Fibrous Materials Research Articles

Cellulose acetate/chitosan composite film loaded with ground cinnamon for active packaging: water vapor sorption kinetic, compounds release, and antimicrobial effect

This study evaluated structural, physical, and water sorption properties of cellulose acetate/chitosan composite film incorporated with ground cinnamon as an antimicrobial. The controlled release of antimicrobial compounds and antimicrobial effects on Escherichia coli and Staphylococcus aureus were also monitored. The composite film formed highly porous and fibrous materials with higher thermal resistance. A higher ratio of chitosan in the film improved the swelling degree and water-vapor absorption capacity but reduced adsorption rates. Consequently, antimicrobial compounds, including eucalyptol, naphthalene, and β-caryophyllene, were more quickly released from the composite film with a larger chitosan ratio, affecting stronger antimicrobial effects. The inclusion of ground cinnamon with residual fat content in the film contributed to an extended inhibition of microbial growth in an indirect packaging system. Understanding the chitosan/cellulose acetate ratio in the film composite formation and the incorporation of ground cinnamon is important to control the compounds' release and generate long-term antimicrobial effects of active packaging materials on fresh food products.

Development of an empirical model for the prediction of the sound absorption coefficient for thin and low-density fibrous materials

Currently, FEA software such as ABAQUS uses empirical models to predict the sound absorption coefficient of poroelastic materials. However, based on a recent review of the literature it was found that the current sound absorption empirical models are inadequate for accurate prediction of thin (t < 20 mm), low-density materials (ρB < 50 kg/m3). Therefore, the predictions of the sound pressure levels in vehicle cabins, using such software, will be inaccurate since the trim materials are thin and have a low density. Thus, this research aimed to develop an empirical model that can accurately predict the sound absorption coefficient of these materials. Hence, polypropylene fibres consisting of four different diameters were manufactured and converted into nonwovens. Thereafter, airflow resistivity and impedance tube experimental testing were performed on the specimens. Subsequently, statistical analysis of the data was performed using SAS software. SAS was used to identify which independent variables should be included in the models to be developed. The empirical models were developed using the regression analysis toolbox in Microsoft Excel. Once the models were developed, various checks were performed to validate the assumptions of linear regression. The software NumXL was used to perform Cook’s distance tests. Thereafter, the models were validated against the validation dataset, where it was found that the developed exponential model performed best. Finally, the exponential model was compared to existing models using two data sets i.e. an internal dataset, and an external dataset derived from the literature. The developed model outperformed all the historic models on both datasets.

Coarse graining with control points: a cubic-Bézier based approach to modeling athermal fibrous materials

Fibrous materials continue to be of central importance to modern life, including traditional materials, such as textiles and paper, modern materials, such as polymeric materials and glass fiber, and emerging materials, such as carbon nanotube yarns. Developing constitutive laws for the mechanical behavior of such materials can be challenging owing to the often non-periodic microstructure, resulting in fairly large and computationally intractable representative volume elements. Therefore, it is imperative to design novel coarse-grained models that can bridge the computational gap and capture accurate physics associated with the mechanical behavior of fibrous materials. In this work, cubic-Béziers are used to represent fiber-segments, allowing for up to C 2(curvature)-continuous representation of curved fibers. Equations of motion are derived in terms of the control points, which allow for minimization and time integration strategies with the Lagrangian and Hamiltonian formalism. This coarse-grained model promises faster and more accurate computational performance compared to discrete approaches.

Experimental and mesoscopic simulation study of size effect on splitting tensile performance of spontaneous combustion coal gangue concrete

The spontaneous-combustion coal gangue concrete (SCGAC) demonstrates different mechanical behavior compared to ordinary concrete owing to its distinct porous structure and the presence of fibrous materials in its coarse aggregates. Presently, research on the macroscopic mechanical properties of SCGAC is reasonably comprehensive; however, it falls short of fully understanding its size effect. This study examines the splitting tensile strength of cubic SCGAC specimens with three strength grades, i.e., C30, C35, and C40, and three sizes, i.e., 100 mm, 150 mm, and 200 mm; proposes a mesoscopic modeling approach based on the computer vision; analyzes the intrinsic mechanisms of splitting failure and the size effect of different strength grades on the SCGAC by utilizing mesoscopic simulation methods. Subsequently, an analysis of the size effect on the splitting tensile strength of SCGAC is conducted based on classical size effect laws. The results reveal the following: The method proposed in this study for mesoscopic modeling is recognized for its low cost, high efficiency, and accurate simulations, fulfilling the required standards for mesoscopic mechanical analysis. SCGAC, as a heterogeneous material, demonstrates significant size effect phenomena that become more pronounced with enhancements in strength grades. The Carpinter fractal size effect law is ideally suited to characterize the size effect patterns in SCGAC. This paper enhances the comprehension of the size effect of SCGAC through a combination of macroscopic experiments and mesoscopic simulations, thereby facilitating its engineering applications.

