Cycloaliphatic epoxy (CE) systems are resistant to many aging mechanisms, which make them useful in applications with harsh environments. Reinforcement has been used in epoxy systems to decrease water absorption and improve aging resistance; thus, it is expected that talc would benefit CE systems in a similar manner. Neat, 10, and 20 wt% talc/CE composites were aged at 50 °C and 100% relative humidity for up to 398 hr. Three‐point bend testing and dynamic mechanical analysis were performed on the aged and unaged samples. Talc reduced the amount of water absorbed in the composites significantly, and increased the composite flexural stiffness at all aging levels. Talc does not appear to mitigate the negative effects of aging on flexural strength or glass transition temperature (Tg). POLYM. COMPOS., 40:2946–2953, 2019. © 2018 Society of Plastics Engineers

Additive Manufacturing (AM) has opened the door for portable and self-sufficient fabrication. However, environments with base vibration degrade part quality during production. This work focuses on investigating and mitigating the effects of base vibration on AM part quality. Factors influencing part quality initiated the approach, followed by experiments on an extrusion-type printer to inspect and minimize vibration effects. Part roughness was used as the part quality metric based on preliminary experimental observations. A modal impact test identified the print bed and print head gantry as vibration-sensitive components at ≈ 40 Hz. These vibration modes were targeted with experiments to evaluate and reduce vibration effects. Vibration originating from machine operation and vertical base vibration were compared. Part quality was impacted by base vibration 600 × more than by machine operation. Part roughness correlated with vertical base vibration intensity as the roughness standard deviation increased over 85%, from 187.71 μ in to 349.01 μ in, for parts printed with base vibration compared to parts printed without. This result indicated base vibration as the primary vibration source that leads to part quality degradation. A passive vibration control scheme was implemented resulting in a 93% reduction in the relative motion between the print head and bed, from 23.71 to 1.75 g/g, and a 16% improvement in part surface roughness, from 1015.60 to 850.39 μ in. This research provides direction for extending AM to harsh operational environments.