Fiber Entanglement Research Articles

A greener approach for physical separation of polycotton textile waste

Most textile waste ends up in the landfill. Clearly, enhancing textile recycling is urgently needed. For circularity, efficient means for separating the constituents of the textile blends is crucial. Targeting the popular polycotton textile blend, a method was developed to physically separate cotton and PET (polyethylene terephthalate) from waste textiles. First, the waste polycotton textile was milled into smaller fibers to mitigate entanglement. Then, leveraging the relatively higher hydrophilicity of cotton, three liquids (namely, water, mineral oil, and ethanol) were mixed to form a two-phase liquid-liquid system, which induced the preferential segregation of cotton to the water-rich bottom liquid phase. Factors studied included liquid composition and milling method. The best-performing liquid mixture allowed for 84.7 % of the cotton and 85.5 % of the PET from the waste polycotton (WPC) sample to be recovered respectively from the bottom liquid phase (BLP) and top liquid phase (TLP). The separation effectiveness can be further enhanced if fiber entanglement issue can be mitigated. The recovery of about 99.9 % PET and 86.7 % cotton from a prepared mixture of pure cotton and pure PET textile wastes is a case in point, demonstrating the efficacy of the method that is fast, at ambient condition, and does not require extensive chemicals. While the interwoven design of cotton and PET in textiles confers benefits like comfort and strength, the resulting entanglement is detrimental for circularity. SynopsisAn eco-friendly yet rapid two-phase liquid-liquid system was developed for separating polycotton textile fibers, aimed at enhancing sustainability and circularity

Effects of Dowel Rotation Welding Conditions on Connection Performance for Chinese Fir Dimension Lumbers

In this study, the rotating welding process of Chinese fir (Keteleeriafortunei) in Guizhou, China, was systematically analyzed. The effects of rotating welding conditions, including the dowel-to-guide hole diameter ratio, welding time, depth, base surface, angle, and dowel type, on the performance of welded Chinese fir were explored. Moreover, the physical and chemical changes oftheChinese fir interface during welding were revealed by Fourier-Transform Infrared Spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The results indicated the following: (1) The rotating welding technology can quickly achieve a strong connection between wood through friction heat without chemical adhesives and compared with traditional wood connection technology such as gluing or mechanical fixing;it has the advantages of simple operation, high production efficiency; and environmental friendliness. (2) Aftertherotating welding, the wood underwent significant pyrolysis, especially the degradation of hemicellulose. The heat generated in the welding process caused good melting and mechanical interlocking between the dowel and the wall of the guide hole, but it was also accompanied by afriction loss of the dowel and the substrate. (3) The welding parameters affected the wood’s connection strength and stability by altering heat production, distribution, transfer, and frictional losses. The impact of the dowel-to-guide hole diameter ratio had a great influence on the connection strength. When the diameter ratio was 1:0.7, the tensile strength was the highest, reaching 2.27 MPa. (4) The analyses of XPS, FTIR, XRD, and SEM proved thatthechemical composition changes at the interface, leading to a more structured crystalline bond and enhanced connection strength due to fiber entanglement and interlocking. This research providesatheoretical and experimental basis forthefurther innovation and development of wood processing technology and provides a new technical path forthegreen manufacturing of wood structure buildings.

Selection of suitable cellulose nanofibers derived from eco-friendly sources for the production of lightweight cementitious composites with tuned rheological, mechanical, and microstructure properties

Different cellulose nanofibers (CNF) and ordinary Portland cement (OPC) were combined to prepare CNF-OPC composite pastes at different water to cement ratios (W/C) to optimize density, thermal conductivity, and mechanical strength. The rheological data of CNF-OPC composites showed that the viscosity and yield stress of the mixtures were abruptly increased in comparison to those of OPC pastes at equal W/C. Rheological and morphological data showed that the uniformity of the CNF and degree of fiber entanglement plays a significant role in tuning the composite properties. CNF suspensions with short fibers were observed to improve the mechanical properties of the composite while suspensions with entangled fiber networks were found to decrease density and thermal conductivity. Loss of flexural strength of CNF-OPC compared to OPC was found to be to a lesser extent than loss of compressive strength. The dry density and thermal conductivity of the CNF-OPC composites were substantially reduced to the range of 750 (kg/m3) and 0.1 (W/m−1K−1) at W/C = 2. CNF caused a reduction in peak temperature and postponed the hydration peak by more than 2 h compared to OPC.

