effective strategy to strengthen the thermal, mechanical and chemical properties. [5][6][7][8][9] XLPE is extensively utilized in the insulation of HV and UHV power cables and is superior to all other insulation materials due to its high thermal stability, mechanical and electrical properties, as well as a wide range of voltages.…”

“…Polyethylene has excellent electrical insulation, chemical resistance, and high impact strength. However, low thermal stability and breakdown strength of PE limit its industrial applicability, especially in the field of high‐voltage (HV) and ultrahigh voltage (UHV) power cables 2–4 . Therefore, crosslinking of polyethylene (XLPE), which forms a three‐dimensional network through intra‐ or intermolecular chemical bonding, is an effective strategy to strengthen the thermal, mechanical and chemical properties 5–9 .…”