Basic Mechanical Properties Research Articles

Research Progress on Electrical Properties of Self-sensing Concrete

In order to effectively avoid the different degrees of impact and damage to the existing buildings and structures, it is particularly important to strengthen the health detection of such structures and facilities, which is also an important research field in the development of green building discipline. Smart concrete is both structural and functional, and has the potential of self-monitoring of concrete structures. This paper reviews the basic concepts of self-sensing concrete, including the research progress of self-sensing concrete materials, and summarizes the classification of different conductive phase materials and their conductive properties. Secondly, the basic mechanical properties and electrical properties of self-sensing concrete are discussed. The factors affecting the perceptual performance of self-sensing concrete considered by different scholars are summarized. It is concluded that few scholars have studied the mechano-electric interaction evaluation mechanism that takes the electrical parameters into account the stress, strain, crack or damage of concrete, and evaluates mechanical properties and crack propagation length through the change of electrical signals. Finally, the importance of self-sensing performance of intelligent concrete is emphasized, and the prospect of future research is put forward.

The Concept of Using 3D Printing Technology in Ceramic Foundry Filter Manufacturing

AbstractThe article presents the concept of using 3D printing technology in ceramic foundry filter manufacturing. They are a crucial component for obtaining an acceptable quality of nickel superalloys by carrying out the process using the precision casting method. Commonly used filters of this type have a number of disadvantages. They are characterized by irregularity of the filtering structure, high brittleness, lack of resistance to mechanical shocks, and impacts of a stream of liquid metal. All these factors create a risk of introducing the material from the damaged filter into the casting mold, which translates into contamination of the casting alloy, and thus the occurrence of casting defects such as nonmetallic inclusions. The hope for a change in this state of affairs is the use of additive manufacturing technology in their production, which by assumption will allow to obtain a product with a repeatable shape, high mechanical resistance, and a specially designed structure regulating the flow of liquid metal into the mold during casting. The suitability of robocasting and binder jetting technology for producing filtration structures was initially assessed. The results have presented the selection of ceramic powder, as well as the development of the composition of the ceramic paste. The parameters of paste preparation and 3D printing individual processes were described. Moreover, the representative microstructures and basic mechanical properties of samples obtained by both of the compared technologies were presented. Furthermore, the final effect of prototype casting filters with a repeatable shape, manufactured with the use of both technologies, was presented, which were transferred for further technological research in a foundry producing critical aircraft engine parts. The possibilities of using each technology in various applications were also discussed.

Effect of Vinyl Acetate, Glass Fibers Contents, and Buffer Space on EVA's Mechanical Property and Shock Absorption Ability.

The aim of the study was to evaluate the mechanical properties and impact absorption capacity of prototype materials comprising ethylene vinyl acetate (EVA) of different hardness reinforced using different amounts of glass fibers (GFs), considering a buffer space. Six prototype materials were made by adding E-GFs (5 and 10 wt%) to EVA with vinyl acetate (VA) contents of 9.4 wt% ("hard" or HA) and 27.5 wt% ("soft" or SO). Durometer hardness and tensile strength tests were performed to evaluate the mechanical properties of the materials. Moreover, an impact test was conducted using a customized pendulum impact tester to assess the impact absorption capacity (with or without a buffer space) of the specimens. The mechanical properties of the prototypes, namely, durometer hardness, Young's modulus, and tensile strength, were significantly higher in the HA group than in the SO group, regardless of the presence or added amount of GFs. The addition of GFs, particularly in a large amount (10 wt%), significantly increased these values. In terms of the impact absorption capacity, the original hardness of the EVA material, that is, its VA content, had a more substantial effect than the presence or absence of GFs and the added amount of GFs. Interestingly, the HA specimens with the buffer space exhibited significantly higher impact absorption capacities than the SO specimens. Meanwhile, the SO specimens without the buffer space exhibited significantly higher impact absorption capacities than the HA specimens. Moreover, regardless of the sample material and impact distance, the buffer space significantly improved impact absorption. In particular, with the buffer space, the impact absorption capacity increased with the added amount of GFs. The basic mechanical properties, including durometer hardness, Young's modulus, and tensile strength, of the EVA prototype were significantly increased by reducing the amount of VA regardless of the presence or added amount of GFs. Adding GFs, particularly in large amounts, significantly increased the values of aforementioned mechanical properties. Impact absorption was significantly affected by the hardness of the original EVA material and enhanced by the addition of the buffer space. The HA specimen had a high shock absorption capacity with the buffer space, and the SO specimen had a high shock absorption capacity without the buffer space. With the buffer space, impact absorption improved with the amount of added GFs.

