Plastination Research Articles

Study on the fabrication and mechanical properties of SiCp/SiC gradient lattice structure based on selective laser sintering technology

ABSTRACT Conventional uniform lattice structures are subject to non-uniform loads or concentrated loads alternating back and forth during service, which can no longer meet the refinement requirements. In this paper, SiCp/SiC gradient lattice structures are prepared by selective laser sintering (SLS) technology and polymer impregnation pyrolysis (PIP) process, and compression standard specimens with different tilt angles are prepared according to the structural model by changing the printing direction, to analyze the influence of the anisotropic properties of the materials due to the SLS molding technology on the load-bearing behaviour of the core rod, and to further study the mechanical properties of the gradient lattice structures and the Failure behaviour. The results show that: with the increase of the angle of printing direction, the compression performance of the densification specimen decreases gradually; the compression strength of the gradient lattice structure is 13.95 MPa. During compression, the core rods with tilt angles of 60° and 75° mainly exhibit shear failure and crushing failure, respectively. The theoretical and simulated compression strengths were 16.08 and 16.32 MPa, respectively. This paper provides a new insight into the research and application of gradient lattice structures.

Impregnation, dehydration and crosslinking of responsive organoboron polymer to generate smart gating membrane for multimolecular gradient separation

Responsive materials have garnered increasing attention in the membrane separation field. However, fabricating smart gating membranes with tunable pore sizes to separate complex systems remains challenging. Herein, gating membranes with boroxine skeleton and temperature-tunable pores were successfully fabricated by fixing lower critical solution temperature (LCST)-type organoboron polymers (poly(N-isopropylacrylamide-co-glycidyl methacrylate/3-aminophenylboronic acid), PNG-APBA) onto the membrane surface via "impregnation-dehydration-crosslinking" strategy. The conformational behavior of the NIPAM-containing polymer chains (shrinking above LCST-stretching below LCST) serves as a functional gate, enabling the membranes to achieve reversibly tunable pore sizes and surface properties. The modified membranes exhibit gradient separation capabilities for small/medium/large molecules in complex polymer systems through temperature-tunable channels. The tunable pores also provided a potential tool for the high-selectivity separation of mixed proteins, such as lysozyme (LZM) and hemoglobin (Hb). Notably, the conformational behavior of the polymer chains endowed the membranes with excellent self-cleaning ability (FRR> 99.5%), while the boroxine network enhanced the grafting stability of the polymer chains, ensuring effective reversibility and repeatability of membranes.

Functional Insights in PLS3-Mediated Osteogenic Regulation.

Plastin-3 (PLS3) encodes T-plastin, an actin-bundling protein mediating the formation of actin filaments by which numerous cellular processes are regulated. Loss-of-function genetic defects in PLS3 are reported to cause X-linked osteoporosis and childhood-onset fractures. However, the molecular etiology of PLS3 remains elusive. Functional compensation by actin-bundling proteins ACTN1, ACTN4, and FSCN1 was investigated in zebrafish following morpholino-mediated pls3 knockdown. Primary dermal fibroblasts from six patients with a PLS3 variant were also used to examine expression of these proteins during osteogenic differentiation. In addition, Pls3 knockdown in the murine MLO-Y4 cell line was employed to provide insights in global gene expression. Our results showed that ACTN1 and ACTN4 can rescue the skeletal deformities in zebrafish after pls3 knockdown, but this was inadequate for FSCN1. Patients' fibroblasts showed the same osteogenic transdifferentiation ability as healthy donors. RNA-seq results showed differential expression in Wnt1, Nos1ap, and Myh3 after Pls3 knockdown in MLO-Y4 cells, which were also associated with the Wnt and Th17 cell differentiation pathways. Moreover, WNT2 was significantly increased in patient osteoblast-like cells compared to healthy donors. Altogether, our findings in different bone cell types indicate that the mechanism of PLS3-related pathology extends beyond actin-bundling proteins, implicating broader pathways of bone metabolism.

