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Abstract We present a study of the controlled biodegradation of polylactic acid (PLA) reinforced with high lignin containing microfibrillated cellulose (MFLC) isolated from chemi-thermomechanical pulp. The surface of MFLC was modified using an acetylation method to decrease its polarity. Biocomposites with different MFLC and acetylated MFLC (Ac-MFLC) contents were fabricated via a solvent casting method. The biodegradation of biocomposites was performed by burying in soil and holding at 45 °C for 30 days. After soil burial, MFLC/biocomposites exhibited higher weight loss (5.4 %) compared to neat PLA (4.2 %) and Ac-MFLC/biocomposites (4.6 %). Morphological analysis results showed surface erosion of the PLA to change with the addition MFLC and Ac-MFLC, resulting in porous formations on the surface of biocomposites. These formations led to the loosening of microfibril-PLA interface in the internal structure, resulting in a significant decrease in the storage modulus of biocomposites. The biocomposites exhibited no antimicrobial properties, confirming their biotic degradability. Graphical Abstract

Wool fiber is widely used for clothing in our daily life due to its excellent physical and mechanical properties. However, in the daily laundry process, wool products can shrink severely by strong mechanical action in a warm and moist environment due to the fiber surface scales. Aiming to overcome the difficulty of washing delicate clothes such as wool and silk, Panasonic Intellectual Property Management Co. Ltd. invented a new washing machine for delicate clothes, based on tapping actions. The washing performance of wool sweaters in tapping washing is compared with that of hand washing and gentle and normal machine washing. The results show that tapping washing always gives wool sweaters the best appearance, dimensional stability and mechanical property up to 10 washing cycles. The changes in appearance and mechanical properties of wool sweaters are mainly due to the rate of felting shrinkage. By comparing the magnitude, duration, number of mechanical actions and direction of the forces acting on the fabric in tapping washing, hand washing and gentle machine washing, it can be concluded that the direction of forces acting on the fabric has a significant effect on wool fabric felting shrinkage, and unidirectional force has less effect on felting shrinkage than multidirectional forces. Tapping washing can give the lowest felting rate to wool samples because the forces in tapping washing on all parts of the fabric have a similar direction.

Current biodegradable drinking straws suffer from poor heat resistance and rigidity when wet, causing user dissatisfaction. Here, a fully biodegradable straw formed by stereocomplexation of poly (lactic acid) (SC-PLA) is reported. Because of the unique strong interaction and high density of link chains between stereocomplex crystallites (over 70% crystallinity), SC-PLA straws outperform their counterparts on the market. This coupled with the advantages of simple processing (solution casting and annealing) and relatively low cost (~2.06 cents per straw) makes SC-PLA drinking straws a superior substitute for plastic ones. Commercially available PLLA straws lose almost 60% of their flexural strength when wet compared to less than 5% of the SC-PLA straws proposed in this study.

Copyright © 2022 The Authors. The mixing of non-woven steel fibres in melt overflow process for use in automotive muffler systems was simulated. The aim was to identify optimum parameters for achieving a good fibre mix. Numerical models of mixing chambers of melt overflow process were developed. Multiphysics analyses involving heat transfer, fluid flow and particle tracking were carried out using COMSOL code. The influence of air jet configurations on the fibre distribution was studied. The fibres settled on the moving bed within the mixing chamber were examined for their uniformity. The effect of additional air jets to the existing chamber in a range of regions was explored. An optimum configuration was identified by analyzing the compactness of the particle clusters deposited in the simulation and validated using pixel data acquired from real time imaging. The results showed that by employing dual air jets at the front end of the chamber, the density of the fibre material has improved. We conclude that through multi-physics modelling, it was possible to identify the optimum air-jet configurations leading to fibre uniformity and its distribution. This work also paves the way for incorporating a vision system to evaluate fibre density in real time. Innovate UK No. 102792

In this paper, the problem of inferring fabric mechanical properties based on three-dimensional (3D) fabric drape model and fabric weight was studied. Firstly, the three-dimensional point cloud of ...

In order to generate the three-dimensional (3D) mesh of draped fabric based on a two-dimensional (2D) fabric projection, the 3D point cloud of draped fabric was scanned via a self-built 3D scanning...

In this research work, a nondestructive technique of image analysis was explored to determine the fibre orientation and void content in Bagasse fibre reinforced composites. Fibre length, alkali treatment and fibre loading were studied as variables. The fibre orientation was irrespective of the fibre length, fibre loading and alkali treatment variables. The void content and size decreased with increases in fibre length and alkali treatment. The alkali treatment resulted in the removal of lignin, making the surface of the fibres rough. It also led to making the fibre count fine i.e. reducing the diameter of the fibres and thus presenting more fibres for interaction with resin. Both these phenomena resulted in a slower flow of resin. The void content of bagasse fibre composites decreased with higher fibre loading because a higher number of fibres slows the resin flow. However, the size i.e. area of the voids increased with the fibre loading from 20 to 30%, probably due to increased wetting difficulty.

