Poor Mechanical Characteristics Research Articles

BACTERIAL CELLULOSE-BASED COMPOSITES: RECENT TRENDS IN PRODUCTION METHODS AND APPLICATIONS

Bacterial cellulose (BC) has attracted significant attention due to its distinct structural attributes and remarkable physico-mechanical properties, making it highly popular in biomedical applications, such as artificial skin, blood vessels, tissue scaffolds, and wound dressings. However, its widespread application in a variety of fields is often limited by poor mechanical properties and functional characteristics. The development of BC-based composites by incorporating synthetic materials has been widely investigated to address these limitations. This review paper summarizes the fabrication strategies for BC composites in-situ and ex-situ methods for their development, and highlights their wide range of applications in diverse fields. Various strategies have been designed for the synthesis of BC composite functionalized materials, tailored to the specific nature of their intended application. In the synthesis of BC composites, either in-situ addition of reinforcing materials to the synthetic media or ex-situ incorporation of these materials into the microfilaments of the BC microfilaments is primarily involved. A wide range of materials have been used as reinforced materials, ranging from organic polymers to inorganic nanoparticles. These composite materials have the potential to be used for tissue regeneration, wound healing, enzyme immobilization, and the development of medical devices. Recent years have seen the development of BC composites incorporating conductive materials, being used in the production of various electrical products, such as biocatalysts, enzymes, e-papers, displays, electrical instruments, and optoelectronic devices. In summary, the synthesis of BC composites and their applications offers a path for producing advanced biomaterials with enhanced properties and diverse functionalities, exploring their potential as environmentally friendly and versatile materials applicable across multiple sectors.

Electronically Conductive Polymer Enhanced Solid-State Polymer Electrolytes for All-Solid-State Lithium Batteries

All-solid-state lithium batteries (ASSLBs) have gained enormous interest due to their potential high energy density, high performance, and inherent safety characteristics for advanced energy storage systems. Although solid-state ceramic (inorganic) electrolytes (SSCEs) have high ionic conductivity and high electrochemical stability, they experience some significant drawbacks, such as poor electrolyte/electrode interfacial properties and poor mechanical characteristics (brittle, fragile), which can hinder their adoption for commercialization. Typically, SSCE-based ASSLBs require high cell stack pressures exerted by heavy fixtures for regular operation, which can reduce the energy density of the overall battery packages. Polymer–SSCE composite electrolytes can provide inherently good interfacial contacts with the electrodes that do not require high cell stack pressures. In this study, we explore the feasibility of incorporating an electronically and ionically conducting polymer, polypyrrole (PPy), into a polymer backbone, polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), to improve the ionic conductivity of the resultant polymer–SSCE composite electrolyte (SSPE). The electronically conductive polymer-incorporated composite electrolyte showed superior room temperature ionic conductivity and electrochemical performance compared to the baseline sample (without PPy). The PPy-incorporated polymer electrolyte demonstrated a high resilience to high temperature operation compared with the liquid-electrolyte counterpart. This performance advantage can potentially be employed in ASSLBs that operate at high temperatures. In our recent development efforts, SSPEs with optimal formulations showed room temperature ionic conductivity of 2.5 × 10−4 S/cm. The data also showed, consistently, that incorporating PPy into the polymer backbone helped boost the ionic conductivity with various SSPE formulations, consistent with the current study. Electrochemical performance of ASSLBs with the optimized SSPEs will be presented in a separate publication. The current exploratory study has shown the feasibility and benefits of the novel approach as a promising method for the research and development of next-generation solid composite electrolyte-based ASSLBs.

