Nanofiller Content Research Articles

Effects of interfacial interactions on structural, optical, thermal degradation properties and photocatalytic activity of low-density polyethylene/BaTiO3 nanocomposite

Barium titanate (BaTiO3) filled low density polyethylene (LDPE), (LDPE)100−x/(BaTiO3)x (where x = 0, 2, 4, 6 and 10) nanocomposites are prepared via a solvent-free melt-mixing method. The effects of nano-sized BaTiO3 (nBT) on the structural, optical and thermal degradation properties of LDPE are investigated to address the qualitative interfacial interaction effects due to the spatial distribution of nBT particles in the LDPE matrix. X-ray diffraction (XRD) results confirm the uniform dispersion of nBT nano-fillers in the LDPE polymer matrix. The crystallite size of LDPE increases with increasing the nBT content. Fourier transform infrared spectroscopy (FTIR) results indicate the enhancement in interfacial physical interactions between the polymer and nano-fillers with increasing nano-filler content. The band gap energy of the nanocomposites decreases with increasing nano-filler content, which suggests chemical imperfections close to the interfaces. DSC results depict higher Tm values for the composites which is attributed to the heterogeneous nucleating effects of the nBT particles. Thermo-gravimetric analysis (TGA) results indicate an increase in the decomposition temperature (TD), thermal stability and good dispersibility probability of nBT with increasing nBT. The photocatalytic decomposition of MB is highest (73.52%) for the 10% nBT incorporated LDPE nanocomposite sample. These results correlate with the effect of the interfacial interactions between the nBT fillers and the LDPE polymer matrix.

Structural and optical investigations on ZnO-PVDF-NiO advanced polymer composites for modern electronic devices

Polymer composites are recently introduced as flexible candidates for modern electronic devices. Transition metals oxides incorporated PVDF polymer composite thin films were successfully synthesized and investigated for an optical response. The effect of ZnO and NiO nanoparticles as PVDF fillers is studied in this work. Experimentally pure and doped PVDF uniform and evenly distributed thin films were synthesized by sol-gel based spin coating method. Structural studies were carried out with x-ray diffraction analysis which reveals the sharp traces of ZnO and NiO and endorses the presence of crystalline fillers in PVDF polymer composite thin films. The Field emission scanning electron microscope was used to examine the surface morphology of prepared thin films containing a smooth, uniform distribution and compact polymer traces. Refractive index, extinction, absorption coefficient, reflectivity, optical conductivity and real epsilon were extracted using spectroscopic ellipsometry. Enhanced response of optical parameters was observed in nanoparticles containing PVDF polymer composites. The absorption coefficient seems to increase with the increment of nano-filler contents, which makes these materials suitable for photovoltaic applications. The maxima of the refractive index were recorded as 1.6 for pure PVDF and 2.1 for maximum nano-filler content with an incredible shift to higher energy values. The optical conductivity was observed to increase with the incorporation of nanoparticles in PVDF. The maximum values of real epsilon were recorded as 2.3 for pure PVDF and 3.9 for the highest nano-filler containing composition. The increasing trend of real epsilon in nano-fillers containing compositions is attributed to the enhanced polarization and storage capability of these composites. The outcomes of this work are considered that ZnO-PVDF-NiO advanced polymer composites are promising candidates for enhanced modern electronic devices.

ENHANCING THE MECHANICAL, THERMAL AND ELECTRICAL PROPERTIES OF ALUMINA-MWCNT HYBRID NANOFILLER REINFORCED EPOXY COMPOSITES