Purpose Porosity is one of the most important properties of the textile substrate. It can influence the comfort of a garment by affecting its breathability and thermal conductivity. During the process of dyeing, the dye liquor comes in contact with the substrate; the absorption of the dye liquor into the substrate will be dependent on its porosity. The concept of porosity between the yarns of fabric is a common phenomenon; however, the porosity between the fibres in the yarn can also influence the dyeing behaviour of the fabric. Design/methodology/approach In this research, ring and rotor yarns of 25/s and 30/s counts are considered as textile substrates. The porosity of yarns was determined theoretically and experimentally using the image analysis method. Findings It was found that theoretical porosity is independent of the yarn manufacturing method. In addition, 30/s yarn was more porous as compared with 25/s yarn having a higher pore area. Rotor yarns had higher porosity, dye fixation and K/S as compared with ring yarns. Dyeing behaviour was also dependent on the count of yarn. Specifically, 30/s yarns have higher dye fixation as compared with 25/s yarns. However, 25/s yarns were dyed with deeper shades showing higher K/S values. Also, 25/s yarns are coarser than 30/s yarns having higher diameters and cross-sectional area, thus resulting in deeper shades and higher K/S values. Originality/value This novel technique is based on the comparative study of the porosity of various types of yarns using the image analysis technique. This investigation shows that the porosity between the fibres in the yarn can also influence the dyeing behaviour of the yarn.

In this study, a versatile method for the manufacturing of chitosan-grafted porous poly (L-lactic acid) (P-PLLA) nanofibrous membrane by using polydopamine (PDA) as an intermediate layer has been developed. P-PLLA fibreswere electrospun and collected as nano/micro fibrous membranes. Highly porous fibres could serve as a substrate for chitosan to adsorb heavy metal ions. Moreover, PDA was used to modify P-PLLA surface to increase the coatinguniformity and stability of chitosan. Due to the very high surface area of P-PLLA membranes and abundant amine groups of both PDA and chitosan, the fabricated membranes were utilized as adsorbent for removal of copper(Cu2+) ions from the wastewater. The adsorption capability of Cu2+ ions was examined with respect to the PDA polymerization times, pH, initial metal ion concentration and time. Finally, the equilibrium adsorption data of chitosan-grafted membranes fitted well with the Langmuir isotherm with the maximum adsorption capacity of 270.27 mg/g.

The present study relates to manufacturing, characterization and optimization of bagasse fiber reinforced composites. For this purpose, response surface methodology was applied to simultaneously optimize the tensile strength, tensile modulus and tensile strain of bagasse fiber reinforced composites. Three levels of process variables, including concentration of sodium hydroxide for bagasse fiber treatment (4, 6, and 8%), content of bagasse fiber (10, 20, and 30 wt%), and length of bagasse fiber (1, 2, and 3 inch) were used to design the experiments according to the Box–Behnken design. Experimental results were analyzed by analysis of variance and fitted to second order polynomial models by using multiple regression analysis. The Derringer’s desirability function revealed that the values of process variables leading to optimized tensile strength, tensile modulus and tensile strain are 4%, 14.2 wt% and 1 inch for concentration of NaOH for bagasse fiber treatment, content of bagasse fiber and length of bagasse fiber, respectively. Validation experiments were carried out and high degree of correlation was found between the actual values and the predicted values of tensile properties of bagasse fiber reinforced composites.

This article investigates how the bending stiffness of the core thread and the effect threads affect the average values and the variability of the structural properties of resultant fancy yarns. The Design of Experiment technique was used to study the effects of individual factors and the interactions of factors. The analysis indicated that that the bending stiffness of the effect thread was a main factor. Increases in the effect thread bending stiffness led to significant increases of the size of fancy profile and reductions of the number of fancy profiles. Additionally, there was a strong interaction effect between the bending stiffness of the core thread and the bending stiffness of the effect thread which influenced the structures of the resultant fancy yarns. It was also found that variations in the bending stiffness of the input threads were reflected in similar variations in the size and number of fancy profiles. The study is important for engineering the structure and the variation in structural properties of fancy yarns by selecting appropriate input threads.

Bone tissue engineering has become one of the most promising therapeutic methods to treat bone defects. A suitable scaffolding material to regenerate new bone tissues should have a high specific surface area, high porosity and a suitable surface structure which benefit cell attachment, proliferation, and differentiation. In this study, an acetone post-treatment strategy was developed to generate heterogeneous structure. After PLLA/PCL nanofibrous membranes were electrospun and collected, they were treated with acetone to generate a highly porous structure. Meanwhile, part of PCL was extracted from the fibre and enriched on the fibre surface. The cell affinity of the nanofibrous membrane was verified by human osteoblast-like cells assay. The proliferation rate of heterogeneous samples increased 190.4 %, 265.5 % and 137.9 % at day 10 compared with pristine samples. These results demonstrated that the heterogeneous PLLA/PCL nanofibrous membranes could enhance osteoblast adhesion and proliferation. With high surface area (average surface area 36.302 m2/g) and good mechanical properties (average Young's modulus 1.65 GPa and average tensile strength 5.1 MPa), the heterogeneous PLLA/PCL membrane should have potential applications in the field of bone regeneration.

