Coat Weight Research Articles

Properties of Coated Paper Containing Cellulose Nanofibrils as an Additive

Cellulose nanofibrils (CNF) derived from wood can be used as thickening agents for suspensions or slurries because they form a gel structure by absorbing water and demonstrate an excellent shear thinning behavior. When used as a thickening agent for paper coating, CNF influences the rheological properties and water retention of the coating color, affecting the properties of the coated paper. In this study, the effects of CNF and carboxymethyl cellulose (CMC) on the properties of the coated paper were investigated. In contrast to the CMC-coating, the gloss of the CNF-coating was not improved, even when the coating weight was increased, because of the irregular shrinkage of CNF in the wet coating layer through its gel-formation characteristics. The CNF-coating exhibited a much higher ink and vehicle absorption rate than the CMC-coating. The CNF-coating showed lower variation in the printing density depending on the coat weights. Moreover, the open structure of the CNF-coating improved the absorption rate of the coated paper compared to the CMC-coating, resulting in reduced mottling.

Evaluation of variability in seed coat color, weight, oil content, and fatty acid composition within the entire USDA‐cultivated peanut germplasm collection

AbstractNatural genetic diversity in plant germplasm collections provides the genetic variability for crop improvement. To explore this natural genetic variability, over 8,800 accessions within the USDA cultivated peanut (Arachis hypogaea L.) germplasm collection were evaluated for several seed quality traits including seed coat color, 100‐seed weight, oil content, and fatty acid composition. After removing contaminated and/or mixed accessions, the remaining 8,466 accessions were used for further data analysis. The mean of 100‐seed weight was 49.44 g with a wide range of 21.84 to 148.36 g (6.8‐fold difference). Six accessions (PI 414995, PI 648234, PI 318740, PI 336978, PI 320059, and PI 578229) with 100‐seed weight >110 g were identified. The mean of oil content was 48.94% with a range of 36.51 to 59.45% (1.6‐fold difference). Seven accessions (PI 471949, PI 472001, PI 497369, PI 442739, PI 343423, PI 161298, and PI 668582) with oil content >58% were identified. The mean of oleic acid was 45.2% with a wide range of 39.99 to 82.08% (2.1‐fold difference). The mean of linoleic acid was 32.56% with a wide range of 2.0 to 46.68% (23.3‐fold difference). Thirty‐seven accessions were identified with >65% oleic acid. Among them, PI 636472 and PI 596800 had the highest level of oleic acid (82.1 and 81.8%, respectively). Significant variation in these traits was also identified between subspecies and among botanical varieties. Some significantly positive and negative correlations among these traits were also determined. The results presented here will be useful for peanut breeders, geneticists, and other users.

Systematic analysis of the impact of slurry coating on manufacture of Li-ion battery electrodes via explainable machine learning

The manufacturing process strongly affects the electrochemical properties and performance of lithium-ion batteries. In particular, the flow of electrode slurry during the coating process is key to the final electrode properties and hence the characteristics of lithium-ion cells, however it is given little consideration. In this paper the effect of slurry structure is studied through the physical and rheological properties and their impact on the final electrode characteristics, for a graphite anode. As quantifying the impact of the large number of interconnected control variables on the electrode is a challenging task via traditional trial-and-error approaches, an explainable machine learning methodology as well as a systematic statistical analysis method is proposed for comprehensive assessments. The analysis is based upon an experimental dataset in lab-scale involving 9 main factors and 6 interest variables which cover practical range of variables through various combinations. While the predictability of response variables is evaluated via linear and nonlinear models, complementary techniques are utilised for variables importance, contribution, and first and second order effects to increase the model transparency. While coating gap is identified as the most influential factor for all considered responses, other subtle relationships are also extracted, highlighting that dimensionless numbers can serve as strong predictors for models. The impact of slurry viscosity and surface tension on electrode thickness, coat weight and porosity are also extracted, demonstrating their importance for electrode quality. These variables have been rarely considered in previous works, as the relationships are difficult to extract by trial and error due to interdependencies. Here we demonstrate how model-based analysis can overcome these difficulties and pave the way towards an optimised electrode manufacturing process of next generation Lithium-ion batteries.

