Hot Extrusion Method Research Articles

Fabrication and characterization of new hot extruded ZK60/CNTs+AgNPs nanocomposites for biomedical applications

Magnesium (Mg), with properties such as biodegradability and having a density and elasticity coefficient close to the bones of the body, has attracted a lot of attention as a serious option for orthopedic applications. However, the low compressive strength of Mg compared to the human bone and its weak antibacterial function limit its applications as a substitute for temporary implants to be used under load-bearing conditions. The aim of this paper is to evaluate the synergistic effect of CNTs + AgNPs nanofillers on the in vitro degradation, mechanical and antibacterial behavior of new ZK60/xCNTs + xAgNPs(x: 0, 0.25, 0.5, 1) composites made using semi powder metallurgy, followed by hot extrusion method. The ZK60/0.5CNTs+0.5 AgNPs (CA2) composite boasts a higher ultimate compressive strength (UCS) of 371 ± 15 MPa compared to 297 ± 6 MPa for ZK60 based alloys. The CA2 composite also exhibits a grain size of 9.8 μm and a microhardness of 81 HV.Also, the antibacterial activity assessment demonstrated that adding CNTs + AgNPs hybrid nanofillers to the Mg matrix could notably prevent growing and penetration of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), which indicates the synergy between antibacterial mechanisms of CNTs and AgNPs. Cytotoxicity studies confirm that composites with low amounts of CNTs + AgNPs did not show cytotoxic behavior against MG63 cells, although higher loading of CNTs + AgNPs caused toxicity. Also, the examination of osteogenic activity is consistent with other results. In general, according to the results, the potential application of CA2 composite for under load bearing implant application and bone infection treatment is proved.

Biocompatible Natural Polymers and Cutting-Edge Fabrication Techniques in the Development of Next-Generation Oral Thin Films for Enhanced Drug Delivery Systems.

Oral thin films are changing the way drugs are delivered, making drug administration more convenient and patient-friendly. This review delves into the fascinating possibilities of natural polymers in thin film design. We consider the benefits of biocompatible polymers produced from chitosan, gelatin, and pullulan. Their intrinsic biodegradability and safety make them excellent for use with a wide range of patients. Additionally, the research investigates novel strategies for creating these distinctive drug delivery systems. We look beyond standard solvent casting techniques, hot melt extrusion methods, rolling methods, etc. These technologies provide exact control over film qualities, allowing for tailored medication delivery and increased patient compliance. This review seeks to bridge the gap between natural polymers and cutting-edge fabrication processes. By investigating this combination, we pave the road for the development of next-generation oral thin films that are more efficacious, patient-acceptable, and environmentally-friendly.

Hexagonal-inner-cladding fluorotellurite fiber based on hot-extrusion

Laser output power can be significantly enhanced by a double-cladding fiber, as it possesses a large area of inner-cladding for pumping. However, the coupling efficiency of the double-cladding fiber (DCF) is impacted by the shape of the inner cladding. In this study, the simulation results showed that, the hexagonal inner cladding fiber exhibits the highest absorption efficiency of 94.07 % among the fibers with various typical shapes using the three-dimensional ray tracing method at a length of 100 mm. For the experiments, a type of fluorotellurite (TBY, TeO2-BaF2-Y2O3) glass was chosen for its high capacity of rare-earth ions adoption. Subsequently, a finely structured erbium-doped hexagonal DCF was fabricated based on the hot-extrusion method for the first time, with a minimum loss of 1.25 dB/m at 1310 nm. Additionally, the coupling efficiency of the hexagonal DCF was recorded to be 39.47 % at a fiber length of 53 cm, based on the energy distribution experiment. The damage threshold of the hexagonal DCF at 980 nm could be increased to above 26.5 W, nearly doubling that of the single-cladding fiber. Furthermore, a wider fluorescence spectrum with a full width at half maximum (FWHM) of 30 nm was demonstrated by the hexagonal double-cladding fiber, which indicates its potential for high-power laser applications.

