A sequential evaluation workflow for early‑stage screening of outdoor electrical insulation polymer-based materials: a comparative case study

Polymer‑based outdoor electrical insulation materials are subjected to combined environmental and electrical stresses. Such stresses progressively influence material properties such as surface wettability, tracking and erosion resistance, UV stability, flammability, and dielectric performance. During material development, extensive qualification testing is often required. This highlights the need for structured experimental strategies that facilitate early‑stage screening. In this work, a sequential evaluation workflow is proposed to systematically assess key surface‑related and bulk material properties relevant to outdoor insulation applications. The workflow prioritizes early characterization of static and dynamic wettability, followed by electrical tracking and erosion testing as a primary performance discriminator. Subsequent experimental steps—including UV/water‑spray aging, hydrophobicity transfer, flammability classification, adhesion testing for coatings, and dielectric or mechanical characterization for bulk systems—provide additional insight into performance‑relevant material responses. The approach is demonstrated through a comparative case study involving two polymer‑based material classes: a silicone‑based composite coating applied to an epoxy substrate and a bulk hydrophobic cycloaliphatic epoxy formulation. The study does not aim to establish a universally valid or optimal qualification methodology. Instead, it demonstrates how a hierarchical testing sequence can support transparent comparison of polymer‑based insulation materials and guide early down‑selection during material development.