Basis Weight Research Articles

Prediction of the structure of polymer-coated cardboards produced by thermocompression using I-optimal design of experiment.

The production of contrasted polymer-coated cardboards is necessary to establish the structure/properties relationships and produce the « just necessary » packaging materials. For that purpose, the impact of the processing parameters on the resulting structure of polymer-coated cardboards was modeled using a statistical Design of Experiment (DOE) approach. Five independent factors were considered: three numeric continuous factors, the pressure, the temperature, and the duration of thermocompression, one numeric discrete factor, the initial polymer film thickness, and one categorical factor, the cardboard basis weight. Four responses were considered: the thicknesses of each of the three layers constituting polymer-coated cardboards (i.e., the free polymer, the impregnated, and the free cardboard) and the material’s curvature. The choice of the adequate DOE was first assessed using a Scoping Design and coupled with the characterization of the used polymer, i.e., poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV). The I-optimal DOE was found to be the most suitable and was therefore implemented. To validate the model, the DOE was then used to produce two targeted structures, one with no impregnation of the polymer and another one with a complete impregnation of the cardboard. The values of thicknesses and curvature were not significantly different from the model predictions, therefore verifying the model.

Dynamic behavior and mechanistic analysis in filtration of dilute particulate suspensions through nanofibrous membrane

Nanofibrous membranes have garnered significant interest in membrane filtration due to their high porosity, small pore sizes, and complex interconnected pore structures. Although many studies focus on size exclusion in surface filtration, the filtration behavior and mechanisms for particles smaller than the pore size have been relatively underexplored. In this study, membrane filtration using nanofibrous membranes was employed to elucidate the filtration behavior and mechanisms for polystyrene latex suspensions with particles smaller than the pore size. The results indicated that reducing fiber diameter decreases the pore size and enhances particle rejection, with particle retention occurring within the intricate three-dimensional nanofiber pore network. In contrast, the effect of the membrane’s basis weight was less significant compared to fiber diameter. This observation can be attributed to the concept of effective thickness; once this thickness is exceeded, particles are prevented from penetrating deeper into the membrane. The filtration model was analyzed using Hermans-Bredée blockage filtration theory and cake filtration theory, considering the mass of trapped particles within the membranes. The model characterizes the filtration process as initially following standard blocking, progressing to cake filtration once a sufficient number of pores become clogged.

Effect of Carboxymethyl Cellulose and Polyvinyl Alcohol on the Dispersibility and Chemical Functional Group of Nonwoven Fabrics Composed of Recycled Carbon Fibers.

In this study, recycled carbon fibers (rCFs) recovered from waste carbon composites were used to manufacture wet-laid nonwoven fabrics. The aim was to improve dispersibility by investigating the changes in the dispersibility of carbon fibers (CFs) based on the content of the dispersant carboxymethyl cellulose (CMC) and the binder polyvinyl alcohol (PVA), and the length and basis weight of the CFs. In addition, the chemical property changes and oxygen functional group mechanisms based on the content of the CMC dispersant and PVA binder were investigated. The nonwoven fabrics made with desized CFs exhibited significantly improved dispersibility. For nonwoven fabrics produced with a fixed binder PVA content of 10%, optimal dispersibility was achieved at a dispersant CMC concentration of 0.4%. When the dispersant CMC concentration was fixed at 0.4% and the binder PVA content at 10%, the best dispersibility was observed at a CF length of 3 mm, while the maximum tensile strength was achieved at a fiber length of 6 mm. Dispersibility remained almost consistent across different basis weights. As the dispersant CMC concentration increased from 0.2% to 0.6%, the oxygen functional groups, such as carbonyl group (C=O), lactone group (O=C-O), and natrium hydroxide (NaOH), also increased. However, hydroxyl group (C-O) decreased. Moreover, the contact angle decreased, while the surface free energy increased. On the other hand, when the dispersant CMC concentration was fixed at 0.4%, the optimal binder PVA content was found to be 3%. As the binder PVA content increased from 0% to 10%, the formation of hydrogen bonds between the CMC dispersant and the PVA binder led to an increase in C=O and O=C-O bonds, while C-O and NaOH decreased. As the amount of oxygen increased, the contact angle decreased and the surface free energy increased.