A Novel Solid State Polymer Electrolyte for All Solid State Lithium Batteries

All-solid-state lithium batteries (ASSLBs) have gained enormous interest due to their potential high energy density, high performance, and inherent safety characteristics for advanced energy storage systems.1 Currently, solid-state ceramic (inorganic) electrolytes (SSCEs), solid-state polymer electrolytes (SSPEs), and a combination of the two (e.g., SSCE fillers in SSPEs) are being developed for ASSLBs.2 Although SSCEs have high ionic conductivity and high electrochemical stability,3 they experience some significant drawbacks, such as poor electrolyte/electrode interfacial properties and poor mechanical characteristics (brittle, fragile),4 which can hinder their adoption to commercialization. Typically, SSCE-based ASSLBs require high cell stack pressures exerted by heavy fixtures for regular operations, which can reduce the energy density of the overall battery packages.5 One promising solution to circumvent the aforementioned issues of SSCE-based ASSLBs is to develop SSPE-based AASLBs, since SSPEs can provide inherently good interfacial contacts with the electrodes that do not require high cell stack pressures. In addition, SSPEs are advantageous in making flexible batteries due to their elastic nature.6 In this study, a novel method was developed to prepare a high-performance SSPE-based ASSLB, where a π-conjugated polymer was incorporated into a baseline polymer backbone, resulting in an improvement in ionic conductivity, thermal stability, and electrochemical stability. The novel SSPE demonstrated a superior electrochemical performance than the baseline when used in ASSLBs. The strategy developed in this study may lead to a new direction for the research and development of next-generation SSPE-based ASSLBs.

Fabrication of 3D printed Si3N4 bioceramics with superior comprehensive performance through ZnO nanowires doping

Silicon nitride (Si3N4) material holds significant potential as a widespread applied biomedical material with high reliability in mechanical properties and biological activity. This study utilized 3D printing techniques to fabricate Si3N4 bioceramics reinforced with zinc oxide (ZnO) nanowires, which overcomes the dilemma faced by traditional Si3N4 materials, which possess excellent mechanical properties but lack sufficient antibacterial performance, or porous Si3N4 materials that exhibit good antibacterial properties yet suffer from poor mechanical characteristics. Compared to Ti-alloy, Al2O3, PEEK, and conventional Si3N4 materials, the Si3N4 bioceramic with an addition of 5 wt percent (wt%) ZnO nanowires retains superior mechanical properties: bending strength of 735 MPa, fracture toughness of 8.25 MPa m1/2, vickers hardness of 14.8 GPa, and compressive strength of 2575 MPa. Furthermore, the material demonstrates commendable biocompatibility and outstanding antibacterial effects. Cellular activity on the surface of this material is also noted to be exceptionally vigorous. Research indicates that the synergistic effects of 3D printing characteristics and the appropriate inclusion of ZnO nanowires, which positively interact with β-Si3N4 crystals, are primarily responsible for the exceptional comprehensive performance of 3D printed Si3N4 bioceramics.

Facile fabrication of linezolid/strontium coated hydroxyapatite/graphene oxide nanocomposite for osteoporotic bone defect

Hydroxyapatite (HAp) coatings currently have limited therapeutic applications because they lack anti-infection, osteoinductivity, and poor mechanical characteristics. On the titanium substrate, electrochemical deposition (ECD) was used to construct the strontium (Sr)-featuring hydroxyapatite (HAp)/graphene oxides (GO)/linezolid (LZ) nanomaterial coated with antibacterial and drug delivery properties. The newly fabricated nanomaterials were confirmed by X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis and morphological features were examined by scanning electron microscope (SEM) analysis. The results reveal multiple nucleation sites for SrHAp/GO/LZ composite coatings due to oxygen-comprising moieties on the 2D surface of GO. It was shown to be favorable for osteoblast proliferation and differentiation. The elastic modulus and hardness of LZ nanocomposite with SrHAp/GO/LZ coatings were increased by 67 % and 121 %, respectively. An initial 5 h burst of LZ release from the SrHAp/GO/LZ coating was followed by 14 h of gradual release, owing to LZ's physical and chemical adsorption. The SrHAp/GO/LZ coating effectively inhibited both S. epidermidis and S. aureus, and the inhibition lasted for three days, as demonstrated by the inhibition zone and colony count assays. When MG-63 cells are coated with SrHAp/GO/LZ composite coating, their adhesion, proliferation, and differentiation greatly improve when coated with pure titanium. A novel surface engineering nanomaterial for treating and preventing osteoporotic bone defects, SrHAp/GO/LZ, was shown to have high mechanical characteristics, superior antibacterial abilities, and osteoinductivity.

