Polyanthranilic acid (PANA) nanofibres, nanorods, nanospheres and microspheres were synthesized by polymerization of anthranilic acid using ammonium peroxydisulfate (APS) as oxidant without hard or soft templates. Polymerization of anthranilic acid was carried out in aqueous solutions of strong (hydrochloric) and weak (acetic) acids. The influence of synthetic parameters such as oxidant, initiator, dopant acid and its concentration, redox initiator, and reaction medium on the morphology and particle size of PANA have been investigated. PANA nanofibres and nanorods were obtained via redox polymerization of anthranilic acid initiated by FeSO4 as redox initiator. PANA nanospheres and nanofibres were also obtained when used aromatic amines as initiators. When polymerization carried out in the solution of weak (acetic) acid the microsphere morphology obtained and the particle size increase with increasing the concentration of weak acid. PANA nanorods were obtained also by polymerization of anthranilic in ethanol-water mixture unlike interfacial polymerization of anthranilic acid (in chloroform-water) that give PANA microspheres. The morphology and particle size of PANA was studied by scanning electron microscope (SEM) and transmission electron microscope (TEM). The average diameter of nanostructures obtained ≤100 nm. The optical bandgap of microspheres and nanofibers polymeric products were determined using UV-vis spectroscopic technique and found to be 2.0 eV and 1.6 eV, respectively. The bandgap decreased with decreasing the particle size. IR spectrum confirmed the structure of PANA nanofibres (synthesized with FeSO4 as redox initiator) in emeraldine form. The thermal stability of polymer obtained was determined by thermal gravimetric analysis (TGA). The molecular weight was determined also by gel permeation chromatography (GPC). |