In this work, alumina and multi-wall carbon nanotube (MWCNT) hybrid nanofiller reinforcing pure epoxy at varying weight fractions of (0.1, 0.2, 0.3, 0.4 and 0.5) w/% is investigated to enhance the mechanical, electrical and thermal properties. The porosity, tensile strength, electrical and thermal conductivity of epoxy hybrid nanocomposites are studied after the effects of the alumina-MWCNT hybrid nanofillers. The interfacial adhesion and mechanical interlocking between the hybrid nanofillers and epoxy are greatly increased with the addition of alumina and MWCNTs, thus leading to an improvement in the mechanical properties. Additionally, a uniform distribution of hybrid nanofillers results in a larger increase in the thermal and electrical conductivity. The presence of voids in specimens is gradually decreased when the nanofiller content is increased up to 0.3 w/%. The alumina-MWCNT reinforcement significantly improves the tensile strength, by 88 %, compared with pure epoxy. Similarly, the electrical and thermal conductivity increase by 85 % and 64 %, respectively, when compared with low weight fractions of the hybrid nanofiller. Agglomeration during the fabrication of nanocomposites is manageable but it is inevitable. During the formation of chains and networks, the alumina-MWCNT reinforcement of pure epoxy greatly influences the thermal conductivity. This strategy provides a prospective new concept for the use of epoxy and its composites in structural and thermal engineering applications.

Dielectric, Mechanical, and Thermal Properties of Crosslinked Polyethylene Nanocomposite with Hybrid Nanofillers

Crosslinked polyethylene (XLPE) nanocomposite has superior insulation performance due to its excellent dielectric, mechanical, and thermal properties. The incorporation of nano-sized fillers drastically improved these properties in XLPE matrix due to the reinforcing effect of interfacial region between the XLPE-nanofillers. Good interfacial strength can be further improved by introducing a hybrid system nanofiller as a result of synergistic interaction between the nanofiller relative to a single filler system. Another factor affecting interfacial strength is the amount of hybrid nanofiller. Therefore, the incorporation amount of hybridising layered double hydroxide (LDH) with aluminium oxide (Al2O3) nanofiller into the XLPE matrix was investigated. Herein, the influence of hybrid nanofiller content and the 1:1 ratio of LDH to Al2O3 on the dielectric, mechanical, and thermal properties of the nanocomposite was studied. The structure and morphology of the XLPE/LDH-Al2O3 nanocomposites revealed that the hybridisation of nanofiller improved the dispersion state. The dielectric, mechanical, and thermal properties, including partial discharge resistance, AC breakdown strength, and tensile properties (tensile strength, Young's modulus, and elongation at break) were enhanced since it was influenced by the synergetic effect of the LDH-Al2O3 nanofiller. These properties were increased at optimal value of 0.8 wt.% before decreasing with increasing hybrid nanofiller. It was found that the value of PD magnitude improvement went down to 47.8% and AC breakdown strength increased by 15.6% as compared to pure XLPE. The mechanical properties were enhanced by 14.4%, 31.7%, and 23% for tensile strength, Young's modulus, and elongation at break, respectively. Of note, the hybridisation of nanofillers opens a new perspective in developing insulating material based on XLPE nanocomposite.

Graphene in Polymeric Nanocomposite Membranes—Current State and Progress

One important application of polymer/graphene nanocomposites is in membrane technology. In this context, promising polymer/graphene nanocomposites have been developed and applied in the production of high-performance membranes. This review basically highlights the designs, properties, and use of polymer/graphene nanocomposite membranes in the field of gas separation and purification. Various polymer matrices (polysulfone, poly(dimethylsiloxane), poly(methyl methacrylate), polyimide, etc.), have been reinforced with graphene to develop nanocomposite membranes. Various facile strategies, such as solution casting, phase separation, infiltration, self-assembly, etc., have been employed in the design of gas separation polymer/graphene nanocomposite membranes. The inclusion of graphene in polymeric membranes affects their morphology, physical properties, gas permeability, selectivity, and separation processes. Furthermore, the final membrane properties are affected by the nanofiller content, modification, dispersion, and processing conditions. Moreover, the development of polymer/graphene nanofibrous membranes has introduced novelty in the field of gas separation membranes. These high-performance membranes have the potential to overcome challenges arising from gas separation conditions. Hence, this overview provides up-to-date coverage of advances in polymer/graphene nanocomposite membranes, especially for gas separation applications. The separation processes of polymer/graphene nanocomposite membranes (in parting gases) are dependent upon variations in the structural design and processing techniques used. Current challenges and future opportunities related to polymer/graphene nanocomposite membranes are also discussed.

