Synthesis and charactirezation of surface-activated multiwalled carbon nanotubes-polymer composite electrospun nanofiber

The major problem in the development of polymer nanofiber composites with the infusion of multiwalled carbon nanotubes (MWCNTs) is to ensure good dispersion of the MWCNTs within the polymer matrix. This study reports an effective approach to activate the surface of MWCNTs by a non-covalent binding strategy, and incorporation of MWCNTs in poly (L-lactide-co-e-caprolactone) (PLCL) using electrospinning process. The debundling of the MWCNTs aggregates through the non-covalent surfactant attachment on their outer layers was studied using surfactants with different ionic characters, which were sodium dodecyl sulphate (anionic, SDS), cetyltrimethyl ammonium bromide (cationic, CTAB), and polysorbate 80 (non-ionic, Tween-80) surfactants. Results obtained from the Atomic Force Microscopy (AFM) analysis of surface roughness of the surfactant-MWCNTs aggregates show different contours which were assigned to the size of the aggregates, distribution and orientation of the deposited surfactants on the surfaces of MWCNTs. The dispersion behavior of the respective surfactant molecules studied showed that the non-ionic surfactant molecules of Tween-80 have better adsorption coverage on MWCNTs surface due to the hydrophobic interactions between the liquid-solid interfaces, rather than the ionic surfactants of SDS and CTAB. The orientation of the adsorbed surfactants on the surfaces of MWCNTs was found to be strongly associated with the surfactant affinity, which was contributed by the surfactants head groups ionization. The surface morphology of each adsorbed surfactant molecule onto MWCNTs surface was determined by the Field Emission Scanning Electron Microscopy (FESEM) analysis. Furthermore, the infusion of the Tween-80-MWCNTs usability as the nanofiller component to produce electrospun polymer nanofiber composites was conducted using a customized electrospinning reactor system. The inclusion of Tween-80-MWCNTs resulted in superior electrospun MWCNTs-PLCL nanofiber composite with tensile stress value of 5.82-15.95 MPa, with the incorporation of MWCNTs ranging from 0.1wt% to 1.0wt%. Characterization by Transmission Electron Microscopy (TEM) depicted the homogenous distribution of MWCNTs within the polymer matrix. The manipulation of the electrospinning operational parameters in producing different structural features of the polymer nanofibers from PLCL was successful in producing both solid and porous structured nanofibers through the variation of solvent composition used. The solid PLCL nanofibers were formulated from the optimized polymer solution of 11wt% (w/v) of PLCL in dichloromethane/ dimethyl formamide (DCM/DMF) (70:30) at an applied voltage of 14kV with spinning solution flow rate of 1.0 mL/hr. While the porous PLCL nanofibers were formulated from the optimized polymer solution of 11wt% (w/v) of PLCL in DCM/acetone (70:30) at an applied voltage of 14kV with spinning solution flow rate of 1.0 mL/hr. The substitution of DMF to acetone in binary solvent system has resulted in highly-porous PLCL nanofibers. The AFM characterization revealed the differences in the surface roughness and pore depths of both dense and porous PLCL electrospun nanofibers fabricated

Dope-Dyeing of Polyvinyl Alcohol (PVA) Nanofibres with Remazol Yellow FG

The lack of aesthetic properties of electrospun nanofibres in terms of colour appearance is the drive in this preliminary study. This research is conducted to study the dyeing behaviour and colorimetric properties of electrospun nanofibres blended with Remazol Yellow FG reactive dye using dope-dyeing method via electrospinning process. This paper reports the colorimetric properties of dyed poly vinyl alcohol (PVA) nanofibres within the range of 2.5 wt.% to 12.5 wt.% dye content. The electrospinning parameters were fixed at the electrospinning distance of 10 cm, constant feed rate of 0.5 mL/h and applied voltage of 15 kV. The resulting impregnated dye of 10 wt.% exhibits acceptable colour difference of dyed PVA nanofibres, with a mean fibre diameter of 177.1 ± 11.5 nm. The SEM micrographs show the effect of dye content on morphology and fibre diameter upon the increment of dye used. Further increase of dye content adversely affects the jet stability during the electrospinning, resulting in macroscopic dropping phenomenon. The presence of all prominent peaks of Remazol dye in the PVA nanofibers was supported with FTIR analysis. The addition of dye into the nanofibres has resulted in the enhancement of thermal stability of the PVA as demonstrated by TGA analysi

A review on antimicrobial packaging from biodegradable polymer composites

The development of antimicrobial packaging has been growing rapidly due to an increase in awareness and demands for sustainable active packaging that could preserve the quality and prolong the shelf life of foods and products. The addition of highly efficient antibacterial nanoparticles, antifungals, and antioxidants to biodegradable and environmentally friendly green polymers has become a significant advancement trend for the packaging evolution. Impregnation of antimicrobial agents into the packaging film is essential for impeding or destroying the pathogenic microorganisms causing food illness and deterioration. Higher safety and quality as well as an extended shelf life of sustainable active packaging desired by the industry are further enhanced by applying the different types of antimicrobial packaging systems. Antimicrobial packaging not only can offer a wide range of advantages, but also preserves the environment through usage of renewable and biodegradable polymers instead of common synthetic polymers, thus reducing plastic pollution generated by humankind. This review intended to provide a summary of current trends and applications of antimicrobial, biodegradable films in the packaging industry as well as the innovation of nanotechnology to increase efficiency of novel, bio-based packaging systems

