Preparation and Characterization of Thermally Stable Nanofiber Based on Polyamide 66/ Poly (amide-imide) Blend

Using aliphatic polyamides in electrospinning is very interesting due to their unique properties such as processability. But these polymers have some disadvantages of low dimensional stability and poor thermal stability that limited their use. To solve this problem, various methods such as polymer blending have been suggested. In this research, for the first time, a newly synthesized poly (amide-imide) (PAI) polymer was added to polyamide 66 (PA66) and nanofibers fabricated from PA66/PAI blend with different amounts of PAI polymer. Morphology, dynamical-mechanical properties and thermal stability of nanofibers were analyzed by SEM, DMTA, and TGA, respectively. SEM images revealed that the PA66/PAI nanofibers with uniform structure and without beads were prepared even for nanofibers containing 50% PAI. Moreover, with increasing PAI polymer content in PA66/PAI solution, the average nanofiber diameter increased from 319±66 nm for neat PA66 to 522±65 nm for nanofibers containing 50% PAI polymer. DMA results showed that the storage modulus of PA66/PAI nanofibers in both glassy and rubbery regions were higher than that of neat PA66 nanofibers. At 60 °C, the storage modulus values for neat PA66 nanofibers and PA66/PAI containing 50% PAI were 16.85 MPa and 70 MPa, respectively, showing about four times increase. Furthermore, by incorporating PAI polymer into PA66 matrix, glass transition temperature was moved to higher temperatures. TGA data indicated that with increasing the content of PAI polymer, thermal stability of PA66/PAI nanofibers improved significantly; 65 °C increase in Tmax was obtained for nanofibers containing 50% PAI as compared to neat PA66 nanofibers.