Coarse-grained molecular dynamic model and wettability simulation of graphite materials

Although progress has been made in high-performance computing, there are still limitations on temporal and spatial scales of molecular dynamic calculations. A major issue in molecular dynamic (MD) simulations is the computational cost, and coarse-grained methods can save computational costs and accelerate calculations by reducing the degrees of freedom in the system. This method takes a selected group of representative atoms in the atomic microstructure as a bead and uses the proportional relationship of atomic scale atomic potentials in MD simulation to define the interaction between beads and solve the motion equation of beads. This article proposed a coarse-grained potential for graphite based on the modification of Airebo potential, with an n3: 1 mapping, and established a corresponding n3: 1 coarse-grained model, where one bead represents the number of n3 atoms. The results indicated that the coarse-grained model well reflected the basic thermal and mechanical properties of graphite. In addition, this article also proposed a coarsening method for the Lennard–Jones (L–J) potential function parameters and established a coarse-grained wetting model with n = 2. The results indicate that the coarse-grained wetting model can effectively predict the wetting performance of copper droplets on graphite in only 60% of the time using the all-atom model. The coarsening potential function and model proposed in this article are also applicable to graphite with rough surfaces. It can be anticipated that coarse-grained molecular dynamics methods will have more applications in the future, as they can handle large-scale calculations more quickly.

3D melt blowing of Elastollan thermoplastic polyurethane for tissue engineering applications: A pilot study

Scaffolds, in addition to being biocompatible, should possess structural and mechanical properties similar to the natural tissues they intend to replace. Many tissue engineering applications require porous 3D scaffolds characterized by unique microfibrous organization and mechanical anisotropy. Manufacturing process principles and process parameter-biomaterial interactions ultimately govern the properties that can be achieved in the scaffold. In this study, we investigate a recently developed nonwoven scaffold fabrication process, 3D melt blowing (3DMB), for processing Elastollan®, a thermoplastic polyurethane with basic mechanical properties suitable for musculoskeletal tissue engineering. The range of feasible processing parameters was screened and the effects of two sets of critical process parameters (fiber deposition offset and surface velocity of the collector) that produced contrasting scaffold morphologies were assessed. Results showed that scaffolds of Group B that were fabricated at the higher fiber deposition offset (90 %) and higher surface velocity of the collector (6 × 105 mm/min) possessed significantly smaller fiber diameter and higher porosity and degree of fiber alignment along the principal direction of collector rotation during 3DMB (all p < 0.05) compared to Group A scaffolds (fabricated at 50 % offset and 1 × 105 mm/min surface velocity). Although both groups possessed similar tensile stiffness, the elongation at failure was significantly different (p < 0.0001). The higher elongation at failure of Group B correlated with the higher degree of fiber alignment in these scaffolds. In contrast, the more isotropic fibrous organization of Group A contributed to their higher compressive stiffness (p = 0.004). The introduction of NaOH treatment to improve hydrophilicity of the scaffolds resulted in a significant reduction of tensile stiffness of Group A (p < 0.05) but not Group B. This treatment did not significantly affect the elongation at failure or compressive stiffness of both groups. With NaOH-treatment, both groups demonstrated good biocompatibility when seeded with fibroblast cells over 14 days. This study confirms the ability to fabricate via 3DMB, biocompatible, micro-fibrous, Elastollan scaffolds relevant for musculoskeletal tissue engineering.

Advances in Highly Ductile Concrete Research.

In recent years, high-ductility concrete (HDC) has gradually become popular in the construction industry because of its excellent ductility and crack resistance. Concrete itself is a kind of building material with poor tensile properties, and it is necessary to add a large number of steel bars to improve its tensile properties, which increases the construction cost of buildings. However, most of the research studies on high-ductility concrete are scattered. In this paper, the basic mechanical properties of high-ductility concrete and the effects of dry and wet cycles, freeze-thaw cycles, and salt erosion on the durability of high-ductility concrete are obtained by comprehensive analysis. The results show that the tensile properties of HDC can be significantly improved by adding appropriate fiber. When the volume fraction of steel fiber is 2.0%, the splitting tensile strength of concrete is increased by 98.3%. The crack width threshold of concrete chloride erosion is 55-80 μm, and when the crack width threshold is exceeded, the diffusion of CL-1 will be accelerated, and the HDC can control the crack within the threshold, thereby improving the durability of the concrete. Finally, the current research status of high-ductility concrete is analyzed, and the future development of high-ductility concrete is proposed.