Antibacterial cellulose solution-blown nonwovens modified with salicylic acid microcapsules using NMMO as solvent

Solution blowing process was used to prepare cellulose nonwovens, by using N-methyl morpholine-N-oxide (NMMO) as solvent, and salicylic acid (SA) microcapsules as antibacterial additives. The structure and properties of cellulose nonwovens modified with different SA microcapsules contents were compared and evaluated. The results showed that more uniform and denser web structure was formed with the increase of SA microcapsules content, the average fiber diameter of cellulose nonwoven increased from 1.99 μm to 2.65 μm. The air flow resistance and filtration efficiency of cellulose nonwovens increased with addition of SA microcapsules, whereas the mechanical properties, and wearing comfort including air permeability, moisture vapor transfer rate, and softness of cellulose nonwovens decreased slightly, under the same basis weight. SA microcapsules modified cellulose nonwovens exhibited good sustained-release behavior and antimicrobial activity against Escherichia coli. The higher SA microcapsules content in cellulose nonwovens, the faster release rate and the higher antimicrobial activity. The cellulose solution-blown nonwovens modified with SA microcapsules are expected to find applications in medical and healthcare fields due to its antibacterial activity and biodegradability.

Efficient capture of particulate matter with composite air filters comprising bamboo-derived nanofiber and base paper

Particulate-matter (PM) air filters comprising chemically synthesized polymers and petroleum-based materials are not environmentally sustainable because they do not biodegrade, causing secondary environmental pollution. To overcome this problem, we synthesized and analyzed the PM-capturing performance of composite sandwich-structured air filters containing bamboo-derived lignocellulose nanofibers and lignocellulose base paper. Bamboo pulp was produced through an organosolv process, and lignocellulose nanofibers and lignocellulose base paper were manufactured via electrospinning and paper processes, respectively. The manufacturing process was not only optimized via a rheological analysis of the precursor solution with different mixed solvent composition (6:4, 5:5, and 4:6 of 1-ethyl-3-methylimidazolium acetate:dimethylformamide) and different lignocellulose weight percent (3.3, 4.0, and 4.6 wt%), but also via nanofiber characterization, including electrospinnability, diameter distribution, and basis weight. The base paper condition was optimized based on analyses of the air permeability, PM filtration efficiency, and strength according to the paper thickness of 0.38 ± 0.05 and 0.10 ± 0.05 mm. As the lignocellulose nanofibers and base paper effectively captured particles smaller and larger than 2.5 μm, respectively, the structure of their composite sandwich-structured air filter was optimized to improve its PM-capturing performance. The study results provide new insights into the manufacturing of highly efficient PM air filters suitable for practical applications with diverse PM size distributions.

Relating the ultrasonic and aerosol filtration properties of filters

Non-contact methods are useful to improve the quality control of particle filtration media. The purpose of this paper is to investigate the correlation between the filtration efficiency of a porous sheet and its ultrasonic properties obtained using a non-contact technique. An air-coupled ultrasonic technique is used to obtain rapid measurements without affecting the integrity of the material. High frequencies (from 0.1 to 2.5 MHz) are used to improve technique sensitivity, and transmitted waves are measured to probe the internal properties of the material. Measurements of transmission coefficient spectra (amplitude and phase) and the corresponding ultrasound velocity and attenuation coefficient at different frequencies are obtained for a set of filtration media with well-characterized properties. Results show that the ultrasonic properties of filtration media vary as a function of basis weight, and therefore filtration efficiency, for a given charge state. However, the effect of electrostatic charge on ultrasonic propagation is almost negligible, as expected. We conclude that ultrasonic transmission may provide a valuable tool for the continuous online monitoring of material quality during fabrication and as a method to tease apart mechanical and electrostatic contributions to particle filtration.