The Air Permeability and the Porosity of Polymer Materials Based on 3D-Printed Hybrid Non-Woven Needle-Punched Fabrics.

The possibility of controlling the porosity and, as a result, the permeability of fibrous non-woven fabrics was studied. Modification of experimental samples was performed on equipment with adjustable heating and compression. It was found that the modification regimes affected the formation of the porous structure. We found that there was a relationship between the permeability coefficient and the porosity coefficient of the materials when the modification speed and temperature were varied. A model is proposed for predicting the permeability for modified material with a given porosity. As the result, a new hybrid composite material with reversible dynamic color characteristics that changed under the influence of ultraviolet and/or thermal exposure was produced. The developed technology consists of: manufacture of the non-woven needle-punched fabrics, surface structuring, material extrusion, additive manufacturing (FFF technology) and the stencil technique of ink-layer adding. In our investigation, we (a) obtained fibrous polymer materials with a porosity gradient in thickness, (b) determined the dependence of the material's porosity coefficient on the speed and temperature of the modification and (c) developed a model for calculating the porosity coefficient of the materials with specified technological parameters.

A review of helicoidal composites: From natural to bio-inspired damage tolerant materials

Helicoidal composites have been found in shrimp club, lobster claw, beetle cuticle, crab shell, scorpion pincer, and fish scale as a natural material. The helicoidal composite possesses excellent impact resistance and extraordinary damage tolerance due to its hierarchical structure and the unique helicoidal arrangement of its reinforcement fibres. Its structure and performance have been studied through various characterisation and mechanical testing methods. Based on the structure-property relationship of the natural helicoidal composite, researchers have been able to mimic the unique fibre arrangement and develop bio-inspired helicoidal composites with enhanced impact performance. Various helicoidal composites comprising of synthetic fibrous materials such as carbon fibre (CF), glass fibre (GF), and aramid fibre, and matrix materials such as thermoset and thermoplastic polymers have been developed through biomimicry. The failure mechanisms of the bio-inspired helicoidal composites have been studied and the advantages of arranging the fibre reinforcement into helicoidal architectures have been elucidated over conventional composite constructions such as quasi-isotropic (QI) and cross-ply layups. This review systematically elaborates the recent progress of the research work on both natural and bio-inspired helicoidal composites. It sheds light on the distinctive construction of the natural helicoidal composites found in different animals such as shrimps, lobsters, crabs, beetles, scorpions, and fish, and their energy absorption mechanisms. Different manufacturing methods for developing bio-inspired helicoidal composites are discussed and various reinforcements and matrix materials used in the composites are described. The processing-structure-property interrelationship of the bio-inspired helicoidal composites is summarised. This review will contribute to the advancement of the knowledge of the natural helicoidal composite and potentially help researchers to develop highly efficient bio-inspired damage tolerant helicoidal composites.

Sida hermaphrodita Rusby as a papermaking raw material – Chemical and morphological characteristics

A continually increasing demand for papermaking materials and simultaneously growing disproportion between the request for fiber and the limited resources of wood have forced scientists and the papermaking industry to search for the new sources of fibrous raw materials. A new promising set of raw materials for papermaking comes from energy crops. This paper presents Sida hermaphrodita Rusby L., as a non-woody raw material for papermaking. From the studies of chemical composition, it follows that cellulose content of more than 40% characterizes phloem of stems and branches, whereas in xylem exhibits more than 32%. The lowest is the concentration of cellulose in leaves and flowers of Sida. The content of lignin is lower than 24% and 16% in stem xylem and phloem, respectively. In Sida, hemicelluloses and mineral substances stand for being not more than 30% and 2%, respectively. The morphology of Sida cells is similar to hardwood, with fiber length of 0.383, 0.470 and 1.025 mm for parenchyma, xylem, and phloem, respectively. The chemical composition of Sida hermaphrodita together with its morphological characteristics make this raw material suitable for a production of papers intended for printing, writing and tissue.