Ni0.5Zn0.5Fe2O4 nanoparticles reinforced polyester composite for advanced radiation shielding applications: A detailed discussion for synthesis, characterization, and gamma-ray attenuation properties

The current study focuses on improving the polyester's ability to protect against gamma radiation by utilizing a nanofiller made of Ni0.5Zn0.5Fe2O4. Therefore, four polyester samples doped by Ni0.5Zn0.5Fe2O4 nanoparticles with various concentrations were fabricated via the sol-gel auto-combustion technique. The characterization of the fabricated composites was performed experimentally using the XRD (Bruker AXS D8 Advanced diffractometer), EDX, and Fourier transform infrared spectroscopy. Besides, the scanning electron microscope and transmission electron microscope were applied in order to describe the particle size of the nano filers and the particle distribution of the additive nanofiller in the fabricated composites. Furthermore, the evaluation of the composites' γ-ray shielding characteristics was done using the Monte Carlo simulation method. According to the study, the inclusion of the nanofiller improved the linear attenuation coefficient of the existing polyester. For example, the linear attenuation coefficient at 662 keV was enhanced with a factor of ≈64% by raising the nanofiller concentration between 0 wt% and 40 wt%. The linear attenuation coefficient shows also a high decrease with a factor of ≈99%, when the photon energy raised from keV to 1332 keV, respectively, for the polyester sample reinforced by 40 wt% of the nanofillers.

Effect of curing condition on the piezoresistivity of multi-walled carbon nanotube/epoxy nanocomposites

Non-monotonic electrical resistance changes have been observed in multi-walled carbon nanotube (MWNT)/epoxy nanocomposites subjected to tensile loading, but the mechanism is not fully understood. While most previous works investigated the effect of nanofiller content on the piezoresistivity of MWNT/epoxy nanocomposites, this work evaluates the impact of curing condition. The results indicate that the monotony of the piezoresistivity could be enhanced by using a higher curing temperature. It is therefore proposed that when cured under a different temperature, an epoxy matrix would exhibit a different level of spatial heterogeneity in molecular structure and hence in mechanical properties, causing the MWNT network inside the matrix to undergo a different movement trend under tensile loading. This study will facilitate future research on elucidating the underlying mechanism of the non-monotonic piezoresistivity of CNT/epoxy nanocomposites through considering the contribution of the molecular structure of the polymer matrix.

Evaluating the effect of nanofillers on cement-based composites strength via artificial neural network and genetic algorithm

This paper investigated the contributions of nanofillers’ characteristics and contents on the strength of cement-based composites. For this purpose, an artificial neural network and genetic algorithm model was developed based on 150 compressive/splitting tensile experimental results of cement-based composites, comprehensively considering chemical compositions (silica, titania, zirconia, carbon, and boron nitride nanofillers), physical dimensions (minimum size, aspect ratio, and diameter-thickness ratio), surface treatments (surface hydroxyl treatment and surface nickel coating), and contents of nanofillers. The research results indicated that the chemical compositions, physical dimensions, surface treatments, and contents of nanofillers present distinct effects on the compressive strength and splitting tensile strength of cement-based composites. The chemical compositions and surface treatment of nanofillers are the primary factors determining the compressive strength of nano-engineered cement-based composites, and the influence weights of carbon and surface hydroxyl treatment are 41.6% and 12.0%, respectively., respectively. In contrast, the splitting tensile strength of nano-engineered cement-based composites is notably affected by the diameter-thickness ratio and minimum size of nanofillers, and the corresponding influence weights equal to 28.2% and 17.3%, respectively. These findings provide a guideline for designing and controlling the strength of nano-engineered cement-based composites.