Development of biodegradable film from cactus (Opuntia Ficus Indica) mucilage loaded with acid-leached kaolin as filler

Nowadays, substituting petroleum-based plastics with biodegradable polymers made from polysaccharides loaded with various reinforcing materials has recently gained attention due to the impact of conventional plastics wastes. In this study, polysaccharidic mucilage from Ethiopian cactus (Opuntia Ficus Indica) was derived using microwave-assisted extraction technique to develop biodegradable polymers that were inexpensive, readily available, simple to make, and ecofriendly. The effect of microwave power 300–800 W, solid-liquid (cactus-sodium hydroxide solution) ratio 1:5–1:25, sodium hydroxide concentration 0.1–0.8 mol/L, and extraction time 2–10 min on mucilage extraction were studied and the maximum yield of mucilage was attained at optimized parameters of 506 W, 1:20, 0.606 mol/L, and 9.5 min, respectively. Biodegradable polymers made with mucilage alone have poor mechanical characteristics and are thermally unstable. Thus, to overcome the stated problems, glycerol as a plasticizer and acid-leached kaolin crosslinked with urea as a reinforcing material were used. Moreover, the effect of acid-leached kaolin and glycerol on the physico-chemical properties of the films was studied, and a maximum tensile strength of 6.74 MPa with 18.45 % elongation at break, thermally improved biodegradability of 26 %, were attained at 10 % acid-leached kaolin and 20 % glycerol crosslinking with 2 % urea. But the maximum degradability of 53.5 % was attained at 30 % glycerol content. The control and reinforced biodegradable films were characterized using TGA, FTIR, SEM, and XRD to determine the thermal, functional group, morphology, and crystallinity of the bioplastics, respectively. These biodegradable plastics may be used for packaging application.

Continuous production of ultratough semiconducting polymer fibers with high electronic performance.

Conjugated polymers have demonstrated promising optoelectronic properties, but their brittleness and poor mechanical characteristics have hindered their fabrication into durable fibers and textiles. Here, we report a universal approach to continuously producing highly strong, ultratough conjugated polymer fibers using a flow-enhanced crystallization (FLEX) method. These fibers exhibit one order of magnitude higher tensile strength (>200 megapascals) and toughness (>80 megajoules per cubic meter) than traditional semiconducting polymer fibers and films, outperforming many synthetic fibers, ready for scalable production. These fibers also exhibit unique strain-enhanced electronic properties and exceptional performance when used as stretchable conductors, thermoelectrics, transistors, and sensors. This work not only highlights the influence of fluid mechanical effects on the crystallization and mechanical properties of conjugated polymers but also opens up exciting possibilities for integrating these functional fibers into wearable electronics.

Application of Plant Oils as Functional Additives in Edible Films and Coatings for Food Packaging: A Review.

Increasing environmental concerns over using petroleum-based packaging materials in the food industry have encouraged researchers to produce edible food packaging materials from renewable sources. Biopolymer-based edible films and coatings can be implemented as bio-based packaging materials for prolonging the shelf life of food products. However, poor mechanical characteristics and high permeability for water vapor limit their practical applications. In this regard, plant oils (POs) as natural additives have a high potential to overcome certain shortcomings related to the functionality of edible packaging materials. In this paper, a summary of the effects of Pos as natural additives on different properties of edible films and coatings is presented. Moreover, the application of edible films and coatings containing POs for the preservation of different food products is also discussed. It has been found that incorporation of POs could result in improvements in packaging's barrier, antioxidant, and antimicrobial properties. Furthermore, the incorporation of POs could significantly improve the performance of edible packaging materials in preserving the quality attributes of various food products. Overall, the current review highlights the potential of POs as natural additives for application in edible food packaging materials.

A Systematic Investigation on the Effect of Carbon Nanotubes and Carbon Black on the Mechanical and Flame Retardancy Properties of Polyolefin Blends.

