Showing papers in "Journal of Applied Polymer Science in 2023"
4 citations
TL;DR: In this paper , the effect of titanium dioxide (TiO2) on the performance of chlorinated natural rubber/polyindole (ClNR/PIN) blend nanocomposites was systematically studied.
Abstract: The synthesis of highly flexible conductive rubber blend nanocomposites using a conductive polymer with metal oxide is a new and promising approach. In this work, the effect of titanium dioxide (TiO2) on the performance of chlorinated natural rubber/polyindole (Cl-NR/PIN) blend nanocomposites was systematically studied. Fourier-transform infrared spectra revealed the successful incorporation of nanoparticles in the blend system. UV analysis assessed the increased absorption spectra of the nanocomposite compared to the pure blend. The X-ray diffraction confirms the presence of TiO2 nanostructure in the blend. The high resolution transmission electron microscope results exhibited the uniform dispersion of TiO2 in the blend. Differential scanning calorimetry and thermogravimetric analysis show the increased glass transition temperature and thermal stability of the blend nanocomposite with an increase in TiO2 concentration. The linear low-frequency AC conductivity demonstrated the occurrence of electrode polarization and the exponential increase in AC conductivity after a threshold frequency illustrated the semiconducting behavior of the composites. The maximum dielectric constant and AC conductivity were measured for the composite with 5 wt% filler loading, as the threshold level for the maximum interfacial contact. The hopping conduction, activation energy, improved conductivity and dielectric properties suggest that these blend nanocomposite films are promising candidates for the development of flexible energy storage devices.
4 citations
TL;DR: In this article , the anticorrosion, flame retardant, and mechanical properties of polyurethane (PU) coatings have been improved by the integration of nickel disulfide (NiS2), 2,5-Bis(4-aminophenyl)-1,3,4-oxadiazole (BAO), and graphene oxide (GO).
Abstract: The anticorrosion, flame retardant, and mechanical properties of polyurethane (PU) coatings have been improved by the integration of nickel disulfide (NiS2), 2,5-Bis(4-aminophenyl)-1,3,4-oxadiazole (BAO), and graphene oxide (GO). The structural, morphological, dielectric, and hydrophobic behaviors of the films were characterized for the different formulations of coatings such as pure PU, PU-NiS2, PU-BAO/NiS2, PU-GO/NiS2, and PU-GO/BAO-NiS2 (nanocomposite) by means of scanning electron microscope/X-ray energy dispersive spectroscopy, transmission electron microscope, thermogravimetric analysis, X-ray photoelectron spectroscopy, X-ray diffraction, and contact angle measurement. As a result, with the addition of only 0.3% GO/BAO-NiS2, the dielectric constant of PU was increased by 81-fold at 1 Hz. Additionally, the nanocomposite had significantly lower peak heat release rate and overall heat released values than pure PU, a difference of 57% and 51%, respectively, demonstrating its greater flame retardancy. The electrochemical techniques and mechanical testing confirmed that GO/BAO-NiS2 (0.3%) composite exhibit enhanced anticorrosive, hydrophobic, flame retardancy, and mechanical performance of the PU coating. The super hydrophobic behavior is confirmed by its water contact angle of 165°. Furthermore, the resistance of the nanocomposite was found to be much higher (16,985.6 kΩ.cm2) than that of the pure PU (145.4 kΩ.cm2) and the microhardness and tensile strength were increased sharply. Therefore, the nanocomposite could act as a potential coating material for industrial applications.
3 citations
TL;DR: In this article , a simple and efficient humidity and ammonia sensors based on a chemiresistor design employing a differential measurement technique is presented, where interdigitated electrodes are connected via PEDOT:PSS or P3HT polymers and a reproducible and scalable fabrication procedure is presented.
Abstract: We hereby present the fabrication of simple and efficient humidity and ammonia sensors based on a chemiresistor design employing a differential measurement technique. Interdigitated electrodes are connected via PEDOT:PSS or P3HT polymers and a reproducible and scalable fabrication procedure is presented. This procedure utilizes pneumatic nozzle printing instead of drop or spin-based processes and includes an optimized encapsulation procedure and material for sealing the reference electrodes. The suitability of the NH3 sensor for quantifying ammonia in a range of 2 to 100 ppm within a period of several months is furthermore presented. The developed humidity sensor is operational for several months in a humidity range between 10 and 60% RH. Once this range is exceeded, a sensor decay by irreversible saturation can be observed. Based on the low fabrication costs of the sensors (~0.5 $ when ordering 1000 pcs of the platform + printing work), they provide a very attractive tool for industrial humidity and ammonia sensing applications.
3 citations
TL;DR: In this article , the impact of dual shells on the dielectric properties and polarization mechanism of composites were explored by fitting the experimental data with a Havriliak-Negami (H-N) equation.