Recent progress in reinforcement of nanofillers in epoxy-based nanocomposites

Now a days, nanocomposites have brought the attentions due to their small dimensions, ultimate large surface area, along with large applications in industrial fields. This review gives detailed information about the epoxy composites and nanofillers to improve their crystallinity, nanostructures and mechanical strengths. Due to the presence of aromatic rings in the structure, epoxy polymer has heat and chemical resistance of high limit. Epoxy and their composites have large applications in coatings and aircrafts. Since their commercial inception in 1947 by the Devve-Raynolds Company, epoxy has become the most extensively studied, researched thermoset polymer. Bisphenol A and Epoxy Novolac Resins are most commonly used epoxy resins. Their multi functionality is about 2.5 to 6.0 which differs epoxy resins from standard Diglycidyl ether of Bisphenol A (DGEBA)based epoxy resins. Epoxy is preferred over other polymer matrix due to its high durability, chemical resistance and high adhesive properties. Currently modified epoxy resins are used in making of natural fibre reinforced composites and different instrumental parts in industries and aircrafts. This review also aims to give emphasis on the recent advancements in fabrication of epoxy polymer composites and their various strengths with respect to different concentration of nanofillers. As we know that formation of composite is an exothermic process, thus this review also carries the promise to enhance the thermal and electrical conductivity of the epoxy polymer by encapsulating suitable nanofillers with appropriate molecular wt%.

Biocompatible Poly(Vinyl Alcohol)-Copper Oxide-Graphene Oxide (PVA-CuO-GO) Nanocomposites: Synthesis, Structural and Optical Properties

Motivated by the unique combination of copper oxide (CuO) and GO (graphene oxide) nano-fillers with optimized composition in the PVA (poly vinyl alcohol) polymer, the studies in this paper have been directed towards the synthesis and characterization of (PVA-CuO-GO) polymer nanocomposites. The polymer nanocomposites, i.e., PVA-CuO-GO have been prepared by melt blending technique considering GO and CuO with variable wt.% (ranging from 0.5 to 3 wt.%). The composite was made in the shape of a dumble-like structure. To get the structural information, optical properties, surface morphology and available functional groups in the composites and their mechanisms, XRD (x-ray diffraction), UV-Vis-NIR spectrophotometer, photoluminescence (PL), FESEM (field emission scanning electron microscope) and FTIR (Fourier transform infrared) techniques have been used, respectively. From XRD data, the effect of wt.% of nano-fillers on crystalline size and micro-strain has been studied. The average crystalline size and micro-strain were calculated as ∼32 nm and ∼0.0250, respectively. From UV-Vis-NIR spectrophotometer data, tauc plots have been studied which tells that the increment in wt.% of nano-fillers causes the optical band gap to increase. On increasing the concentration of nano-fillers from 0.5 to 3 wt.%, the bandgap was increased from 2.5 to 2.8 eV. This tuning of bandgap can be supposed as fine tuning in near UV region. According to PL results, all the composites show a wide emission band in the UV-Vis region with the maximum at 487 nm when excited by 415 nm wavelength. Further, the luminescence intensity has been found to decrease with the addition of wt.% of the loading. The smoothness of the surfaces of the composites has also been studied with EDAX analysis. According to FTIR spectra, the available functional groups were found as: C–O, C–H stretch, C–H asymmetric stretch, C=O carbonyl stretch and C–H bending and deformation vibrations. In view of the characterizing results, the synthesized polymer nanocomposites can be used in several kinds of optoelectronics applications.

Analysis of Selected Dielectric Properties of Epoxy-Alumina Nanocomposites Cured at Stepwise Increasing Temperatures

The paper presents the effects of gradual temperature curing on the dielectric properties of epoxy nanocomposite samples. Samples were prepared based on Class H epoxy resin filled with nano-alumina (Al2O3) for different wt% loadings (0.5 wt% to 5.0 wt%) and two different filler sizes (13 nm and <50 nm), i.e., two different specific surface area values. During the research, specimen sets were cured gradually at increasingly higher temperatures (from 60 °C to 180 °C). Broadband dielectric spectroscopy (BDS) was used to determine the characteristics of the dielectric constant and the dielectric loss factor in the frequency range from 10−3 Hz to 105 Hz. As a result, it was possible to analyze the impact of the progressing polymer structure thermosetting processes on the observed dielectric parameters of the samples. The nano-Al2O3 addition with 0.5 wt%, 1.0 wt%, and 3.0 wt% resulted in a decrease in dielectric constant values compared to neat epoxy resin samples. The most significant reductions were recorded for samples filled with 0.5 wt% of 13 nm and <50 nm powders, by about 15% and 11%, respectively. For all tested samples, the curing process at a gradually higher temperature caused a slight decrease in the dielectric constant (approx. 2% to 9%) in the whole frequency range. Depending on the nanofiller content and the curing stage, the dielectric loss factor of the nanocomposite may be lower or higher than that of the neat resin. For all tested samples cured at 130 °C (and post-cured at 180 °C), the differences in the dielectric loss factor characteristics for frequencies greater than 100 Hz are low. For frequencies < 100 Hz, there are prominent differences in the characteristics related to the size of the nanoparticle and the individual wt% value. At a small nanofiller amount (0.5 wt%), a decrease in the dielectric constant and dielectric loss factor was observed for frequencies < 100 Hz for samples with nanofillers of both sizes.