The application of high speed air flow in the textile field represents the frontier development direction in this field. However, the coupling mechanism between air flow and fiber is extremely complicated which greatly limits the development and application of new textile technologies. For this reason, this research study is intended to focus on the common cutting-edge basic scientific problem of the air-flow-fiber coupling mechanism, the vortex spinning technology is taken as a breakthrough point for research. Three-dimensional numerical models of air flow in vortex spinning nozzle and a free-end fiber were established. The hybrid grids including the structured hexahedral grids and the unstructured tetrahedral grids were used to divide the air-flow computational region, the realizable κ- ε model was used to solve the turbulent characteristics of air flow, and the wall function method was used to solve the air flow in the near wall region. The displacement and deformation of a single free-end fiber under the action of the air-flow force was solved by the second-order nonlinear double asymptotic method and interpolation method. The dynamic twist process of a free-end fiber was simulated in three-dimensional space by taking into account the fiber characteristics, such as straightening, bending, and torsion. In addition, a high magnification microscope was used to observe the free-end fiber motion during the spinning process. The results show that the numerical simulation is consistent with the experimental observation, proving that dynamic numerical simulation can solve difficult problems in the unobserved dynamic twisting process, and this deepens the understanding of the spinning mechanism in vortex spinning.

Vortex spinning technology adopts high speed swirling air-flow to rotate the fibers with open-ends to form the yarn with real twists. The air-flow behavior within the nozzle has a great effect on yarn formation process. In this study, the three-dimensional calculation nozzle model and the corresponding three-dimensional air-flow region model were established to proceed the numerical calculation; the air-flow behavior: the pressure, the velocity and the turbulent air-flow field, as well as the streamline of air-flow, were investigated in the presence of fiber bundles within the vortex spinning nozzle. Hybrid hexahedral/tetrahedral control volumes were utilized to mesh the grids in the calculation region. To consider air-flow diffusion and convection in the nozzle, the Realizable k-ε turbulence model with wall function was adopted to conduct the calculation. The dynamic pressure and the static pressure were obtained by numerical analysis to predict the action of the inner surface of nozzle and the wall resistance on the high speed swirling air-flow. The numerical simulation of dynamic air-flow behavior can generate great insight into the details of air-flow behavior and its distribution characteristics, as well as be conducive to understand the spinning mechanism and promote the optimization of spinning process.

In this research article, the PVDF (polyvinylidene fluoride)–PANI (polyaniline)–titanium nanotube (TNT) based nanocomposite membranes were synthesised through phase inversion method. The composition and structural properties of nanocomposite membranes were characterised by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscope (SEM). The significant properties of synthesised membranes such as distribution of pore size, thermal properties, mechanical properties, and photocatalytic behaviour of membranes were also studied. The hydrophilic properties of the composite membranes increased with filler content (PANI-TNT) and results in improved pure water flux (484.8 ± 2.9 L/m2 h−1) compared to that (312.0 ± 1.91 L/m2 h−1) of the pure PVDF membrane. The pure PVDF and nanocomposite membrane were further analysed in terms of their filtration properties such as adsorption of dyes (methyl orange, Allura red) and UV self-cleaning properties. The newly developed nanocomposite membranes showed excellent pollutant removal efficiency (~90%). The synthesised nanocomposite membranes also showed photocatalytic activities due to the presence of TNTs, and adsorption of methyl orange (MO) reduces significantly with the UV light irradiations. The UV self-cleaning property of the composite membrane was further confirmed due to their high flux recovery ratio of about 94%. The results show that embedded PANI-TNT within nanocomposite was photo-catalytically active and degrade the dye molecules from the surface of the nano composite membrane.

To evaluate the ability of woven fabrics to drape in a more accurate way, a three-dimensional point cloud of a draped woven fabric was captured via an in-house drape-scanner. A new indicator, total drape angle (TDA), was proposed based on the three-dimensional fabric drape to characterize the ability of a woven fabric to drape. The relationship between TDA and the drape coefficient (DC) was analyzed to validate the performance of TDA. The result indicated that TDA is more stable and representative than the traditional DC in characterizing the ability of a woven fabric to drape. In addition, the drape angle distribution function (DADF) of the triangular mesh was employed to describe fabric drape, as well as to bridge the gap between drape configuration and the warp bending rigidity of woven fabric. The results showed that the correlation coefficient between the real warp bending rigidity value and what was predicted warp based on DADF and fabric weight was 0.952.

For nonwovens, fiber orientation distribution is an important structural characteristic that directly influences the anisotropic properties of the materials. Different Vslurry/Vbelt ratios were adopted to fabricate nonwovens during the wet-laid process. The results indicated that fiber orientation distribution of nonwovens can be regulated by adopting different Vslurry/Vbelt ratios owing to the web-forming principle of wet-laid techniques. Mechanical tests showed that both wet and dry tensile strength of nonwovens in different angle directions present anisotropy under different Vslurry/Vbelt ratio parameters. A liquid spreading distribution experiment proved that liquid spreading length and area of nonwovens could be manipulated using different Vslurry/Vbelt ratios in the fabrication process. Therefore, specific anisotropic properties of wet-laid hydroentangled nonwovens can be realized by controlling the process parameters for particular end-use applications.

