Polyamide Nylon Research Articles

Microplastics (PN6) as secondary pollutants: The desorption of radionuclides in simulated human digestive fluids

Plastic pollution, particularly in the form of microplastics (MPs), poses a significant threat to both, the environment and human health. Despite extensive research, gaps still exist in understanding the behavior of MPs as carriers of toxic pollutants, including radionuclides. This study investigates the desorption of uranium (U-232) and americium (Am-241) from polyamide nylon 6 (PN6) MPs under various conditions, including acidic environments and simulated human digestive systems. Results demonstrate that PN6-MPs can absorb radionuclides from contaminated waters and extensively desorb them in simulated digestive systems. The desorption efficiency is higher for Am-241 compared to U-232 across different pH ranges, suggesting a nuanced interplay between pH and desorption efficiency. Specifically, PN6-MPs can desorb up to 80 % of bound radionuclides in simulated digestive systems within 24 h and almost quantitatively after 120 h. These findings highlight the potential of PN6-MPs to act as covert carriers of waterborne pollutants, underscoring the need for further research to mitigate the risks posed by plastic pollution to both, the environment and human health.

Effect of SbCl5 Doping on the Electrical and Optical Properties of Polyamide Nylon 6 Films

Polyamide nylon 6 (PA6) films were fabricated using a solution casting method and the films were doped with SbCl5. The electrical conductivity increased with the dopant concentration due to the increase in formation of radical cations through the charge transfer from the isolated double bonds (–C=O–) in the polymer chains. The DC electrical conductivity reached a maximum of 0.01 S/cm for 0.5 ml SbCl5 doped films. Structural and optical characteristics of the pure and doped films were examined using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-Ray Diffraction (XRD), and Ultraviolet-Visible (UV-Vis) absorption spectra. The doped films exhibited discernible shifts in the optical band gap energy. The direct band gap values of PA6 films were reduced from 4.5 eV to 1.7 eV when doped with 0.5 ml SbCl5. ATR-FTIR spectral studies, and optical studies indicated the formation of charge transfer complexes with the amide group of nylon 6, resulting in the electrical conduction. The XRD studies disclosed the reduction in the crystallinity of the doped films. The thermal stability was studied using differential scanning calorimetry (DSC) and thermogravimetric analysis-derivative thermogravimetric (TGA-DTG) studies. The melting and crystallization temperatures were recorded from the DSC thermograms. The peak melting temperature of PA6 reduced from 217 °C to 186 °C for 0.5 ml SbCl5 doped films. The peak of crystallization observed at 182 °C for pure films was absent, for the doped samples. The peak degradation temperatures for both pure and doped samples were above 400 °C, revealing the thermal stability of both materials. The thermally stable, semi-crystalline and semiconducting polymer films, we suggest, would be suitable for optoelectronic applications.

Application of finite element analysis in the development of the pedal assembly of the Formula Student racing car

The study is focused on presenting an assessment of additive manufacturing usage in modern technological processes, including the manufacturing of parts of the racing car participating in Formula Student project. It shows the necessity of simulating physical processes during the design stage using the finite element analysis. The issues of calculating the strength of pedals of various functional purposes are considered. The boundary conditions imposed on the accelerator pedal are presented. It was found that loads applied with an offset to the edge of the support platform cause higher stresses in the item. The distribution patterns of the safety factor of an accelerator pedal created by additive method from materials: acrylonitrile butadiene styrene, polyamide Nylon 6/6 and polyamide Nylon 6/6 reinforced with fiberglass are presented. The results of modeling the rigidity of the pedal structure and the maximum stresses arising in it under load are indicated. The results of simulation of the prefabricated structure of the accelerator pedal with an aluminum alloy lever with a pedal plate obtained by additive manufacturing are shown.