Basic Mechanical Properties of Self-Compacting Concrete Prepared with Aeolian Sand and Recycled Coarse Aggregate

To protect the environment and reduce the consumption of natural resources, this study investigated the performance of self-compacting concrete (SCC) utilizing aeolian sand (AS) as a replacement for fine aggregate and recycled coarse aggregate (RCA) as a replacement for natural coarse aggregate. Twelve mixing ratios were prepared, with AS replacement ratios at 0, 20%, 40%, and 60% and RCA replacement ratios at 0, 25%, and 50%. The evaluation primarily focused on workability, uniaxial compressive strength, split tensile strength, stress–strain curve, modulus of elasticity, and axial compressive strength. The results indicated that both AS and RCA can enhance the performance of SCC at appropriate replacement ratios, and a 20% AS and 50% RCA replacement ratio significantly improved the performance of SCC. In addition, the effects of AS and RCA replacements on SCC were evaluated by several performance indexes, which provides a basis for subsequent experimental studies and demonstrates the feasibility of incorporating AS and RCA into SCC.

Finite Element Method Simulation Study on the Temperature Field of Mass Concrete with Phase Change Material

Phase change materials can be converted between solid, liquid, and gaseous states, absorbing or releasing a large amount of heat. PCM is incorporated into concrete to adjust the temperature difference between inside and outside of concrete, which can reduce cracking. In this paper, the finite element analysis method is used to establish the model of an ordinary concrete structure, doped with phase change materials, on the basis of mechanical properties and a temperature regulation test performed by calculating the adiabatic temperature rise of concrete with different contents of composite phase change material, comparing the experimental and simulation results of the ordinary concrete structures with phase change materials, and analyzing the change in temperature field of the concrete structure with the content of self-prepared composite phase change materials. It is found that the addition of self-prepared composite phase change materials reduces the temperature peak of the concrete structure in the stage of hydration heat and delays the time taken to reach the temperature peak. Then, the temperature field of the phase change mass concrete structure is established, and the influence law of composite phase change material admixture on the temperature field of mass concrete is summarized through the time–temperature curves of different admixture amounts and positions so as to predict the possibility of cracks in mass concrete.

Compressive mechanical performance and microscopic mechanism of basalt fiber-reinforced recycled aggregate concrete after elevated temperature exposure

To improve the mechanical properties of recycled aggregate concrete (RAC) after elevated temperature exposure, this study employed basalt fiber (BF) as reinforcing material incorporated into RAC. The replacement ratio of recycled coarse aggregate (RCA), the content of BF, and the temperature were utilized as the change parameters, and 27 groups of basalt fiber reinforced recycled aggregate concrete (BFRRC) specimens were designed to carry out the compressive strength test after elevated temperature. The heating rate was set at 2.5 °C/min to avoid any possible explosion of the cylindrical specimen during the heating process. The specimens were treated for 6h after reaching the desired temperature, and then the furnace door was opened for natural cooling to room temperature. After observing the physical properties of the specimens, the basic mechanical properties test was carried out, and the microscopic mechanism was analyzed in depth by electron microscopy. The results showed that the defects inherent in RCA and the continuous accumulation of elevated temperature damage gradually reduced the compressive mechanical performance of BFRRC but that the toughening and cracking-resistance action of BF effectively improved the compressive mechanical performance of BFRRC. BF enhanced the compressive mechanical performance of RAC through bridging and crack resistance action mechanisms, but the higher the temperature became, the smaller the enhancement was. The cube compressive strength and axial compressive strength of the specimens decreased with the increase of temperature. With the same replacement ratio and fiber dosage, increasing the temperature from 300 °C to 600 °C, the decrease in cube compressive strength and axial compressive strength was the most significant, which was between 36.4 %–48.1 % and 51.1 %–62.6 %, respectively.