Abstract: Polymeric dielectrics with high dielectric permittivity (ɛ′) and low loss have momentous applications in energy storage devices. In this study, to concurrently improve the ɛ′ and restrain the loss of original Zn (Zinc)/poly(vinylidene fluoride, PVDF), the [email protected] structured [email protected](zinc oxide)@PS(polystyrene) particles were prepared and composited with the PVDF. The impacts of the dual shells on the dielectric properties and polarization mechanism of composites were explored by fitting the experimental data with a Havriliak–Negami (H–N) equation. The [email protected]@PS/PVDF exhibit remarkably higher ɛ′ in comparison to the raw Zn and [email protected] fillers owing to the induced multiple polarizations originating from the combined contributions of the α relaxation of PVDF, slow interparticle polarization and fast intraparticle polarization. More importantly, the ɛ′ of the composites remarkably increases with the PS shell’ thickness, while the loss is still kept at rather low levels owing to the PS shell’ barrier effect on long-range charges migration. So, the introduction of the PS shell synchronously promotes both the interparticle and intraparticle polarizations in the [email protected]@PS/PVDF composites toward enhanced dielectric properties. The developed strategy opens a novel path to the design and fabrication of polymer composites with desirable dielectric performances for applications in electronics and electrical industry.
3 citations
TL;DR: In this paper , 3D-printed scaffolds comprising of SA and chitosan biopolymers of natural origin are reported, and the fabricated scaffolds possess many desired properties that are vital for tissue regeneration purposes.
Abstract: In tissue engineering technique, a biological scaffold with appropriate composition and structure for promoting growth and differentiation of cells thereby regenerating damaged tissue, is a prime necessity. In this paper, 3D-printed scaffolds comprising sodium alginate (SA) and chitosan (CH) biopolymers of natural origin are reported. Bioinks with varying ratios of SA and CH were prepared and scaffolds were fabricated by 3D printing. The fabricated scaffolds possess many desired properties that are vital for tissue regeneration purposes. The scaffolds possess open pore microstructures with interconnected pores and desired pore size as revealed by scanning electron microscopic image analysis. The polyelectrolyte complex formation (PEC) between SA and CH as revealed by Fourier-transform-infrared spectroscopic analysis is favorable as it offers a better surface for cell attachment and proliferation, and an ideal microenvironment for bone regeneration. Among the scaffolds, SA/CH with 60:40 showed controlled swelling and degradation behavior, with higher tensile strength of 0.387 ± 0.015 MPa. In vitro-biomineralization showed superior apatite layer deposition ability over the SA/CH: 60/40 scaffold surface. The fabricated SA/CH scaffolds are hydrophilic and biocompatible as evident from the contact angle, protein adsorption, MTT assay, and cell attachment studies. However, SA/CH: 60/40 is shown to have superior biological properties compared with the other SA/CH compositions. Thus, it is concluded that 3Dv printed SA/CH: 60/40 scaffold having some superior properties and bioactivity can be used as a suitable matrix for future bone tissue regeneration applications.
3 citations
TL;DR: In this article , the authors reviewed both literature as well as industrial products that used carbohydrates and proteins in wound dressing for the treatment of the wound and the outcome was chitosan (CS), as a carbohydrate, has the most clinical application as it is readily available and affordable, and has shown excellent antibacterial activity.
Abstract: Natural biopolymers (carbohydrates and proteins) are the family of natural polymers that are widely used in wound healing. This is due to their biocompatibility and their chemical structural similarity to the extracellular matrix (ECM). Wound healing is a complex process and requires a multidisciplinary approach and appropriate treatment product to enable a full recovery. Chronic nonhealing wounds significantly caused the reduction. Currently, diabetic and nonhealing wounds are considered the unmet clinical need and a new effective treatment will benefit patients and the economy. This research was aimed to critically review both literature as well as industrial products that used carbohydrates and proteins in wound dressing for the treatment of the wound. The outcome was chitosan (CS), as a carbohydrate, has the most clinical application as it is readily available and affordable, and has shown excellent antibacterial activity. Among proteins, keratin (Kr) can be an option with similar characteristics, however, Kr has not yet found clinical use when compared with CS.
2 citations
TL;DR: In this paper , a synthesis of bio-polyurethane (Bio-PU) using isosorbide (ISO) and poly(lactic acid) (PLA) diols, (propanediol based poly(Lactic acid), (propriediol-based poly(naphthane) (PLAP) and PLA esterified with Soybean oil (PLASO)) and pentamethylene (PDI) isocyanate were performed.