Thermodynamic characteristics of the aliphatic polyamide crystal structures: Enhancement of nylon 66α, 610α and 77γ polymers

Despite the polymer industry's reliance on nylon polymers, numerous questions remain about their crystal structures, modeling, and other features. This work discusses the thermodynamic properties and molecular modeling of a polyamides nylon 66α, 610α, and 77γ crystal structure systems for use in various electronics and Nano-devices that feature distinct properties such as exceptional optoelectronic properties at a low cost compared to other structures. This study looked at the crystal structure of a linear polyamide chain made up of repeating units. The influence of the thermal expansion coefficient and thermodynamic parameters on crystal structures' characteristics at different temperatures has previously been explored. The findings of this study demonstrate, on the one hand, the influence of the amorphous phase on the final thermodynamic characteristics of semi-crystalline polymers and, on the other hand, pave the way for greater improvement in the durability of these polymers by increasing their crystalline features. The values of the thermodynamic parameters for nylon 66α, 610α and 77γ such as enthalpy (ΔHExp.) were 35.08, 40.25, and 1.44 kJ/mol, entropy (ΔSExp.) 113.75, 128.84, and 15.10 J/mol-K, free energy (ΔGExp.) was −44.57, −46.62, and −6.86 kJ/mol, respectively. When the nylon data is compared, the nylon 610α exhibits a significantly higher free energy, at high temperatures, the process is spontaneous and exergonic, making it a potentially viable material for use as fibers and engineering thermoplastics.

Multi-Spectroscopic Characterization of MgO/Nylon (6/6) Polymer: Evaluating the Potential of LIBS and Statistical Methods.

The potential of using laser-induced breakdown spectroscopy (LIBS) in combination with various other spectroscopic and statistical methods was assessed for characterizing pure and MgO-doped nylon (6/6) organic polymer samples. The pure samples, obtained through a polycondensation chemical technique, were artificially doped with MgO prior to analysis for comparative purposes. These artificially doped samples served as crucial reference materials for comparative analysis and reference purposes. The LIBS studies were performed under local thermodynamic equilibrium (LTE) and optically thin plasma conditions. To assess the structural crystallinity of the nylon (6/6) polymer samples, X-ray diffraction (XRD) analysis, and Fourier transform infrared (FTIR) spectroscopy were employed to detect functional groups such as N-H, C-H, and C-N in the adsorbent polyamide nylon sample. Additionally, diffuse reflectance spectroscopy (DRS) analysis was conducted to investigate the effects of doping and temperature on the band gap and material reflectance across different sample temperatures. Chemical compositional analysis was performed using X-ray photoelectron spectroscopy (XPS) with the carbon C1s peak at 248.8 eV serving as a reference for spectrum calibration, along with energy-dispersive X-ray (EDX) analysis, which demonstrated good agreement between the techniques. To validate the different methodologies, the results obtained from CF-LIBS and EDX were compared with those from the standard inductively coupled plasma mass spectrometry (ICP-MS) technique. Finally, for classification analysis, principal component analysis (PCA) was applied to the LIBS spectral data at different sample temperatures (25 °C, 125 °C, 225 °C, and 325 °C). The analyses demonstrated that the combination of LIBS with PCA, along with other methods, presents a robust technique for polymer characterization.

Fabrication and Enhancement of Organic Photodetectors Based on Iron Phthalocyanine Films

Iron–phthalocyanine (FePc) organic photoconductive detector was fabricated using pulsed laser deposition (PLD) technique to work in ultraviolet (UV) and visible regions. The organic semiconductor material (iron phthalocyanine) was deposited on n-type silicon wafer (Si) substrates at different thicknesses (100, 200 and 300) nm. FePc organic photoconductive detector has been improved by two methods: the first is to manufacture the detector on PSi substrates, and the second is by coating the detector with polyamide–nylon polymer to enhance the photoconductivity of the FePc detector. The current–voltage (I–V) characteristics, responsivity, photocurrent gain, response time and the quantum efficiency of the fabricated photoconductive detector were measured. The performance of the fabricated detector was taken under dark and illumination using two types of light sources: UV LED with wavelength (365[Formula: see text]nm), power of (10[Formula: see text]W) and Tungsten lamp with wavelength range between (500–800) nm and the optical power of (250[Formula: see text]W). The photoresponse enhancement was improved by coating the FePc films with 200[Formula: see text]nm of polyamide nylon polymer. This type of coating, which can be considered as a surface treatment, highly increased the photoresponse of the fabricated FePc UV detector. The results show that the responsivity increased four orders of magnitudes more than the responsivity of the uncoated FePc film. The effects of the coated polymers on the responsivity and the response time of the detector were investigated.