Due to high filler loading, clean, commercial, thermoplastic, flame-retardant materials are mechanically unstable when insulating wires and cables. In this study, composite formulations of linear low-density polyethylene (LLDPE)/ethylene-vinyl acetate (EVA) containing a flame retardant, such as magnesium hydroxide (MH; formula: Mg(OH)2) and huntite hydromagnesite (HH; formula: Mg3Ca(CO3)4, Mg5(CO3)4(OH)2·3H2O), were prepared. The influence of carbon nanotubes (CNTs) and carbon black (CB) on the mechanical properties and flame retardancy of LLDPE/EVA was studied. Three types of CNTs were examined for their compatibility with other materials in clean thermoplastic flame-retardant compositions. The CNTs had the following diameters: 10-15 nm, 40-60 nm, and 60-80 nm. Optimum mechanical flame retardancy and electrical properties were achieved by adding CNTs with an outer diameter of 40-60 nm and a length of fewer than 20 nm. Large-sized CNTs result in poor mechanical characteristics, while smaller-sized CNTs improve the mechanical properties of the composites. CB enhances flame retardancy but deteriorates mechanical properties, particularly elongation at break, in clean, black, thermoplastic, flame-retardant compositions. Obtaining satisfactory compositions that meet both properties, especially formulations passing the V-0 of the UL 94 test with a minimum tensile strength of 9.5 MPa and an elongation at break of 125%, is challenging. When LLDPE was partially substituted with EVA, the limiting oxygen index (LOI) increased. The amount of filler in the formulations determined how it affected flammability. This study also included a reliable method for producing clean, black, thermoplastic, flame-retardant insulating material for wire and cable without sacrificing mechanical properties.

Clayey Soil Improvement with Polyethylene Terephthalate (PET) Waste

Population expansion and the development of technology have led to an increase in construction activities. In many cases, foundation grounds do not have a high enough bearing capacity and are not capable of ensuring the safe exploitation of the construction. A soil with poor mechanical characteristics must be improved using various methods, such as adding hydraulic binders (lime and cement), natural fibres, or more recently, plastic waste materials. This work aims to study the behaviour of plastic waste materials made from polyethylene terephthalate (PET) in soil improvement. Thus, the mechanical characteristics of a clay improved with shredded PET were studied. PET was added in relation to the dry mass of the clay, in percentages of 2%, 4% and 6%. The studied clay was collected from a construction site around Cluj-Napoca, Romania, from a depth of 1 ÷ 10 m. PET was provided by a local plastic waste repository. It comes from recycled water, beer and soda bottles and was cleaned using specific methods for cleaning and recycling plastic waste. PET was shredded into irregular shapes with sizes ranging from 3 mm to 12 mm and was randomly distributed in the test specimens. Compression and direct shear tests were carried out to study the compressibility and shear parameters of the improved soil (internal friction angle and cohesion). The experimental results showed an improvement in the mechanical characteristics of the clay even at a low PET addition of 2% and 4%. This method can contribute to solving two current problems of the modern world: reducing pollution by recycling plastic waste materials and using them to improve the mechanical characteristics of soil.

A systematic review of clay shale research development for slope construction

The issue of stability controlling cutting slopes is particularly important in clay-shale slopes, a typical expanding sedimentary layer with poor engineering geological conditions and mechanical characteristics. Therefore, research on the causes of failure and remedies for clay-shale cutting slopes is required to serve as an overview for handling and preserving clay-shale slopes in identical conditions. However, the trusted information about the need for further related clay shale research and clay shale in slope stability has yet to be specifically presented. This review study summarizes the published research for clay shale beginning in 1980, presents a bibliometric analysis to examine the published research based on year and country, and provides various study trends in cluster diagram using the VOSviewer program. The analysis also summarized some key goals, effective methodology, and significant findings from the most recent studies to extract information from them that would benefit future research. In conclusion, the results show the need for developing research to fill the knowledge gap regarding clay shale, landslide, and clay mineralogy. In addition, the clay shale slope analysis has revealed the need for additional research into dynamic force and its deformation.