MATERIALS FOR IMPREGNATION OF POROUS METALLIZATION THERMAL SPRAYED ANTICORROSIVE COATINGS OF SUBMERSIBLE OILFIELD EQUIPMENT. Part 2

The use of thermal sprayed coatings in aggressive petroleum fluid is limited due to the presence of porosity in it. When fluid gets into the pores, corrosion processes begin and thereby reduce the protective properties of thermal sprayed coating. The application of impregnating compounds makes it possible to seal open porosity and prevent the penetration of aggressive environments into the metal under the coating, thereby increasing the barrier properties of the coating. Epoxy polymer materials demonstrate high corrosion resistance and are widely used in the oil industry to protect pipeline elements and submersible oilfield equipment during operation. The second part of the article presents both traditional polymer impregnation materials and new compositions with magnetic nanoparticles and nanocarbon fillers (fullerenes, graphene and nanotubes) which, due to the created magnetic field, are evenly distributed throughout the polymer matrix and increase the crack resistance of the matrix. Polymer impregnating materials of both domestic and foreign production based on phenolic, epoxy, acrylic and urethane resins, modes of their application, conditions of their operation and temperature restrictions are considered. The possibility of using existing independent anti-corrosion polymer coatings as an impregnation of metallization thermal sprayed layers is discussed. Their advantages and disadvantages are highlighted. Examples of self-healing polymer matrices are given that are capable of recognizing the onset of corrosion processes and responding by releasing appropriate effective self-healing agents. The possibility of adding inhibitors to the polymer matrix is described, which helps to increase the anti-corrosion properties of the coating and thereby increase the time between failures of equipment. The issue of normative regulation of the use of impregnating compositions in various fields of industry is covered. The main directions of research that need to be carried out to solve the problem of using polymer materials as the most promising impregnating compositions for anti-corrosion thermal sprayed coatings of submersible oilfield equipment have been identified. First of all, it is necessary to reduce the viscosity of polymer resins to increase their penetration into open pores.

Microstructure evolution and failure mechanism of 2D Cf/SiBCN–ZrB2 composite at elevated temperatures

SiBCN ceramic has already been widely used in the thermal insulation field. To further enhance their mechanical properties in high-temperature environments, the preparation of SiBCN and ZrB2 based pyrolytic carbon (PyC) modified carbon fiber reinforced composite, i.e., 2D Cf/SiBCN–ZrB2, was proposed in this study. By using five cycles of polymer impregnation and pyrolysis (PIP), the composite could be synthesized with a high flexural strength at room temperature, i.e., 275 ± 15 MPa. To understand the evolution of the microstructure caused by high temperatures and their influences on the mechanical properties, the composite samples were heat treated at 1200, 1400, 1600, and 1800 °C for 2 h, respectively. Comparing the flexural strengths of the samples before and after the heat treatments, and meanwhile combining the advanced microstructural characterizations, it was found that the composite was stable when the treating temperature was below 1400 °C, i.e., the flexural strength was 250 ± 15 MPa with a strength retention rate of over 90 %. However, once the temperature was above 1600 °C, due to the crystallization of SiBCN–ZrB2 matrix, the pyrolysis of PyC interfaces, the carbothermal reduction reaction and the erosion of carbon fibers, the mechanical properties of the composite would reduce to 74 ± 9 MPa. This study provides a new method for preparing 2D Cf/SiBCN–ZrB2, which reduces the number of PIP cycles of composite materials and enables rapid prototyping of composite materials. Additionally, this research can help materials scientists understand the mechanical properties of 2D Cf/SiBCN–ZrB2 composite materials in high-temperature environments and the evolution of their microstructure, identifying the range of application temperatures for 2D Cf/SiBCN–ZrB2.

