Generation and characterization of carbon nano-fiber–poly(arylene ether sulfone) nanocomposite foams

In this study, carbon nano-fibers (CNFs) were used to increase the compressive properties of poly(arylene ether sulfone) (PAES) foams. The polymer composite pellets were produced by melt blending the PAES resin with CNFs in a single screw extruder. The pellets were saturated and foamed with water and CO2 in a one-step batch process method. Dynamic mechanical thermal analysis (DMTA) was used to determine the reduced glass transition temperature (Tg) of the CNF–PAES as a result of plasticization with water and CO2. Sharp transitions were observed as peaks in the tan δ leading to accurate quantitative values for the Tg. By accurately determining the reduced Tg, the foaming temperature could be chosen to control the foam morphology. Foams were produced which ranged in density from 290 to 1100 kg/m3. The foams had cell nucleation densities between 109 and 1010 cells/cm3, two orders of magnitude higher than unreinforced PAES foam, suggesting that the CNFs acted as heterogeneous nucleating agents. The CNF–PAES foam exhibited improved compressive properties compared to unreinforced PAES foam produced from a similar method. Both the specific compressive modulus and strength increased by over 1.5 times that of unreinforced PAES foam. The specific compressive strength of 59 MPa for the CNF–PAES foam is similar to that of commonly used high performance structural foam, poly(methacrylimide foam).