Nuray Kizildag

Synergistic effect of polyaniline, nanosilver, and carbon nanotube mixtures on the structure and properties of polyacrylonitrile composite nanofiber

In this study, various amounts of carbon nanotubes (CNTs), nanosilver (AgNPs), and polyaniline (PANI) were incorporated at the same pot into the structure of composite polyacrylonitrile (PAN) nanofibers, which were produced by electrospinning process in order to see synergistic effect of the additives on the final properties of the composite materials. Performance and characteristic properties of composite nanofibers were analyzed by tensile tester, electrical conductivity meter, Fourier Transform Infrared Spectroscopy, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and antimicrobial activity test. Statistical analysis (analysis of variance) was performed to see whether the differences were statistically significant or not. It was seen that samples with AgNPs had higher breaking strength and electrical conductivity than the samples with CNTs. Generally, PANI improved the crystallinity of the composite material more than the nanoparticles (CNTs and AgNPs). Even though each of the nanoparticles was used in low concentrations, the composite materials (PAN–1CNT–1AgNO3–R and PAN–PANI–1AgNO3–R) gained antimicrobial properties due to the synergistic effect of additives. The results suggested that PAN composite nanofibers with 3 wt% PANI and 1 wt% AgNO3 generally presented better performance than the other samples in terms of electrical conductivity, antimicrobial activity, mechanical strength, crystallization, and thermal stability.

Polyacrylonitrile-polyaniline composite nanofiber webs: Effects of solvents, redoping process and dispersion technique

This study was carried out to examine the effect of different solvents (DMSO, NMP, DMF) and solvent mixtures, application of dispersion and mixing techniques during solution preparation and redoping process on polyacrylonitrile (PAN) and camphorsulfonic acid (CSA) doped polyaniline (PANI) composite nanofibers. It was observed that nanofibers produced from DMSO and NMP solvents had larger fiber diameters than nanofibers produced from DMF. When the crystallinity of the 100 % PAN nanofibers were compared, the nanofibers electrospun from DMSO had the lowest crystallinity values. The tensile breaking stress values of the nanowebs produced from DMSO and NMP were higher than nanowebs produced from DMF while the breaking elongation values of the nanowebs produced from DMF was higher. Mechanical dispersion technique resulted in higher tensile breaking stress values than corresponding magnetic stirring. The redoping process also affected the tensile properties of the nanowebs by increasing the breaking stress values and decreasing the breaking elongation values. When DMSO was used as a solvent for the production of composite nanofibers, the electrical conductivity values at around 10−6 S/cm were obtained corresponding to the semiconductive material range. The use of solvent mixtures resulted in better conductivity values than their counterparts. When CSA-NMP and CSA-NMP/DMF were compared, the nanofibers produced from the solvent mixture had higher conductivity values. On redoping, the conductivity increased 10 times and reached 1.2×10−5 S/cm. The reference samples with DMSO had the lowest cyclization temperature and enthalpy. Addition of PANI increased the thermal stability of the composite nanofibers in comparison with pure PAN.

The effect of the dissolution process and the polyaniline content on the properties of polyacrylonitrile–polyaniline composite nanoweb

There are several studies regarding polyacrylonitrile composite nanofibers with polyaniline doped with dodecylbenzene sulfonic acid and solved by N,N′-dimethyl formamide which were mostly performed to analyze the thermal and morphological properties. In this study, camphor sulfonic acid-doped polyaniline and polyacrylonitrile composite nanofibers were electrospun from solutions in dimethylsulfoxide and the effect of polyaniline content and the application of different dissolution methods on the morphology, chemical structure, conductivity, crystallinity, mechanical, and thermal properties of nanowebs were investigated. Morphology, nanofiber diameters, chemical structure, crystallinity, mechanical properties, and thermal properties of the nanofibers were all affected by the polyaniline addition. Compared to the conductivity of neat polyacrylonitrile nanofibers, the conductivity of the composite nanofibers was improved, reaching a value higher than 10−6 S/cm with 3 wt% polyaniline content which was in the range for electrostatic discharge applications (10−9 to 10−6 S/cm). Increase in dissolution time and application of ultrasonic homogenization affected the diameter, mechanical properties, crystallinity, and thermal properties of the nanofibers, while they had negligible effects on conductivity.