Byssinosis is a chronic obstructive pulmonary disease very common in textile cotton workers due to inhalation of fine cotton dust and gram negative bacteria. A three layer composite respiratory filter was developed for Byssinosis prevention by using the combination of polypropylene (PP) based meltblown layers and chitosan nanofibres (CSNF). Filtration efficiency against fine particulates ranges from 100 nm to 2.5 μm and anti-bacterial activity against Pantoea agglomerans were investigated. Chitosan nanofibres were produced by using the electrospinning process and were sandwiched between two PP layers to improve the overall surface area of the filter as well as providing a protective barrier against bacterial pathogens. The filter sample with just 2 hour’s CSNF coating showed more than 99% filtration efficiency with a low pressure drop of 71.6 Pa and a high quality factor value 0.082. The antibacterial performance of CSNF layers achieved up to 91% against the Pantoea agglomerans. Finally, results concluded that the developed respiratory filter can potentially reduce Byssinosis in textile workers.

Nanofibres with high surface area have various applications in many fields, such as filtration, tissue engineering and drug delivery. In the previous reported works, a lot of researchers have fabricated porous polymer nanofibres with porous surface structure, but few researchers could produce thoroughly hollow porous nanofibres by electrospinning. Here, we developed porous poly( l -lactide) (PLLA) fibres with good internal pore connection by two methods, i) removal of a pore-forming agent from PLLA composite fibres; ii) non-solvent induced re-crystallization of pure PLLA fibres. In the first method, electrospun PLLA/cellulose acetate butyrate (CAB) composite fibres were immersed into acetone to remove CAB. Results showed that the fibres with less CAB could produce porous structures. However, with the increasing of CAB content, the fibre surface had only a collapsed structure. In the second method, while pure PLLA fibres were immersed into acetone, the solvent-induced recrystallization of PLLA generated porous structures throughout the whole fibres. Owing to the higher crystallization, the mechanical properties of PLLA fibres were also highly improved.

ObjectivesCeftazidime/avibactam is not active against MBL-producing bacteria. Combining ceftazidime/avibactam or avibactam with aztreonam can counter the resistance of MBL-producing Enterobacterales. The aim of this study was to evaluate whether the addition of avibactam could reduce or close the mutant selection window (MSW) of aztreonam in Escherichia coli and Klebsiella pneumoniae harbouring MBLs; MSW is a pharmacodynamic (PD) parameter for the selection of emergent resistant mutants.MethodsIn vitro susceptibility of 19 clinical isolates to ceftazidime/avibactam, aztreonam alone, and in co-administration (aztreonam/ceftazidime/avibactam and aztreonam/avibactam) was determined, as well as the mutant prevention concentration (MPC). The fraction of time within 24 h that the free drug concentration was within the MSW (fTMSW) and the fraction of time that the free drug concentration was above the MPC (fT>MPC) in both plasma and epithelial lining fluid (ELF) were determined from simulations of 10 000 profiles. The joint PTA was used to derive a joint cumulative fraction of response (CFR).ResultsAll isolates were resistant to ceftazidime/avibactam or aztreonam. Combining aztreonam and avibactam or ceftazidime/avibactam resulted in synergistic bactericidal activities against all isolates. Synergism was primarily due to the aztreonam/avibactam combination. For aztreonam/avibactam dosing regimens evaluated in clinical trials, fT>MPC values were >90% and >80%, whereas fTMSW measures were ConclusionsEffective antimicrobial combination optimized the PD parameters measuring selection for emergent mutants by increasing fT>MPC and reducing fTMSW.

In a bid to develop a cheaper alternative material for particleboard, fiber/particulate reinforced cement-paper composites were produced. The paper-cement matrix had 12 wt. % of cement and the matrix was reinforced with 10 wt. % fixed amount of coconut shell powder and varied amount of palm kernel fiber (0, 0.5, 1.0, 1.5, 2.0, and 2.5 wt. %). Two separate groups of samples were produced; one containing untreated fiber (UPKF), in varied proportions of 0–2.5 wt. % and the second containing alkaline-treated fiber (TPKF), in varied proportion of 0–2.5 wt. % fiber. Samples produced were cured for 28 and 49 days and examined for physical, mechanical, and thermal properties as well as microstructural features. The result obtained revealed improvement in properties of samples as fiber proportion increased. Comparison of the properties obtained indicates that alkaline-treated samples gave a better performance than the untreated counterparts, which was reflected in the sum of property ratio for each mix. The value for TPKF samples was higher than the value for UPKF samples. Also, samples cured for 49 days had better performance than the ones cured for 28 days for both UPKF and TPKF. Evaluation of the three experimental variables, fiber addition, alkaline treatment, and curing length proved that curing was more effective in enhancing the properties of the composites developed, especially the mechanical properties.

