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oa Synthesis, characterization and industrial application of conducting copolymers of poly(aniline-co-2-bromoaniline)
- الناشر: Hamad bin Khalifa University Press (HBKU Press)
- المصدر: Qatar Foundation Annual Research Forum Proceedings, Qatar Foundation Annual Research Forum Volume 2012 Issue 1, أكتوبر ٢٠١٢, المجلد 2012, EEP97
ملخص
Objectives: The main objective of the present study is the development of a new generation of conducting polymers with different properties wrt conductivity, viscosity, solubility, UV and IR-spectroscopy etc. We also explore the synthesized new materials in industrial applications from the monomers to copolymer, such as aniline and ortho-bromoaniline. Aniline is widely used as a base material for synthesizing conducting polymers, but it has a solubility problem. These copolymers of aniline and substituted anilines show improved solvent solubility, while maintaining high electrical conductivity. Using aniline as one of the monomers, a copolymer of polyaniline (PA) with a desired molecular weight can be designed with enhanced physical and chemical properties. Methods: The homopolymers PA and poly(2-bromoaniline) (P-2-BrA) were chemically synthesized by oxidation of aniline and m-bromoaniline in hydrochloric acid medium. Results and discussions: The ring substituents introduce flexibility to the rigid PA backbone structure, and as a result the copolymers show higher solubility than PA. The second factor for increased solubility is the low molecular weight of the copolymers. The electrical conductivity of the copolymer is strongly dependent on the amount of substituted aniline incorporated. The PA is 1.25 x 10¯¹ S/cm and that of P-2-BrA is 1.59 x 10¯⁶ S/cm. Electrical conductivity of the polymer increases with the amount of 2-bromoaniline and, conversely, decreases with bromoaniline which may be restricting the mobility of electron. Conclusion: Aniline copolymerized with 2-bromoaniline forms soluble copolymers. The solubility decreases with increasing aniline monomer concentration in the copolymer chain. The different reactivity ratio of two monomers, 2-bromoaniline and aniline. Copolymers have lower conductivity and good solubility due to the existence of 2-bromoaniline molecules in the main chain of the copolymer. The solubility and electrical conductivity can be modified by varying comonomer composition and is dependent on the substituted groups. A soluble polymer is more easily processable than a insoluble one and is thus more attractive to industry.