Abstract: Synthesis of bio-polyurethane (Bio-PU) using isosorbide (ISO) and poly(lactic acid) (PLA) diols, (propanediol based poly(lactic acid) (PLAP) and PLA esterified with Soybean oil (PLASO)) and pentamethylene (PDI) isocyanate were performed. Crosslinked Bio-PUs were obtained, and the details of the curing kinetics were determined via Fourier transform infrared spectroscopy (FTIR) spectra and differential scanning calorimetry (DSC). Distinct curing behaviors between Bio-PUs with different PLA diol formulations were observed. The addition of PLAP and PLASO increased the curing conversion at approximately 460% higher than Bio-PU without PLA content, as verified by FTIR. The curing peak temperature (Tp) of Bio-PUs with PLAP ranged from 94 to 163°C, while for PLASO Tp was 132–175°C. Bio-PUs based on PLA diols displayed lower activation energy (Ea) during curing as demonstrated using Friedman model, and higher thermal stability as evidenced through thermogravimetric analyses. Reported data offer reliable tools to evaluate the best rote to synthesize biobased polyurethane and manipulate the degree of crosslinking based on composition and processing conditions, allowing product processing to the desired application.
2 citations
TL;DR: In this paper , the use of single-ion conducting block copolymer (SIC) as an additional lithium salt additive to a ternary solid polymer electrolyte (SPE), consisting of a poly(styrene-b-1-((2-acryloyloxy)ethyl)-3-butylimidazolium bis(trifluoromethanesulfo-nyl)imide) (S-ImTFSI64-16) block Copolymer, a N-propyl-N-methylpyrrolidinium bis (C3mpyrFSI) ionic liquid (IL), at various molar ratios.
Abstract: Herein, we describe the use of single-ion conducting block copolymer (SIC) as an additional lithium salt additive to a ternary solid polymer electrolyte (SPE), consisting of a poly(styrene-b-1-((2-acryloyloxy)ethyl)-3-butylimidazolium bis(trifluoromethanesulfo-nyl)imide) (S-ImTFSI64-16) block copolymer, a N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (C3mpyrFSI) ionic liquid (IL) and a lithium bis(fluorosulfonyl) imide (LiFSI) salt. For this purpose, the S-ImTFSI64-16 was substituted by a SIC, based on poly(styrene-b-((4-styrenesulfonyl)(trifluoromethanesulfonyl)imide lithium salt)) (S-STFSILi64-16), at various molar ratios. The impact of the SIC concentration on the phase behavior and transport properties of the SPEs was investigated by means of differential scanning calorimetry, electrochemical impedance spectroscopy, and diffusion NMR. In addition, the electrochemical performance of the SPEs was assessed in lithium symmetrical cell at 50 and 80°C. Finally, the cycling performance of a selected SPE was also assessed at 80°C in a Li│NMC111 cell with capacity loading of 1.3 mAh.cm−2 at a C-rate of 0.1 C. The Li│NMC111 full cell was able to deliver a stable capacity of 0.94 mAh.cm−2 after 20 cycles, corresponding to a capacity of 117 mAh.g−1. These results demonstrates that PIL block copolymer—IL—salt composites represent a promising choice of electrolyte for the next generation of solid-state high energy density lithium metal batteries.
2 citations
TL;DR: In this article , the N-(4-hydroxyphenyl) maleimide (4-HPM) modified waterborne polyurethane emulsions (MWPU) were used as surface sizing agents to improve the interfacial adhesion between carbon fibers (CF) and epoxy resin matrix.
Abstract: The N-(4-hydroxyphenyl) maleimide (4-HPM) modified waterborne polyurethane emulsions (MWPU) were used as surface sizing agents to improve the interfacial adhesion between carbon fibers (CF) and epoxy resin matrix. Dynamic light scattering (DLS), transmission electron microscope (TEM), and thermogravimetric analysis (TGA) showed the particle size distribution, storage stability, and thermal stability of the modified MWPU. And the surface reactivity of CF increased significantly after sizing. The interfacial shear strength (IFSS) and the interlaminar shear strength (ILSS) of CFREs were tested, and the fracture morphology was observed. The result showed that a continuous and uniform sizing layer is formed on the surface of CF. In particular, the comprehensive performance and interfacial modification effect of the MWPU emulsion outperformed other samples when the 4-HPM content was 1.0 wt%. Compared with unsized carbon fibers, the IFSS and ILSS are up to 71.30% and 30.81% higher, respectively.
TL;DR: In this paper , compounds of LLDPE with thermoplastic elastomers (TPV) were made, and they were irradiated with doses reaching from 99 to 231 kGy.
Abstract: Linear low-density polyethylene (LLDPE) crosslinks under irradiation in the range of up to 250 kGy. Crosslinking leads to better chemical and thermal resistance but causes reduction in mechanical performance. To counter this reduction, compounds of LLDPE with thermoplastic elastomers (TPV) were made. Specimens were irradiated with doses reaching from 99 to 231 kGy. Gel content shows a decrease of around 12% for compounds with 20 wt% of TPV compared to pure LLDPE. It is also found that compounds containing 10 wt% TPV experience a 4% higher gel content than predicted. For higher amounts of TPV elongation at break increases from 689% for pure LLDPE to 769% and tensile strength decreases from 31.9 to 30.5 MPa. Under irradiation, a trend to lower elongations and tensile strengths is observed. Elongation at break decreased around 200% and tensile strength around 5 MPa under irradiation. Thermal analysis of TPV showed that while the melting temperature decreases, its crystallinity first rises for doses up to 165 kGy before decreasing. Infrared spectroscopy was used to identify changes in the chemical structure, where evidence of surface oxidation under irradiation is found for all compounds with LLDPE.
