Exploring the Weathering and Accelerated Environmental Aging of Wave-Transparent Reinforced Composites

Approaches to retain or improve wave-transparent composite properties received ongoing attention. Silica glass fiber composites are being utilized in wave transparency applications owing to their excellent dielectric properties. During operational service life, they are exposed to ambient and harsh environments, which degrade their performance and properties. The objective is to evaluate the progressive degradation of silica fiber wave-transparent composite material's properties and overall performance. Silica fiber/epoxy wave-transparent composites (SFWCs) were fabricated by stacking high-silica glass cloth (HSG) plies via multi-layer compression and curing at 150 °C (14 hrs) and were investigated upon one-year real-time weathering and 20-year accelerated aging (Hallberg peck model). The morphology of one-year-aged SFWC composite was found to be better than that of 20-year-aged SFWC, where relatively weakened interfacial bonding and composite structure were observed. One year weathering the dielectric constant (ε_r) was increased to 4.34%, and dielectric loss (δ) was found to be 5.6%, whereas upon accelerated conditions (equivalent to 20 yrs of ambient conditions), ε_r was significantly raised 30.63% from its original value (3.2), and δ was increased 22.8% (0.035). In the 20-year aged SFWC composite, the maximum absorbed moisture was 3.1%. Tensile strength dropped from 147.8 MPa to 136.48 MPa, and compressive strength from 388.54 MPa to 374.41 MPa. Upon aging (from 1 year of weathering to 20 years of accelerated aging), SFWC composite properties and functional performance were lowered but remained reasonable. SFWC properties, as revealed by microscale characterization, can contribute to the determination of the impact of deterioration and useful service life in respective microelectronics wave transparency applications.