Release of microplastic fibers from synthetic textiles during household washing

Textile materials are one of the primary sources of microplastic pollution. The washing procedure is by far the most significant way that textile products release microplastic fibers (MPFs). Therefore, in this study, the effects of various textile raw materials (A acrylic, PA polyamide, PET polyester, RPET recycled polyester and PP polypropylene), fabric construction properties (woven, knitted), thickness and basis weight values on MPFs release at different washing stages (pre-washing, soaping/rinsing) were examined separately. To mimic the most popular home washing procedures, a 10-min pre-wash and a 35-min soaping/rinsing phase at 40 °C were selected for the washing procedure. Utilizing the Image J program on macroscopic images captured by a high-resolution SL. R camera, the microfibers collected by filtering the water have been visually counted. According to the results, knitted fabrics released fewer MPFs than woven fabrics, with the woven acrylic sample (A3-w) exhibiting the highest release (2405 MPFs). The number of MPFs increased along with the thickness and weight of the fabric. Recycled polyester was found to release more MPFs than virgin polyester under the same conditions (1193 MPFs vs. 908 MPFs). This study demonstrates how recycled polyester, although initially an environmentally beneficial solution, can eventually become detrimental to the environment. Furthermore, it is known that the pre-washing procedure—which is optional—releases a lot more MPFs than the soaping and rinsing procedures, and that stopping this procedure will drastically lower the amount of MPFs incorporated into the water.

Improved vacuum dewatering of grease-proof paper utilizing a multi-slit vacuum suction box in laboratory scale

Grease-proof paper is an energy-demanding paper product to manufacture, especially during refining and dewatering. Increases in energy efficiency in either stage could result in major savings. This article investigates the potential gains with addition of a stepwise progression vacuum suction box to the forming section during production. For both a lighter, 50 g/m2, and a heavier paper grade, 100 g/m2, with a pulp-drainability of 86 °SR, a stepwise progression vacuum suction box in four steps would result in increased dryness, simultaneously with decreased energy expenditure. The observed effects were higher for the lower basis weight paper (50 g/m2). Both basis weights experienced clogging of the forming fabric due to the high degree of refining. This adversely affected the dewatering rate, decreasing the amount of air pulled through the paper even when increasing the vacuum pressure. When a stepwise progression suction box in four steps was compared to a single vacuum suction box, there was a 14% increase in dryness for lighter paper, over an equal energy consumption, measured as amount of air pulled through the paper. For the 100 g/m2 paper, the increase in dryness was 3% compared to the 50 g/m2 paper run over a single vacuum suction box. The results show great promise for energy savings when utilizing stepwise progression suction box dewatering for grease-proof paper production.

Sustainable Greeting Card – paper Products Produced on a Laboratory Paper Machine

Paper products have been used for thousands of years for art and communication purposes. The presented project describes the development of a unique greeting card art paper product, comprised of a card stock with a basis weight of 150 g/m2 having a purple color tone and inlay paper product with a basis weight of 100 g/m2. The inlay paper product should have a gras fiber content that is visualized by a tree cut out in the cover paper. The inlay paper should be printable with a standard ink-jet printer as well as be able to write on with a fountain pen. Both paper grades were developed with a hand sheet study and then upscaled to a small 225 mm wide laboratory Fourdrinier paper machine. The produced cover paper and inlay paper had a basis weight of 152.20 g/m2 for the cover paper having a purple color tone and 102.64 g/m2 for the inlay paper, meeting all mechanical and optical properties as required. The finished cover and inlay paper product was converted into DIN A5 and DIN A6 card stock, including cutting out the tree image from the cover paper using a laser cutter.