Adsorption of Reactive Red 120 Dye by Polyamide Nylon 6 Microplastics: Isotherm, Kinetic, and Thermodynamic Analysis

In this work, we investigated the effect of various adsorption parameters (solution pH, temperature, contact time, and the presence of phosphate and nitrate ions) on the adsorption of Reactive Red 120 (RR120) dye by Polyamide Nylon 6 (PN6) microplastics (MPs). Maximum uptake was achieved at pH 2.0, and the temperature rise from 295 to 313 K resulted in the decrease of the RR120 sorption by PN6. Equilibrium was achieved after 7 h, and the adsorption kinetic data obeyed the pseudo-second-order kinetic model. The experimental adsorption data were better fitted by the Langmuir isotherm model, and the qm was found to be 3.96 mg/g at pH 2.0 and 295 K. Thermodynamic studies pointed out that the adsorption was spontaneous and exothermic, with decreasing entropy at the solution/solid interface. Future work will focus on the effect of aging on the adsorptive properties of PN6 toward RR120 dye.

Investigation of Global Trends of Pollutants in Marine Ecosystems around Barrang Caddi Island, Spermonde Archipelago Cluster: An Ecological Approach.

High-quality marine ecosystems are free from global trending pollutants’ (GTP) contaminants. Accuracy and caution are needed during the exploitation of marine resources during marine tourism to prevent future ecological hazards that cause chain effects on aquatic ecosystems and humans. This article identifies exposure to GTP: microplastic (MP); polycyclic aromatic hydrocarbons (PAH); pesticide residue (PR); heavy metal (HM); and medical waste (MW), in marine ecosystems in the marine tourism area (MTA) area and Barrang Caddi Island (BCI) waters. A combination of qualitative and quantitative analysis methods were used with analytical instruments and mathematical formulas. The search results show the average total abundance of MPs in seawater (5.47 units/m3) and fish samples (7.03 units/m3), as well as in the sediment and sponge samples (8.18 units/m3) and (8.32 units/m3). Based on an analysis of the polymer structure, it was identified that the dominant light group was MPs: polyethylene (PE); polypropylene (PP); polystyrene (PS); followed by polyamide-nylon (PA); and polycarbonate (PC). Several PAH pollutants were identified in the samples. In particular, naphthalene (NL) types were the most common pollutants in all of the samples, followed by pyrene (PN), and azulene (AZ). Pb+2 and Cu+2 pollutants around BCI were successfully calculated, showing average concentrations in seawater of 0.164 ± 0.0002 mg/L and 0.293 ± 0.0007 mg/L, respectively, while in fish, the concentrations were 1.811 ± 0.0002 µg/g and 4.372 ± 0.0003 µg/g, respectively. Based on these findings, the BCI area is not recommended as a marine tourism destination.

Neptunium interaction with microplastics in aqueous solutions

The neptunium sorption by different microplastic materials (MPs) has been studied in laboratory water and seawater samples, which had been previously traced with the Np-237 isotope. The microplastics used were polyethylene terephthalate (PET) and polyamide nylon (PN6), and the investigations included the pH effect and seawater composition on the sorption efficiency. The evaluation of the experimental data (Kd values) revealed that the sorption efficiency does not differ significantly from one microplastic to another and mainly the hydrolysis of Np(V) in alkaline conditions affects the sorption efficiency. In seawater the Kd values decline dramatically because of the increased ionic strength (salinity) and the occurrence of various cations (e.g. Ca2+, Fe2+), which effectively compete Np(V) sorption by the MPs.