Fabrication of multi-layered polymer-based polypill using single-nozzle Fused Deposition Modeling and its dissolution mechanism

The meteoric rise of additive manufacturing has enabled it to create remarkable feats in the field of pharmaceutics and drug delivery applications. The main objective of this study was to print a polypill, having two drugs of common ailments in different layers, using a single nozzle Fused Deposition Modeling (FDM), instead of using a complex and cost-intensive dual extrusion printer. This was accomplished through a thermally fused filament. Myo-inositol (MI) and methylcobalamin (MCB) were the two drugs used for the present study. Initially, polyvinyl alcohol (PVA) filaments have been loaded with these drugs using Hot Melt Extrusion (HME) method and then, fused using heat and this blended filament has been fed into the FDM printing apparatus. These filaments have been used to finally obtain a polypill containing drugs in an alternate layer fashion. Various tests related to the filaments and tablets have been carried out to analyse the chemical, physical and thermal feasibility of this research attempt. The thermal analysis like Differential Scanning Calorimetry (DSC), Thermogravimetric (TGA) analysis tests confirmed filaments to be stable at printing temperature and FTIR results affirmed non-existence of any adverse degradation reaction in the drugs or other constituents. In-vitro dissolution studies were also conducted on the polypill and it was revealed that the dissolution rate for MI has been significantly higher than that of MCB drug. MI drug released completely in 5 h while MCB part was complete by 6.5 h. Finally, the drug dissolution behaviour was examined based on the dissolution data.

Thermal and Mechanical Properties of Bio‐Based Polyamide 56/6 Filled with Talc

AbstractPolyamide composites with varying filler concentrations are prepared using the hot melt extrusion method, employing polyamide 56/6 (PA56/6) and modified talc as fillers. Initially, the thermal characteristics of PA56/6 composites (PA56/6‐talc) are examined through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), encompassing parameters such as melting temperature, crystallinity, and decomposition temperature. The hydrophilicity and barrier properties of PA56/6‐talc are assessed using an optical contact angle meter, a water vapor transmission rate tester, and an oxygen transmission rate tester. Furthermore, the mechanical properties of PA56/6‐talc are also scrutinized. The results indicate that PA56/6 exhibits superior hydrophobic, barrier, and mechanical properties, thereby demonstrating its immense potential in garment fabrics and packaging materials.

High Mechanical Property and Texture Degree of Hot-Extruded Bi0.905Sb0.095

Bi1−xSbx crystal is one of the best n-type thermoelectric materials below 200 K, but its weak mechanical strength hinders practical applications for deep refrigeration. Herein, we adopted the mechanical enhancement method of hot extrusion to investigate the comprehensive mechanical and thermoelectric properties of Bi0.905Sb0.095. It revealed that reducing the grain size of the matrix and increasing the extrusion ratio can improve the gain size uniformity and mechanical properties. Meanwhile, the thermoelectric performance depends on the texture, grain size, and local composition. The extruded sample prepared by ingot with the high extrusion ratio of 9:1 generated uniform small grains, which resulted in the high bending strength of Bi1−xSbx~130 Mpa and a high power factor of ~68 μW·cm−1·K−2@173 K, as well as the relatively high figure of merit of 0.25@173K. This work highlights the importance of the uniform distribution of the grain size and the compositions for Bi1−xSbx, as well as the required universal key parameter for the hot extrusion method.

Hot extrusion-induced Mg-Ni-Y alloy with enhanced hydrogen storage kinetics

In this work, the influence of the hot-extrusion method on the hydrogen storage kinetics of Mg-Ni-Y alloy was investigated. It was shown that the extruded Mg91.47Ni6.97Y1.56 alloy exhibits improved hydriding and dehydriding (H/D) kinetics, with a capacity of 3.5 wt.% H2 absorption within 60 s and 5.4 wt.% H2 desorption within 5 min at 573 K. The dehydrogenation activation energy of extruded alloy is 71.4 kJ mol−1, smaller than that of as-cast alloy (140.5 kJ mol−1). The enhancement of H/D kinetics is attributed to the microstructural refinement and increased grain/phase boundaries introduced by hot extrusion, as well as the catalytic effects from the in-situ generated and grain-refined Mg2Ni and YH2 particles during the H/D process. Furthermore, the dehydrogenated rate-determining step transforms from hydrogen diffusion in the hydride (as-cast alloy) to the surface penetration of hydrogen atoms (extruded alloy). These findings provide crucial insights for the design of Mg-based hydrogen storage alloys in the future.