Further understanding of the improved mechanical properties for SiCf/BN/SiC composites prepared by CVI+PIP hybrid technique: Application of micro-mechanical methods

In this work, a chemical vapor infiltration (CVI) combined with polymer impregnation and pyrolysis (PIP) technique was used to prepare high-performance SiCf/BN/SiC composites. Compared with the SiCf/BN/SiC composite fabricated by conventional PIP technique, the SiCf/BN/SiC composite fabricated by CVI + PIP hybrid technique showed the significantly improved flexural strength and toughness. The microstructures, macro-mechanical and micro-mechanical properties were systematically investigated and compared. By applying various micro-mechanical tests (fiber push-in, micropillar compression and micropillar splitting), the in-situ mechanical parameters of different micro-zones for SiCf/BN/SiC composites were obtained accurately. Based on the characterization results of microstructures and micro-mechanical properties, the corresponding toughening process was analyzed in combination of the classical He-Hutchinson criterion. The results indicate that the micro-mechanical test methods can provide accurate and effective data for the analysis of toughening and fracture process, presenting great potentials in the further understanding of the improvement in mechanical properties of ceramic matrix composites.

Transforming oil palm trunk waste into high-performance lightweight materials

Addressing the growing demand for efficient sustainable materials, this study presents the development of a high-performance lightweight material utilizing oil palm trunk—a waste product from oil palm (Elaeis guineensis) cultivation. The proposed novel process involves polymer impregnation of sawn oil palm trunk under ambient conditions for 24-h soaking intervals, resulting in loadings of polymethyl methacrylate ranging from 0 wt% to 220 wt%. Subsequent polymerization at temperatures (90 and 103°C) commonly employed in the wood drying industry enhances the water resistance of the material, making it comparable to that of commercially available timber. Remarkably, the treated oil palm lumber attained a maximum density of approximately 450 kg/m3, making it a lightweight material. Furthermore, the impregnation process significantly improves the decay resistance of this product under natural weathering conditions. The treated oil palm lumber also displayed an increase of up to five times in the bending and compressive strength. Interestingly, a linear correlation between these enhanced properties and the density of this material was observed. This suggests the possibility of systematically producing the high-performance oil palm lumber through a simple and industry-accessible process.

Plastin 3 Expression in Circulating Tumor Cells as a Predictor of Cancer Status in Patients with Prostate Cancer

Abstract Objectives To identify the role of plastin3 (PLS3) expression in circulating tumor cells (CTCs) of early stage prostate cancer (PCa). Materials and Methods CTCs were collected from 23 prostate cancer patients based on cell surface markers targeting prostate cancer by V-BioChip. Condition of Plastin3 expression and correlations to the prostate cancer were also analyzed. Results Of the 23 patients with prostate cancer, total CTCs (CK+ or PLS3+) were found in 11 patients and PLS3+ CTCs were detected in 10 patients. When the cohort was stratified by risk group, 90% of the high-risk patients were found to have PLS3+ circulating tumor cells (9/10 patients). However, only 15.4% of low/intermediate-risk patients had PLS3+ circulating tumor cells (2/13 patients). The number of PLS3+ CTCs was higher in the high-risk group. Conclusions The expression of PLS3 in CTCs is associated with prostate cancer risk. Further study of PLS3+ CTCs for prognosis prediction is required for clinical application in prostate cancer patients.

Enhancing concrete durability with polymer impregnation: A comparative study of corrosion and freeze-thaw resistance

This study explores the efficacy of Polymer Concrete (PC) in bolstering the durability and performance of concrete structures under diverse environmental conditions. Three variants of PC were examined: Polymer Impregnated Concrete (PIC), Polymer Portland Cement Concrete (PPCC), and Polymer Concrete (PC). The study focused on their resistance to corrosion and freeze-thaw cycles. The research also delved into the protective influence of various polymers, including silicone and epoxy, on both concrete and steel. The findings revealed that PIC surpassed other PC types in terms of corrosion and freeze-thaw resistance, while PC and PPCC necessitate further improvements. Silicone emerged as the most potent polymer for enhancing the durability of concrete and steel. PIC, exhibiting superior compressive strength and durability compared to control samples, was proposed as an apt material for construction projects in cold and corrosive environments. The PIC samples, composed of polymer, silicone, and polyvinyl acetate, displayed a significant improvement in their corrosion potential. Over a 90-day period, these samples showed a reduction of approximately 70 units, resulting in a value of 560 mV. When juxtaposed with other PC variants tested in the study, the PIC samples demonstrated superior corrosion resistance. The PIC samples also exhibited a higher average compressive strength and improved frost resistance compared to the PPCC and PC samples. The strength of PIC samples was 16.7% and 14.3% higher than control before and after cycles, respectively. Conversely, PPCC and PC samples displayed lower strengths than control, with PC samples recording the lowest. The strength reduction due to freeze-thaw cycles was least in PIC samples. In conclusion, PIC holds promise as a material for enhancing the durability and performance of concrete structures. Further research is recommended to assess its cost-effectiveness and environmental impact.