A review on antimicrobial packaging from biodegradable polymer composites

The development of antimicrobial packaging has been growing rapidly due to an increase in awareness and demands for sustainable active packaging that could preserve the quality and prolong the shelf life of foods and products. The addition of highly efficient antibacterial nanoparticles, antifungals, and antioxidants to biodegradable and environmentally friendly green polymers has become a significant advancement trend for the packaging evolution. Impregnation of antimicrobial agents into the packaging film is essential for impeding or destroying the pathogenic microorganisms causing food illness and deterioration. Higher safety and quality as well as an extended shelf life of sustainable active packaging desired by the industry are further enhanced by applying the different types of antimicrobial packaging systems. Antimicrobial packaging not only can offer a wide range of advantages, but also preserves the environment through usage of renewable and biodegradable polymers instead of common synthetic polymers, thus reducing plastic pollution generated by humankind. This review intended to provide a summary of current trends and applications of antimicrobial, biodegradable films in the packaging industry as well as the innovation of nanotechnology to increase efficiency of novel, bio-based packaging systems

Characteristic of mild acid functionalized multiwalled carbon nanotubes towards high dispersion with low structural defects

Multiwalled carbon nanotubes (MWCNTs) have a great potential in wide applications but faces limitation in term of dispersion feasibility. The aggregation of MWCNTs floss has restricted its usage and thus, acid treatment is expected to promote the MWCNTs reaggregation. The functionalization process of MWCNTs involves oxidation reaction using mild aqueous acid mixture of HNO3 and H2SO4 (1:3 v/v), via ultrasonication technique. The results were then confirmed by Fourier Transform Infrared Spectroscopy (FTIR), Xray Diffraction (XRD), Thermogravimetry Analysis (TGA), Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) analysis. From the FTIR spectrum, the existence of carboxyl group indicates the oxidation of MWCNTs on the outer surface wall. TEM and FE-SEM micrographs show the occurrence of surface modification on the MWCNTs structure. The method used in functionalization MWCNTs has created fragmented structure toward the functionalized MWCNTs. TGA analysis on functionalized MWCNTs also shows the presence of the oxygenated group decomposition. Finally, a well dispersed of MWCNTs colloidal was successfully obtained with less MWCNTs structure collapsed

Improvement of moisture management properties of face masks using electrospun nanofiber filter insert

Face coverings such as a face mask are one of the important preventive measures amidst the COVID-19 pandemic, by limiting exhaled particles and reducing expiratory droplet spread. Adding a filter to face masks may offer extra protection against the virus. Nevertheless, there remains a significant concern where thicker, tightly woven materials of masks may reduce the ability to breathe comfortably, due to inadequate moisture management properties of woven fabric in existing disposable surgical face masks. Therefore, the study on the properties of air permeability, water vapor permeability, and flexural rigidity of a face mask fabric is highly essential. This study is aimed at analyzing the potential application of electrospun nanofibers fabricated from electrospinning technique, as filter inserts in commercial surgical face masks. The function of electrospun nanofiber filter (NF) inserted in commercial surgical face masks was introduced in the study. The results indicated the significant reduction in air permeability and water vapor permeability along with the additional usage of electrospun NF within the surgical face masks, due to the smaller fiber size and interspaces in the filter layer as analyzed from FESEM analysis. The percentage of air permeability value was slightly decreased by 15.9%, from 339.5 to 285.5 mm/s, whereas the value of flexural rigidity of surgical face masks with and without electrospun NF insert is 0.1358 and 0.1207 mg/cm, respectively. Hence, the NF inserts are recommended as the potential core component in a face mask

Advanced application of electrospun polycaprolactone fibers for seed germination activity

The increasing intensity of coronavirus (COVID-19) spreading emphasizes the significant development in home food production to reduce the incoming socioeconomic impact from soaring food prices, supply chain fragility, and severe economic crisis. This preliminary study was initiated to demonstrate the possibility of using electrospun fibers as a potential substrate in the application of seed germination activity. The drive of this preliminary study was to integrate the electrospun nanofiber-based material in exploring the current surge in home food production via seed germination in order to introduce cheap source of food without being distracted by the pandemic impact in general. Mung bean (Vigna radiata L. Wilczek) was chosen as it is easy and fast to sprout. Four samples of poly (ε-caprolactone)- (PCL-) based fibers were prepared by means of electrospinning technique, with the optimized flow rate between 0.05 and 0.20 ml/min at a fixed distance of 10 cm needle tip to collector. Mung bean seeds were allowed to germinate on the fabricated electrospun PCL fibers for 96 hours. Our observations include germination percentage, seedling weight, radicle length, and plumule growth. The highest radicle length and plumule length of seedlings were 27.8 mm and 6.7 mm, respectively. There were no inhibitory effects on seed germination and minimal structural fragmentation of smaller diameter electrospun fibers as revealed by FESEM. These results show that the seeds were able to germinate on electrospun PCL fiber substrate, owing to the properties of high surface area and excellent fluid water uptake of PCL fibers