Treatments Technology and Mechanisms of East Asia Black Cotton Soil

The East Asia black cotton soil (BCS) cannot be used as embankment filling directly due to its high clay content, liquid limit, plasticity index, and low CBR strength (CBR &lt; 3%). This study evaluates the effects of treating East Asia BCS with lime, volcanic ash, or a combination of both on its engineering properties. Experiments were conducted to analyze the basic physical properties, swelling characteristics, and mechanical properties of the treated soil. Results indicate that lime addition significantly reduces the free swelling rate, improves limit moisture content, increases optimum moisture content, decreases maximum dry density, and enhances CBR value. Although volcanic ash also improves BCS performance, its effects are less pronounced than those of lime. The combined treatment with lime and volcanic ash exhibits superior performance, greatly reducing expansion potential and significantly increasing soil strength. Specifically, a mixture of 3% lime and 15% volcanic ash optimizes the liquid limit, plasticity index, and CBR value to 49.2%, 23.8, and 24.7%, respectively, meeting the JTG D30-2015 requirements and reducing construction costs. The treatment mechanisms involve hydration exothermic reactions, volcanic ash reactions, and semipermeable membrane effects, which collectively enhance the soil’s properties by producing dense, high-strength compounds.

Study of glutaraldehyde-treated crosslinking protocols for placental decellularized matrix sponges

Extracellular matrix sponge plays a positive role in the wound healing process, but requires proper structural strength and biological properties. In order to solve the problem of lyophilized dissolution of placenta-derived sponge, glutaraldehyde was selected for use in the lyophilized crosslinking process to improve the necessary mechanical properties of the placental decellularization matrix sponge. In this work, the effects of three cross-linking methods of glutaraldehyde (Fumigation/Slurry/Soak) on the physical and biological characteristics of lyophilised sponges derived from placental acellular matrix was investigated. The results revealed that the sponges prepared by all three cross-linking methods exhibited excellent blood coagulation ability and stability. The fumigation cross-linked sponges had good mechanical properties of soft and elastic, and safe cytotoxicity, which were more compatible with the requirements of wound dressing. The slurry cross-linking process was uneven due to the stacked matrix materials, resulting in obvious cracks and easy to break when stretching. The soak crosslinking can obtain a higher degree of crosslinking, which leads to the poor antibacterial performance and the harder sponge scaffold with larger elastic modulus and smaller tensile ratio. In general, fumigation cross-linking is more suitable for the preparation of acellular sponge derived from placenta materials which can maintain basic mechanical properties and biological validity.

TRIBOLOGICAL AND MECHANICAL CHARACTERIZATION OF AL6060/SI3N4/BN HYBRID ALUMINIUM METAL MATRIX COMPOSITES

In recent years, aluminium-based composites have emerged as preferable substitutes for conventional aluminium alloys in various contemporary applications, like the aerospace and automotive industries. This shift can be attributed to their enhanced characteristics and superior properties. Improved strength-to-weight ratio, reduced thermal expansion, and superior wear resistance are just a few of the benefits. Several researchers have created aluminium metal matrix composites (AMMCs) by combining various ceramic reinforcing elements with aluminium alloys. Ceramic reinforcing materials increase the strength, hardness, and wear resistance. The aim was to enhance the mechanical and wear characteristics of a composite material, i.e., to find the mechanical characteristics of an Al6060/BN hybrid alloy, such as tensile strength, impact, hardness, etc. The composites were developed by incorporating silicon nitride (Si3N4), a hard ceramic material, as the main reinforcing component, along with boron nitride (BN), a solid lubricant, as the secondary reinforcement. The stir-casting technique was employed to fabricate aluminium metal matrix composites with varying weight fractions (0, 5, and 10) w/% of Si3N4 and BN. Tensile and hardness tests were conducted to analyse the basic mechanical properties of the resulting composites.

A novel high-molecule inorganic composite material with excellent elasticity and toughness used in tunnel isolation – Material design and basic mechanical properties

Cross-sea engineering plays a crucial role in the advancement of human society. However, due to geological constraints, cross-sea tunnels, as the primary infrastructure of such projects, are prone to instability and compromised safety during severe seismic events. Existing tunnel isolation materials face challenges such as susceptibility to cracking and difficulty in withstanding cyclic loads. Therefore, the development of tunnel isolation materials with strong elasticity and toughness is of significant importance. This study addresses this need by developing a high-elasticity, super-tough polymer-inorganic composite tunnel isolation material. Drawing on the microphase separation structure of polyurethane elastomers and polymer-based composite material interfaces, the innovative material was synthesized and characterized. Uniaxial and cyclic loading tests were conducted to evaluate its mechanical behavior, while scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to examine filler-polyurethane matrix bonding, microstructural changes, and interface modifications. These analyses revealed the synergistic mechanisms of the composite components. Results demonstrated significant enhancements in compressive performance and unit volume energy consumption, with the elastic modulus controllable at approximately 10 MPa, and the strain recovery rate stabilizing at 82 %. Moreover, a mix design model was developed for predicting compressive strength, elastic modulus, tensile strength, and elongation at break concerning PVA fiber content.