INVESTIGATING THE THERMAL TREATMENT PROCESSES OF REINFORCED ALUMINUM DEFORMABLE CASTING ALLOYS OBTAINED BY HOT EXTRUSION

The processes of heat treatment and formation of the structure and properties of aluminum deformable casting alloys reinforced with steel fibers obtained by the method of hot extrusion are studied. As a result, optimal tempering and aging temperatures are selec-te¬d. Тr = 530±100С, Тag = 80±100С, the duration of aging. τag=36 hours, which provide high mechanical properties. σT = 570...580 МН/m2, HB = 1240...1250 MPa, δ = 8.5...9,5%.

Influence of carbon fiber failure mode caused by TiO2 coating on the high temperature tensile strength of carbon fiber reinforced 7075 Al alloy composites

To enhance the mechanical properties of carbon fiber (CF) reinforced 7075 Al alloy material at high temperature conditions, TiO2 coating was prepared on the surface of CF by chemical vapor deposition. The composites were prepared by hot pressing sintering and hot extrusion methods. The evolution of the compositional components of the composite interface was investigated. The density, hardness, and tensile strength of the samples were measured, and the strength/density ratio of the samples was calculated at 150 °C. The results indicate that the tensile strength of coated CF reinforced composite (535 MPa) was increased by 21.3% and 5.7% compared to the tensile strength of 7075 Al alloy (441 MPa) and uncoated CF reinforced composite (506 MPa), respectively. Furthermore, the strength/density ratio of the composite also increased with the addition of TiO2 coating. The enhancement of coating on CF on tensile strength is attributed to the transformation of CF failure mode.

The Use of Hot Melt Extrusion to Prepare a Solid Dispersion of Ibuprofen in a Polymer Matrix.

In this work, we report the use of the hot melt extrusion method in harsh extrusion conditions, i.e., screw rotation speed of 250 rpm, temperature above 100 °C, and two mixing zones, in order to obtain an amorphous dispersion of an active pharmaceutical ingredient (API) that is sparingly soluble in water. As a polymer matrix Eudragit EPO (E-EPO) and as an API ibuprofen (IBU) were used in the research. In addition, the plasticizer Compritol 888 ATO (COM) was tested as a factor potentially improving processing parameters and modifying the IBU release profile. In studies, 25% by weight of IBU, 10% of COM and various extrusion temperatures, i.e., 90, 100, 120, 130, and 140 °C, were used. Hot melt extrusion (HME) temperatures were selected based on the glass transition temperature of the polymer matrix (Tg = 42 °C) and the melting points of IBU (Tm = 76 °C) and COM (Tm = 73 °C), which were tested by differential scanning calorimetry (DSC). The thermal stability of the tested compounds, determined on the basis of measurements carried out by thermogravimetric analysis (TGA), was also taken into account. HME resulted in amorphous E-EPO/IBU solid dispersions and solid dispersions containing a partially crystalline plasticizer in the case of E-EPO/IBU/COM extrudates. Interactions between the components of the extrudate were also studied using infrared spectroscopy (FTIR-ATR). The occurrence of such interactions in the studied system, which improve the stability of the obtained solid polymer dispersions, was confirmed. On the basis of DSC thermograms and XRPD diffractograms, it was found that amorphous solid dispersions were obtained. In addition, their stability was confirmed in accelerated conditions (40 °C, 75% RH) for 28 days and 3 months. The release profiles of prepared tablets showed the release of 40% to 63% of IBU from the tablets within 180 min in artificial gastric juice solution, with the best results obtained for tablets with E-EPO/IBU extrudate prepared at a processing temperature of 140 °C.