Electrospinning has been widely used to fabricate polymer fibrous scaffolds for bone tissue engineering because of their highly porous structures. In order to improve the biocompatibility of polymer scaffolds, some nano particles have been introduced into electrospun fibres. For example, silica nanoparticles (SiNPs), with high surface area and good biocompatibility, have been used forbone tissue engineering for better bone cell attachment. In this work, porous poly(L-lactic acid) (PLLA) fibrous membrane with high surface area was fabricated by electrospinning and posttreatment process. The membrane can serve as substrates of SiNPs for bone tissue engineering. Dopamine (DOP) was applied to modify the surface of PLLA fibres, which improved the coatingstrength of SiNPs on PLLA fibres. SiNP coating significantly improved the mechanical properties and hydrophilicity of PLLA/DOP/SiNP composite membranes. As a result of SiNPs coating, PLLA/DOP/SiNP membrane exhibited better cellular biocompatibility, more cell attachment and proliferation. These results demonstrate that porous PLLA/DOP/SiNP composite membrane withhigh surface area has high potential for periosteum in the field of bone regeneration applications.

Electrospinning has been widely used to fabricate polymer fibrous scaffolds for bone tissue engineering because of their highly porous structures. In order to improve the biocompatibility of polymer scaffolds, some nano particles have been introduced into electrospun fibres. For example, silica nanoparticles (SiNPs), with high surface area and good biocompatibility, have been used for bone tissue engineering for better bone cell attachment. In this work, porous poly(L-lactic acid) (PLLA) fibrous membrane with high surface area was fabricated by electrospinning and post-treatment process. The membrane can serve as substrates of SiNPs for bone tissue engineering. Dopamine (DOP) was applied to modify the surface of PLLA fibres, which improved the coating strength of SiNPs on PLLA fibres. SiNP coating significantly improved the mechanical properties and hydrophilicity of PLLA/DOP/SiNP composite membranes. As a result of SiNPs coating, PLLA/DOP/SiNP membrane exhibited better cellular biocompatibility, more cell attachment and proliferation. These results demonstrate that porous PLLA/DOP/SiNP composite membrane with high surface area has high potential for periosteum in the field of bone regeneration applications.

In order to understand the impact of mechanical action on the wrinkling of cotton fabrics in a drum washer, fabric movement was observed and a movement index system was developed to characterize the textile motion. Results showed that wash load and spinning speed were the major factors influencing the smoothness of cotton fabrics, with a p value of 0.032 and 0.00 respectively at 95% confidence level. The analysis of fabric movement illustrated that when the wash load increased, the free motion region decreases and the ratio of passive motion region increase, resulting in severe wrinkling of cotton fabric.A regression model was developed to characterize the relationship between fabric movement and smoothness.. These findings help the understanding of the mechanism of wrinkling during a drum washer washing.

This study examines the relationships between the structure of fancy bouclé yarns and the bending stiffness of the input threads that are used to make those fancy yarns. Four fancy bouclé yarns and an extra two confirmation bouclé yarns were made to test the impact of the bending stiffness of the effect input threads. Six fancy yarns were made to test the impact of bending stiffness of the core thread on the fancy yarn structure. The structure of the fancy yarn was defined by the number of fancy profiles, the size of fancy profile, the circularity ratio of fancy profile and the shape factor of fancy yarn. It was found that increasing the value of the stiffness of the effect thread increased the size of fancy profile but decreased both the number of fancy profiles and the shape factor of fancy yarn. Those relationships were represented by regression models that were significant at α = 0.10. The deviation between the theoretical values and the real values was −14.39% and 2.07%. Further, up to a value of 8.636 g mm2, the bending stiffness of the core thread appeared not to have an effect on the structure of the fancy yarns. This study is important as it is the first that accounts statistically for the impact of bending stiffness of the input threads on the structure of the resultant fancy yarns. Therefore, it aids fancy yarn manufacturers when designing fancy yarns with predicted structures.

Purpose The purpose of this paper is to mathematically model the structure of doubled fancy yarns made by combining together several threads. Design/methodology/approach It was assumed that such a structure may have two distinctive parts – sinusoidal and helical (i.e. sigmoidal). This model is based on calculating the length of the effect thread in relation to the core thread. The case of having several variants of such a structure was discussed to account for several types of doubled fancy yarns. The number of wraps of the binder, the overfed ratio, and heights of the fancy profiles in the different parts were the fundamental parameters of this model. The effects of changes in the number of wraps, the overfeed ratio or both simultaneously, on this model, were also considered. The shape factor of fancy yarn was also modelled depending on the basic model of the structure. Findings The model was tested and the correlation coefficient between the theoretical value and the real value of length of the effect thread was 0.90. Originality/value This model is useful for predicting the length of the effect component based on the type, dimension and number of the fancy profiles of doubled fancy yarn, and for understanding the changes of the multiple-thread structure of fancy yarn when the overfeed ratio and/or the number of wraps were to change.