TL;DR: In this paper , the authors divide PEM into three groups according to chemical structure: organic-inorganic hybrid composite membranes, nanofiber composite membranes and composite membranes with long-range order.
Abstract: In the proton exchange membrane fuel cell, proton exchange membrane (PEM) serves as both the main conductor of protons and the fuel-blocking membrane. Thus, high proton conductivity and excellent stability are expected for PEMs at the same time. According to chemical structure, this review divides PEM into three groups. Recently, high-performance PEM has been made possible by controlling chemical structure, organic–inorganic hybrid composite membranes, and nanofiber composite membranes. One of them, nanofiber composite membranes, is distinguished by long-range order and is capable of achieving both strong proton conductivity with exceptional stability. The high-performance PEM has been accomplished by the presence of an acid-rich layer, acid–base interaction, and proton transport channel in PEMs are also summarized in this paper. We believe that our discussion will help the researcher create high-performance PEM and pave the way for further developments in the field of energy materials as a whole.
TL;DR: In this article , an efficient binary filler network regulation method has been proposed for superior absorption-dominated electromagnetic interference (EMI) shielding, which achieved a superior conductivity of 1.28 S cm−1 and an outstanding electromagnetic shielding interference and effectiveness of 44.5 dB.
Abstract: Excellent conductivity and optimized impedance matching are vital for superior absorption-dominated electromagnetic interference (EMI) shielding. An efficient binary electromagnetic filler network regulation method has been proposed. Poly- (vinylidenefluoride)-ferroferric oxide-reduced graphene oxide/single-wall carbon nanotube (PVDF-Fe3O4-RGC) composite has been synthesized as a layered segregated polymer composite structure by using an electrostatic assembly and hot compression strategy. Binary electromagnetic filler networks have surpassed the obstacles of magnetic materials in conductive networks, and are thereby beneficial for outstanding conductivity and impedance matching. Therefore, a superior conductivity of 1.28 S cm−1 and an outstanding electromagnetic shielding interference and effectiveness of 44.5 dB have been obtained for loading of 2.02 vol.% single-wall carbon nanotubes (SWCNTs), with an absorption rate larger than 85.0% in the X-band. The enhanced EMI shielding performance is attributed to the regulation of the binary electromagnetic filler network.
TL;DR: In this paper , 3-(potassiumsulfonyl)propyl methacrylate (SPMA) monomer, ethylene glycol dimethacryl crosslinker and ammonium persulfate initiator were reacted to yield poly[3-((1-hydroxybenzo(d)(1,2,3)diazaborininin-2(1H)-yl)sulfonic acid]-(PSPMA-DAZ) microparticles.
Abstract: Transmission of infectious diseases and resistance by microorganisms is a global health threat. Antimicrobial polymers are increasingly being developed as biocides with greater applications than traditional antibiotics. In this study, 3-(potassiumsulfonyl)propyl methacrylate (SPMA) monomer, ethylene glycol dimethacrylate cross-linker and ammonium persulfate initiator were reacted to yield poly[3-(potassiumsulfonyl)propyl methacrylate] microgels (PSPMA). Surface modification of PSPMA with thionyl chloride yielded poly[3-(chlorosulfonyl)propyl methacrylate microparticle] (PSPMA-Cl) which was reacted with hydrazinehydrate to obtain poly[3-(hydrazinylsulfonyl)propyl methacrylate] microparticles (PSPMA-NH2). Finally, 2-formyl benzeneboronic acid was added to give the final product poly[3-((1-hydroxybenzo(d)(1,2,3)diazaborinin-2(1H)-yl)sulfonyl)propyl methacrylate] (PSPMA-DAZ) microparticles. The modified microparticles were characterized using attenuated total reflectance-Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and energy-dispersive x-ray analyses. The polymeric microparticles showed good antibiofilm activity against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Candida albicans ATCC 10239 and Candida tropicalis ATCC 13803 while low to moderate biofilm inhibitions were observed against Listeria monocytogenes ATCC 7644, Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 27853 and Salmonella typhi ATCC 14028. Surface group modification from PSPMA, PSPMA-Cl, PSPMA-NH2 to PSPMA-DAZ increased violacein inhibition, quorum-sensing inhibition and antimicrobial activity but reduced swarming. These polymer microparticles can be used to reduce spread of microbial infections and resistance.