Characterization of UV Light Curable Piezoelectric 0-0-3 Composites Filled with Lead-Free Ceramics and Conductive Nanoparticles

Lead-free piezoelectric materials are essential for our healthy future but offer lower performance than lead-based materials. Different material combinations are explored to improve the performance of lead-free materials. By filling the UV light curable photopolymer resin with 30 vol.% lead-free piezoelectric ceramics and with up to 0.4 wt.% conductive nanofillers, thin and flexible piezoelectric 0-0-3 composites are formed. Two particle sizes of Potassium Sodium Niobate (KNN) and Barium Titanate (BTO) ceramics were used with four conductive nanofillers: Graphene Nanoplatelets (GNPs), Multi-Walled Carbon Nanotubes (MWCNTs), and two types of Graphene Oxide (GO). Resulting high viscosity suspensions are tape-cast in a mold as thin layers and subsequently exposing them to UV light, piezoelectric composite sensors are formed in 80 s. Even low nanofiller concentrations increase relative permittivities, however, they strongly reduce curing depth and increase undesirable dielectric losses. Non-homogeneous dispersion of nanofillers is observed. In total, 36 different compositions were mixed and characterized. Only six selected material compositions were investigated further by measuring mechanical, dielectric, and piezoelectric properties. Results show KNN composite performance as piezoelectric sensors is almost six times higher than BTO composite performance.

Durability of graphene-modified epoxy vinyl resin served as matrix phase of composite bar in simulated concrete environment

The polymer resin is usually used as an adhesive for repairing and strengthening concrete structures or served as the matrix phase of composite bar. Because the alkaline environment of concrete makes polymer resin degradation with time, the toughening modification of polymer resin has great significance. Herein, the effects of nanofiller content and exposure time on the durability of graphene-modified epoxy vinyl resin in the simulated ordinary concrete environment were evaluated by the accelerated aging method at 60 °C. The results indicated that the addition of 0.3 wt% graphene made the tensile, compressive, flexural strengths and fracture toughness of epoxy vinyl resin samples improve by 18.5%, 2.6%, 29.7% and 22.1% compared to the plain resin samples, respectively. Meanwhile, a novel multi-stage compressive constitutive model was proposed to describe the stress-strain response of polymer-based composite. Additionally, a series of tests illustrated that the durability of graphene-modified epoxy vinyl resin samples was enhanced after exposure to the simulated concrete environment. The degradation degrees of tensile, compressive, flexural strength and fracture toughness of the samples with a 0.3 wt% incorporating content of graphene declined by 7.9%, 10.4%, 5.5% and 10.4% after twenty-eight days of exposure compared to those of the exposed plain resin samples, respectively.

Preparation and characterization of glycerol plasticized yam starch-based films reinforced with titanium dioxide nanofiller

In this study, yam starch was extracted from yam tubers using water and used for preparation of glycerol plasticized and titanium dioxide (TiO2) nanofiller reinforced films. The effects of TiO2 nanofiller concentration on the properties of the film were studied. Concentration of TiO2 nanofiller affects the mechanical and morphological properties of the film. The tensile strength and percent elongation were modeled and optimized by a three-variable, three-level Box-Behnken Design (BBD) using Response Surface Methodology (RSM). An optimal tensile strength (4.68 MPa) and elongation percentage (32.96%) were observed with the model at starch (3.60 g), glycerol (1.40 mL) and TiO2 nanofiller concentration (0.35 g) for the reinforced starch film. The experimental tensile strength and elongation percentage at break were 4.45 MPa and 37.77%, respectively. This shows the model can reasonably predict the optimum tensile strength and elongation of the current biofilms. Moreover, the biodegradability and antimicrobial properties of biofilms prepared at optimum tensile strength and elongation percentage were conducted. About 29% of the initial weight of the film was decomposed in the soil in the first 15 days. Moreover, an E. Coli inhibition zone of 3.25 mm was observed for the TiO2 reinforced films.