Experimental studies of reinforced clay bases of logging roads

The construction and operation of logging roads often takes place in unfavorable engineering and geological conditions. Very often, clayey soils with poor physical, mechanical and strength characteristics lie in the bases of logging roads. Improving these soil characteristics is an urgent task. For this purpose, reinforcement of soil bases with the help of geotextile materials is used. Most often, a horizontal arrangement of reinforcing geosynthetic layers is used. To date, there are a large number of studies of reinforced soil structures of logging roads, but they mainly concern the use of geosynthetics in sandy soils. Research in clayey soils is not enough. Therefore, experimental studies of the operation of reinforced foundations in clayey soils were carried out. The paper presents the results of stamp tests of clay soils reinforced with horizontal reinforcing layers. The studies were carried out in two stages. At the first stage, stamp model studies were performed, which made it possible to establish the optimal designs of reinforced clay bases. Based on the results of this stage, a single-layer horizontal reinforcing layer of geosynthetic material with a tensile rigidity of 2100 kN/m, an outer diameter equal to three stamp diameters, located at a depth equal to 0.25 stamp diameters was selected. The base soil was soft plastic clay. At the second stage, field stamping tests of the reinforced and non-reinforced clay base were performed. To study the stress-strain base, pressure sensors were selected to measure vertical normal stresses and a measuring system for their registration. Vertical displacements at various points of the active zone of soil foundations were evaluated by soil marks having a wire connection with deflection meters. The results of stamp tests showed that the bearing capacity of the reinforced base is 1.5 times higher than the bearing capacity of the unreinforced base. The deformation modulus of the reinforced base is 1.18 times higher than the unreinforced base in the load range from 0 to 100 kPa. The reinforcing layer is included in the work when the precipitation of the stamp is more than 30 mm. The stress-strain state of a reinforced base has significant differences from an unreinforced one. The reinforcing layer significantly reduces vertical stresses in the upper part of the active zone of the base, by an average of 22%/. The experimental stamp tests carried out made it possible to obtain a qualitative and quantitative picture of the operation of reinforced clay bases of logging roads.

Effects of surface modified recycled coarse aggregates on concrete’s mechanical characteristics

Sustainable concrete using recycled coarse aggregates from construction and demolition waste is gaining popularity in the construction industry, but has poor mechanical characteristics due to old cement mortar adhering to aggregate surfaces. This study uses two processes (abrasion treatment and cement slurry treatment) to modify the surface of recycled coarse aggregates (RCA) to minimize the strength loss of RCA and enhance the bonding properties of the concrete matrix and RCA. Surface-modified RCA replaced coarse aggregates in varying percentages, ranging from 0 to 100% in 25% increments. To comprehend the effects of surface-modified RCA, the workability, compressive strength, flexural strength, split tensile strength, microstructural characteristics (XRD, SEM, and EDAX), and modulus of elasticity of concrete are evaluated. Surface-modified RCA improves concrete’s mechanical characteristics, but abrasion-treated RCA has significantly greater strength than reference concrete up to 50% replacement level, while cement slurry treatment has slightly lower strength. Test findings reveal that among all the two processes of surface modifications of RCA, abrasion treatment is more effective and efficient. At 100% replacement level, surface-modified RCA by abrasion treatment reduces compressive, flexural, and split tensile strength by 10.89%, 10.42%, and 09.92% compared to reference concrete, while surface-modified RCA by cement slurry treatment reduces these values by 14.80%, 13.27%, and 12.76%. Surface modifications improve bonding properties of RCA and cement matrix, reducing porosity and resulting in dense and strong ITZs compared to unmodified RCA.

Visible to Mid-IR Supercontinuum Generation in Cascaded PCF-Germanate Fiber Using Femtosecond Yb-Fiber Pump

Broadband supercontinuum (SC) fiber sources covering the mid-IR range have many significant applications, largely due to their compactness, reliability, and ease of use. However, most of the existing SC fiber sources cannot boast of either high reliability or a wide bandwidth. Thus, supercontinuum sources based on silica fibers are robust, but are not capable of generating SC in the mid-IR range. Sources based on soft glasses (tellurite, chalcogenide, etc.) generate broadband SC in the mid-IR range but are not used commercially, due to the poor mechanical and chemical characteristics of such fibers. In this work, we propose a new approach consisting of cascade generation of a supercontinuum sequentially in a silica photonic crystal fiber (PCF) and a germanate fiber. Using a standard ytterbium chirped-pulse amplification (CPA) laser system for pumping, we have demonstrated a supercontinuum in the range of 450–2950 nm in PCF and germanate fiber firmly connected by a standard fusion splicing technique. Further optimization of the cascade pump will make it possible to create a compact and reliable all-fiber SC source from the visible to mid-IR range.