Large-scale fabrication of graphene/polyamide-6 composite as a high thermal conductivity engineering composite for thermal radiators

In this study, graphene was mass-produced from graphite through ultrasonic-assisted exfoliation in N-methyl-2-pyrrooxone (NMP) and then mixed with polyamides Nylon (PA6) to obtain a high thermal conductivity engineering polymer (GP6). The thermal conductivity of GP6 is 30 W m−1 K−1 and the density is 1.8 g cm−1. GP6 could be used in heat dissipation systems of LED lamps and cameras with injection molding at 260 °C, thus cutting the cost by 30% and reducing the carbon emission.

Difficulty in Advancing Flexible Epidural Catheters When Establishing Labor Analgesia: An Observational Open-label Randomized Trial

(Anesth Analg. 2021;133:151–159. doi: 10.1213/ANE.0000000000005526) Flexible epidural catheters have a lower incidence of both paresthesias and intravascular catheter placement. This study aimed to compare and analyze the efficacy of 2 commercially available epidural kits: kit “A” (single-end hole wire-reinforced polyurethane epidural catheter; n=135) and kit “B” (multi-orifice wire-reinforced polyamide nylon blend epidural catheter; n=122).

Polyamide nylon 6 as a potential carrier of nitrate anions in aqueous environments

Νitrates and microplastics may co-exist in terrestrial and aquatic ecosystems implying potential interaction and, subsequently affecting their environmental fate and the ecosystem quality. However, studies highlighting the interaction between these substances do not exist or are very limited. In this study, batch-type experiments were carried out using aqueous solutions (20 mL, pH 6) to investigate the effect of different parameters such as the polyamide nylon 6 (PN6) dose (0.2, 1.0, 1.5, and 2.0 g), initial nitrate concentration (2, 25, 50, 100, and 150) and contact time on the sorption capacity of PN6 for nitrate anions. The experimental data revealed that microplastic addition results in a remarkable decrease of nitrates in solution (qmax = 3.5 mg/g), mostly during the first 3 days of experimentation. In addition, the FTIR spectra of PN6 aliquots prior and after sorption indicated that the sorption occurs basically via electrostatic attraction between the negatively-charged nitrate anion and positively charged moieties on the PN6 surface, assuming that PN6 microplastics may act as potential carriers of nitrates in aqueous environments, and affect their transport in the geosphere and in living organisms.

Microplastics as carriers of hydrophilic pollutants in an aqueous environment

Plastic materials such as polyethylene (PE), polyvinyl chloride (PVC), and polyamide nylon 6 (PN6) are extensively used worldwide. Significant quantities end up in the environment as waste, which gradually deteriorate and may travel for long distances. In this study, the capacity of these microplastics to sorb RR 120, an anionic dye commonly found in textile wastewaters, was investigated. PN6 showed the highest sorption capacity of 4.80 mg g−1, at a dose of 0.4 g and pH 2, whereas increasing the dose of the microplastic resulted in a gradual decrease of the sorption capacity for all materials. Increasing the dye concentration, resulted in higher sorption capacities. The FTIR analysis of the microplastics before and after sorption of RR 120, indicated no chemical bonding pointing out the absence of covalent bonds with specific surface groups of the microplastics in the sorption of RR 120. A plausible explanation for the highest sorption capacity of PN6 is the presence of N and O, which can readily form H bonds with the hydroxyl groups of RR 120.

The fate of three common plastic nanoparticles in water: A molecular dynamics study

