Search

Polyamide-imides (PAIs) are highly desired in many applications because of their superior thermal and mechanical properties. In this work, PAI was prepared from an amide-containing diamine and dianhydride by polycondensation and thermal treatment. Both PAI films and aligned electrospun nanofibers (ANFs) were fabricated. FT-IR was used to determine the structure formation of PAI at different annealing temperatures. DSC and TGA were used to evaluate the thermal properties of PAI, while tensile test was applied to evaluate the mechanical properties of PAI films and ANFs. The results indicated that the PAI possessed both outstanding thermal stability and mechanical properties, which provide opportunities for applications in gas separation, high temperature filtration, reinforcement, etc. [ABSTRACT FROM AUTHOR]

High mechanical performance carbon nanofibers are highly required for the carbon nanofiber-reinforced composites, and it is necessary to develop novel precursors for the preparation of carbon nanofibers. In this work, blends of poly(acrylonitrile-butyl acrylate mono-butyl itaconate) (co-PAN) and polyamic acid (PAA) were electrospun into aligned nanofibers and the nanofibers were converted to carbon nanofibers by thermal imidization, pre-oxidation and high-temperature carbonization. FT-IR spectroscopy was applied to monitor the chemical structures of the nanofibers before and after pre-oxidation. Tensile tests were used to characterize the mechanical properties of electrospun carbon nanofibers (ECNFs). The microstructures of ECNFs were investigated by high-resolution TEM and Raman spectroscopy. The results indicated that the ECNFs derived from blend of co-PAN/PAA with molar ratio of 6/4 and with carbonization temperature of 1400 °C possessed the highest tensile strength of 1212 MPa, which could be attributed to the ordered graphitic structures in ECNFs. [ABSTRACT FROM AUTHOR]