The Effect of Artificial Ageing on the Changes in Selected Properties of Organic Coated Sheets.

This contribution presents the results of research focused on changes in selected properties of organic-coated steel sheets in a corrosive environment of salt mist. The aim of this study was to characterise coated sheets and to analyse the influence of elevated temperature on changes in their selected properties. The methodology and experiments were chosen to simulate the accelerated ageing and to evaluate the surface of organic-coated steel sheets. During the research, the effect of artificial ageing due to increased temperature on changes in mechanical properties of coated sheets was monitored, which were determined by tensile testing according to STN EN 10002-1. The fracture surface of the test samples was analysed using a SEM. The following observations were made for the evaluation of coating by cross-cut tests according to EN ISO 2409. Corrosion tests were carried out by conducting salt spray corrosion tests according to EN ISO 9227. The test specimens were artificially sectioned using a laser beam. The results of the research experiments confirmed the assumption that the utilisation of the laser beam was convenient for the creation cross-cut test of the material. After the ageing test, only small significant changes in the basic mechanical properties of the tested materials were observed. It is necessary to take into account that there were changes in the appearance of the coating. The cross-cut test confirmed the results that the plastic-coated sheets could be utilised in salt corrosion environments.

Failure mechanisms and reinforcement support of soft rock roadway in deep extra-thick coal seam: A case study

The soft rock roadway in deep extra-thick coal seam is prone to large deformation disaster. In order to solve this problem effectively, taking the W3101 coalface of Xiao’kang coal mine as the engineering background, the failure mechanisms and the corresponding control technology were investigated by the methods of laboratory test, numerical simulation and field measurement. First, a series of tests were carried out on the basic mechanical properties of rock mass, in-situ stress and loose zone, and it was found that the failure mechanisms of soft rock roadway in deep extra-thick coal seam are poor lithology of surrounding rock, high in-situ stress, large loose circle and unreasonable original support. Then, based on the supporting mechanisms of grouting cable and concrete-filled steel tube (CFST) of bottom angle, a new collaborative reinforcement support (CRS) technology combining the two was proposed. Next, the numerical simulation shows that the CRS technology has good applicability in controlling large deformation of soft rock roadway in deep extra-thick coal seam. Finally, to exhibit the engineering application effect of the proposed CRS scheme, it was also applied in Xiao’kang coal mine. Comparing to the controlling effect of original support scheme, it can be seen that the average deformation of soft rock roadway reduces by 73.2 % under the proposed CRS scheme, and the steel arch frame of bottom angle is slightly deformed. Meanwhile, it is found that the grouts diffusion radius is nearly 1.21 m, and the deepest diffusion depth is 4.25 m, which also indicates again that the feasibility of the proposed CRS scheme in controlling large deformation of soft rock roadway in deep extra-thick coal seam.

Analysis of the Tensile Properties and Probabilistic Characteristics of Large-Tow Carbon Fiber-Reinforced Polymer Composites.

Large-tow carbon fiber-reinforced polymer composites (CFRP) have great application potential in civil engineering due to their low price, but their basic mechanical properties are still unclear. The tensile properties of large-tow CFRP rods and plates were investigated in this study. First, the tensile properties of unidirectional CFRP rods and plates were studied, and the test results of the relevant mechanical properties were statistically analyzed. The tensile strength of the CFRP rod and plate are 2005.97 MPa and 2069.48 MPa. Second, the surface of the test specimens after failure was observed using a scanning electron microscope to analyze the type of failure and damage evolution process. Finally, the probabilistic characteristics of the mechanical properties were analyzed using normal, lognormal, and Weibull distributions for parameter fitting. Quasi-optimality tests were performed, and a probability distribution model was proposed for the mechanical properties of large-tow CFRP rods and plates.

Effects of Polyethylene Terephthalate Particle Size on the Performance of Engineered Cementitious Composites.