The widespread contamination of aqueous environments with micro and nanoplastics (MNPs) is an emergent environmental problem that has been gathering increasing public concern. In addition to the known harmful effects on the ecosystems and living organisms, there have been raising worries that MNPs may adsorb trace pollutants such as heavy metals and organics, accumulate them and substantially concentrate them relative to their concentrations in the original aqueous medium. The tendency of MNPs to adsorb compounds may be linked to the particle sizes as well as to their final shapes. In order to assess MNPs behavior in the water environment, namely in terms of particle shapes, structures, interactions and aggregation, differently sized nanoparticles of three common plastics, polyethylene, polyethylene terephthalate and the polyamide nylon 6, were analyzed by molecular dynamics simulations. In all cases, a fast and spontaneous aggregation of the initially dispersed nanoparticles was observed yielding one single larger nanoparticle. In spite of the differences in the type of interactions between each plastic and water, no dispersal and solubilization of any plastic chains was observed during the simulations. The form of aggregation of the various nanoclusters was however very different: compact and ordered for polyethylene, globular and stringy for nylon6, while the PET bent chains form entangled piled-up structures with the aromatic rings preferentially oriented in a parallel-wise ordered way. In addition to the observed aggregation of all the smaller nanoparticles, a rearrangement and a spontaneous self-assembling ordering of the chains was observed as well, particularly in the polyethylene case. The results reinforce the observed tendency of the plastic chains to remain stably associated in clusters with a significant size, in the form of nanoparticles that resist further fragmentation and degradation for all the types of plastic, although the shapes of the particles differ among plastic types.

Enhancement of Photoconductive Detector Based on Carbon Nanotubes Decorated with Silver Nanoparticles by Adding Conductive Polymer

In this work, wide band range photo detector operating in UV, Visible and IR was fabricated using carbon nanotubes (MWCNTs, SWCNTs) decorated with silver nanoparticles (Ag NPs). Silicon was used as a substrate to deposited CNTs/Ag NPs by the drop casting technique. Polyamide nylon polymer was used to coat CNTs/Ag NPs to enhance the photo-response of the detector. The electro-exploding wire technology was used to synthesize Ag NPs. Good dispersion of silver NPs achieved by a simple chemistry process on the surface of CNTs. The optical, structure and electrical characteristic of CNTs decorated with Ag NPs were characterized by X-Ray diffraction and Field Emission Scanning Electron Microscopy. X-ray diffraction patterns of Ag NPs exhibited 2θ values (38.1°,44.3°) corresponding to the Ag nanocrystal, while the XRD pattern of MWCNTs and SWCNTs /Ag NPs peaks appeared at 2θ = 26.2° corresponding to the (002) and at 2theta=44° which corresponds with miller indices (100) for CNTs and (200) for Ag NPs. The optical properties measured by UV-Vis. Spectroscopy. Broad and strong surface plasmon resonance (SPR) peak was detected at 420 nm, for Ag NPs. The absorption of CNTs/Ag NPs increased significantly from UV to near IR region (300-1000 nm). Ag NPs decorated CNTs without any impurities, according to field mission scanning electron microscopy examination, with typical particle sizes of (50-80nm) for Ag-NPs, 44nm for MWCNTs/Ag-NPs, and 30nm for SWCNTs/Ag NPs. ֹThe I-V characteristics at forward bias voltage (0.5-10) volt were studied. The figure of merits (responsivity, photocurrent gain, NEP and detectivity) after coating with polymer of the detector were measured in the dark and after illumination with UV LED (365 nm), Tungsten lamp (500-800 nm) and Laser diode (808 nm).

Transient Confinement of the Quaternary Tetramethylammonium Tetrafluoroborate Salt in Nylon 6,6 Fibres: Structural Developments for High Performance Properties.

A temporary confinement of the quaternary tetramethylammonium tetrafluoroborate (TMA BF4) salt among polyamide molecules has been used for the preparation of aliphatic polyamide nylon 6,6 fibres with high-modulus and high-strength properties. In this method, the suppression or the weakening of the hydrogen bonds between the nylon 6,6 segments has been applied during the conventional low-speed melt spinning process. Thereafter, after the complete hot-drawing stage, the quaternary ammonium salt is fully extracted from the drawn 3 wt.% salt-confined fibres and the nascent fibres are, subsequently, thermally stabilized. The structural developments that are acquired in the confined-nylon 6,6 fibres are ascribed to the developments of the overall fibres’ properties due to the confinement process. Surprisingly, unlike the neat nylon 6,6 fibres, the X-ray diffraction (XRD) patterns of the as-spun salt-confined fibres have shown diminishing of the (110)/(010) diffraction plane that obtained pseudohexagonal-like β’ structural phase. Moreover, the β’ pseudohexagonal-like to α triclinic phase transitions took-place due to the hot-drawing stage (draw-induced phase transitions). Interestingly, the hot-drawing of the as-spun salt-confined nylon 6,6 fibres achieved the same maximum draw ratio of 5.5 at all of the drawing temperatures of 120, 140 and 160 °C. The developments that happened produced the improved values of 43.32 cN/dtex for the tensile-modulus and 6.99 cN/dtex for the tensile-strength of the reverted fibres. The influences of the TMA BF4 salt on the structural developments of the crystal orientations, on the morphological structures and on the improvements of the tensile properties of the nylon 6,6 fibres have been intensively studied.