Improving water vapor barrier of cellulose based food packaging using double layer coatings and cellulose nanofibers

Paper based packaging has the potential to replace many plastic-based systems if the required barrier properties can be obtained. Water borne barrier coatings have the potential to generate good barrier layers, but their performance is often less than expected. Recent work has shown improved performance of these coatings when applied on paper that has a cellulose nanofiber layer.Here, papers with a cellulose nanofiber layer were coated with barrier coatings at different coat weights applied as single-layers, as double-layers, and single-layers pressed together in a hot press in order to generate a packaging system that has good barrier properties. The performance of double-layer samples resulted in moisture transmission rates that were 40–70 % of the value of the single-layer systems. Surprisingly, the hot-pressing of two dry layers showed no advantage compared to the single-layer system. A barrier pigment added to one formulation improved the performance further and followed the same trends. Three dimensional models of diffusion through layers that have defects help explain the results. The work shows a potential path to produce paper-based packaging that has both good oxygen and water vapor barrier properties.

Development of Cellulose Nanofibre (CNF) Coating on (1) Metal Surface for Free Standing CNF Film and (2) Paper Substrates for CNF Barrier Laminates

Paper is widely used in packaging applications and is biodegradable and therefore perfectly safe as green packaging wrap for the environment. The hydrophilic nature of cellulose fibrils limits the water vapour and oxygen barrier properties of paper. To mitigate these limitations, paper is often associated with other materials, such as plastics, wax and aluminum, for achieving their good barrier properties. However, these materials suffer from serious environmental issues, as difficult and inefficient to recycle. Recently, cellulose nanofibre (CNF) based materials has been considered as an alternative to produce eco-friendly barrier materials. Existing techniques to prepare cellulose nanofibre films/sheets/composites/ laminates on the paper substrates are commercially not feasible and expensive. Therefore, other cost effective and readily implementable methodologies are required to achieve cellulose nanofibre barrier layers. In the present report, a novel approach is developed using spray coating technique to produce CNF materials with excellent barrier properties. Among many coating techniques, the spray coating has many advantages such as the production of even coating surface on the base sheet and contactless coating with the substrate. A laboratory scale spray coating of cellulose nanofibre suspension on a paper substrate was developed. When the cellulose nanofibre suspension concentration was varied from 0.5 to 1.5 wt. %, coat weight is increased from 2.9±0.7 to 29.3±6.9 g/m2. As a result, the air permeability of composite was decreased 0.78±0.17 to <0.0030 µm/Pa.s. Scanning electron microscopy studies of spray coated CNF laminates on the paper confirms that the surface pores in the paper substrates are filled with sprayed cellulose nanofibre and forms a continuous film on the surface of the substrate. These are the probable reasons for the reduction of air permeability of composites. A rapid preparation technique to prepare free standing cellulose nanofibre films/sheets was also developed using a bench scale spray coating system. Cellulose nanofibre suspension with concentration ranging from 1 to 2 wt% was sprayed onto a stainless steel plate, which is moving on a conveyor at a velocity of 0.32 cm/sec and then air dried. The basis weight of produced cellulose nanofibre films is varied from 52.8±7.4 to 193.1±3.4 g/m2. Processing time taken to prepare films was approximately 1.0 min, which is much less than processing times reported in the previous literature. Thus, the significant reduction in preparation time for producing the cellulose nanofibre sheet recommends that this spray coating technique can be utilized for the development of a scalable process for the fabrication of various cellulose based nanocomposite. Therefore, the laboratory scale spray coating confirms that the spraying could provide a platform for development of films/sheets/nanocomposite and also a CNF barrier layer on the base sheet. The future work is the development of a continuous spray coating of cellulose nanofibre on the base sheet and evaluation of mechanical and barrier properties spray coated barrier layers on the base sheet.