Multi-Layer Polyurethane-Fiber-Prepared Entangled Strain Sensor with Tunable Sensitivity and Working Range for Human Motion Detection.

The entanglement of fibers can form physical and topological structures, with the resulting bending and stretching strains causing localized changes in pressure. In this study, a multi-layer polyurethane-fiber-prepared (MPF) sensor was developed by coating the CNT/PU sensing layer on the outside of an elastic electrode through a wet-film method. The entangled topology of two MPFs was utilized to convert the stretching strain into localized pressure at the contact area, enabling the perception of stretching strain. The influence of coating mechanical properties and surface structure on strain sensing performance was investigated. A force regulator was introduced to regulate the mechanical properties of the entangled topology of MPF. By modifying the thickness and length proportion of the force regulator, the sensitivity factor and sensitivity range of the sensor could be controlled, achieving a high sensitivity factor of up to 127.74 and a sensitivity range of up to 58%. Eight sensors were integrated into a sensor array and integrated into a dance costume, successfully monitoring the multi-axis motion of the dancer's lumbar spine. This provides a new approach for wearable biomechanical sensors.

Investigation of a lignocellulose fiber hornification treatment for improving the functionality of apple pomace-based pulp for molded pulp packaging

Transfer molded pulp packaging (TMPP) is a viable alternative to single use plastic packaging. TMPP is typically produced from recycled newspapers, but the availability of this feedstock material is declining. Apple pomace (AP) pulp, primarily composed of cellulose, hemicellulose, lignin, and pectin, can be used as the primary component of TMPP, but its high water retention value (WRV) and separation from other pulps (recycled cardboard (CB) in this study) limits its utilizations in TMPP. A pressing and thermal drying cellulose hornification treatment followed by a repulping step was implemented to reduce pulp WRV and enhance AP and CB fiber entanglements. 11 %, 20 %, and 25 % reductions in WRV were achieved through 1 t-force pressing and drying at 120 °C for 2.5, 15, or 27.5 min, named mild, medium, and strong hornification treatments, respectively. Increased AP and CB fiber entanglements were observed via microscopy with rising hornification drying times. The medium hornification treatment was identified as the optimal treatment for reducing pulp WRV and reducing pulp separation without decreasing pulp sheet tensile strength. This study introduced and validated a novel processing technique for improved functionality of AP-based pulp for packaging applications.

Improving the ablative performance of epoxy‐modified vinyl silicone rubber composites by incorporating different types of reinforcing fibers

AbstractIn this study, ablative resistance of single fiber‐ and hybrid fiber‐reinforced epoxy‐modified vinyl silicone rubber (EMVSR) composites was systematically studied. Three types of fibers, namely aramid fiber (AF), basalt fiber (BF), and carbon fiber (CF), were employed as the reinforcements. The results indicated that the incorporation of fiber reinforcements effectively suppressed the expansion and strengthened the char layer. Besides, the quality of char layer was quite different when different types of fibers were used. The char layer of AF‐modified samples had more surface defects, BF‐modified samples were brittle, and CF‐filled samples were dense and flat. The use of hybrid AF/BF fibers improved the ablation and anti‐erosion performance of EMVSR. Meanwhile, the thermal insulation performance was enhanced because the back‐face temperature was the lowest with the addition of 1 phr AF and 5 phr CF. The above results indicated that the ablation and anti‐erosion resistance and the quality of char layer as well as the thermal insulation behavior of EMVSR were significantly improved by incorporating fibrillar fillers, which demonstrate practical applications as flexible anti‐ablation materials for thermal protection systems.Highlights Epoxy‐modified vinyl silicone rubber was used for preparing ablative composites. The effect of adding different fibers on the ablation properties was studied. The presence of single fibers improved the strength of char layer. The use of hybrid fibers was found effective in enhancing the ablative properties. The intrinsic property and entanglement of fibers affected the ablative properties.