Experimental study and theoretical analysis on tensile properties of concrete reinforced with different polymer-impregnated basalt textiles

Textile-reinforced concrete (TRC) has become a new material for strengthening and constructing structures. The mechanical properties of TRC are significantly influenced by the polymer impregnation of textile. However, the influencing mechanisms of different polymers on the mechanical properties of TRC remain unclear. In this study, the effects of polymer impregnations on tensile behavior of basalt textile reinforced concrete (BTRC) were investigated. The results showed that the epoxy resin-impregnated basalt textile outperformed other polymer-impregnated textiles in improving the tensile properties of concrete, exhibiting an ultimate stress 48%–110% higher than other samples. Increasing the textile layers number from 1 to 3 improved the ultimate stress and energy consumption, with the most notable improvements observed at 146% and 173%, respectively, for samples reinforced with epoxy resin-impregnated textiles. However, the increased textile layers reduced the ultimate strain and fiber strength utilization efficiency due to the inconsistent stress transfer among multi-layer textiles. Only epoxy resin-impregnated textiles reinforced samples exhibited a complete three-stage variation in the tensile stress-strain curve, where the stress fluctuations in the post-cracking stage were attributed to the multiple concrete cracks. In contrast, other polymer-impregnated textile-reinforced concrete samples experienced stress fluctuations in post-cracking stage primarily due to the textile slippage, inconsistent textile fractures, and propagation of initial crack. Furthermore, the epoxy resin-impregnated textiles' superior tensile strength and excellent bond with concrete contributed to reduced stress fluctuation range and smaller stress drop after initial cracking. Finally, an optimized tensile model with high accuracy was proposed to describe the tensile response of polymer-impregnated basalt textile reinforced concrete.

Friction Evolution of Graphite Bearing Impregnated with Polymer Subjected to Vibration Fretting at High Temperature

To address friction and wear challenges in dry contacts, manufacturers often employ self-lubricating materials. Graphite and its derivatives stand out as particularly suitable due to their exceptional tribological properties. However, under intense friction conditions, graphite can experience a decline in lubricating efficiency due to severe abrasive wear. This abrasive damage results in elevated activated carbon surfaces with increased surface energy, fostering greater adhesion between sliding surfaces. The low friction coefficient of graphite is not an inherent property but rather a consequence of water vapor adsorption by the material. Beyond 150 °C, desorption of the vapor occurs, leading to a transition in the friction coefficient from µ = 0.1 to µ = 0.6. To address this issue, impregnation solutions for self-lubricating materials have been developed, with various compositions tailored to specific objectives. Common types include molybdenum disulfide, soft metals and polymers. In this predominantly experimental study, the impact of polymer impregnation on the evolution of friction force and wear rate in graphite material bearings subjected to a dry fretting contact under severe thermal stresses at 270 °C was investigated. Additionally, the mechanical stresses in the bearings throughout different phases of our tests were analyzed using a numerical model.

Flexible transparent wood with reversible photoresponsive property

Flexible photoresponsive transparent wood (FPTW) has potential applications in electronic equipment, sensors, and other fields. In this study, flexible and photoresponsive transparent wood was synthesized through the impregnation process, utilizing epoxy resin and a spiropyran solution. This process endowed the wood with intelligent response and flexible capabilities. Scanning electron microscopy (SEM) revealed the impregnation of the flexible polymer into the porous structure of natural wood. Further validation was conducted to affirm the sample responds to ultraviolet light, employing analyses of infrared spectroscopy, UV–visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). Through the measurement of chromaticity parameters, encompassing lightness (L*), redness (a*), yellowness (b*), and total color difference (ΔE*), before and after UV irradiation, it is indicated that the wooden samples manifest commendable photoresponsive properties. Testing the fluorescence properties of the samples, the spiropyran completed the opened-loop and closed-loop transitions under irradiation with UV and visible light. In addition, the FPTW has excellent mechanical properties, with a tensile strength of 0.98 GPa and an elastic modulus of 0.65 GPa.