Polylactide (PLA) single polymer composites (SPCs) were prepared using PLA nonwovens made of core-sheath PLA fibers as raw materials by hot-pressing. The core and sheath materials were poly(l-lactide) (PLLA) and PLA with d-lactide of about 10 mol% (PLA90), respectively. The melt processing window of PLA SPCs reached more than 40 °C. The effects of hot-pressing temperature on the crystallinity, the size distribution of crystallites, the lamellar thickness and mechanical property of PLA SPCs were significant while those of hot-pressing pressure were small. The strong interfacial adhesion between matrix and reinforcement led to high mechanical properties of PLA SPCs. For pure PLA materials prepared at 180 °C, the tensile strength (σb), elongation at break (εb), the work of rupture (W) and impact strength (αcU) were only 19 MPa, 1.8%, 0.15 J, and 2.8 kJ/m2, respectively while those of the SPCs prepared at 130–160 °C were 47–65 MPa, 15–32%, 9–22 J, and 14.9–67.2 kJ/m2, respectively. With the increase of hot-pressing temperature, the σb, W and αcU decreased. Keywords: Polylactide, Core-sheath fibers, Single polymer composites, Melt-processing window

Chitosan crosslinked with 3-aminopropyltriethoxysilane was coated on porous poly (L-lactic acid) nanofibrous membrane to remove dyes from wastewater in the present study. The adsorption capacity of the composite membrane for the removal of methylene blue and rhodamine B was comprehensively studied. Large porous framework provided a high surface area to effectively immobilize the cross-linked chitosan on nanofibrous membranes. Batch trials were performed to evaluate the adsorption behaviour of membranes with variable crosslinking ratio, pH, initial concentration, temperature and time. Moreover, the adsorbent membranes before and after adsorption were characterized using scanning electron microscopy, x-ray energy dispersive analysis, and Fourier transform infrared spectrophotometer. Under optimum parameters, the adsorbent showed the removal capacity of 86.43 and 82.37 mg/g for rhodamine B and methylene blue, respectively. Isothermal and kinetic experiments showed that Langmuir isotherm and pseudo second order kinetics correlated best with adsorption data. Finally, the mechanism of adsorption and reusability of membrane for five cycles was studied.

The domestic tumble dryers are becoming indispensable household appliances and responsible for up to 10% of the total residential energy use in developed countries. However, their energy efficiency is low. In this paper, the development of a multi-sensor computer-controlled prototype platform for fabric drying is described for improving the efficiency of dryers. The prototype platform enables the real-time control and recording of key drying parameters including heater power, air flow velocity, rotating speed of drying drum and drying cycle time. These parameters are automatically adjusted according to the exhaust air humidity instead of the temperature which is used traditionally. Additionally, a new drying model of dividing the drying process into 4 stages based on the humidity of the exhaust air has been investigated in order to further increase the energy saving. The performance of this staged drying model is experimentally evaluated in respect to energy consumption, drying time, and the smoothness of fabric after drying. The results clearly indicate that the staged controlling of heating power input not only decreases energy consumption by 21.5% but also improves the fabric smoothness by 0.9 grade compared to using a single heating power input for the whole drying process. The research outcome can enable the design and production of new dryers that are more energy efficient and lead to dried clothes that require less ironing, which in turn further reduces energy consumption.

Two kinds of composite filter materials were prepared by regulating the structure of melt-electrospinning polypropylene (PP) webs. The self-designed multi-nozzle melt-electrospinning device was used to produce PP webs which deposited on PP spunbonded nonwoven. Firstly, the composite filter materials with different thickness and ratios of coarse/fine fibers were prepared, and the effect of the thickness and the ratio of coarse/fine fibers on filtration properties were studied. The results showed that the filtration efficiency and pressure drop increased as thickness increased. In addition, compared with the general filters which were composed of coarse or fine fibers, the filters with coarse/fine fibers had “low pressure drop” under the similar filtration efficiency. In the case of the ratio of coarse/fine fiber about 2:2, this filter achieved optimal performance. When the thickness was 0.42 mm, its filtration efficiency for particles more than or equal to 2.0 μm could reach more than 95 %. Its pressure drop and air permeability were 18.13 Pa and 54.69 mm/s, respectively, while those of general filter were 38.67 Pa and 10.02 mm/s, respectively. After that, the composite filter materials composed of various angles of oriented webs were produced. The results showed that the filtration efficiency for particles with the size of morethan or equal to 2.0 μm was higher than that of filters composed of one angle of oriented webs. In addition, the lower the orientation was, the lower the pressure drop was.