The effect of dispersion technique, silver particle loading, and reduction method on the properties of polyacrylonitrile–silver composite nanofiber

The effect of dispersion technique, reduction method, and the amount of silver nanoparticles on the properties of composite polyacrylonitrile nanofiber containing silver nanoparticles is analyzed using differential scanning calorimetry, scanning electron microscopy, electrical conductivity, tensile testing, X-ray diffraction, and antimicrobial efficiency measurements. Composite nanofibers reduced by hydrazine hydroxide result in smaller diameter, higher electrical conductivity, higher breaking strength, higher cyclization enthalpy than the samples reduced by xenon arc method. Reduction process results in smaller diameter and higher breaking strength than those of non-reduced nanofiber web containing AgNO3 nanoparticles. Dispersion by ultrasonic homogenizer/bath provides higher breaking strength, electrical conductivity than the samples dispersed by only magnetic stirrer. An increase of silver nanoparticle generally results in an increase of enthalpy, a decrease of both cyclization temperatures and crystallinity. While 1 wt% AgNO3 loading is suitable for high breaking strength, 3 wt% AgNO3 loading is suitable for both high electrical conductivity and antimicrobial properties. Insulator polyacrylonitrile polymer becomes a semiconducting material.

Polyacrylonitrile/polyaniline composite nanofiber webs with electrostatic discharge properties

In this study, composite nanofibers of polyacrylonitrile (PAN) and polyaniline (PANI) were successfully produced by electrospinning technique and the effects of different dopants such as camphorsulfonic acid (CSA), dodecylbenzene sulfonic acid (DBSA) and dodecylbenzene sulfonic acid sodium salt (DBSANa+), and different solvents such as dimethylsulfoxide (DMSO) and N,N′-dimethylformamide (DMF) on the properties of PAN/PANI composite nanofiber webs have been investigated. It has been observed that nanofibers produced from DMSO generally had larger fiber diameters and higher breaking strength than nanofibers produced from DMF. CSA could dope better than DBSA(iso) and DBSANa+. CSA resulted in the highest conductivity when DMSO was used while it resulted in lower conductivity in DMF. The insulator PAN became a semiconductive material with the incorporation of CSA-doped PANI. The highest electrical conductivity obtained was 10−6 S/cm which is in the range suitable for electrostatic discharge applications.

Investigation of the properties of PAN/f-MWCNTs/AgNPs composite nanofibers

In this study, composite nanofibers from a solution of polyacrylonitrile (PAN), functionalized multi-walled carbon nanotubes (f-MWCNTs), and silver nitrate (AgNO3) in dimethylsulfoxide were successfully produced by the electrospinning method. Aqueous solution of hydrazinium hydroxide was used for the chemical reduction of silver ions. The effects of the simultaneous use of carbon nanotubes (either pristine or amine-functionalized) and silver nitrate in different percentages and the application of chemical reduction on the properties of the nanocomposite nanowebs were investigated. FTIR, SEM, conductivity meter, tensile tester, XRD, and DSC were used for the characterization. Antibacterial activities of the nanocomposite nanowebs were determined against S. Aureus. Full factorial experimental design was utilized in order to be able to evaluate the contributions of the selected factors (f-MWCNT content, AgNO3 content, and application of reduction process) to the variations in ultimate tensile strength, elongation, and conductivity of the composite nanowebs. Analysis of variance (ANOVA) and multiple comparisons were carried out to evaluate the average nanofiber diameters and mechanical properties. PAN/f-MWCNTs/AgNPs nanowebs displayed enhanced conductivity and antimicrobial properties particularly when the chemical reduction process was applied. Besides they showed improved crystallinity compared with pure PAN nanofibers. While the reduction process made the highest contribution to the ultimate tensile strength, elongation, and conductivity of the nanowebs, f-MWCNT content had negligible effect on conductivity of the nanowebs. Considering all the results obtained in this study, composite nanofiber webs of PAN with 1 w% f-MWCNTs and 1 w%AgNO3 can be suggested for use as antistatic and antibacterial filaments.