Mechanical properties of SiCf/SiC composites with h‐BN interphase formed by the electrophoretic deposition method

AbstractSilicon carbide fiber–reinforced silicon carbide (SiCf/SiC) composites have been expected to be used as next‐generation heat resistant structural materials with high reliability. The fiber/matrix interface for SiCf/SiC composites plays an important role for toughening and strengthening, and it is important to form the optimal interphase for SiCf/SiC composites. In this study, hexagonal‐boron nitride (h‐BN), which shows better oxidation resistance than carbon, was selected as the interphase for SiCf/SiC composites, and h‐BN coating was formed on low‐conductive SiC fibers by the electrophoretic deposition (EPD) method using flaked h‐BN suspension prepared by wet‐jet milling. Unidirectional SiCf/SiC composites with the BN interphase formed by the EPD method were prepared by polymer impregnation and pyrolysis (PIP) method, and their mechanical properties were evaluated. The uniform h‐BN interphase was successfully formed on the low‐conductive SiC fibers by EPD when thin polypyrrole (Ppy) coating, that is, conductive polymer, was formed on the SiC fibers. The h‐BN coating became denser by heat‐treatment at 1000°C, and the h‐BN coating deposited tightly on the SiC fibers was confirmed. It was demonstrated that the SiCf/SiC composites with the uniform and relatively dense h‐BN interphase formed by EPD using flaked h‐BN particles exhibited pseudo‐ductile fracture behavior with large amount of fiber pullout and higher fracture energy.

Effect of PyC/BN interfacial phases on mechanical behavior of SiC/SiC composites

AbstractPyC/BN multiphase interfacial phases were prepared on the surface of SiC fiber preform, then the near stoichiometric ratio SiC fiber reinforced SiC ceramic matrix composites were obtained by polymer impregnation and pyrolysis (PIP) process. The mechanical behavior of SiC/SiC composites was characterized by three‐point bending tests and fracture toughness tests. The stress release and load transfer effects of the interfaces under external loads were analyzed by scanning electron microscope (SEM). Results showed that with the increasing of PyC component thickness from .10 to.30 µm in the PyC/BN multiphase interfacial phases, the bending strength and fracture toughness both increased first and then decreased. The results occurred due to the competition between load transfer and stress release of the interfaces. The relatively optimized interfacial phase structure was that the thickness of the PyC interfacial phase and BN interfacial phase were .20 and.30 µm. The bending strength and fracture toughness of the optimized SiC/SiC composites reached 660.65 MPa and 29.01 MPa•m1/2. Respectively, many matrix cracks appeared in the horizontal and vertical directions, occupying almost the entire fracture section. The growth path of the matrix crack was significantly increased with many long fibers pulled out and broken, which was conducive to the strengthening and toughening of SiC/SiC composites.

The SMA Modifier Plastin 3 Targets Cell Membrane-Associated Proteins in Motoneurons.

Loss of the Survival Motor Neuron (SMN) gene inevitably leads to spinal muscular atrophy (SMA), one of the most common fatal neuromuscular diseases in children with FDA and EMA approved therapies. However, the cellular mechanisms leading to neuromuscular junction (NMJ) dysfunction due to impaired Ca2+ homeostasis in the presynaptic compartment remain largely unexplained. In the last decade, the so-called SMA modifiers have gained attention. The F-actin bundler Plastin 3 (PLS3) is one of them and counteracts neurotransmission defects, including altered vesicle endocytosis, in Smn-deficient NMJs. Properly bundled F-actin is the basis for the translocation and arrangement of transmembrane proteins at the cell surface. Our recently published data by Hennlein et al., J Cell Biol. (2023) clearly showed that Smn deficiency impairs the F-actin dependent translocation of the high-affinity BDNF receptor TrkB to the cell surface resulting in reduced BDNF-mediated TrkB activation in motor axon terminals. Strikingly, the overexpression of PLS3 restores TrkB availability, and significantly improves the clustering of the active zone-associated voltage-gated calcium channel Cav2.2 in growth cones of Smn-deficient motoneurons. These observations raise the question of how PLS3 mediates the proper cell surface localization and cluster-like formation of Cav2.2 in motor axon terminals.