Multi-functional medical grade Polyamide12/Carbon black nanocomposites in material extrusion 3D printing

Carbon black (CB) modified polyamide 12 (PA12) nanocomposites (PA12/CB) were fabricated through melt mixing extrusion for a range of different filler weight-to-weight ratios (0.1%, 0.5%, 1.0%, 2.5%, 5.0%, and 10.0%). Filaments fabricated via thermomechanical extrusion, were employed to manufacture electrothermally conductive nanocomposites, through 3D Printing Fused Filament Fabrication (FFF). Mechanical performance was assessed, whilst, the electrical percolation threshold was identified, with the nanocomposites exhibiting electrical conductivity for a filler ratio of 2.5 wt% and above. Scanning Electron Microscopy (SEM) was conducted to reveal nanocomposite’s fracture mechanisms. Dynamic Mechanical Analysis (DMA) tests revealed a stiffening mechanism, while the antibacterial response of the nanocomposites for two bacteria was also investigated through a screening process, i.e., Escherichia coli (E. Coli) and Staphylococcus aureus (S. aureus). The highest reinforcement was observed at the PA12/CB 5.0 wt% nanocomposite material. The increase of the nanofiller concentration increased the electrical conductivity and the antibacterial performance of the nanocomposites. A better biocidal response was found against the S. aureus bacterium than the E. Coli bacterium. The studied nanocomposites, exhibited multifunctional behavior, suitable for various applications requiring enhanced mechanical performance, such as free-of-shape and stretchable conductors, circuitry resistors, Joule-heating elements, piezoresistive sensors, etc., as well as medical supplies.

Dispersion controlled nanocomposite gradient index lenses

The degrees of freedom afforded by nanocomposite materials and additive manufacturing allow for the precise control over the chromatic properties of gradient index (GRIN) optics. The ability to engineer nanocomposite optical materials using blends of three or more constituents makes it possible to independently specify the refractive index gradient and the dispersion of optical materials. The refractive index spectra of the primary nanocomposite feedstock are defined relative to one another using various concentrations of monomers and nanofillers. Inkjet deposition is then used to print-compose specific feedstock to form refractive index gradients with precise control over dispersion. Arrays of 4-mm-diameter spherical GRIN lenses were fabricated using different nanomaterial compositions. The ability to positively and negatively control dispersion and to obtain achromatic performance was demonstrated. Control over partial dispersion is also shown.

Morphological, structural, optical, broadband frequency range dielectric and electrical properties of PVDF/PMMA/BaTiO3 nanocomposites for futuristic microelectronic and optoelectronic technologies