How Resilient is Wood Xylan to Enzymatic Degradation in a Matrix with Kraft Lignin?

Despite the potential of lignocellulose in manufacturing value-added chemicals and biofuels, its efficient biotechnological conversion by enzymatic hydrolysis still poses major challenges. The complex interplay between xylan, cellulose, and lignin in fibrous materials makes it difficult to assess underlying physico- and biochemical mechanisms. Here, we reduce the complexity of the system by creating matrices of cellulose, xylan, and lignin, which consists of a cellulose base layer and xylan/lignin domains. We follow enzymatic degradation using an endoxylanase by high-speed atomic force microscopy and surface plasmon resonance spectroscopy to obtain morphological and kinetic data. Fastest reaction kinetics were observed at low lignin contents, which were related to the different swelling capacities of xylan. We demonstrate that the complex processes taking place at the interfaces of lignin and xylan in the presence of enzymes can be monitored in real time, providing a future platform for observing phenomena relevant to fiber-based systems.

Orthotropic failure criteria based on machine learning and micro-mechanical matrix adapting coefficient

Several studies have examined the use of fibrous and non-fibrous anisotropic materials in various industries and proposed failure criteria for consideration. These criteria can be categorized into theories that address specific failure modes and those that do not. However, these theories often fail to address both the representation of inherent material properties and the combination of different loading modes. To address this, a micromechanical approach called micromechanical modeling of laminates (“MACML”) has been developed, which gradually transitions from anisotropic to isotropic materials by incorporating reinforcement and adapting coefficients. MACML combines machine learning (ML) techniques and introduces a new method to identify safe and failure-prone regions in composites. This approach allows for independence from the influence of fibers by representing them as an active stress proportion of the isotropic matrix. Additionally, standard experimental procedures can be applied based on the isotropic matrix, and experimental results have been conducted to validate the established failure criteria in the MACML method.

Iterative method for large-scale Timoshenko beam models assessed on commercial-grade paperboard

AbstractLarge-scale structural simulations based on micro-mechanical models of paper products require extensive numerical resources and time. In such models, the fibrous material is often represented by connected beams. Whereas previous micro-mechanical simulations have been restricted to smaller sample problems, large-scale micro-mechanical models are considered here. These large-scale simulations are possible on a non-specialized desktop computer with 128GB of RAM using an iterative method developed for network models and based on domain decomposition. Moreover, this method is parallelizable and is also well-suited for computational clusters. In this work, the proposed memory-efficient iterative method is numerically validated for linear systems resulting from large networks of Timoshenko beams. Tensile stiffness and out-of-plane bending stiffness are simulated and validated for various commercial-grade three-ply paperboards consisting of layers composed of two different types of paper fibers. The results of these simulations show that a linear network model produces results consistent with theory and published experimental data

Pressure evaluation in highly porous medium hydrodynamic bearings

This paper presents an experimental investigation into lift generation during the tangential motion of an inclined surface over a compressible porous layer, focusing on an exceptionally slow sliding speed, a condition that has not been considered in previous studies. Specifically, we validated Pascovici's one-dimensional lubrication model for an inclined slider under the above condition. Additionally, we explore the use of woven fibrous material for soft porous lubrication, broadening the range of media for future studies.

Boron Nitride/Carbon Fiber High-Oriented Thermal Conductivity Material with Leaves-Branches Structure.

In the realm of thermal interface materials (TIMs), high thermal conductivity and low density are key for effective thermal management and are particularly vital due to the growing compactness and lightweight nature of electronic devices. Efficient directional arrangement is a key control strategy to significantly improve thermal conductivity and comprehensive properties of thermal interface materials. In the present work, drawing inspiration from natural leaf and branch structures, a simple-to-implement approach for fabricating oriented thermal conductivity composites is introduced. Utilizing carbon fibers (CFs), known for their ultra-high thermal conductivity, as branches, this design ensures robust thermal conduction channels. Concurrently, boron nitride (BN) platelets, characterized by their substantial in-plane thermal conductivity, act as leaves. These components not only support the branches but also serve as junctions in the thermal conduction network. Remarkably, the composite achieves a thermal conductivity of 11.08 W/(m·K) with just an 11.1 wt% CF content and a 1.86 g/cm3 density. This study expands the methodologies for achieving highly oriented configurations of fibrous and flake materials, which provides a new design idea for preparing high-thermal conductivity and low-density thermal interface materials.