TL;DR: Based on the excellent adhesion and antioxidant properties of polydopamine (PDA), this paper employed a one-pot method to modify the surface of silica substrates using PDA containing a polyphenol structure, to prepare a reinforced silica-PDA composite latex material with antioxidant properties.
Abstract: Since the outbreak of COVID-19, the demand for natural latex products with increased mechanical properties and aging resistance has surged. Based on the excellent adhesion and antioxidant properties of polydopamine (PDA), we employed a one-pot method to modify the surface of silica substrates using PDA containing a polyphenol structure, to prepare a reinforced silica-PDA composite latex material with antioxidant properties. As expected, the silica-PDA composite achieved both uniform dispersion and good interfacial interactions with natural rubber latex (NRL). In addition, compared with common NRL/silica films, the mechanical properties of the NRL/silica-PDA film were significantly improved;specifically, silica-PDA can highly-enhanced the mechanical property of NRL film from 24.94 to 32.18 MPa of tensile strength. Further, the antioxidant activity of the silica-PDA film exceeded that of commercially available antioxidant D. Considering the notable performance boost of silica-PDA composites on NRL films, we believe that the treatment of silica with natural polyphenols offers a convenient and facile new route for the preparation of environmentally friendly multifunctional silica additives. © 2023 Wiley Periodicals LLC.
TL;DR: In this article , a Pectin/eugenol (Pe/Eu) composite film is prepared by casting from pectin and eugenol, and the morphology and wettability of the composite film are characterized.
Abstract: Biodegradable active packaging materials have received growing attention for extending the shelf life of foodstuffs. A Pectin/eugenol (Pe/Eu) composite film is prepared by casting from pectin and eugenol. The morphology and wettability of the composite film are characterized. The antioxidant activity of the composite film is determined with DPPH method. Special attention is given to the release kinetics of Eu from Pe/Eu composite film and its application in pork preservation. The results display that Eu increased the surface roughness, hydrophobicity, and antioxidant activity of the composite film. In addition, the release mechanism of Eu from Pe/Eu composite film is controlled by diffusion. The release behavior of Eu in Pe/Eu composite film can prolong the shelf life of pork. Therefore, our results suggest that Pe/Eu composite films can provide new ways for active packaging materials to extend the shelf life of animal-based protein foods.
TL;DR: In this article , the fracture behavior of polypropylene (PP)/ethylene-vinyl acetate (EVA)/exfoliated graphite (EG) blend nano-composites is investigated.
Abstract: Polymer nano-composites have an extensive diversity of applications in many areas, including automotive, construction, healthcare, and electronics. Excellent tensile and fracture properties are commonly required to achieve the appropriate properties. In this research, the tensile and fracture behavior of polypropylene (PP)/ethylene-vinyl acetate (EVA)/exfoliated graphite (EG) blend nano-composites are investigated. The exfoliated graphite was either unmodified or surface-modified with ammonium polyphosphate (APP). When the modified exfoliated graphite (EG-g-APP) was added to PP/EVA compounds, the tensile properties were more enhanced compared to unmodified EG. The elongation at break was around 2 times greater in the blend containing EG-g-APP. The essential work of fracture (EWF) approach was utilized to evaluate the effect of EG and EG-g-APP on the fracture behavior of PP/EVA blends. The we and βwp values of the nano-composites including EG-g-APP were mainly higher than nano-composites containing EG at the same nano-filler concentration. Also, according to SEM imaging, the EWF analysis results suggested that the preeminent mechanism of fracture in various compounds is the debonding of EVA from PP, which causes shear yielding and fibrillar structures on the surface of the compounds. It was observed that as EVA increased, the number of cavities and the size of fibrillar structures were increased. Enhancement in fracture toughness and matrix resistance was attributed to a growth in the number of nano-voids and a decrease in voids' size.
TL;DR: In this article , a new hyperbranched sulfonated poly(arylene aliphatic ketones) (HB-SPAAK) has been synthesized and loaded with titania nanoparticles to obtain HB-SP AAK/TiO2 nanocomposites for thermally stable proton-conducting electrolyte membrane fuel cell (PEMFC) applications.