INFLUENCES OF ALKALI PRETREATMENT ON LYOCELL WOVEN FABRIC PROPERTIES AFTER ABRASION

In this study, alkali pretreatment in various concentrations were applied to Lyocell woven fabrics to decrease the fibrillation tendency of fibers and the influences of alkali pretreatment on tensile and tearing properties of Lyocell fabrics after abrasion were investigated. Alkali pretreatment reduced fibrillation of Lyocell fibers. However, fabric shrinkage occurred because of the increased volume and damaged twisted structure of yarns due to the lateral fiber swelling. The warp/weft densities and crimp ratios increased as the alkali concentrations increased. The breaking and tearing loads of untreated Lyocell fabrics were higher than those of alkali pretreated fabrics since the strength loss caused by alkali pretreatment. The abrasive load caused fiber breakages and fiber entanglements on fabrics and decreased the both breaking and tearing loads. The weave types with long floating interlacements on the fabric surface were more severely damaged by exposing to abrasive load and resulted as higher strength reduction.

Effect of fiber entanglement in chopped glass fiber reinforced composite manufactured via long fiber spray-up molding

Long Fiber Spray-up Molding (LFSM) deviates from the conventional approach in liquid composite molding (LCM) processes by utilizing extremely long chopped strands of fibers as the primary reinforcement material in its fabrication process. In LFSM, chopped fibers are impregnated with resin that is sprayed vertically downwards before reaching the mold surface. The spraying mechanism is mounted on an actuator, which is capable of spraying freely in any specified pattern or direction. Under LFSM, it is extremely difficult to fabricate a composite part with uniformly distributed fiber content throughout its volume. The consequences of the non-uniform fiber volume distribution arise from the fiber entanglement as the length of the fiber reaches up to 100 mm in LFSM. In this study, the effect of fiber entanglement during LFSM was analyzed through various approaches. This included measuring the coefficient of friction between fibers in contact and examining the correlation between fiber lengths and the number of intersections. Furthermore, the viscoelastic properties of the uncured composite part were assessed by experimenting with the influence of viscosity on fiber length during compression molding. The results were then computed, modeled, and visualized in MATLAB, considering variations in viscosity and fiber length, both before and after compression molding.

Fiber Stiffness: An Essential Parameter of the Effectiveness of Fiber-Based Lost Circulation Materials—A CFD-DEM Numerical Investigation

Summary Fiber materials have become an attractive choice for lost circulation material (LCM) applications recently. While there has been significant attention on the size, aspect ratio, and size distribution of fibers, the stiffness or basically the effect of their deformability on the sealing capability has not been studied rigorously. Experimental evaluations of fibers with different material properties could be a cumbersome, time-consuming, and expensive process. Most laboratory studies are limited to one or just a few different types of materials. Hence, a novel two-way-coupled computational fluid dynamics and discrete element method (CFD-DEM)-based numerical model is used to overcome this limitation and to simulate motion, collision, deformation, and finally entanglement of individual LCM fibers moving with the fluid along a fracture. Fiber stiffness is determined by the Young’s modulus, the fiber diameter, and the fiber length. Therefore, we investigate this effect in a parametric study with a focus on the impact of the length, diameter, and Young’s modulus of the fiber on their sealing capability. An in-depth analysis reveals that the bridging mechanism for fiber LCM changes with the stiffness of the fiber. Two distinct bridging mechanisms dependent on the fiber stiffness for fiber LCMs are identified. Based on the simulation results, we developed a conceptual model for the different mechanisms that fibers use for bridge initiation. It is also observed that in determining LCM effectiveness, both the fiber stiffness and the fiber dimensions go hand in hand. Stiff fibers were associated with greater maximum plugging pressures (MPPs). The effect of using a mix of soft and stiff fibers on fracture plugging effectiveness has been evaluated. The fiber LCM effectiveness as a consequence of the bending stiffness on bridging larger fractures is also investigated. Key Terms and Phrases lost circulation materials, fibers, fracture sealing, bridging mechanism

