Functionally graded carbon nanofiber-phenolic nanocomposites for sudden temperature change applications

Functionally graded carbon nanofiber-phenolic nanocomposites (FGN) with four different gradient patterns and the same total carbon nanofiber (CNF) content and geometry were designed and fabricated. A Non-graded nanocomposite (NGN) was also fabricated for comparison purposes. Microstructural characteristics were examined by optical and scanning electron microscopy. Temperature-dependent thermal conductivity and heat capacity of the FGN components were measured and used in finite element analysis. A finite element analysis of transient thermal behavior of FGNs and NGN subjected to sudden temperature changes was performed to investigate the effects of compositional patterns on temperature gradient field. The finite element model was validated using a custom-made experimental setup. The results showed that the FGN with a gradual decrease in CNF content from the temperature-exposed side to the other had the lowest temperature gradient field and transient time.