Polyacrylonitrile/polyaniline composite nano/microfiber webs produced by different dopants and solvents

In the present study, the effects of different dopants such as camphorsulfonic acid (CSA), dodecylbenzene sulfonic acid (DBSA) (70 wt% in isopropanol), and dodecylbenzene sulfonic acid sodium salt (DBSANa+), and different solvents such as N-methylpyrrolidone (NMP), and N,N-dimethylformamide (DMF) on the structure and properties of polyacrylonitrile (PAN)/polyaniline (PANI) composite nano/microfiber web produced by the electrospinning technique have been investigated and compared to each other. It has been observed that the nano/microfibers produced from NMP solvent generally had larger fiber diameters than the nano/microfibers produced from DMF, while the use of DBSANa+ resulted in the formation of larger diameters in comparison to other dopants. The use of NMP as the solvent resulted in higher breaking stress values for the reference samples and the composite samples, which contained CSA-doped PANI while the samples that contained DBSA(iso) and DBSANa+-doped PANI showed lower breaking stress values when electrospun from NMP. While the solutions prepared using DBSANa+ showed higher solution conductivities, the use of NMP as the solvent resulted in lower solution conductivity values. Higher conductivity values were obtained with CSA in NMP and with DBSA(iso) in DMF. The conductivity values of the composite nano/microfiber webs were around 10−8 and 10−9 S/cm, which is the range for antistatic materials instead of insulator materials as pure PAN.

Nanocomposite polyacrylonitrile filaments with electrostatic dissipative and antibacterial properties

In this study, silver nitrate was added to polyacrylonitrile filament structure and chemical reduction was applied to composite filaments in order to develop multifunctional polyacrylonitrile filaments with electrostatic dissipative and antibacterial properties. Composite filaments of polyacrylonitrile and silver nitrate were characterized and evaluated in terms of morphology, chemical structure, tensile properties, crystallinity, conductivity, thermal properties, silver ion release behaviour and antibacterial activity. Additionally, ultraviolet-visible spectroscopy was used to confirm the formation of nanoparticles and the variation in the concentration of the nanoparticles with the application of the chemical reduction process. Scanning electron microscope images and ultraviolet-visible spectroscopy results confirmed the formation of nanoparticles in the filament structure. Breaking strength and breaking elongation increased at silver nitrate content of 1%. Composite filaments displayed improved thermal stability and their conductivities were in the semiconductive range. Atomic absorption spectroscopy confirmed that necessary amounts of silver release for antibacterial activity occurred, while the antibacterial activity analysis showed that the composite filaments have excellent antibacterial activity. The results obtained were promising and showed that the composite filaments could be used in electrostatic dissipative and antibacterial applications.

Nanocomposite polyacrylonitrile filaments with titanium dioxide and silver nanoparticles for multifunctionality

Nanocomposite polyacrylonitrile filaments containing titanium dioxide and silver nanoparticles were produced by wet-spinning method with the aim of developing multifunctional filaments showing antibacterial activity, photocatalytic activity, and electrical conductivity. The nanocomposite filaments were characterized regarding their morphology, composition, nanoparticle dispersion, tensile properties, crystallinity, conductivity, thermal properties, photocatalytic, and antibacterial activity. The nanoparticles were observed to be well dispersed. The composite filaments with 3 wt% silver nitrate showed improved crystallinity. The highest breaking tenacity of 8.72 cN/tex was observed for the filament with 1 wt% TiO2 and 3 wt% AgNO3. The conductivity of the nanocomposite filaments were on the order of 10−4 S/cm, which is in the semiconductive range. The nanocomposite filaments displayed both antibacterial and photocatalytic activity. This study showed the possibility of producing multifunctional filaments with the simultaneous addition of different types of nanoparticles into the filament structure.

Electrospinning Functional Polyacrylonitrile Nanofibers with Polyaniline, Carbon Nanotubes, and Silver Nitrate as Additives

Electrospinning of composite nanofibers has been attracting great attention as a way of producing functional nanofibers. Composite nanofibers are produced with the incorporation of the additives into the polymer melt/solution before electrospinning process and reported to show many superior properties such as high modulus, increased strength, improved thermal stability, or some new functionalities such as flame retardancy, antimicrobial properties, water repellency, soil resistance, decreased gas permeability, electromagnetic shielding, electrical conductivity, and so on. The availability of the wide range of additives makes it possible to produce a wide range of functional nanocomposite nanofibers that are promising for various applications. Polyaniline (PANI) as an inherently conductive polymer is being investigated as an additive for improving conductivity. Carbon nanotubes (CNT) are widely used for either their reinforcement ability or their superior electrical conductivity. Silver nanoparticles (AgNPs) are being incorporated into polymer matrices to obtain antibacterial activity. This chapter provides a comprehensive review about polyacry‐ lonitrile (PAN) nanofibers with PANI, CNTs, AgNPs, and their combinations and highlights the synergistic effects obtained by their combined use.