Bionanocomposites films applied as active and smart food packaging: A review

AbstractFood packaging is used worldwide and is a common technique for protecting food safety and quality while increasing shelf life. Environmental issues caused by using polymers in packaging derived from petroleum are becoming more significant and more well‐known. Interest in ecofriendly packaging materials made of renewable resources (biopolymers) has steadily increased, particularly for temporary and throw‐away packaging applications. However, biopolymers frequently have poor processability, poor mechanical, and poor barrier characteristics, restricting their industrial application and scalable manufacturing. Researchers have created bionanocomposites with improved packaging qualities like antibacterial function, mechanical toughness, optical clarity, and gas and water barrier properties to overcome these restrictions. This review seeks to inform readers about recent advances in active food packaging that use biopolymers and bionanocomposite materials. The difficulties and possibilities presented by such resources for the food packaging sector have been examined. This review is timely given the recent spike in interest in research projects both in academia and industry seeking to create a new group of materials for packaging based on biopolymer for food with potential uses elsewhere.

Preparation of Nanocellulose Whisker/Polyacrylamide/Xanthan Gum Double Network Conductive Hydrogels

Hydrogels’ poor mechanical and recovery characteristics inhibited their application as a plastic deformable three-dimensional cross-linked network polymer with electrical properties for intelligent sensing and human motion detection. Cellulose has also been added to the hydrogel to enhance its mechanical properties. The hydrogel has been enhanced this way, and the double-network hydrogel has superior recovery and mechanical capabilities. This study used the traditional free radical polymerization method to prepare double-mesh hydrogels, with polyacrylamide as the backbone network, xanthan gum double-helix structure, and Al3+ complex structure as the second cross-linked network, and endowing the hydrogels with good mechanical recovery and mechanical properties. Adding cellulose nanowafers (CNWs) improved the mechanical properties of the hydrogels. The hydrogel could detect body movements and various postures in the same environment. Moreover, the hydrogel has excellent recovery, mechanical properties, and tensile strain; the maximum fracture stress is 0.14 MPa, and the maximum strain is 707.1%. In addition, Fourier infrared spectroscopy (FTIR) of xanthan gum and Xanthan gum—Al3+ were analyzed, and thermogravimetric analysis (TGA) and LCR bridge were used to analyze the properties of hydrogels. Notably, hydrogel-based wearable sensors have been successfully constructed to detect human movement. Its mechanical properties, sensitivity, and wide range of properties make hydrogel a great potential for various applications in wearable sensors.

Bio-Assisted Improvement of Shear Strength and Compressibility of Gold Tailings

Safe storage of mine tailings has challenged engineers as shown by numerous historical tailings dam failures. While the storing of tailings behind tailings dams is the most practical containment solution, poor mechanical characteristics (low strength and high compressibility) of these waste materials raises serious concerns regarding the stability of tailings dams. In this study, the microbially-induced calcite precipitation (MICP) technique is used to treat gold tailings. Accordingly, tailings were enriched with Sporosarcina pasteurii and flushed with different concentrations of cementation solution to find the CaCl2 amount that produces the highest shear strength in studied tailings. Their shear strength and compressibility were measured in direct shear and one-dimensional oedometer tests and compared with those of the untreated tailings. Results showed that the 50 mM CaCl2 cementation solution proved the most effective treatment solution with respect to MICP, reducing compressibility of tailings by about 300% when loaded up to 800 kPa and improving shear strength by 140%. X-Ray Diffraction (XRD) analysis and Scanning Electron Microscope (SEM) images of treated samples further illustrated the effects of MICP on the composition and structure of the tailings specimens.

