Characterization of Non-PFAS Underfill Behavior Under Harsh Operating Conditions

Abstract Per- and polyfluoroalkyl substances, or PFAS for convenience, are a group of synthetic chemicals that were first produced in the 1940s and are being widely used across a variety of industries. Their unique properties, including their resistance to heat, water, oil, and stains, are what make them so useful. Due to their remarkable persistence in the environment, they are often simply known as “forever chemicals.” Because PFAS have been found in water sources, soil, and wildlife, they are hard to eliminate from the environment and can accumulate in our bodies over time. They have also been linked to a variety of health issues, such as immune system dysfunction, developmental issues, and some cancers. More stringent regulations and the elimination of PFAS from consumer products and industrial applications are called for by governments, government agencies, and special-interest groups. In this paper, the influence of high-temperature storage at various temperatures and hygrothermal exposure under varied conditions on the development of non-PFAS underfill characteristics is examined. The samples are placed in high temperature ranges from 100 °C to 150 °C and kept in the humidity chamber for the absorption of moisture under 85 °C/85% relative humidity condition. Then, the underfill samples are tested under dynamic mechanical analyzer (DMA) with three-point bend mode. The oxidation layer developed after exposure of samples under a harsh environment is studied under polarized optical microscopy.