Investigation of microstructure, mechanical, and tribological properties of SiC/h-BN/Gr hybrid reinforced Al6061 matrix composites produced by hot extrusion method

In this study, new generation hybrid composite materials were produced by adding SiC, h-BN and Graphite (Gr) to the Al6061 alloy, which has light, corrosion resistant, good formability and weldability properties, giving it abrasion resistance and high strength properties. Five different reinforced and non-reinforced samples were produced, namely Al6061, Al6061%10SiC, Al6061%8SiC%2 h-BN, Al6061%8SiC%2Gr, and Al6061%8SiC%1 h-BN%1Gr, by the hot extrusion method. The density, hardness, microstructure, tensile strength, transverse rupture strength (TRS), and abrasion properties of the synthesized samples are reported in this study. While small agglomerations were observed in the composite materials (10%SiC) produced with a single reinforcement element, it was almost absent in the hybrid composite materials. The hardness of the SiC- and h-BN-containing composites were higher than those of Al6061. The tensile strength and TRS improved relative to those of the reinforcement elements. The addition of h-BN and Gr improved the wear properties.

Synergistically enhanced thermoelectric and mechanical performance of Bi2Te3 via industrial scalable hot extrusion method for cooling and power generation applications

To meet the fast-expanding needs of thermoelectric cooling for high heat flux systems, high-performance thermoelectric devices must be constructed with materials possessing both high thermoelectric properties and mechanical strength. However, the synergistic improvement of thermoelectric and mechanical properties is challenging because of the anisotropic thermal and electrical transports in the layered Van der Waals structure of Bi2Te3, particularly for n-type Bi2(TexSe1-x)3 material. The hot extrusion (HE) technique was believed as the most efficient approach to decoupling the thermoelectric and mechanical properties of Bi2Te3. However, the mechanism and performance of Bi2Te3 materials prepared by the HE method have been elusive. In this work, we developed an industrial-scalable HE technique to manipulate the texture ordering in Bi2Te3 material, achieving simultaneous improvement of thermoelectric and mechanical properties. Compared to SPS samples, our HE samples not only show 19% enhancement of the peak ZT, but also exhibit record high compressive strength of 205 MPa and flexural strength of 79 MPa, respectively. Furthermore, 7-pairs thermoelectric modules were fabricated to verify the cooling and power generation performance. A maximum temperature difference of 72 K (Th = 300 K) compared to 68 K for commercial devices and a maximum conversion efficiency of 5% at Th ≤ 500 K were realized.

Effervescence-induced amorphous solid dispersions with improved drug solubility and dissolution

The current study aimed to investigate drug carrier miscibility in pharmaceutical solid dispersions (SD) and include the effervescent system, i.e. Effervescence-induced amorphous solid dispersions (ESD), to enhance the solubility of a poorly water-soluble Glibenclamide (GLB). Kollidon VA 64, PEG-3350, and Gelucire-50/13 were selected as the water-soluble carriers. The miscibility of the drug-carrier was predicted by molecular dynamics simulation, Hansen solubility parameters, Flory-Huggins theory, and Gibb’s free energy. Solid dispersions were prepared by microwave, solvent evaporation, lyophilization, and Hot Melt Extrusion (HME) methods. The prepared solid dispersions were subjected to solubility, in-vitro dissolution, and other characterization studies. The in-silico and theoretical approach suggested that the selected polymers exhibited better miscibility with GLB. Solid-state characterizations like FTIR and 1H NMR proved the formation of intermolecular hydrogen bonding between the drug and carriers, which was comparatively higher in ESDs than SDs. DSC, PXRD, and microscopic examination of GLB and SDs confirmed the amorphization of GLB, which was higher in ESDs than SDs. Gibb’s free energy concept suggested that the prepared solid dispersions will be stable at room temperature. Ex-vivo intestinal absorption study on optimized ESDs prepared with Kollidon VA64 using the HME technique exhibited a higher flux and permeability coefficient than the pure drug suggesting a better drug delivery. The drug-carrier miscibility was successfully studied in SDs of GLB. The addition of the effervescent agent further enhanced the solubility and dissolution of GLB. Additionally, this might exhibit a better bioavailability, confirmed by ex-vivo intestinal absorption study.