Polymer blend nanocomposite (PBNC) films consisted of fluoropolymer poly(vinylidene fluoride) (PVDF) and plexiglass polymer poly(methyl methacrylate) (PMMA) blend host matrix (fixed composition blend of PVDF/PMMA = 80/20 wt/wt%) with barium titanate (BaTiO3) ceramic nanofiller of varying concentrations (x = 0, 2.5, 5, 10, and 15 wt%) were prepared via a state-of-the-art solution-cast method. Scanning electron microscope (SEM) images evidenced high homogeneity of these PBNC films and a huge alteration in the spherulite morphology of the PVDF with the increase in dispersed BaTiO3 concentration in the polymer blend matrix. The X-ray diffraction (XRD) patterns identified the presence of electro-active polar β- and γ-phases of the PVDF crystallites in all the composite materials which are supported by the results of Fourier transform infrared (FTIR) spectra. The differential scanning calorimeter (DSC) thermograms explained the high melting temperature of these overlapped PVDF polymorphs and the degree of crystallinity altered anomalously with the variation of nanofiller concentration. The absorbance of ultraviolet-visible (UV-Vis) radiations enhanced while the direct energy band gap of the 80PVDF/20PMMA blend matrix and also the semiconducting BaTiO3 was found to decrease with the increased concentration of nanomaterial in the host polymer matrix. The ambient temperature broadband dielectric spectra covering the frequency range from 20 Hz to 1 GHz explain that the real part of complex dielectric permittivity reduced with a huge dispersion at higher radio frequencies where the dielectric loss tangent and electric modulus spectra exhibited an intense chain segmental relaxation process. The electrical conductivity of these PBNC films increased with frequency augmented and illustrated a small variation for different concentration composites. The experimental results demonstrated that these PVDF/PMMA/BaTiO3 films could be potential candidates for frequency tunable nanodielectric, electromagnetic interference shielders, a flexible dielectric substrate, thermal insulators, and bandgap regulated materials for futuristic microelectronic, capacitive energy storage, and optoelectronic technologies.

Nanocomposites based on halloysite nanotubes and sulphated galactan from red seaweed Gloiopeltis: Properties and delivery capacity of sodium diclofenac

We developed novel composite films based on biocompatible components, such as halloysite clay nanotubes and sulphated galactan (Funori) from red seaweed Gloiopeltis. The filling of the nanotubes within the sulphated galactan matrix was carried out by a green protocol (aqueous casting method) assuring that Funori/halloysite nanocomposites can be totally considered as sustainable materials. The amount of halloysite in the composites was systematically changed to explore the effects of the nanofiller concentration on the mesoscopic properties of the films. We observed that the halloysite content significantly affects the initial water contact angle and the light attenuation coefficient of the Funori based films. These results were interpreted according to SEM images, which showed that the surface morphologies of the nanocomposites depend on the halloysite amounts filled within the polymeric matrix. The mechanical characterization of the nanocomposites was conducted by tensile experiments performed using a linear stress ramp. Moreover, tensile tests were conducted in oscillatory regime at variable temperature to investigate the viscoelastic properties of the nanocomposites.Finally, we filled the biopolymeric matrix with halloysite nanotubes containing sodium diclofenac. The drug release kinetics from the nanocomposites at variable halloysite contents were studied to evaluate their suitability as oral dissolving films for pharmaceutical applications.

Tuning Nanofillers in Sprayed Coating Toward High Flashover Strength

Various surface modification methods have been developed to improve flashover strength in gas–solid composite insulation, among which composite coating is recognized as a flexible and promising approach. However, there is still limited knowledge about the effect of different nanofillers on the surface insulation properties of nanocoating. To this end, spraying coating of high concentration of nanofillers is developed as a universal strategy to improve surface flashover strength and hydrophobicity, in which the nanofillers are tuned to achieve high flashover strength. Five kinds of nanofillers including Al2O3, SiO2, TiO2, SiC, and ZnO are introduced to fabricate the coatings. The effect of nanofillers physical properties on surface trap characteristics and micro-topography is explored to guide the development of coatings and understand the underlying mechanism. Micro-nanoscale hierarchical morphology or porous structure are created in the spraying process, which hinders the development of collision ionization and enhances the flashover voltage of all kinds of coatings. Shallow traps are introduced in the coatings with semi-conductive fillers such as ZnO, SiC, and TiO2, which is beneficial to charge dissipation. Owing to the combined effect of accelerated charge dissipation and hindrance of collision ionization by nanosized pore structures, the SiC coating presents largest enhancement of flashover strength among all coatings, with an increment of 50.3%. The spraying coating of high centration of nanofillers provides a universal strategy for simultaneously improving the flashover strength and hydrophobicity.

Creating poly(lactic acid)/carbon nanotubes/carbon black nanocomposites with high electrical conductivity and good mechanical properties by constructing a segregated double network with a low content of hybrid nanofiller

Creating poly(lactic acid)/carbon nanotubes/carbon black nanocomposites with high electrical conductivity and good mechanical properties by constructing a segregated double network with a low content of hybrid nanofiller