Electrical Properties of LLDPE/LLDPE-g-PS Blends with Carboxylic Acid Functional Groups for Cable Insulation Applications

Abstract

To improve the electrical properties of linear low-density polyethylene/linear low-density polyethylene-graft-polystyrene (LLDPE/LLDPE-g-PS) blends, carboxylic acid (−COOH) functional polystyrene (PS)-poly­(styrene-co-p-acryloyoxybenzoic acid) (P­(St-co-ABA)) was prepared by the copolymerization method. The effects of functional PS on the electrical and other properties of LLDPE/LLDPE-g-PS blends were systematically investigated. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results showed the addition of the copolymer had little influence on the crystal form and crystal size but increased the crystallinity degree of LLDPE/LLDPE-g-PS. Compared with LLDPE/LLDPE-g-PS blends, the dielectric constant and the dielectric loss tangent almost had no change. Due to the introduction of a polar group, the breakdown strength of blends was enhanced dramatically with an enhancement of 14.98%. Also, the space charge accumulation was suppressed obviously with a minimum mean volume charge density of 1.35 C/cm3. This supplies a serviceable means to obtain the high voltage direct current (HVDC) cable insulating materials.

Polystyrene: A Self-Dispersing, Ultralow Loading Additive for Improving the Breakdown Strength of Polypropylene for High Voltage Power Cable Applications

“…19,20 Most previous works have utilized aromatic small molecules with benzene derivatives, which could be incorporated into the polymer matrix through physical addition or chemical grafting with the PP matrix. 21,22 However, the physically mixed small molecules are quite volatile, and the chemical grafting requires a quite complicated procedure based on a wet chemical reaction. 23,24 Although one can expect that the polymeric materials would be potential additives to replace such small molecules, only few results on several polymers with aromatic conjugation, such as polypyrrole and poly(3hexylthiophene), have been reported and particularly rarely studied for a PP matrix.…”

“…A variety of inorganic nanoparticles (NPs), especially oxide NPs, such as SiO 2 , Al 2 O 3 , TiO 2 , MgO, ZnO, and ZrO, have been widely studied, and the electrical durability could be improved by the addition of a small amount of such NPs that act as trapping sites for charge carriers to lower their mobility. − Nevertheless, there are still many challenges for the use of inorganic NPs because their high surface energy makes them prone to agglomerate, giving rise to poor dispersion in the polymer matrix . Recently, organic additives have attracted much attention as voltage stabilizers (VSs) for PP materials due to their good compatibility with the PP matrix, allowing better dispersion than inorganic additives as well as efficiency in improving electrical durability, even at lower additive levels. , In particular, VSs with benzene derivatives have been found to facilitate the increase of the insulation properties such as volume resistivity and BD strength (BDS) because the benzene ring with delocalized electrons can capture high-energy electrons, thereby inhibiting the impact on polymer molecules. , Most previous works have utilized aromatic small molecules with benzene derivatives, which could be incorporated into the polymer matrix through physical addition or chemical grafting with the PP matrix. , However, the physically mixed small molecules are quite volatile, and the chemical grafting requires a quite complicated procedure based on a wet chemical reaction. , Although one can expect that the polymeric materials would be potential additives to replace such small molecules, only few results on several polymers with aromatic conjugation, such as polypyrrole and poly­(3-hexylthiophene), have been reported and particularly rarely studied for a PP matrix. ,, …”

Thermal and dielectric properties of two‐dimensional layered MXene (Ti3C2Tx) filled linear low‐density polyethylene composites

“…This semi-crystalline, nonpolar matrix has great flexibility, toughness, and stress-cracking resistance. 17 The viscosity of the material is high even in the molten form. The introduction of MXene can enhance not only its thermal, mechanical strength but also the electrical properties of LLDPE composite.…”

“…Linear low‐density polyethylene (LLDPE), thermoplastic extensively studied as power cable insulation. This semi‐crystalline, nonpolar matrix has great flexibility, toughness, and stress‐cracking resistance 17 . The viscosity of the material is high even in the molten form.…”

Modified Molecular Chain Displacement Analysis Employing Electro-Mechanical Threshold Energy Condition for Direct Current Breakdown of Low-Density Polyethylene

“…Polymeric insulators must endure a severe operating environment with a high DC voltage [ 4 , 5 ]. In an HVDC environment, many space charges are accumulated inside the polymeric insulator due to continuously applied one-directional voltage [ 6 , 7 , 8 , 9 ]. This space charge causes a distorted electric field, which plays a critical role in lifetime reduction [ 10 , 11 , 12 , 13 ].…”