Micrometer‐Thin Nanocellulose Foils for 3D Organic Electronics

AbstractCellulose is a natural polymer with great properties such as high optical transparency and mechanical strength, flexibility, and biodegradability. Hence, cellulose‐based foils are suitable for the replacement of synthetic polymers as substrate materials in organic electronics. This article reports the fabrication of ultrathin, free‐standing cellulose foils by spraying aqueous 2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐nanocellulose (TEMPO) fibrils ink layer‐by‐layer on a hot substrate using a movable spray nozzle. The resulting foils are only 2 ± 1 µm in thickness with an average basis weight of 1.9 g m−2, which ranges in the same scale as the world's thinnest paper. The suitability of these ultra‐thin nanocellulose foils as a sustainable substrate material for organic electronic applications is demonstrated by testing the foils resistance against organic solvents. Furthermore, silver nanowires (AgNWs) and the blend poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) are integrated into the foils, and the foils are molded into 3D paper structures in order to create conductive, paper‐based building blocks for organic electronics.

Semi-theoretical compression model of wet fiber web for the prediction of airflow rate in vacuum dewatering process of papermaking

This study expands the investigation of a mathematical method for predicting the airflow rate during the vacuum dewatering process of papermaking based on our previous research. By integrating poroelastic theory and initial saturation thickness, based on experimental data with a range of 20–60 kPa pressure difference and 20-200 g · m − 2 basis weight, a mathematical method with a semi-theoretical model for compression characteristics of the wet fiber web, the poroelastic porosity model (PEPM), was developed to support and expand on our previously established empirical model for porosity variations in wet fiber web, the variable porosity model (VPM). The accuracy of the mathematical method with the PEPM in predicting the airflow mass flux passing through the wet fiber web was validated using experimental data with a range of 0–60 kPa pressure difference and 20-200 g · m − 2 basis weight. The mean relative errors with the PEPM within the pressure difference range of 0-20 kPa and 0-60 kPa were 7.68% and 8.80%, respectively, compared to 17.44% and 11.67% for those with the VPM, demonstrating the improved applicability and generalization of the mathematical method, particularly in the zone of low pressure difference exceeding the range of the modeling experimental data. The PEPM effectively revealed the strain hardening behavior during the compression process and the diminishing returns of energy in the vacuum dewatering process with an increasing pressure difference. The developed mathematical method with the PEPM for the compression characteristics of the wet fiber web provides an effective and accurate way to predict the airflow rate during the vacuum dewatering process of papermaking.

Effect of chitosan and cationic polyacrylamide on optical and mechanical properties of paper made from chemi-mechanical pulps

The influences of nano-chitosan and cationic polyacrylamide (cPAM) on the optical and mechanical properties of paper made from chemi-mechanical pulp (CMP) were investigated. Bleached chemi-mechanical pulp (CMP) was selected as the control sample. The cPAM was considered at four levels (0%, 0.25%, 0.5%, and 0.75%), while chitosan was added to the CMP suspension at three levels (0%, 1%, and 2%). Paper test specimens were prepared according to TAPPI standards with a basis weight of 60 g/m2, and their optical and mechanical properties were measured. The results indicated that the opacity, greenness, tear strength, burst strength, and Gurley seconds were increased, whereas brightness, water absorption, and a* factor were decreased by increasing the amount of cPAM. Adding chitosan to CMP increased the a* factor, tear strength, breaking length, burst strength, Gurley seconds, water absorption, and greenness in the resulting paper. When polyacrylamide and nano-chitosan were added simultaneously to CMP, the brightness, water absorption, and greenness of the resulting paper decreased, but opacity, burst strength, tear strength, and air resistance had an appropriate increase. In all treatments, the best results were found at 1% chitosan and 0.5% cPAM due to favorable optical and mechanical properties.

Synthesis of lignin-based polyurethane (LPU) and fabrication of degradable mulch film through LPU coating on cellulose paper

The use of non-degradable plastic mulch film causes significant environmental pollution and poses a threat to human and ecological safety. To address this issue, a viable solution is to develop bio-based and biodegradable paper mulch films to replace non-biodegradable ones in agricultural soils. In this study, a green and straightforward process was used to synthesize lignin-based polyurethane (LPU), which was then coated on cellulose paper (CP) of low basis weight of 30 g/m2 to fabricate a composite LPU/CP mulch film. An ultra-thin and lightweight LPU/CP mulch film was successfully fabricated with basis weight, thickness, and specific density of 40 g/m2, 80 µm, and 0.5 g/cm3, respectively. It was observed that surface coating was very effective in improving the physical strength of composite film as indicated by the improvement of tensile index from 19.3 N·m/g of CP to 65.0 N·m/g of LPU/CP mulch film. Moreover, LPU/CP mulch film presented excellent water resistance properties as suggested by the water contact angle of 107° and the water vapor transmission rate of 639.3 g/m2·day. LPU/CP mulch film also shows a balance between degradability and durability that it starts to break down into fractions after being buried for 28 days as a result of microbiological degradation. This work provides a feasible technology for fabricating eco-friendly, cost-effective, and biodegradable paper mulch film.