Abstract: A new hyperbranched sulfonated poly(arylene aliphatic ketones) (HB-SPAAK) has been synthesized and loaded with titania nanoparticles to obtain HB-SPAAK/TiO2 nanocomposites for thermally stable proton-conducting electrolyte membrane fuel cell (PEMFC) applications. The synthesis of HB-SPAAKs was carried out through the polycondensation reaction of different aliphatic and aromatic acids with simultaneous loss of H2O, trifluromethane sulfonic acid used as catalyst. The long chain hyperbranched polymers and TiO2-loaded nanocomposites were characterized by FT-IR, 1H-NMR, SEM and HR-TEM. Proton conductivity (PC), swelling ratio, water uptake and oxidative stability. The SEM image of TiO2 NPs and HB-SPAAKs/TiO2 nanocomposites membrane clearly showed the spherical of TiO2 and porous structure of HB-SPAAKs with a pore diameter of 2–50 μm. TEM image reveals the uniform particle size distribution of TiO2 nanoparticles having a nanosize of 100 nm. TiO2 loaded polymer nanocomposites showed lower values of W/U and S/R when compared to the unmodified HB-SPAAK, while 3% TiO2 loaded HB-SPAAKs exhibited a threefold increment of proton conductivity of 1.439 × 10−2 S cm−1 compared to HB-SPAAKs (0.41 x 10−2 S cm−1) and lower than that of Nafion 117 (0.1003 S cm−1 at 80°C). The 5% TiO2 NPs-embedded with HB-SPAAKs nanocomposites membranes also presented admirable oxidative stability with a degradation value of 13.8% during immersion in Fenton reagent for 8 h at 70°C.
TL;DR: In this article , a stretchable and compressible strain sensor was fabricated from conductive porous carbon nanotubes/polydimethylsiloxane (CNT/PDMS-P) high internal phase emulsion (HIPE), which was obtained by simple mechanical mixing of CNTs, PDMS, and water.
Abstract: In this work, a stretchable and compressible strain sensor was fabricated from conductive porous carbon nanotubes/polydimethylsiloxane (CNT/PDMS-P) high internal phase emulsion (HIPE), which was obtained by simple mechanical mixing of CNTs, PDMS, and water. Micropores were uniformly distributed in the PDMS matrix, with diameters mainly in the range of 3–9 μm and averaging 5.3 μm. Due to the confined dispersion of CNTs in the porous PDMS framework, the CNT/PDMS-P achieved a lower percolation threshold of 0.29 wt%. Compared to the non-porous composite (CNT/PDMS), its percolation threshold was reduced by 25%. Besides, the CNT/PDMS-P showed excellent sensitivity and cyclic stability. The sensitivity of CNT/PDMS-P was 50% higher than that of CNT/PDMS in the tensile strain range of 0%–10%. The stability tests for 1000 loading/unloading cycles showed that the maximum offset rate of CNT/PDMS-P was 58% lower than that of CNT/PDMS. The sensitivity of CNT/PDMS-P compression sensor was S = 0.00259 kPa−1, which could detect the stress up to 600 kPa and maintain the standard waveform even after 1000 compression cycles. Finally, the potential application scenarios of the sensor, such as perception of human body limb movement, facial movement, gesture transformation, and human-computer interaction scenarios, were explored.
TL;DR: In this article , the authors focused on the characterization of polylactic acid (PLA) and polyethylene terephthalate glycol (PETG) composites under compressive force to learn more about how various nozzle diameter (ND) and infill pattern (IP) affect the fabricated specimens.
Abstract: Additive manufacturing technique fused filament fabrication (FFF) has found widespread usage in a variety of sectors, because of its ability to produce parts with arbitrary geometries and intricate internal structures. This study focuses on the characterization of polylactic acid (PLA) and polyethylene terephthalate glycol (PETG) composites under compressive force to learn more about how various nozzle diameter (ND) and infill pattern (IP) affect the fabricated specimens. The specimens are created with various combination of IPs (triangular, honeycomb, and rectilinear) and NDs (0.2, 0.4, and 0.6 mm) utilizing three polymer composites namely carbon fiber filled PLA (CF-PLA), carbon fiber filled PETG (CF-PETG), and multi walled carbon nano tubes filled PLA (MWCNTs-PLA). According to the findings, the higher ND improves the compressive properties of the polymer composites. The IP also has significant impact on the compressive properties of the fabricated specimens. The overall minimum compressive strength of 14.612 MPa at ND 0.2 mm and honeycomb IP for CF-PLA specimen. The overall maximum compressive strength achieved is 45.269 MPa at ND 0.6 mm and rectilinear IP for MWCNTs-PLA specimen. Therefore, the compressive strength is enhanced by 209.81% by modifying the process parameters and filament material. Based on statistical analysis using Taguchi method, the ND contributes highest, 79.61% to compressive strength of MWCNTs-PLA specimens, but for CF-PLA and CF-PETG specimens, IP contributes highest, 52.65% and 57.91%, respectively. The aforementioned findings will be extremely useful to scientists attempting to achieve sustainability through the use of polymer composites and FFF process.
TL;DR: In this article , a ZnO-doped carbon aerogel is synthesized from cellulose in coconut peat with sodium alginate as a binder via both freeze-drying and pyrolysis processes.