Central Composite Design of Spraying Process to Laminate the Paper Substrates with Cellulose Nanofibers (CNF) as Green Packaging Wrap

Green packaging wrap is now required to replace the synthetic plastic coating on the paper substrates. The coating of natural biopolymers on the paper substrates would be a potential method to achieve an ecofriendly coating to replace the synthetic materials which give a threat to the environment. Recently, spraying cellulose nanofiber (CNF) on the paper substrates to boost the barrier and mechanical properties of the paper is a flexible process and potential for scalability. Sprayed cellulose nanofibrils fill the surface pores of the paper substrates and form a barrier film on the paper surface. The spray‐coated CNF barrier film on the paper substrates reduced the air passage and increased the mechanical strength. To scale up the process of spraying, the optimization was performed via response surface methodology to investigate the interaction between input variables and their response in spraying process. The variables impacting on the barrier performance, CNF coat weight, and thickness of the coat during spraying are CNF suspension concentration (A), fiber diameter (B), and spray distance from tip to the surface (C). The linear models were developed for CNF coat weight and thickness of the CNF coat weight on the paper substrates. The quadratic model for air permeability was developed with input variables. It concludes that the CNF suspension concentration is a strong parameter for controlling the CNF coat weight and thickness of the CNF coat on the paper substrates. The developed linear and quadratic models were validated with the experimental data confirming that it was a good fit to the real experimental data. From the CCD investigation of spray coating of CNF on the paper substrates, >1 wt.% CNF coating on the paper surface produces good thickness and coat weight on the paper substrates and gives an impermeable CNF laminate on the paper substrates against air. In conclusion, these models could provide a platform for scaling up the spraying process for coating CNF‐based nanomaterials on the paper substrates.

Cross-sectional analysis of lithium ion electrodes using spatial autocorrelation techniques.

Join counting, a standard technique in spatial autocorrelation analysis, has been used to quantify the clustering of carbon, fluorine and sodium in cross-sectioned anode and cathode samples. The sample preparation and EDS mapping steps are sufficiently fast for every coating from two Design of Experiment (DoE) test matrices to be characterised. The results show two types of heterogeneity in material distribution; gradients across the coating from the current collector to the surface, and clustering. In the cathode samples, the carbon is more clustered than the fluorine, implying that the conductive carbon component is less well distributed than the binder. The results are correlated with input parameters systematically varied in the DoE e.g. coating blade gap, coating speed, and other output parameters e.g. coat weight, and electrochemical resistance.

Tetraethyl orthosilicate-containing dispersion coating — water vapor and liquid water barrier properties

An aqueous styrene-butadiene latex dispersion coating containing in-situ processed tetraethyl orthosilicate (TEOS) applied on paperboard demonstrated improved water barrier performance. Coatings containing TEOS equivalent to 0.8% silicon dioxide (SiO2; dry basis) exhibited water vapor performance of < 25 g/m2/day (23°C, 50% relative humidity [RH]) and liquid water barrier performance Cobb 1800 s of < 6 g/m2, when applied as a single-layer 18 g/m2 coating. Cobb 1800 s barrier performance was still good (< 11 g/m2) at coat weights of 7–10 g/m2. The use of filler materials such as kaolin improved the vapor barrier properties of the coating, but this was not critical to the liquid water barrier properties.

Potential Investigation on Multiphase Flow of Loaded Dispersion for the Production of Metallized Paper

The current review research's main objective is to develop dispersion models in the multilayer curtain coating with the production of metallized paper. To achieve this, the curtain coating on the paper substrate is employed with respect to multilayer coating of polymers. The first layer of polymer is applied to the paper and then it is subjected to vacuum metallization with aluminum deposition. After it, another second layer of polymer is subjected on it to prevent it from oxidation. These coated polymers are different in nature. The metallized paper will be produced which has high strength will be formulated in this application of curtain coating. The instability of curtain and air entrainment will be minimized from high Weber number, low Reynolds number, Optimum web speed and Coat weights. The above demonstrated process simulation will be modelled in Ansys-CFD. The dispersion of solids in the curtain flow through substrate moving on the web will be evaluated from different numerical methods. Each method has its own characteristics to study the nature of solids dispersion. The high loaded solids dispersion will be investigated from numerical methods including Langrangian Point Particle, Coarse grained molecular dynamics, Stokesian Dynamics, Brownian Dynamics, Point Particle Method Reynolds Averaged Navier Stokes equation, Eulerian Method, Langrangian-Eulerian Point Particle, Large Eddy Simulation point particle, Combined discrete element and Large Eddy Simulation and Discrete Element Methods.

