In situ polymerization of aniline in the presence of carbon black

Abstract

A hybrid material of polyaniline doped with dodecylbenzenesulfonic acid and conductive carbon black (PaniDBSA/CB) was prepared by in situ polymerization. The presence of low amount of CB (up to 25 wt %) resulted in a decrease in resistivity as compared to pure PaniDBSA. Composite with 25 wt % of CB presented the lowest resistivity and a tubular morphology characterized by microtubules with high aspect ratio evidenced by SEM examination. Higher amount of CB give rise to materials with higher resistivity values and a granular morphology, similar to pure carbon black. Ultraviolet-visible and electron paramagnetic resonance analyses were employed to evaluate the polaron concentration. X-ray diffraction was used to characterize the molecular structure of these composites. It was observed a decrease in the crystallinity degree and a shift of the polaron band transition toward lower wavelength as the amount of CB in the composite increases. From the EPR measurements, one can suggest that the higher chain order and polaron mobility is observed in hybrid with 25% of CB. This behavior is in agreement to the electrical resistivity values and SEM microscopy. The effect of CB on thermal stability of the composites was also investigated. The effect of the PaniDBSA/CB hybrid material on the processability and resistivity of the composites based on styrene-butadiene-styrene (SBS) block copolymer as the insulating matrix have been also evaluated.

A Sensor for Acid Concentration Based on Cellulose Paper Sheets Modified with Polyaniline Nanoparticles

“…Although improvement of electrical resistivity is not pursued in this work, some differences were observed between the electrical resistivities of the original and modified paper strips. Original paper strips presented electrical resistivity of (1.4 ± 0.3) × 10 10 Ω · cm −1 , while PAni DBSA presented electrical resistivity of (1.9 ± 0.5) × 10 2 Ω · cm −1 and paper strips modified with PAni DBSA presented electrical resistivity of (5.4 ± 0.3) × 10 8 Ω · cm −1 , which may be regarded as a very large value 44–49. Although this value is not very impressive, it must be noticed that the amount of PAni DBSA incorporated into paper strips was very small and equal to (1.3 ± 0.4) × 10 −4 g · cm −2 .…”

Natural Brazilian Amazonic (Curauá) Fibers Modified with Polyaniline Nanoparticles

“…After modification with PAni Á H 2 SO 4 , electrical conductivity increases 2 500 times, reaching (1.01 AE 0.01) Â 10 À4 S Á cm À1 . Although these may be regarded as low conductivity values, [35][36][37][38][39][40][41][42][43][44] modified fibers can be used for manufacture of electronic devices that are fed by 9 V batteries, as usually employed when safe human applications are pursued, including applications in the automobile industry. [35,36] (It is worthy mentioning that less than 2 wt.-% of PAni was used to prepare the modified curauá fibers.…”

In situ determination of aniline polymerization kinetics through near‐infrared spectroscopy

“…Pani·DBSA was synthesized through a one‐step route in water according to a procedure reported elsewhere 8, 21. The reactions were performed under a normal air atmosphere, as we never observed significant differences among the results obtained from different runs (probably because of the relatively large concentrations of free radicals in the system).…”

“…NIR conversions were calculated with absorbance data obtained at 1026 nm. The gravimetric conversion of aniline was calculated with the assumptions that 50% of the nitrogen atoms of the Pani chains were in the imine form and that all imine groups were protonated by DBSA 8…”

“…Polyaniline (Pani) has attracted much attention in the last 2 decades because of its potential for different electro/electronic applications 1–7. In addition, Pani, when compared to other conducting polymers, shows remarkable advantages, including easy chemical synthesis, high stability toward environmental exposition, and special electronic properties, which can be reversibly controlled through charge‐transfer doping and protonation 8…”