Copper metabolism-related Genes in entorhinal cortex for Alzheimer's disease

The pathological features of Alzheimer's disease are the formation of amyloid plaques and entanglement of nerve fibers. Studies have shown that Cu may be involved in the formation of amyloid plaques. However, their role has been controversial. The aim of this study was to explore the role of Cu in AD. We applied the “R” software for our differential analysis. Differentially expressed genes were screened using the limma package. Copper metabolism-related genes and the intersection set of differential genes with GSE5281 were searched; functional annotation was performed. The protein–protein interaction network was constructed using several modules to analyse the most significant hub genes. The hub genes were then qualified, and a database was used to screen for small-molecule AD drugs. We identified 87 DEGs. gene ontology analysis focused on homeostatic processes, response to toxic substances, positive regulation of transport, and secretion. The enriched molecular functions are mainly related to copper ion binding, molecular function regulators, protein-containing complex binding, identical protein binding and signalling receptor binding. The KEGG database is mainly involved in central carbon metabolism in various cancers, Parkinson's disease and melanoma. We identified five hub genes, FGF2, B2M, PTPRC, CD44 and SPP1, and identified the corresponding small molecule drugs. Our study identified key genes possibly related to energy metabolism in the pathological mechanism of AD and explored potential targets for AD treatment by establishing interaction networks.

Dynamic mechanical analysis for assessment of carbon fillers in glass fiber epoxy composites

AbstractThe effect of incorporation of micron sized aluminum trihydrate, multi‐walled carbon nanotubes, and graphene nano platelets into glass fiber reinforced epoxy matrix is investigated using dynamic mechanical analysis. The objective of the investigation was to develop polymer central core of high temperature low sag transmission conductor. The effect of individual and hybrid carbon fillers on the viscoelastic properties of the epoxy composites is investigated and discussed. The storage modulus of the glass reinforced epoxy increases by 20% at room temperature due to incorporation of carbon nanofillers. In glass transition region, the increase is higher between 40% and 60% and it varies up to 90% in the rubbery region. Key attributes of carbon filler addition are limited enhancement of storage modulus at room temperature, higher enhancement over glassy, glass transition, and rubbery regions. The carbon fillers extend the temperature range of the glassy region. The cross‐link density, filler efficiency, and degree of entanglement of fibers are estimated to understand the implications of the carbon fillers on the viscoelastic properties. The loss modulus peak of glass epoxy composite increases from 2800 to 3900 MPa with carbon fillers and the increase in glass transition temperature is 47°C. Incorporation of carbon fillers leads to increase of damping factor peak from 0.2 to 0.28. Cole–Cole plots have established the inherent heterogeneity of epoxy systems due to the presence of carbon fillers. Prediction models for storage modulus and damping factor have been proposed to highlight the influence of geometry and size of carbon filler.

Multifunctional bacterial cellulose photothermal aerogels with multi-bonded network assisted by carbon nanotube

As one of the important ways to utilize solar energy, it is of great significance to construct composite photothermal materials with high photothermal conversion and multifunctionality for in-depth investigation of their application performance. The nanofiber network and the reactivity of a large number of hydroxyl groups on the surface of environmentally friendly bacterial cellulose (BC) provide a prerequisite for its use as an excellent matrix material. Here, we use bacterial cellulose nanofibers (BCNFs) as the matrix, methyltrimethoxysilane (MTMS) as the crosslinking agent and hydroxylated multi-walled carbon nanotubes (MCNT − OH) as the photothermal absorber and conductive substrate to construct a multifunctional BC photothermal aerogel with multi-bonded network structure. Multiple chemical bond and physical bond interactions are formed between BCNF, MTMS and CNT, and fiber entanglement is combined to make CNT uniformly dispersed. This optimal photothermal aerogel has rich network structure with high hydrophobicity of 147°, compressive strength of 17.62 kPa and high elasticity. It also shows high light absorption of 93.5%, eminent photothermal conversion of 80.4 °C and photothermal stability under 1 kW m−2 irradiation with a low CNT content of 27.1%. Therefore, the photothermal aerogel shows potential of multi-scenario applications in the field of solar-driven high-viscosity crude oil recovery and piezoresistive strain sensors.