Abstract: In this study, ZnO-doped carbon aerogel is synthesized from cellulose in coconut peat with sodium alginate as a binder via both freeze-drying and pyrolysis processes. Of those, zinc nitrate is used as not only a crosslinking agent to form gel but also a precursor source to dope ZnO in the carbon aerogel matrix. The effect of precursor ratios on the characterization and energy storage capacity of composite aerogel is investigated. As a result, it is indicated that the formed ZnO-doped carbon aerogel possesses a highly porous structure which is typical for aerogel structure shown by SEM images, density, and porosity. Besides, via the XRD patterns, the confirmation of the ZnO crystal structure is found within the carbon aerogel lattice. In terms of energy storage, based on the specific capacitance results, the ZCA-4 sample with a sodium alginate and cellulose weight ratio of 1:20 shows the best energy storage with a specific capacitance of 105 F/g in the voltage range of 0–0.5 V and scan-rate speed of 0.005 V. Therewithal, the ZCA-4 also performs high durability, high scanning speed tolerance, and stable storage performance with efficiency reaching more than 99% after 500 consecutive scan cycles. These results demonstrate that the ZnO-doped carbon aerogel has potential applications as electrode materials in supercapacitors.
TL;DR: In this paper , a new nanohybrid catalyst ([email protected]@CH) was synthesized by immobilizing tungstophosphoric acid (TPA) on the surface of polyaniline (PAN) and chitosan (CH) polymers.
Abstract: To obtain clean gasoline, a new nanohybrid catalyst ([email protected]@CH) was synthesized by immobilizing tungstophosphoric acid (TPA) on the surface of polyaniline (PAN) and chitosan (CH) polymers. The features of the materials were detected by FT-IR, UV/vis, XRD, FE-SEM, and EDX methods. The XRD patterns demonstrate that the average crystallite size of the [email protected]@CH is estimated to be approximately 45 nm, which corresponds to the results of the FE-SEM. The catalytic performance of the [email protected]@CH was tested in the nano-catalytic oxidative desulfurization (Ncat-ODS) of gasoline and model fuels by H2O2/AcOH (volume proportion of 2:1) oxidizing agent. The best desulfurization outcomes were achieved by 0.1 g of the [email protected]@CH as a nanocatalyst at 35°C under mild reaction conditions. Based upon the above findings, the sulfur content could be declined from 0.4986 to 0.0193 wt%, which corresponds to performance of 96%. Mercaptan concentration decreased from 98 to 4 ppm, and the removal efficiency of model fuels declined in the order of DBT ≥ BT > Th. The high catalytic activity of [email protected]@CH was maintained for five cycles without significantly diminishing its performance. This work suggested the potential application of the [email protected]@CH for eliminating of hazardous sulfur compounds that significantly affect the efficacy of the Ncat-ODS.
TL;DR: In this article , the effects of multiwall carbon nanotubes (MWCNTs) on the electrical, dielectric, and piezoelectric properties of the ferroelectric ceramic/castor-oil polyurethane (PUR) composite films were evaluated.
Abstract: The effects of multiwall carbon nanotubes (MWCNTs) on the electrical, dielectric, and piezoelectric properties of the ferroelectric ceramic/castor-oil polyurethane (PUR) composite films were evaluated. The three-phase piezoelectric composites were produced by keeping PUR concentration constant while varying lead zirconate titanate (PZT) volume fractions between 10 and 50 vol.%, at two MWCNT concentrations: above and below percolation threshold. The dc electrical conductivity analysis revealed that small amounts of MWCNTs dispersed within PUR/PZT composite films can significantly improve electrical and piezoelectric properties due to their ability to act as conductive bridges between PZT particles in the samples. Using Jonscher's power law, it was possible to determine that the electrical conduction in ac regime occurs through spatial charge hopping between states located within the piezoelectric composite. Analyzing the piezoelectric properties through the d33 coefficient, it was found that PUR-MWCNT/PZT piezoelectric composite displayed higher d33 values (20 pC/N) in comparison to the PUR/PZT two-phase composite (9.5 pC/N) for all PZT loadings. According to these results, the dispersion of MWCNT nanoparticles influences the poling effectiveness of the PZT particles and increases the d33 coefficient of three-phase piezoelectric composites.
TL;DR: In this paper , a hybrid manufacturing method combining the advantages of injection molding (IM) in terms of manufacturing efficiency and high precision with those of 3D printing (3DP) to produce mixed-material bilayer tensile specimens is described.
Abstract: In this paper, a hybrid manufacturing method combining the advantages of injection molding (IM) in terms of manufacturing efficiency and high precision with those of three-dimensional printing (3DP) in terms of minimum waste and a high degree of freedom is described to produce mixed-material bilayer tensile specimens. 3DP was first utilized to fabricate polylactic acid substrates with four varied geometries and two infill densities and an overmolding technique was employed to finish the manufacture using acrylonitrile butadiene styrene under two IM pressure. analysis of variance and scanning electron microscopy (SEM) were used to investigate the tensile properties and microstructures of the samples. The results showed that a greater tensile performance could be found in those specimens with greater infill density. Lower-pressure overmolded specimens performed better than those with higher IM pressure. In addition, female joints outperformed male joints in the tensile performances of finished specimens. This study optimized the parameters for this hybrid manufacturing process for building mixed-material parts and has potential applications in manufacturing, particularly manufacturing as a service.