Light stabilizer-modified hydrocharging melt-blown nonwovens with superior charge stability for air filtration

Particulate matter poses substantial risks to human health, air visibility, climate, and ecological equilibrium. Electret materials are instrumental in air purification and personal protection, as they significantly enhance filtration efficiency without increasing pressure drop. Despite these advantages, developing electret filters with both high filtration efficiency and stable performance under thermal conditions and prolonged storage has proven challenging. In this study, we introduce a novel electret melt-blown filter fabricated through hydrocharging technology supplemented with the light stabilizer UV3346. The interaction of water and air molecules with melt-blown fibers generated abundant positive and negative charges, thereby amplifying the electrostatic attraction effect. Concurrently, UV3346 mitigated the formation of reactive free radicals and minimized charge exchanges, thus enhancing charge storage stability. Owing to the incorporation of UV3346, the UV3346/PP-0.8 melt-blown nonwovens, having a basis weight of 22 g/m2, demonstrated a filtration efficiency of 99.55 %, a low pressure drop of 59.45 Pa, and marginal decrease in filtration efficiency after heat treatment at 130 °C. Notably, the filtration efficiency experienced only a 0.30 % reduction after a two-year storage period, markedly outperforming commercial alternatives. This study is expected to inform future work on high-performance air filtration materials suitable for both air purification and personal protection equipment.

Katmanlı ve bimodal nanolifli yapılarla filtrasyon performansının artırılması

Particulate matter (PM) must be removed from the air because it is a serious threat to human health. Micro and/or nanoporous nonwoven fabrics are commonly used to filter these particles. In our study, the filtration performances of nanofibrous mats, which were obtained by combining fibers produced by two different production methods in a layered and bimodal manner, were evaluated. Fibrous layers produced by the meltblown (MB) method were obtained with similar fiber diameters and different thicknesses by different feeding speeds. Bimodal structures obtained by adding fibers with an average diameter of 225 nanometers produced by the solution blowing (SB) method into fibers with an average diameter of around 800 nm obtained at 1, 5 and 10 rpm screw rotating/feeding speeds had higher filtration performance than the samples without SB nanofibers. Then, among the 4 samples with an average basis weight of 15 gsm, the sample MB only without (electro-blown nanofiber); the EB sample contains only EB nanofibers; the sample (L) containing 4 gsm EB nanofibers and the 4-layer sample (4L) containing 4 gsm EB nanofibers (138 nm) were compared. The 4L sample had the highest quality factor (0.0353) with a filtration efficiency of %96.01 and a pressure drop of 135 Pa. Although the filtration efficiency increased in all samples with the subsequent corona treatment, the highest value (99.34%) was obtained from the 4L sample.

Non-empirical description of nuclear collective motion with optimized basis for multi-reference density functional theory

The generator coordinate method (GCM) has been a well-known method to describe nuclear collective motions. In this method, one a priori specifies collective degrees of freedom as inputs of the method based on empirical and/or phenomenological assumptions. We here present an extension of the GCM, in which both the basis Slater determinants and weight factors are optimized in a non-empirical manner. The result for 16O nucleus with the Skyrme functional suggests that a collective coordinate should be determined in a more complex way than what has been assumed so far.