Mechanical properties evaluation of FFF-printed ABS samples based on different process parameters combined with ANOVA and regression analysis

The fused fabrication process (FFF), is one of the most popular additive manufacturing technologies used for prototyping and production applications. On the other hand, poor mechanical characteristics significantly impact the application of FFF parts, and a variety of process parameters can influence the effectiveness of parts produced with FFF. Infill density, layer thickness, print speed, and extrusion temperature are the essential FFF parameters for fabricating parts and the dimensional integrity of printed specimens. This research aims to examine the functional performance of ABS fabricated through FFF. The study’s various variables include extrusion temperature (230°C, 240°C, and 220°C), feed rate (20, 35, and 50 mm/s), and layer height (0.1, 0.15, and 0.2 mm). Based on various combinations, elongation at break, energy, tensile strength, and compressive strength will be assessed. The measured lowest tensile and compressive strengths are 25.252 and 38.52 MPa, respectively, and highest tensile and compressive strengths are 33.96 and 185.94 MPa, respectively. As a result, changing the different process variables increases tensile strength by 34.49% and compressive strength by 382.71%. Fractography analysis is also performed to understand the failure modes of specimens, indicating pulling, necking, failure of raster’s, and voids for the considered specimens. To examine the dependency and relationship of the tensile and compressive strength on the process parameters, statistical analysis is performed using ANOVA, Taguchi’s L27 array design of experiment, and regression analysis. It indicates that layer height has the most significant influence on tensile and compressive strength, followed by extrusion temperature and feed rate.

Squid/synthetic polymer double-network gel: elaborated anisotropy and outstanding fracture toughness characteristics

The hierarchical anisotropy of a biotissue plays an essential role in its elaborate functions. To mimic the anisotropy-based functions of biotissues, soft and wet synthetic hydrogels with sophisticated biotissue-like anisotropy have been extensively explored. However, most existing synthetically manufactured anisotropic hydrogels exhibit fundamental anisotropy and poor mechanical toughness characteristics. In this paper, natural/synthetic hybrid double-network (DN) hydrogels with hierarchical anisotropy and high toughness characteristics are reported. These DN gels are prepared directly by using a squid mantle as an anisotropic soft bioproduct for the primary network and polyacrylamide (PAAm) as a synthetic polymer for the secondary network. The obtained squid/PAAm DN gel maintains the complex orientation of the muscle fibers of the squid mantle and exhibits anisotropic, enhanced mechanical properties and excellent fracture resistance due to its unique composite structure. This hybrid strategy provides a general method for preparing hydrogels with elaborated anisotropy and determining functions derived from the anisotropy.

FORMULATION AND EVALUATION OF CLOBETASOL-17-PROPIONATE-LOADED CARBOXYMETHYL CHITOSAN NANOPARTICLE

Objective: Formulation and evaluation of clobetasol-17-propionate-loaded carboxymethyl chitosan nanoparticle. Psoriasis is a chronic skin disorder caused due to the autoimmune factors. It has a detrimental psychological and physiological impact on patients due to the emergence of apparent skin. The systemic therapy with anti-psoriatic drugs such corticosteroids, immunosuppressant, and gene suppressors causes severe side effects. As a result, increasing the effectiveness and safety of the aforementioned medicines when applied topically would be extremely useful in avoiding the side effects associated with the systemic route of administration. Methods: Chitosan (CS) has not been widely used in the clinic applications but due to its limited solubility and poor mechanical characteristics. CS, on the other hand, is chemically changed to form carboxymethyl (CMC), which is soluble at both neutral and basic pH. Chemical modifications can also be used to attach different functional groups and control hydrophobic, cationic, and anionic properties. CMC is a promising carrier that might possibly traverse the thick scales of psoriatic skin since it is a penetration enhancer that allows drug diffusion through either the transcellular or paracellular pathways. Comparative study is done using CMC as a polymer and CD as a polymer. Results: CP-loaded CMC nanoparticles show better result results than CP-loaded CD polymer. Conclusion: Clobetasol-17-propionate-loaded carboxymethyl chitosan nanoparticle shows better results with improved solubility.