Hepatic Spheroid Formation on Carbohydrate-Functionalized Supramolecular Hydrogels.

Two synthetic supramolecular hydrogels, formed from bis-urea amphiphiles containing lactobionic acid (LBA) and maltobionic acid (MBA) bioactive ligands, are applied as cell culture matrices in vitro. Their fibrillary and dynamic nature mimics essential features of the extracellular matrix (ECM). The carbohydrate amphiphiles self-assemble into long supramolecular fibers in water, and hydrogels are formed by physical entanglement of fibers through bundling. Gels of both amphiphiles exhibit good self-healing behavior, but remarkably different stiffnesses. They display excellent bioactive properties in hepatic cell cultures. Both carbohydrate ligands used are proposed to bind to asialoglycoprotein receptors (ASGPRs) in hepatic cells, thus inducing spheroid formation when seeding hepatic HepG2 cells on both supramolecular hydrogels. Ligand nature, ligand density, and hydrogel stiffness influence cell migration and spheroid size and number. The results illustrate the potential of self-assembled, carbohydrate-functionalized hydrogels as matrices for liver tissue engineering.

Inducing Fiber Entanglement to Achieve Realistic Tow Fiber Volume Fractions in Textile Reinforced Composite Models

Meso-scale modeling can be an effective way to predict textile-reinforced composite performance when the geometry of the textile is known. Digital element fiber models can be used to obtain the geometry of the textile reinforcement, but these are frequently too compact because the fibers are parallel within a tow and do not provide as much resistance to compaction as tows with fiber entanglement found in textiles. A novel entanglement simulation procedure was created to obtain more realistic textile geometry. By combining artificial fiber entanglement with manufacturing process simulation, a method was developed to create fiber bundle models using entanglement to control the compaction behavior. To introduce fiber entanglement into a tow, select fibers are swapped with each other in the tow at a cross-section. This allows entanglement to be introduced after the basic textile structure is already made, and prevents individual fibers from leaving the tow and getting entangled into neighboring tows. This fiber entanglement process was controlled by three parameters, which dictate how many, how often, and how far away from each other fibers are swapped. A parametric study was conducted which showed that the entanglement within a fiber bundle could be used to control the compaction pressure versus fiber volume fraction response of the bundle. The method was then applied to a woven textile model where it was found that increasing the amount of entanglement within the tows increased the pressure required to compact the textile to the desired thickness. This method for artificial fiber entanglement and manufacturing process simulation shows the potential to be able to predict the entanglement required to create fiber bundles using a desired mold compression pressure to achieve a desired compaction behavior.

Functionalization of various coffee husk biofibers on the rheological and thermomechanical properties of poly(butylene succinate)-urethane blended composites

Many studies have reported that surface-functionalized biofibers originating from plant waste can be used to improve the compatibility and processability of polymer blend systems. This study investigated the effects of size distribution and surface treatment of coffee husk (CH) biofibers on the rheological and thermomechanical properties of poly(butylene succinate)/thermoplastic polyurethane polymer blend composite. CH is a coffee waste with interlinked complex macromolecular structure of lignocellulose materials like cellulose, hemicellulose, and lignin. It was found that the handling and processability of the composites improved after the CH was surface-functionalized with diisocyanate/methacrylate prior to composite fabrication. Smaller-sized surface-treated CHs showed superior processability owing to the entanglement of fibers through the matrices associated with the improvement of interfacial adhesion. Therefore, the frequency-dependent rheological test revealed an increase in complex viscosity and storage modulus with the surface treatment and size reduction of CHs. Regardless of the size distribution, the degree of crystallinity of poly(butylene succinate) in the composites filled with surface-treated CHs reduced by about 20%. The composites with treated CHs also demonstrated superior thermal stability than their corresponding composites with raw CHs.

