Date Approved

9-8-2026

Embargo Period

9-8-2026

Document Type

Thesis

Degree Name

M.S. Mechanical Engineering

Department

Mechanical Engineering

College

Henry M. Rowan College of Engineering

Advisor

Wei Xue, Ph.D.

Committee Member 1

Behrad Koohbor, Ph.D.

Committee Member 2

Xiaohui Xu, Ph.D.

Disciplines

Engineering | Mechanical Engineering

Abstract

High-temperature superconducting (HTS) cables require dielectric insulation materials that can withstand cryogenic operating environments while maintaining electrical reliability, mechanical stability, and manufacturing compatibility. This thesis investigates polyamide-based polymer nanocomposites as candidate HTS cable insulation materials and develops cryogenic testing platforms for evaluating thin-film dielectrics at reduced temperatures. Two silicon-based filler systems are studied: sol-gel-derived silicon dioxide (SiO 2 ) nanoparticles and polyhedral oligomeric silsesquioxane (POSS). Dielectric breakdown behavior is evaluated under DC and AC high-potential testing, while mechanical behavior is assessed through tensile testing. The results show that PA/SiO 2 nanocomposites provide the strongest overall balance of mechanical reinforcement and cryogenic dielectric performance, while POSS/PA nanocomposites demonstrate strong room-temperature dielectric enhancement at low loading but require further processing optimization. In addition, liquid-nitrogen-cooled testing systems and a gaseous-helium dielectric testing system are developed and refined to expand laboratory- scale cryogenic characterization capability. Overall, this work identifies key material tradeoffs in PA-based silicon nanocomposites and establishes testing methods for future HTS insulation-material development.

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