Characterization of the Paper Coated with Polyhydroxybutyrate/Ethyl Cellulose Blends

In this study, paper was surface-treated with biodegradable blends made from polyhydroxybutyrate (PHB) and ethyl cellulose (EC) in various ratios to prepare coated paper, whose surface structure, barrier properties, and mechanical properties were analyzed to evaluate its applicability as a packaging material. It was found that as the coat weight increased, a continuous and smooth coating layer was formed, and the barrier properties and mechanical strength of the coated paper improved. When paper was surface-treated with a mixture of PHB and EC, the uniformity of the coating layer was increased and barrier properties were improved compared with the case where only PHB or EC was used as a surface treatment. The tensile strength of the coated paper improved as the mixing ratio of EC increased, but there was no significant change in elongation except under the condition of surface treatment with EC alone. Consequently, it could be considered that when PHB was applied as a surface treatment material for paper, the addition of EC was effective in improving the physical properties required as a packaging material.

Colloidal Lignin Particles and Epoxies for Bio-Based, Durable, and Multiresistant Nanostructured Coatings.

There is a need for safe and sustainable alternatives in the coating industry. Bio-based coatings are interesting in this perspective. Although various oils and waxes have been used as traditional wood coatings, they often lack sufficient durability. Lignin is an abundant natural polyphenol that can be used to cure epoxies, but its poor water solubility has impeded the use of unmodified lignin in coatings in the past. To address this issue, water-dispersible colloidal lignin particles (CLPs) and an epoxy compound, glycerol diglycidyl ether (GDE), were used to prepare multiprotective bio-based surface coatings. With the GDE/CLP ratios of 0.65 and 0.52 g/g, the cured CLP–GDE films became highly resistant to abrasion and heat. When applied as a coating on wooden substrates, the particulate morphology enabled effective protection against water, stains, and sunlight with very thin layers (less than half the weight of commercial coatings) while retaining the wood’s breathability excellently. Optimal hydrophobicity was reached with a coat weight of 6.9 g(CLP)/m2, resulting in water contact angle values of up to 120°. Due to their spherical shape and chemical structure, the CLPs acted as both a hardener and a particulate component in the coating, which removed the need for an underlying binding polymer matrix. Light interferometry measurements showed that while commercial polymeric film-forming coatings smoothened the substrate noticeably, the particulate morphology retained the substrate’s roughness in lightweight coatings, allowing for a high water contact angle. This work presents new strategies for lignin applications in durable particulate coatings and their advantages compared to both currently used synthetic and bio-based coatings.

Rethinking the paper cup — beginning with extrusion process optimization for compostability and recyclability

More than 50 billion disposable paper cups used for cold and hot beverages are sold within the United States each year. Most of the cups are coated with a thin layer of plastic — low density polyethylene (LDPE) — to prevent leaking and staining. While the paper in these cups is both recyclable and compostable, the LDPE coating is neither. In recycling a paper cup, the paper is separated from the plastic lining. The paper is sent to be recycled and the plastic lining is typically sent to landfill. In an industrial composting environment, the paper and lining can be composted together if the lining is made from compostable materials. Coating paper cups with a compostable performance material uniquely allows for used cups to be processed by either recycling or composting, thus creating multiple pathways for these products to flow through a circular economy. A segment of the paper converting industry frequently uses an extrusion grade of polylactic acid (PLA) for zero-waste venues and for municipalities with ordinances for local composting and food service items. The results among these early adopters reveal process inefficiencies that elevate manufacturing costs while increasing scrap and generally lowering output when using PLA for extrusion coating. NatureWorks and Sung An Machinery (SAM) North America researched the extrusion coating process utilizing the incumbent polymer (LDPE) and PLA. The trademarked Ingeo 1102 is a new, compostable, and bio-based PLA grade that is specifically designed for the extrusion coating process. The research team identified the optimum process parameters for new, dedicated PLA extrusion coating lines. The team also identified changes to existing LDPE extrusion lines that processors can make today to improve output. The key finding is that LDPE and PLA are significantly different polymers and that processing them on the same equipment without modification of systems and/or setpoints can be the root cause of inefficiencies. These polymers each have unique processing requirements with inverse responses. Fine tuning existing systems may improve over-all output for the biopolymer without capital investment, and this study showed an increase in line speed of 130% by making these adjustments. However, the researchers found that highest productivity can be achieved by specifying new systems for PLA. A line speed increase to more than 180% and a reduction in coat weight to 8.6 µm (10.6 g/m2 or 6.5 lb/3000 ft2) was achieved in this study. These results show that Ingeo 1102 could be used as a paper coating beyond cups.