Tunable spectral properties of PVB/WS2 impregnated fabrics in VIS, IR and RF part of the EMS

The application of nanomodified polymer impregnation on knitted polyester fabrics was studied to improve camouflage characteristics in VIS, IR, and RF domains to enhance multispectral camouflage protection. Nanoparticles of tungsten disulfide (WS2) were dispersed in an ethanol solution of poly (vinyl butyral) (PVB) and applied as a thin impregnation on polyester fabrics already dyed in camouflage shades. A reference sample impregnated only with PVB, without WS2, was also prepared in the same way. Parallel to the impregnated fabrics, a neat knitted polyester textile sample was submitted to all the examination methods. Diffuse reflection, specular gloss, and color coordinates were measured for all the samples. Moreover, the samples were observed using IR thermography in medium and long-wavelength infrared parts of the electromagnetic spectrum. The best suppression (≥20%) in the IR range of EMS was achieved for the dark green shade sample by applying PVB alone and/or adding PVB/ WS2. RF domain measurement analysis of how impregnated fabrics influence effective Radar Cross Section (RCS), K band radar was used, with the measurements done in terrain conditions. The decrease of the mean RCS value between 11% and 41% was achieved. The obtained results indicate that the addition of WS2 has a positive effect on the observed characteristics and that there is a possibility of using this newly impregnated knitwear in the wider area of the EMS as a camouflage material.

The actin-bundling protein, PLS3, is part of the mechanoresponsive machinery that regulates osteoblast mineralization.

Plastin-3 (PLS3) is a calcium-sensitive actin-bundling protein that has recently been linked to the development of childhood-onset osteoporosis. Clinical data suggest that PLS3 mutations lead to a defect in osteoblast function, however the underlying mechanism remains elusive. To investigate the role of PLS3 in bone mineralization, we generated MC3T3-E1 preosteoblast cells that are stably depleted of PLS3. Analysis of osteogenic differentiation of control and PLS3 knockdown (PLS3 KD) cells showed that depletion of PLS3 does not alter the first stage of osteoblast mineralization in which a collagen matrix is deposited, but severely affects the subsequent mineralization of that matrix. During this phase, osteoblasts heavily rely on mechanosensitive signaling pathways to sustain mineral deposition in response to increasing stiffness of the extracellular matrix (ECM). PLS3 prominently localizes to focal adhesions (FAs), which are intricately linked to mechanosensation. In line with this, we observed that depletion of PLS3 rendered osteoblasts unresponsive to changes in ECM stiffness and showed the same cell size, FA lengths and number of FAs when plated on soft (6kPa) versus stiff (100kPa) substrates in contrast to control cells, which showed an increased in each of these parameters when plated on 100kPa substrates. Defective cell spreading of PLS3 KD cells on stiff substrates could be rescued by expression of wildtype PLS3, but not by expression of three PLS3 mutations that were identified in patients with early onset osteoporosis and that have aberrant actin-bundling activity. Altogether, our results show that actin-bundling by PLS3 is part of the mechanosensitive mechanism that promotes osteoblast mineralization and thus begins to elucidate how PLS3 contributes to the development of bone defects such as osteoporosis.

