Study on the Influence Mechanism of Molecular Sieve Structure on the Dielectric Properties of Ldpe Composites

Nano-doping is a useful technique for improving the dielectric characteristics of polymers in the field of engineering dielectrics. The structure, size, and content of filler particles are some of the variables that affect the macroscopic dielectric characteristics of composites. It has been demonstrated that molecular sieves, inorganic porous materials, are advantageous for enhancing the dielectric performance of materials. The influence of porous materials and their diverse pore architectures on composite dielectric characteristics is the main focus of this investigation. For the studies, two kinds of molecular sieves were chosen: MCM-41 (1D straight pores) and MCM-48 (3D interconnected pores). They were mixed with low-density polyethylene (LDPE) to create composites with mass fractions of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.1 w t \%, 0.3 w t \%$</tex>, and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.5 w t \%$</tex> following surface modification using a coupling agent. The findings demonstrated that KH550 was successfully grafted onto the molecular sieves; however, in contrast to MCM-48, MCM-41 did not disperse well in the composite. The conductive current properties of LDPE and molecular sieve/LDPE composites were examined at 30° C in various electric fields. Smaller pore diameters and more intricate pore architectures resulted in higher threshold field strengths for space charge limited current, while molecular sieve doping decreased the conductive current. Tests of the AC/DC breakdown field strength showed that MCM-48/LDPE composites significantly outperformed LDPE, with low-doped composites having higher breakdown field strengths. Composite dielectrics are generally positively impacted by complicated pore architectures in porous materials, providing insightful information. Overall, complex pore structures in porous materials positively affect composite dielectrics, offering valuable insights for enhancing polymer dielectrics through inorganic pore structure doping and advancing next-generation insulating cables.