Cotton plain fabrics are prone to winkle and shrinkage during daily wear usage and care processes. In this research, cotton fabrics sample are subjected to pre-washing processes and an extended series of tumble-dry cycles using standard drying procedures to investigate the impact of the drying on appearance physical properties of cotton fabric including smoothness appearance (SA), dimensional shrinkage, bending stiffness. And Scanning electron microscopy (SEM), thermo-gravimetric analyzer (TGA) and x-ray diffraction (XRD) were also employed to investigate whether the repeated drying in dryer can cause changes in the thermal stability, the composition transform and microscopic damage of cotton fibers or not. Results showed that smoothness appearance grade of cotton fabrics significantly depended on drying cycles during first 15 drying cycles. The results of dimensional stability showed that the dimensional shrinkage of cotton fabric was slight and had no relationship with drying cycles. And found that the shrinkage of cotton fabrics in the warp direction (1.29-1.71%) is higher than that of cotton fabrics weft direction (0.002-0.045%). The bending stiffness of cotton fabric was enhanced by drum-drying based on the bending stiffness data. TGA curves and XRD analysis showed that drying had little effect on thermal stability and crystallinity of cotton fibers. This indicated that drying only affected the appearance physical properties of cotton fabric such as appearance smoothness, dimensional stability, did not change composition and molecular structure (crystallinity). And from multiple levels including fabric-level, yarn-level and fiber-level, explained reasons of fabric properties change (namely, damage behavior). Moreover, this finding is not only helpful to understand of damage mechanisms of cotton fabrics drying in domestic dryer, but also provided reference for dryer manufacturers to accurately specify the types of clothing that can be dried by using a dryer. Additionally, it is also helpful to guide consumers to correctly care clothing in textile daily care. For example, the drying in dryer was not suitable for 100% cotton shirt with higher requirement of smoothness appearance grade, but it was suitable for fabric that smoothness is not concerned in usage, such as 100% cotton quilts and jeans.

A series of monophenyl borate (MPB) modified high-ortho phenolic copolymer fibers (BOPFs) were prepared by melt-spinning of the high-ortho phenol-formaldehyde resins with different content of MPB, and cured in a formaldehyde solution. The solution curing fibers were heated up to 240 °C at elevated temperatures in N2. The effect of MPB on the structure and properties of the BOPFs was investigated by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The results show that a B-O linkage inserts into the high-ortho phenolic copolymer molecular chain with the addition of MPB, and increases the crosslinkage and thermal stability. The peak of O/P (ortho/para) value of fiber (1.94) and elongation (5.6 %) were obtained when BOPFs-4 was heat-cured at 240 °C for 2 h.

Wet-laid hydroentangled nonwovens are widely used for disposable products, but these products generally do not have good dispersibility and can block sewage systems after being discarded into toilets. In this study, both pulp fibers and Danufil fibers are selected as we hypothesize that the high wet strength and striated surface of Danufil fibers would allow us to produce nonwovens with better dispersibility while having enough mechanical properties. The wet strength and dispersibility of nonwovens are systematically studied by investigating the influence of the fiber blend ratio, fiber length, and water jet pressure. The results indicate that the percent dispersion could be as high as 81.3% when the wet strength is higher than 4.8 N, which has been improved greatly comparing the percent dispersion of 67.6% reported before.

Particulate matter (PM) poses a threat to people’s living environment. Fresh air ventilation systems can filter particulate matter and play an important role in enhancing indoor air quality. A high filtration efficiency material with low pressure drop prolongs the service life of the filters and reduces energy consumption. However, maintaining the long-term storage of charge in electret materials remains a challenge. Herein, we report a novel sheath/core bicomponent spunbond (BCS) electret material with low pressure drop and improved charge stability using polyethylene/polypropylene (PE/PP) as the matrix polymer and magnesium stearate (MgSt) as the charge enhancer. Benefiting from the three-dimensional (3D) fluffy structure created by the spunbond technique and through-air reinforcement, the resulting electret materials exhibit a low pressure drop of 37.92 Pa, excellent dust holding capacity of 10.87 g m–2, and high filtration efficiency of 98.94%. Moreover, due to the introduction of MgSt, the filtration efficiency only decreased by 4.1% in 90 days. The successful fabrication of PE/PP BCS materials with MgSt not only provided a promising medium for particle capture but also developed a new approach for the design of fresh air filtration materials.

Porous poly(L-lactic acid) (PLLA) nanofibrous membrane with the high surface area was developed by electrospinning and post acetone treatment and used as a substrate for deposition of chitosan. Chitosan was coated onto porous nanofibrous membrane via direct immersion coating method. The porous PLLA/chitosan structure provided chitosan a high surface framework to fully and effectively adsorb heavy metal ions from water and showed higher and faster ion adsorption. The composite membrane was used to eliminate copper ions from aqueous solutions. Chitosan acts as an adsorbent due to the presence of aminic and hydroxide groups which are operating sites for the capture of copper ions. The maximum adsorption capacity of copper ions reached 111.66 ± 3.22 mg/g at pH (7), interaction time (10 min) and temperature (25 °C). The adsorption kinetics of copper ions was established and was well agreed with the second-order model and Langmuir isotherm. Finally, the thermodynamic parameters were studied.

A paraffin microsphere-templated 3D porous EcoFlex sponge was prepared to selectively absorb oil or chemicals from water. The technology for producing this EcoFlex sponge does not need complicated synthesis processes or instruments, and the materials applied in this work are ecofriendly. Therefore, this sponge can be employed in the environmental field. EcoFlex sponges showed high hydrophobicity (contact angle = 140-143°) and oleophilicity. The developed sponge exhibits a porous three-dimensional framework inside with excellent internal connectivity, which contributes both better absorption capacity and faster absorption rate. For instance, the absorption capacity for chloroform can reach 3400 wt %. The absorption capacity of the sponge was optimized using different size of paraffin microspheres and these sponges exhibit relatively high absorption capacity in a short time (2 min). The volume of sponge expands in some oils and organic solvents: the increased volume capacity for hexane can reach 2200%. This sponge also has great recovery capability and durability; it keeps its original shape and absorption capacity after 15 cycles of oil absorption and compression.