Preparation and properties of the aramid pulp/nitrile butadiene rubber composites with compatibilization of ionic liquids

AbstractTo improve the uniformity and the mechanical/wear performances of the aramid pulp (AP)/nitrile butadiene rubber (NBR) composites, two types of ionic liquids (ILs), that is, 1‐carboxymethyl‐3‐methylimidazolium chloride ([CmMIM]Cl) and 1‐allyl‐3‐vinylimidazolium chloride ([AVIM]Cl) were applied on the AP surface, respectively. The ILs partially disrupted the hydrogen‐bonds between the aramid chains to mitigate the fiber entanglement, and connected the AP to the rubber matrix by hydrogen‐bond interaction or the crosslinking reaction during the vulcanization. The test results showed that, the IL treatments effectively improved the tensile and tear strengths without obviously affecting the physical characteristics of the composites. The wear properties of the AP/NBR composites also improved due to the enhancements of the tear strength and the connection between the AP and NBR matrix. Compared to the [CmMIM]Cl, the [AVIM]Cl was more efficient to improve the properties attributed to its better compatibilization for the AP/NBR system. For example, the specific wear rate under 20‐N load of the composite with 15‐phr [AVIM]Cl‐AP was 1.1 × 10−7 mm3 N−1 mm−1, which was approximately 25% and 35% lower than that of the composites reinforced with 15‐phr [CmMIM]Cl‐AP and untreated AP, respectively.

Bio-Innovative Pretreatment of Coarse Wool Fibers

From the textile manufacturers’ point of view, coarse and medullated fibers are undesirable in the production of fine woolen materials, but highly desirable in the production of textiles and yarns with special effects, especially in carpet production. For sustainability, the entire sheep fleece should be used, including the coarse and medullated fibers. The raw wool must be scoured to obtain clean wool fibers without damage or excessive fiber entanglement, with a certain moisture content, low dirt content and residual grease for further processing, and proper color. In order to remove the impurities in raw wool with maximum efficiency, save energy and minimize the environmental impact, this study investigated the changes in some fiber properties during the scouring process due to the effect of the enzyme complex on coarse wool fibers. The effects were studied through the amount of clean wool fibers and impurities within the fleece, the fiber diameter and color. Conventional and enzyme scoured coarse wool were bleached with an unconventional bleaching agent, percarbonate, and compared to bleaching with hydrogen peroxide to achieve higher whiteness and brilliant color with minimal fiber property changes. The changes after the bleaching process were determined based on the sorption of moisture and dyes and the color parameters. The bio-innovative pretreatment with enzyme complex scouring and percarbonate bleaching resulted in excellent fiber properties even for coarse wool. SEM analysis was performed to confirm these results. Taking into account the sustainability of the process and environmental protection, enzyme complex scouring and percarbonate bleaching are recommended as pretreatment processes for raw coarse wool.

A Review of the Pathogenesis and Chinese Medicine Intervention of Alzheimer's Disease.

Alzheimer's disease (AD) is an age-related neurodegenerative disease that is primary characterized as a cognitive disorder. Its pathology is characterized by the formation of senile plaques in the brain from amyloid-beta (Aβ) aggregation, neuronal fibrillary tangles from hyperphosphorylated tau protein aggregation, prolonged inflammatory responses, and neuronal death. The pathogenesis and clinical manifestations of AD are complex, but aging is generally accepted as one of the most important contributing factors. In addition, there are several hypotheses, including the Aβ hypothesis based on amyloid plaques, the tau hypothesis based on neuronal fiber entanglement, the inflammation hypothesis based on long-term inflammatory responses causing brain damage, and the neuroprotection hypothesis based on synaptic dysfunction and neuronal death. Although the pathogenesis of AD has been broadly classified into four major hypotheses, there are multiple forms of interactions, which is one of the reasons for its complex pathogenesis. Numerous epidemiological studies have shown the important role of genes in AD, followed by brain damage, hyperlipidemia, diabetes, hypertension, and obesity as risk factors for the disease. Despite years of research, several mysteries in AD remain unsolved. Drugs based on various pathogenetic hypotheses are being investigated in large numbers, but the effects are unsatisfactory. In recent years, traditional Chinese medicine (TCM) has made excellent progress and is expected to provide a new possibility for AD treatment. In this review, we focus on the latest developments in studies on the risk factors-Aβ aggregates and related factors such as apolipoprotein E, synaptic loss, and fatty acids, and then present the progress in the research of TCM based on the above pathogenesis, intended to provide a research reference and treatment for AD.