Пористость консолидированных методом газовой экструзии компактов из никелевых нанопорошков

The method of hot gas extrusion differs from other methods of metal pressure treatment in that the processed material is subjected to intense plastic deformation by extrusion under conditions of high isostatic pressure of inert gas and heating in the area of plastic deformation. The method makes it possible to process powder materials, while inevitably there is a need to control mechanical properties by controlling porosity and pressure inside the pores. The paper presents a method for calculating the pressure inside the pores from the minimum size of the closed pore. The pore pressure was evaluated on materials obtained by the consolidation of nickel nanopowders by hot gas extrusion. Quantitative processing of the material cross-section view images obtained by scanning electron microscopy showed that the minimum pore size is 220 nm. The formula for calculating the pore pressure is derived from the formula for calculating the critical pore radius. It takes into account the external impact pressure (the gas pressure during the extrusion process was equal to 400 MPa), the surface tension coefficient and the yield strength of nickel (at the extrusion start temperature of 910 °С), as well as the minimum pore radius. The proposed method for calculating the pressure inside a closed pore will allow us to evaluate the mechanical properties of materials obtained by various methods of powder metallurgy.

Synergistically Enhanced Thermoelectric and Mechanical Performance of Bi2te3 Via Industrial Scalable Hot Extrusion Method for Cooling and Power Generation Applications

Synergistically Enhanced Thermoelectric and Mechanical Performance of Bi2te3 Via Industrial Scalable Hot Extrusion Method for Cooling and Power Generation Applications

Hot extrusion of high carbon steel cone hollow products

The work is devoted to researching a new method of hot direct-reverse extrusion of hollow conical products from high-carbon steel and determinated parameters for technological design. The considered method makes it possible to obtain in one step hollow products with different wall thickness in height, while the wall thickness in the upper part of the product can be greater than the thickness in the bottom part. The dimensions of the initial workpiece are determined by modeling using the finite element method, which ensures the simultaneous flow of metal in the forward and reverse directions during the process of forming the product, which reduces the deformation force. The use of this method also leads to a decrease in the heating of the deforming tool due to a decrease in the contact area of the deformed workpiece with the tool. The strain rate is determined to ensure the temperature interval of extrusion. The dependencies of the force of extrusion, removal of the punch from the deformed workpiece, pushing the product out of the matrix on the movement of the corresponding tool are established. The final shape and dimensions of the product with the distribution of temperature and deformations were found. For the maximum amount of extrusion force, the distributions of specific forces on the contacting surfaces of the punch, matrix, ejector and stress on the volume of the deformed workpiece were found. According to the obtained data, the technology of direct-reverse extrusion can be developed and implemented on universal press equipment, which has high productivity due to the reduction of the number of stamping steps. The design of the stamp for extruding products of certain sizes with forced cooling of the matrix is given.

Nano-Dry-Melting: A Novel Technology for Manufacturing of Pharmaceutical Amorphous Solid Dispersions.

Amorphous solid dispersions (ASD) are one of the most prominent formulation approaches to overcome bioavailability issues that are often presented by new poorly soluble drug candidates. State-of-the art manufacturing techniques include hot melt extrusion and solvent-based methods like spray drying. The high thermal and mechanical shear stress during hot melt extrusion, or the use of an organic solvent during solvent-based methods, are examples of clear drawbacks for those methods, limiting their applicability for certain systems. In this work a novel process technology is introduced, called Nano-Dry-Melting (NDM), which can provide an alternative option for ASD manufacturing. NDM consists of a comminution step in which the drug is ground to nanosize and a drying step provides a complete amorphization of the system at temperatures below the melting point. Two drug–polymer systems were prepared using NDM with a wet media mill and a spray dryer and analyzed regarding their degree of crystallinity using XRD analysis. Feasibility studies were performed with indomethacin and PVP. Furthermore, a “proof-of-concept” study was conducted with niclosamide. The experiments successfully led to amorphous samples at temperatures of about 50 K below the melting point within seconds of heat exposition. With this novel, solvent-free and therefore “green” production technology it is feasible to manufacture ASDs even with those drug candidates that cannot be processed by conventional process technologies.