Automating Wood Species Detection and Classification in Microscopic Images of Fibrous Materials with Deep Learning.

We have developed a methodology for the systematic generation of a large image dataset of macerated wood references, which we used to generate image data for nine hardwood genera. This is the basis for a substantial approach to automate, for the first time, the identification of hardwood species in microscopic images of fibrous materials by deep learning. Our methodology includes a flexible pipeline for easy annotation of vessel elements. We compare the performance of different neural network architectures and hyperparameters. Our proposed method performs similarly well to human experts. In the future, this will improve controls on global wood fiber product flows to protect forests.

Micro-CT image-based computation of effective thermal and mechanical properties of fibrous porous materials

Fibrous porous materials are extensively employed as heat shielding material for space vehicles and capsules. To predict the performance of these materials using computational modeling at the vehicle/capsule scale, the effective material properties are needed. In this work, the effective thermal conductivity and elastic constants of a carbon fibrous porous material called FiberForm (precursor of PICA) were calculated using a direct image-based approach. In this image-based approach, the microstructures obtained using X-ray computed tomography technique are represented as binary voxel data. Nonlocal interactions are introduced between neighboring voxels. Integro-differential equations, with respect to spatial and temporal dimensions respectively, are developed to govern material thermal and mechanical behaviors. Using this approach, energy-based computational procedures were developed to calculate the effective material properties of fibrous and porous materials irrespective of the periodicity of underlying microstructures. The size of representative volume element was determined by convergence of effective properties with respect to microstructure size.

A traceological and quantitative assessment of the function of the bone bi-pointed tools from the Late Neolithic of the Cueva del Toro (Antequera, Malaga)

This study presents a traceological analysis of bi-pointed bone tools from the Late Neolithic layers of Cueva del Toro (Málaga, Spain). The tools, previously hypothesized as arrowheads, were re-examined using traceological methods combined with confocal microscopy. The analysis refutes their classification as hunting implements. Polished surfaces on the tools, indicative of interaction with fibrous materials, suggest their use in weaving tasks involving wool or similar materials. This study highlights the early use of sheep wool for textiles at Cueva del Toro, dated between 4250 and 3950 cal BCE. This study also emphasizes the significance of craft activities in the Neolithic, with a diverse toolkit for processing fibers and animal materials. By applying quantitative methods to distinguish use-wear traces, the study contributes to the development of use-wear analysis techniques and opens the way for future research in ancient human-material interactions.

Time-dependent thermal degradation of lost circulation materials in geothermal systems

Treatment of lost circulation can represent anywhere from 5 to 25 % of the cost in drilling geothermal wells. The cost of the materials used for lost circulation treatment is less important than their effectiveness at reducing fluid losses. In geothermal systems, the high temperatures (>90 °C) are expected to degrade many commonly used lost circulation materials over time. This degradation could compromise different materials ability to mitigate fluid loss, creating more non-productive time as multiple treatments are needed, but may result in recovering desired permeability zones within the reservoir section over time. This research aimed to study how thermal degradation of eight different lost circulation materials affected their properties relevant to sealing loss zones in geothermal wells. Mass loss experiments were conducted with each material at temperatures of 90–250 °C for 1–42 days to measure the breakdown of the material at geothermal conditions, collecting gases during several experiments to determine the waste produced during degradation. Compaction experiments were conducted with the degraded materials to show how temperatures reduced the rigidity and increased packing of the materials. Viscosity tests were conducted to show the impact of different materials on drilling fluid rheology. Microscope observations were conducted to characterize the alterations to each material due to thermal degradation. Organic materials tend to degrade more than inorganic materials, with organics like microcellulose, cotton seed hulls and sawdust losing 30–50 % of their mass after 1 day of heating at 200 °C, while inorganics like magma fiber only lose ∼5–10 % of its mass after one day of heating at 200 °C. Granular materials are the strongest when compacted despite any mass loss, while fibrous and flaky materials are fairly weak and breakdown easily under stress. The materials do not generally affect fluid rheology unless they have a viscosifying agent as part of the mixture. Microscopic analysis showed that more rigid materials like microcellulose and cedar fiber degrade in brittle manners with splitting and fracturing, while others like cotton seed hulls degrade in more ductile manners forming meshes or clumps of material. The thermal breakdown of lost circulation materials tested suggests that each material should also be classified by its degree of thermal degradability, as at certain temperatures the materials can lose the capability to bridge loss zones around the wellbore.