Effect of polypropylene fiber on properties of modified magnesium-coal-based solid waste backfill materials

Driven by the “dual carbon” goal, modified magnesium-coal-based solid waste backfill materials (MFPB) were gradually used in backfill mining instead of traditional backfill materials. To study the effect of polypropylene (PP) fibers with different contents and lengths on the properties of MFPB, slump tests, rheological tests, uniaxial compressive strength (UCS) tests, permeability tests, and scanning electron microscopy were carried out. The results showed that with the increase in the PP fiber content and length, the flowability of the MFPB characterized by the slump and rheological parameters deteriorated, but the UCS increased significantly, and the permeability first decreased and then increased. The mutual entanglement of PP fibers was the main reason for the poor fluidity of the MFPB. The PP fibers could effectively enhance and improve the strength and toughness of the MFPB by an anchoring effect and irregularly distributed network structure. The strengthening effect mainly occurred in the medium and long term, and the early strengthening effect was not evident. After curing for 28 d, the maximum growth rate of the UCS was 62.5%. After loading failure, the MFPB containing PP fibers still had good integrity and continuity, and there was no shedding phenomenon. The network structure that formed in the early stage due to the PP fibers did not easily segregate and precipitate. The transmission channels between the PP fibers connecting holes were the main reason that the MFPB permeability first decreased and then increased. Therefore, this study can provide a reference for the application of PP fibers to MFPB. Enhancing the performance of the backfill body has important theoretical and practical significance for the development of mine backfill.

Cellulose nanofibers as Scaffold-forming materials for thin film drug delivery systems

We explored the potential of cellulose nanofiber (CNF) for designing prolonged-release, thin-film drug delivery systems (TF-DDS). These delivery systems can be used as locally deployable drug-releasing scaffolds for achieving spatial and temporal control over therapeutic concentration in target tissues. Using doxorubicin (DOX) as a model anticancer drug, CNF-based TF-DDS were prepared using different film-formation processes, such as solvent casting and lyophilization. Formulations were prepared with or without the incorporation of additional macromolecular additives, such as gelatin, to include further biomechanical functionality. We studied the films for their mechanical properties, thermal stability, wettability, porosity and in vitro drug release properties. Our experimental results showed that CNF-based films, when prepared via solvent casting method, showed optimized performance in terms of DOX loading, and prolonged-release than those prepared via lyophilization-based fabrication processes. Scanning electron microscopy (SEM) analysis of the CNF-based films showed uniform distribution of fiber entanglement, which provided the scaffolds with sufficient porosity and tortuosity contributing to the sustained release of the drug from the delivery system. We also observed that surface layering of gelatin on CNF films via dip-coating significantly increased the mechanical strength and reduced the wettability of the films, and as such, affected drug release kinetics. The performance of the TF-DDS was evaluated in-vitro against two pancreatic cancer cell lines, i.e. MIA PaCa-2 and PANC-1. We observed that, along with the enhancement of mean dissolution time (MDT) of DOX, CNF-based TF-DDS were able to suppress the proliferation of pancreatic cancer cells in a time-dependent fashion, indicating that the drug liberated from the films were therapeutically active against cancer cells. Additionally, TF-DDS were also tested ex-vivo on patient-derived xenograft (PDX) model of pancreatic ductal adenocarcinoma (PDAC). We observed that DOX released from the TF-DDS was able to reduce Ki-67 positive, pancreatic cancer cells in these models.