TL;DR: In this article , the effect of different surface treatments of flax fiber on the mechanical properties of the natural fiber reinforced natural rubber (NR) composites was studied and compared with surface treated and untreated natural fiber-reinforced NR composites.
Abstract: The present work is an attempt to study the effect of different surface treatments of flax fiber on the mechanical properties of the natural fiber reinforced natural rubber (NR) composites. In this study, flax fiber was chopped to 1, 1.25, and 1.5 cm in length and mixed with NR in two roll mill. The composite of 20%, 30%, 40%, and 50% fiber loading was prepared from each fiber length. Tensile analysis showed that a 1.25 cm fiber length composite of volume 40% has higher tensile strength compared to others. Hence, this optimized the fiber length and loading has opted for further study. Flax fiber was treated with NaOH and laccase and reinforced into an NR matrix. Properties like tensile strength, hardness, relative density, water diffusion, scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR) for surface treated and untreated natural fiber-reinforced NR composites have been investigated and compared. The reduction in the hydrophilic characteristics of the NaOH and laccase treated fiber was evident from FTIR analysis and increase in the crystallinity index of the fiber depicted by X-ray diffraction (XRD) results. SEM analysis showed the enhanced interfacial interaction of treated flax fiber NR composite compared to untreated composite due to the removal of non-cellulosic contents in fiber and an increase in the surface roughness after treatments. Further, an increase of 9% and 27.4% in tensile and tear strength was found in NaOH treated flax fiber reinforced NR composite.
TL;DR: In this paper , simple solution casting method was utilized for preparing composite films (PVA-30 wt% PVP) incorporated with various content of erbium ions (Er3+) (0.11, 0.37, 1.85, 3.7, 9.25, and 18.5) wt%.
Abstract: The simple solution casting method was utilized for preparing composite films (PVA-30 wt% PVP) incorporated with various content of erbium ions (Er3+) (0.11, 0.37, 1.85, 3.7, 9.25, and 18.5) wt%. The composite films' properties were investigated using XRD, UV–Vis, and dielectric spectrometers. The XRD patterns showed a noticeable decline in structural elements, including crystallinity level. The transmittances of the investigated samples decrease as Er3+ increases. Studies on UV–Vis absorption have revealed that the UV–Vis absorption spectra are shifting to the higher wavelengths, causing a decrease in the optical energy bandgap values from 4.66 to 3.48 eV for an indirect transition and from 5 to 4.84 eV for a direct transition, which suggests that the filler interacts with the blend matrix. As the number of localized states in the forbidden energy bandgap rises, it has been shown that with increasing Er3+- the estimated Urbach's energy increases from 1.95 to 32 meV. The addition of erbium ions raises the refractive index of the blend film. The optical limits of the samples are investigated using a He-Ne laser beam with a wavelength of 632.8 nm and a solid-state green diode laser beam with a wavelength of 532 nm. The prospect of greater charge carrier concentration and mobility was confirmed by increased AC conductivity with increasing frequency. Dielectric permittivity and dielectric loss tangent were utilized to analyze dielectric behavior. The analysis of the electric modulus (M′ and M′′) of as-prepared samples has been completed. These findings are anticipated to notably impact a broad spectrum of applications, including organic semiconductors, optoelectronic devices, polymer solar cells, and polymer waveguides.
TL;DR: In this article , the effect of aligning graphene-oxide nanoplatelets (GONP) on the moisture absorption and thermal stability of polymeric nanocomposites was investigated.
Abstract: This article investigates the effect of aligning graphene-oxide nanoplatelets (GONPs) on the moisture absorption and thermal stability of polymeric nanocomposites. Various nanocomposite specimens were fabricated using different GONP contents to improve water uptake resistance and thermal stability by aligning GONPs using an AC electric field during manufacturing. The results showed that aligning 0.3 wt% GONPs resulted in the most significant improvements, with the reductions of 76% and 54% observed in the water uptake of nanocomposites at the initial and saturation stages, respectively. The thermal stability of the nanocomposite specimens was also investigated using thermogravimetric analysis, in which nanocomposites containing 0.3 wt% randomly dispersed GONPs demonstrated improved performance compared with the neat epoxy specimen. However, aligning GONPs resulted in a marginal effect on the thermal stability parameters of nanocomposites. Moreover, Fourier transform infrared spectroscopy was conducted to investigate the chemical nature and hydrophilicity of the specimens. In addition, the freeze-fractured surfaces of the neat and nanocomposite specimens were investigated using scanning electron microscopy. The results indicated the role of nanoparticle alignment in enhancing the performance of nanocomposites under hygrothermal conditions in terms of water uptake, which is of high importance in the marine industry.