Enhancing the attraction of positively charged precursors of conductive polymer poly(3,4-ethylenedioxythiophene) by anchoring sulfonate groups in cellulose fibres

Interfacial interactions are key to the development of high-performance coatings such as conductive polymer layers on fibrous materials. In this work, we present an approach of strengthening the interaction by forming ionic bonds between cellulose fibres and the conductive polymer layer by introducing a sulfonate group on cellulose fibres. The ionic bonds are formed between anchored sulfonate group and the positively charged precursor 3,4-ethylenedioxythiophene (EDOT), followed by the deposition and polymerisation of poly(3,4-ethylenedioxythiophene):sulfate (PEDOT:SO4) on the fibrous substrate surface. The conductance of the PEDOT:SO4 coated substrate with anchored sulfonate groups coated may be 1.7 times higher compared to the conductance of the unmodified cellulose substrate depending on experimental conditions. EDX measurements confirm the presence of sulfur and a shift of zeta potential at lower pH supports the evidence of the anionic anchored groups on the fibre surface. Our study therefore provides a new way to enhance the affinity of fibrous cellulose materials towards polymer conductive coatings.

Modeling the Deformation Process of a Fibrous Material in the Passage and Winding Zone of a Multidimensional Dynamic Object

Modeling the Deformation Process of a Fibrous Material in the Passage and Winding Zone of a Multidimensional Dynamic Object

Microstructural Evolution and Failure in Fibrous Network Materials: Failure Mode Transition from the Competition between Bond and Fiber.

For the complex structure of fibrous network materials, it is a challenge to analyze the network strength and deformation mechanism. Here, we identify a failure mode transition within the network material comprising brittle fibers and bonds, which is related to the strength ratio of the bond to the fiber. A failure criterion for this type of fibrous network is proposed to quantitatively characterize this transition between bond damage and fiber damage. Additionally, tensile experiments on carbon and ceramic fibrous network materials were conducted, and the experimental results show that the failure modes of these network materials satisfy the theoretical prediction. The relationship between the failure mode, the relative density of network and strength of the components is established based on finite element analysis of the 3D network model. The failure mode transforms from bond damage to fiber damage as increasing of bond strength. According to the transition of the failure modes in the brittle fibrous network, it is possible to tailor the mechanical properties of fibrous network material by balancing the competition between bond and fiber properties, which is significant for optimizing material design and engineering applications.

Facile fabrication of multifunctional aramid fibers for excellent UV resistance in extreme environments

Aramid fibers (AFs) are widely applied as structural material, cordage, and versatile protection in many harsh environments, including space and deep sea. However, intense ultraviolet (UV)/ irradiation, high/low temperatures, and/or chemical solvent with strong acid/alkali/corrosion feature seriously affect their mechanical properties, thus severely shorten the life cycle of AF-based products. Inspiration by the principle of multiple refractions and partly reflections, an innovative strategy by depositing of laminated Al2O3/TiO2 composite onto the surface of poly(m-phenylene isophthalamide) (PMIA) via atomic layer deposition (ALD) technique was presented. The tenacity of ALD-coated PMIA only decreases by ∼ 8 %, and the yellowness index (YI) only increasing to 129.24 %, far lower than 321.63 % of pristine PMIA fabric under the combination of intense UV irradiation (4260 W/m2) and high temperature (200 °C + ) for 6 h, which equals to continuous strong sunlight exposure for approximately 7.5 years. Meanwhile, ultraviolet protection factor (UPF) value increased to 126.4, which is double that of the pristine PMIA fabric, exhibiting an impressive UV-resistance property. Furthermore, the ALD-coated PMIAs also shows a significant enhancement in both chemical and thermal stabilities. In all, this work not only forge a new route for the functionalization of fibrous materials, but also exhibits great promise for next generation advanced composite material and cutting-edge equipment in harsh environment.