Impact of Different Mixing Methods on the Performance of Suspension-Based Transdermal Delivery Systems.

Suspension-based matrix transdermal delivery systems (TDSs) are specialized systems that maintain a continuous driving force for drug delivery over prolonged wear. The pressure-sensitive adhesive (PSA) is the most critical constituent of such systems. Our study aimed to determine the effect of different mixing methods on the performance of silicone PSA-based suspension TDSs. Lidocaine suspension TDSs were prepared using conventional slow rotary mixing, high-speed homogenization, bead-mill homogenization, vortex shaking, and by an unguator. Resultant TDSs were tested for tack, shear, and peel properties and correlated to coat weight, content uniformity, microstructure, and in vitro permeation across dermatomed human skin. Every mixing method tested caused a significant reduction in peel. However, bead-mill homogenization resulted in significant loss of all adhesive properties tested, while unguator-mixed TDSs retained most properties. Good linear correlation (R2 = 1.000) between the shear properties of the TDSs with the average cumulative amount of lidocaine permeated after 24 h was observed, with no significant difference between percutaneous delivery from slow rotary-mixed systems (1334 ± 59.21 μg/cm2) and unguator-mixed systems (1147 ± 108.3 μg/cm2). However, significantly lower delivery from bead-mill homogenized systems (821.1 ± 28.00 μg/cm2) was noted. While many factors affect TDS performance, careful consideration must also be given to the processing parameters during development as they have been shown to affect the resultant system's therapeutic efficacy. Extensive mixing with bead-mill homogenization demonstrated crystallization of drug, loss in adhesive properties, coat weight, and film thickness, with reduced transdermal delivery of lidocaine from the prepared system.

Canine ocular onchocerciasis in New Mexico: Risk factors for disease.

To determine whether dogs are at variable risk of developing canine ocular onchocerciasis based on coat color or size, factors that may influence feeding behavior of the putative vectors of Onchocerca lupi¸ the filarial nematode parasite causing this disease. One hundred twenty-five client-owned dogs diagnosed with confirmed or suspected onchocerciasis. 1255 dogs without signs of this disease were utilized for comparison. Dogs lacking signs of canine onchocerciasis were assessed for coat color and weight. Proportions of dogs with these characteristics were used to predict signalment in a group of dogs with this disease, if the investigated characteristics were unrelated to disease risk. Predicted values were compared statistically with observed values in the diseased dog population. Black fly color preference was assessed utilizing black, brown, and white traps and statistically assessing any differences in trapping based on trap color. Results suggest that large, black dogs are more likely to develop canine ocular onchocerciasis than was predicted by chance alone (p=0.012). Results for smaller dogs with other coat colors were not significant. An increased risk for black dogs was supported by trapping data, as black flies were trapped significantly more often in black traps (p<0.001). While factors other than size and color probably also influence the likelihood of O. lupi infection and disease development, our results may assist clinicians in their diagnosis of canine ocular onchocerciasis and provide them with a tool to help educate their clients as to their dogs' risk of developing this disease.