The main objective of this study is to classify domestic waste via computer vision and sort it automatically according to the four-category regulation. A novel two-stage Waste Recognition-Retrieval algorithm (W2R) is proposed. Its first stage was to train a Recognition Model (RegM) recognizing waste into one of thirteen subcategories. The second stage was to construct the Recognition-Retrieval Model (RevM) classifying the recognized subcategory into one of four categories. Meanwhile, a one-stage waste Classification Model (ClfM) was trained as a comparison. Both best-performing models were selected and installed respectively onto the automatic sorting machine for contrast experiment classifying a set of waste. The machine consisted of three main modules: the Computer-Vision Module, the Sorting Module, and the Customized Module. It was also a platform for data collection. Ten participants also classified and sorted the same set of waste in the experiment of Manual Sorting (MS). The experimental results show that the average accuracy of the RevM, 94.71% ± 1.69, was significantly higher than that of the ClfM-VGG, 69.66% ± 3.43, and that of the MS, 72.50% ± 11.37.

The objective of this study was to assess the impact of breathing resistance on physiological and subjective responses to N95 filtering facepiece respirators (N95 FFRs) during still-sitting and walking. Fifteen subjects sat for 5 min and walked for 5 min while wearing 2 different models of N95 FFRs, 1 model of which was equipped with exhalation valves (N95 FFR/EV). The subjects were monitored by a modified monitoring garment for respiratory signals (RSP) and surface electromyography (sEMG). Subjects also were asked to complete subjective ratings of overall breathing resistance. The results of the physiological measurements in this study have shown that compared with no respirator, wearing N95 FFR had a direct effect on increasing respiratory amplitude, muscle activity and fatigue of abdominal, and fatigue of scalene; The use of N95 FFR/EV conferred limited physiological benefit over N95 FFR in walking; Compared with sitting still, walking significantly decreased respiratory amplitude, but increased respiratory rate, the muscle activity of sternomastoid, scalene, diaphragm and abdominal, the fatigue of scalene and intercostal. The subjective survey showed that wearing respirators and walking had a direct effect on improving the subjective overall breathing resistance. Significantly low to moderate correlation coefficients were shown between physiological values (respiratory amplitude, the muscle activity of diaphragm, the muscle activity and fatigue of scalene and abdominal), and the subjective breathing resistance. This is the first reported study that combines RSP, sEMG and subjective overall breathing resistance to evaluate breathing resistance on the use of N95 FFR in sitting still and walking. The physiological responses to breathing resistance of wearing a N95 FFR for 5 min in still-sitting and walking are relatively small and should generally be well tolerated by healthy persons. Relevance to industry This paper's findings can be readily employed by respirator manufactures and administrations for evaluating the respiratory muscle function (activity, fatigue) and breathing parameters of wearing N95 FFRs. Observations of present study are in support of issuing new regulations to raise the limit for breathing resistance over short periods at low-moderate exertion tasks. Thus, the manufacturers could easily fulfill the requirements for collection efficiency by adding more filter media while still meeting the requirements for air resistance.

The stability of breast plays an important role in the comfort of women’s movement. Women with sagging breasts are faced with more displacement due to the weakened breast internal support. The purpose of this study is to measure the dynamic 3D displacement of sagging breasts. Because of the sagging breast particularity, it is difficult to obtain all the data accurately by the traditional photoelectric capturing system. In this paper, multiple 3-Axes accelerometer sensors are used to measure the acceleration value of the specific points. Besides, the sensors integrated with 3-axes gyroscope which can collect the gyro data at the same time. The obtained accelerometer and gyroscope data will be transferred to the body coordinate from the sensor measuring coordinate. MATLAB will be used to analyze the collected data, and 2D and 3D point Cloud will be carried out. The maximum amplitude and whole picture of trajectory will be calculated, and the dynamic moving results of breast will have a general comparison of different points. The whole picture of sagging breast moving status can help bra designers improve wearing comfortable sensation, and the study can offer a new method for reference.

This paper presents the performance of a new nonwoven piezo-resistive sensor for capturing cardiorespiratory signals. The novel piezo-resistive sensor is fabricated by sandwiching a nano silver electro-conductive ink impregnated nonwoven material between two layers of knitted silver fabric that function as sensor electrodes. The paper describes the technology for minimizing the signal noise due to motion artifacts in the sensor. The nonwoven piezo-resistive sensor is tested on volunteers by capturing their cardiorespiratory signals, where the signal noise is filtered using a bandpass filter. The paper further presents the analysis of the performance of the sensor together with a comparison against a commercially available, portable, cardiorespiratory signal monitoring device. The study shows that the wearable nonwoven piezo-resistive sensor system is highly sensitive, and it is an accurate and reliable sensor for capturing cardiorespiratory signals.