Algorithm to determine local basis weight of random fibrous networks with X-ray microtomography and SEM images

Analysis of the basis weight for random fibrous networks is important to understand their microstructure, properties and performance. Two-dimensional microscopical images show in-plane fibers without giving any information on their distribution in three dimensions. This research introduces a fully parametric algorithm for computing the local basis weight of random fibrous networks using three-dimensional images because out-of-plane fiber orientation is important, especially for high-density or thick networks. Voxel models of real nonwoven webs were generated by an X-ray micro-computed tomography system. The developed algorithm could accurately estimate a local basis weight value for random fibrous networks produced with various manufacturing parameters. Numerical results computed with the developed method were compared with those obtained with a physical weight measurement technique. The algorithm was tested and validated for various nonwoven fabrics with different densities. It was observed that the developed method can be used to examine and/or compare the basis weight of a wide range of random fibrous networks. In addition, it can be used to predict the basis weight for fabrics, especially in a new product development process.

Optimisation of punching parameters for enhanced filtration performance of non-woven by response surface methodology

This work highlights the relevance of punch density, needle penetration depth and basis weight on the nonwoven fabric’s properties. Fibre fineness-specific optimised carding parameters, that is feeder, cylinder and doffer speeds were used for the preparation of carded web to produce considered basis weight of carded batts. Fabric thickness, bursting strength, mean flow pore size, air permeability, air filtration efficiency and pressure drop were extensively investigated, and a relationship was developed using the Box–Behnken design. The punch density and needle penetration depth were optimised to achieve the required levels of mean flow pore size at constant basis weight for enhancing the air filtration behaviour of non-woven fabrics.

Enhancing filtration performance of submicron particle filter media through bimodal structural design

AbstractDepth filtration is a widely utilized mechanism for submicron aerosol filtration using disposable filter cartridges and facemasks. The filter media should be carefully engineered to reach high filtration efficiency and dust‐loading capacity at the expense of a low‐pressure drop (ΔP). Filter media with bimodal fiber diameter distribution enhance particle capture by creating small pores with tiny fibers, while microfibers improve airflow, reduce ΔP, and increase the effective filter area for particle retention. In this study, bimodal filters were achieved through the homogeneous distribution or layered use of nanofibers and microfibers. The impact of the bimodal design was explored using fibrous mats produced through melt‐blowing, solution‐blowing, and electroblowing methods. Keeping the basis weight of filter samples at 30 gsm, using four‐layered filters (4L) improved air permeability compared to single‐layer samples. The 4L sample exhibited the highest performance, achieving 99.52% efficiency at 148 Pa. Moreover, replacing the melt‐blown layer with bimodal mats in the 4L design increased the filtration efficiency to 99.61% keeping ΔP nearly the same. The corona discharge treatment yielded the highest efficiency (99.99%) in the 4BML sample, even after 1 month the efficiency was maintained at 99.90%, highlighting the advantage of bimodal fiber distribution in electret filters.Highlights Four‐layered filter (4L) structures resulted in improved air permeability. Bimodal layer (BL) achieved by adding SB nanofibers into the melt blowing. BL in 4L structure increased the efficiency from 99.52% to 99.61%. Modified BL sample (4BML) provides the highest QF (0.044 Pa−1) after 1 month.

Moisture Transfer of Paper for Food Packaging Applications: A Laboratory Study

Since paper has been invented in Chana in 105 BC by Cai Lun it has transformed human live. Sustainable developments favor paper as packaging media to replace plastic packaging materials.
 Laboratory tests were performed on commercially available packaging papers for the assessment of mechanical properties and vapor transmission rates that might affect the packaging of perishable goods to further develop paper-based packaging materials.
 Research results of the mechanical paper properties values cannot be directly related and compared between the different packaging papers analyzed due to their different basis weight, composition and intended use.
 Research results revealed that the application of a coating material can affect paper properties negatively but decrease the vapor transmission rate measured at 23°C and 50% relative humidity below 1.06 g for wax coating and 0.3 g for polyvinyl coatings. Parchment type paper products without coating can achieve a water vapor transmission rate of 1.35 g per 240 hours. an important factor for packaging perishable goods.
 Therefore, packaging paper are specifically designed for their intended use and application including the application of a coating to the paper material to keep perishable goods longer fresh.