Microstructural design of printed graphite electrodes for lithium-ion batteries

Performance properties of lithium-ion battery electrodes; capacity, rate and lifetime, are determined by the design of the coating composite microstructure. The internal pore structure and electronic networks for high coat weight graphite electrodes are manipulated through changes in the ink rheological properties, and through an syringe dispensing printing process. The rheological properties of a water-based, high viscosity graphite ink were optimised using a secondary solvent for the rheological requirements of a syringe dispensing method. The microstructure of high coat-weight battery electrodes produced from printing and tape cast methods were compared and the electrochemical performance evaluated. Cross sectional analysis of the slurry cast coatings showed improved component homogeneity, lower graphite alignment with 0.1% to 10% weight increase of the secondary solvent, with a corresponding change in tortuosity of the electrodes of 5.3–2.8. Improved cycle life is observed with a printed electrode containing an embedded electrolyte channel. Performance properties were elucidated through charge discharge, GITT and PEIS measurements. Improved electronic conductivities, exchange currents and diffusion coefficients were observed for the syringe deposited electrode. This digital deposition process for manufacturing electrodes shows promise for further optimisation of electrodes for long-life, high energy density batteries.

Corrosion inhibition impact of Pyracantha coccinea M. Roem extracts and their use as additives in zinc electroplating: Coating morphology, electrochemical and weight loss investigations

To prevent steel from corrosion, zinc is often the metal of choice in the electroplating process. The quality of the zinc deposits is improved using organic additives in the electroplating bath for better structural and morphological properties. For this purpose, the performance of Pyracantha coccinea phenolic extracts was experimentally investigated as new eco-friendly plating additives using a direct current (DC) supply at well-defined operating parameters. The zinc deposit quality was evaluated through brightness meter, hardness meter, adhesion test, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), and profilometer from one side. From the other side, the corrosion resistance of the plated substrate was evaluated by gravimetric and potentiodynamic polarization measurements. The obtained results revealed that the electrodeposition process was sensitive to the variation in both additive concentration and extract type. The addition of extracts improved the quality of the deposits by providing smooth with a marked brightness especially in the case of the addition of different concentrations from BE. Furthermore, these results exhibited that the substrates coated in the presence of extracts were more resistant against corrosion than the ones layered in their absence, especially when adding 1.2g/l of EAE, which induce a decrease in the corrosion rate and current density with values of 6.2 × 10−4 mg/cm2 h and 6.6 × 10−3 mA/cm2, respectively.

Development of Duloxetine Hydrochloride Tablets for Delayed and Complete Release Using Eudragit L 100

The purpose of the research was to optimize the preparation of duloxetine hydrochloride (duloxetine HCl) delayed release tablets. Duloxetine HCl produces a toxic substance called alpha-naphthol when duloxetine HCl is in contact with gastric fluid. Thus, duloxetine HCl when given orally needed a protective enteric coating that disable the delivery of duloxetine HCl in gastric fluid while enabling the drug delivery only in small intestine. Four different core tablets were prepared by direct compression technique, and the one which displayed quick disintegration and dissolution was chosen for enteric coating. The compressed tablets were enteric coated by dip coating technique. Since subcoating is required to safeguard the enteric coating, the core tablets were subcoated by using polymer HPMC K15M and then enteric coated with Eudragit L 100. The prepared tablets were assessed for the entire precompression and postcompression characteristics. FTIR study revealed the existence of all prominent peaks signifying its compatibility and authenticity. The in vitro studies showed that enteric-coated tablets were capable of restricting release in acidic media. The formulation F8 was optimised with 5% and 15% increase in weight of seal coat and enteric coat with good dissolution profile. Stability studies revealed that the optimized formulation was intact without any deterioration for 3 months. In conclusion, the optimized formulation could resist the drug release in acidic environment of gastrointestinal region and release the drug at a time once the tablet reaches the intestine.