Improvement of the performance characteristics, fire resistance, anti-bacterial activity, and aggressive attack of polymer‐impregnated fired clay bricks-fly ash-composite cements

The research addressed the creation of various composite cement mixes by replacing 40 % of OPC with industrial solid wastes, Fly ash (FA), and/or Fired clay bricks (FCB) at different water/powder (w/p) ratios. The composite cement pastes were subjected to polymer-impregnation process, using methyl-methacrylate (MMA) monomer and benzoyl peroxide as an initiator. The physico-mechanical and chemical characteristics of the polymer-impregnated specimens, such as compressive strength, bulk density, total porosity, and polymer load, were examined. The findings showed that, as compared to neat pastes (PF1, PF2, and PF3), the compressive strength (CS) of mixes (PFH1, PFH2, and PFH3) rose considerably after 3 months of hydration by 10.53 %, 12.82 %, and 28.85 %, respectively. Additionally, mix PFH1 with a water/powder (w/p) ratio of 0.35 exhibited the greatest bulk density value (2.215 g/cm3) and the lowest total porosity percentage (12.72 %). Data demonstrated that polymer-impregnation is efficacious to strengthen constructions subjected to high temperatures and aggressive salt attacks. The study additionally revealed that, when thermally treated at 200, 400, and 600 °C, respectively, the CS of PFH1 paste increased by 1.44 %, 1.78 %, and 1.48 % after 14 days of curing, but increased by 10.85 %, 5.20 %, and 7.89 % at curing time of 28 days. Likewise, when CS was compared to that before to polymer-impregnation up to three months, it grew by 48.53 % following immersion in 5%-MgSO4 solutions but increased by 13.49 % after immersion in 5%-MgCl2 solutions.Moreover, the composite with a water/powder ratio of 0.45 demonstrated remarkable anti-bacterial activity against both Gram-negative and Gram-positive bacteria. In conclusion, the study shows that the compressive strength, antibacterial activity, fire resistance, and resistance to aggressive attacks of the composites are all improved by MMA polymer impregnation.

Optimization of delignification depth of wood surfaces for skin polymer impregnation

We controlled the degree of surface delignification of a wood specimen to impart functionality to its surface and injected a polymer into the porous structure to investigate using it as a functional material. Generally, balsa wood is used in studies aiming to impart functionality through polymer impregnation. However, we used a native Korean tree (Paulownia tomentosa), which has the lowest specific gravity. Peracetic acid (acetic acid and hydrogen peroxide mixture) was used as the delignification solution. Changes in wood surface properties were analyzed according to the delignification treatment duration. Changes in chemical composition, functional groups, cell wall structure, specific gravity, and pores were also observed. Depending on the delignification time, the specific gravity decreased from 0.24 to 0.12. The lignin content was reduced from 29.2% to 0.9%. Fourier Transform Infrared Spectroscopy revealed changes in the lignin functional groups (1 591, 1 507, and 1 240 cm−1), and changes in functional groups derived from hemicellulose (1 720 and 1 182 cm−1). Epoxy infiltration depth was adjusted according to delignification treatment depth to impart wood surface functionality. Our research results indicated that strength and durability could be improved by selectively impregnating polymers into the wood surface requiring functionality, unlike chemically modifying the entire interior of the wood.

Automated control of thermal vacuum impregnation and swelling of oil- and gasoline-resistant elastomers

Polymeric materials used in the rolling stock are currently subject to increased requirements for durability. We present a method for accelerated and automated rapid analysis of the impregnation of polymeric materials used in various aggressive environments to determine their service life as sealing products. The results of studying changes in the physical and mechanical properties of samples are given on the example of elastomeric materials used as separating and sealing materials made of oil- and petrol resistant rubber MBS-S. Hydrocarbons based on mineral oil products with different viscosity coefficients were used as working media. It is shown that the time of impregnation of the MBS-S polymer, spent on testing according to the standard method, exceeds more than 10 times the standard terms rated for repair and maintenance. Tests using the developed express filling unit showed a reduction of the impregnation time to a level acceptable in production. The derived mathematical dependences for the process of filling MBS-S oil and petrol resistant rubber with a standard working fluid and automation of filling control make it possible to predict changes in the resistance of polymeric materials. The results obtained can be used in developing database of the swelling dynamics for various materials and predicting the service life of polymers in an aggressive environment of various etiology.