Physicochemical properties of novel artificial rice produced from sago, arrowroot, and mung bean flour using hot extrusion technology

Due to high rice consumption, food insecurity can negatively impact health; hence, food diversification is considered an appropriate solution for achieving national food security. Artificial rice production using local natural resources will support food sustainability in Indonesia. Sago, arrowroot tuber, and mung bean flours were the main ingredients for producing artificial rice using the hot extrusion method. The effects of composite flour composition and extrusion temperatures on the nutritional value (carbohydrate, protein, fat, and fiber), morphological structure (scanning electron microscopy analysis), thermal stability (differential scanning calorimetry analysis), and acceptability of artificial rice were investigated in this study. The results showed that the best composition was obtained when using a combination of 50% (w/w) sago flour, 30% (w/w) arrowroot tuber flour, and 20% (w/w) mung bean flour. The results of chemical analysis showed that the best artificial rice in this study contained 11.18% water content, 80.27% carbohydrates, 5.14% protein, 0.46% fat, and 5.14% crude fiber. The product contained sufficient fiber and carbohydrate content to be an appropriate staple food. The best extrusion temperature was 85 °C. Moreover, the differential scanning calorimetry profiles showed that artificial rice began undergoing physical changes at approximately 100 °C. Importantly, the color, texture, aroma, and taste of the cooked artificial rice were accepted by consumers.

Effect of reinforcement size hybridization on the wear properties of SiCp/Cu Composites

Abstract Reinforcement size is an important factor that influences the mechanical and tribological properties of particulate reinforced metal matrix composites (PRMMCs). However, relatively few works have been carried out to investigate this issue. There are still many problems to be solved, on the optimum design of PRMMCs of tribological applications. In this work, copper-matrix composites reinforced with SiC particles of mono-size and hybrid-size are fabricated through a powder-metallurgy plus hot-extrusion method. The main purpose is to investigate the effect of reinforcement size hybridization on the dry sliding wear behavior of PRMMCs. The results indicate that finer particles result in a better reinforcing effect and significantly reduce the plastic flow and adhesive transfer of surface and subsurface material. The deeply embedded coarse particles bear the external applied load and resist the plowing effect of the counterpart. The different roles of the particulate components with various sizes promote the exertion of the other’s strengthening function, therefore resulting in higher wear resistance.

The microstructure, mechanical properties, corrosion performance and biocompatibility of hydroxyapatite reinforced ZK61 magnesium-matrix biological composite

Magnesium (Mg)-based composites, as biomaterials, have attracted widespread attention due to their adjustable mechanical properties like elastic modulus, ductility, ultimate tensile strength, and corrosion resistance. In this study, hydroxyapatite (HA) reinforced ZK61 Mg-matrix composites were prepared by powder metallurgy and hot extrusion methods. The influence of the content of HA (10 wt%, 20 wt%, and 30 wt%) on the microstructure, density, mechanical properties, corrosion property and biocompatibility were investigated. The results showed that the density and yield strength of the composites match those of natural bone. Moreover, the composite with 10 % HA (ZK61-10HA) exhibited the best corrosion resistance, as determined by the electrochemical measurement and immersion test in simulated body fluid (SBF) at 37 °C. In addition, the ZK61-10HA composite significantly enhanced the cell viability (≥78 %) compared with ZK61 alloy in vitro testing. It is demonstrated that the mechanical properties, corrosion resistance and biocompatibility of Mg alloy can be effectively controlled by adjusting the content of HA, which suggested that the ZK61-HA composites were promising candidates for degradable implant materials.