The role of MFC and hydrophobically modified ethyl(hydroxyethyl)cellulose in film formation and the barrier properties of methyl nanocellulose film

Abstract There is currently a great demand for sustainable and bio-derived coatings for fiber-based packaging materials, which are technically implementable with a high performance. The aim of this work was to investigate the grease resistance of coatings prepared from methyl nanocellulose when applied on paperboard. Co-additives selected from native microfibrillated cellulose (MFC) and hydrophobically modified ethyl(hydroxyethyl)cellulose (EHEC) were used in order to determine their impact on film formation and crack resistance for folds. Small and moderate coat weights were applied in order to determine the critical coat weight for the barrier properties. It was found that high grease resistance can be achieved with methyl nanocellulose and a combination of methyl nanocellulose and MFC coatings. Contact angle determinations for water on uncoated and coated materials showed that EHEC-MFC films have a very high contact angle which is due to both the surface chemistry and roughness. This indicates and confirms that EHEC may facilitate the wetting of oil and greases. Methyl nanocellulose mixed with hydrophobically modified EHEC significantly changed the barrier properties indicating a change in the film formation.

Electroconductive nylon-6/multi-walled carbon nanotube nanocomposite for sodium sensing applications

Developing smart fabric materials that can withstand stress, strain, and bending is a key factor to successful integration into smart clothing. The aims of this study were (1) development and characterization of multiwall carbon nanotube (MWCNT)- based electroconductive materials for sensing applications, (2) optimization of experimental fabrication parameters to sensor response, (3) optimization of experimental fabrication parameters for mechanical properties. Nylon-6/MWCNT nanocomposites have enhanced mechanical and electrical properties which make them an ideal candidate for integration into smart clothing. Nylon-6/MWCNT nanocomposites were fabricated by functionalizing an electrospun Nylon-6 scaffold for selective sodium detection. Selective sodium detection is realized using a calixarene functionalization of the MWCNT and the MWCNT is only responsible for increased charge transfer of the nanocomposite. Initially, three factors were considered for optimization of nylon-6/MWCNT nanocomposite fabrication: nanotube type, nanotube concentration, and the weight percent of nylon in the electrospinning solution. The sensing nanocomposite materials were characterized for the electrical and mechanical properties. The sensitivity of the sensor to changing sodium ion concentration (µA/mM) was optimized for 20wt% nylon-6 nanofiber base functionalized in a solution of 0.5 mg/mL of CNT. The optimized sensor has a nanotube length less than 0.2 µm and fiber diameter ranging between 0.25–0.32 µm. The target-controlled coat weight is 20 GSM (g/m2) for electrospun nylon nanofibers. Secondly, the impact of electrospinning conditions, particularly flow rate, on sensor response was considered. Sensor materials produced at an electrospinning flow rate of 1.0 mL/min had an enhanced stress at break, compared to neat nylon-6, without sacrificing elasticity. Additionally, sensors produced at electrospinning flow rates of 1.0 mL/h maintain their sensor response for approximately 20 stretches with no statistical difference between sensor response of the stretched and unstretched sensors.

Study on the Multilayer Barrier Coating Using Cellulose Nanofibrils and Internal Sizing Agent

In this study, we tried to develop techniques to increase coat weight and improve water resistance at a lower number of multilayer barrier coatings with anionic and cationic cellulose nanofibrils (CNFs), which has been reported in previous research. The concentration of CNF slurry was adjusted to increase the coat weight, while alkyl ketene dimer (AKD) was added as an internal sizing agent to the anionic CNF slurry to impart hydrophobicity to the CNFs. After the preparation of CNF slurries, the multilayer barrier coating was applied on never-size base paper. The coat weight, air permeability, and Cobb size degree of the barrier-coated paper were subsequently measured, and the surface of the paper was analyzed via SEM. The coat weight and air permeability of the paper coated four times with CNF slurry at 1.4% concentration were similar to those of the paper coated six times with CNF slurry at 1.0% concentration. In addition, the Cobb size degree of the barrier-coated paper decreased as the AKD addition to anionic CNF at a concentration of 1.4% increased linearly. However, when the addition level of AKD increased more than 5.0%, the Cobb size degree of the barrier-coated paper increased due to the uneven distribution of AKD. Therefore, multilayer barrier coating can be carried out effectively with cationic and anionic CNFs at high concentrations, and AKD improves the water resistance of barrier-coated paper.