This study utilizes polyethylene terephthalate (PET) aggregate of different particle sizes (21 μm, 107 μm, and 244 μm) to replace natural aggregate in the preparation of PET-modified engineered cementitious composite (P-ECC). The impact of PET aggregate particle size on the performance of P-ECC is examined herein from micro to macro levels. The focus is on the influence patterns and mechanisms of P-ECC's workability, its basic mechanical properties, and its microstructure. Crack parameters are processed to quantitatively analyze crack development patterns. Using microscopic techniques, the interfacial transition zone (ITZ) between different aggregates and the cement matrix is compared, and the failure mechanism of P-ECC is analyzed. The results show that the incorporation of PET aggregate can improve P-ECC's workability and reduce its self-weight, but incorporation has a negative effect on compressive strength. Additionally, the particle size of PET aggregate significantly affects the uniaxial tensile performance of P-ECC. Compared to conventional ECC, the tensile strength of P-S (21 μm PET) increased the most markedly (18.1%), and the ultimate tensile strain of P-M (107 μm PET) increased the most markedly (66.0%), with both demonstrating good crack control and deformation energy dissipation capabilities. The uniaxial tensile performance of P-L (244 μm PET) was lower than that of the conventional ECC. Microscopic tests revealed that the increase in PET aggregate particle size enlarges the ITZ width and its surrounding pores. Appropriate pore enlargement is beneficial for enhancing tensile ductility, while excessive pores have a negative effect. The study results reveal the impact of PET aggregate particle size on the performance of P-ECC, providing new insights for the performance optimization of ECC.

Preparing autoclaved aerated concrete using molybdenum tailings

Due to the background of the difficulty in molybdenum tailings disposal and the shortage of siliceous sand for autoclaved aerated concrete (AAC), molybdenum tailings were used for AAC production in this study. The main process parameters including the quicklime-cement ratio (Q/C), the molar calcium-silicon ratio (C/S), the water-solid materials ratio (W/S), the aluminum powder dosage, the autoclaved temperature, and the autoclaved time, on the basic physical and mechanical properties, such as slurry fluidity, foaming curves, dry density, and mechanical strength, were investigated. Moreover, the hydration production and microstructure were analyzed by XRD, thermal analysis, and SEM. The results showed that molybdenum tailings AAC (MAAC) with a dry density and compressive strength of 641.3 kg/m3 and 3.89 MPa, respectively, were successfully obtained under the following optimal conditions: molybdenum tailings, 60.13 %; quicklime 13.02 %; cement 26.03 %; gypsum 1 %; W/S 0.52; aluminum powder 0.07 %; autoclaved temperature 190 °C; autoclaved time 8h. The main mineral components of quartz and feldspar in the molybdenum tailings participated in the autoclaved reaction, while biotite did not. The main hydration products in the MAAC were flocculent C–S–H gel, plate-like, narrow plate-like, and grass-like tobermorite. The C–S–H gel and tobermorite bond each other and made the pore walls much denser, and were the main contributors to the MAAC strength.

Silk fibroin biohydrogel composites for loading and ordered release of multiple active ingredients with enhanced bioactivity

Bioactive hydrogels are currently receiving significant attention. In this study, silk fibroin tyramine-modified gelatin hydrogels (SF-TG) with varying degrees of tyramine root substitution were explored. The physicochemical property and biocompatibility of low degree of substitution tyramine-modified gelatin hydrogel (SF-LTG) and high degree of substitution tyramine-modified gelatin hydrogel (SF-HTG) were compared. The results showed that SF-LTG possessed better mechanical property and higher biocompatibility. Thus, SF-LTG was selected as a bioactive matrix and loaded with basic fibroblast growth factor (bFGF); subsequently, curcumin-coupled chitosan rods (CCCRs-EGF) enriched with epidermal growth factor (EGF) were added to obtain SF-LTG-bFGF@CCCRs-EGF hydrogels. The results showed that SF-LTG-bFGF@CCCRs-EGF retained the basic structural and mechanical properties of the SF-LTG matrix gel material and underwent multiple loading and orderly release with different activities while displaying antioxidant, anti-inflammatory, antimicrobial, and pro-cellular proliferation activities and orderly regulation of activity during wound healing. Therefore, the SF-LTG-bFGF@CCCRs-EGF hydrogel is of great value in healing complex wounds.

LIGNOCELLULOSIC LINERS BASED ON WOOD WOOL

Basic physical and mechanical properties of lignocellulosic liners up to 1.5 mm thick with a compact and non-crumbling surface based on wood wool and thermoplastic water based glues were determined. PVAc and starch glue with a high proportion of water content were used. The dry mat was pressed gradually under high pressure up to 28 MPa and a temperature of around 190°C with the release of steam. Tests according to the CEPI (Confederation of European Paper Industries) standards were adopted. Procedures for tensile strength according to ISO 1924-2 (2008), Burst strength according to ISO 2758 (2014), puncture according to ASTM D781-68 (1973), water absorption according to ISO 5637 (1989) and porosity according to TAPPI Test method T460 were applied.