Difficulty in Advancing Flexible Epidural Catheters When Establishing Labor Analgesia: An Observational Open-Label Randomized Trial.

While flexible epidural catheters reduce the risk of paresthesia and intravascular cannulation, they may be more challenging to advance beyond the tip of a Tuohy needle. This may increase placement time, number of attempts, and possibly complications when establishing labor analgesia. This study investigated the ability to advance flexible epidural catheters through different epidural needles from 2 commonly used, commercially available, epidural kits. We hypothesized that the multiorifice wire-reinforced polyamide nylon blend epidural catheters will have a higher rate of successful first attempt insertion than the single-end hole wire-reinforced polyurethane catheters for the establishment of labor analgesia. The primary outcome was a difference in proportions of failure to advance the epidural catheter between the 2 epidural kits and was tested by a χ2 test. Two-hundred forty epidural kits were collected (n = 120/group) for 240 laboring patients requesting epidural analgesia in this open-label clinical trial from November 2018 to September 2019. Two-week time intervals were randomized for the exclusive use of 1 of the 2 kits in this study, where all patients received labor analgesia through either the flexible epidural catheter "A" or the flexible epidural catheter "B." Engineering properties of the equipment used were then determined. Flexible epidural catheter "A," the single-end hole wire-reinforced polyurethane catheter, did not advance at the first attempt in 15% (n = 18 of 120) of the parturients compared to 0.8% (n = 1 of 120) of the catheter "B," the multiorifice wire-reinforced polyamide nylon blend epidural catheter (P < .0001). Twenty-five additional epidural needle manipulations were recorded in the laboring patients who received catheter "A," while 1 epidural needle manipulation was recorded in the parturients who received catheter "B" (P < .0001). Bending stiffness of the epidural catheters used from kit "B" was twice the bending stiffness of the catheters used from kit "A" (bending stiffness catheters "A" 0.64 ± 0.04 N·mm2 versus bending stiffness catheters "B" 1.28 ± 0.20 N·mm2, P = .0038), and the angle formed by the needle and the epidural catheter from kit "A" was less acute than the angle formed from kit "B" (kit "A" 14.17 ± 1.72° versus kit "B" 21.83 ± 1.33°, P = .0036), with a mean difference of 7.66° between the 2 kits' angles. The incidence of an inability to advance single-end hole wire-reinforced polyurethane catheter was higher compared to the use of multiorifice wire-reinforced polyamide nylon blend epidural catheter. Variation of morphological features of epidural needles and catheters may play a critical role in determining the successful establishment of labor epidural analgesia.

Area-selective molecular layer deposition of nylon 6,2 polyamide: Growth on carbon and inhibition on silica

In microelectronic or nanoelectronic manufacturing, pattern transfer by directional reactive ion etching (RIE) progressively erodes amorphous carbon (aC) hard masks. To maintain critical dimensions and tolerances of high-aspect-ratio device structures, new carbonaceous materials may be added repeatedly to replace the eroded aC hard mask. Such a mask repairing step during RIE needs self-aligning growth of organic materials. Area selectivity is required to deposit the organic material on the aC hard mask exclusively. Deposition on the dielectric or semiconductor device structures underlying the mask would complicate their precise etching or later cleaning. When ashing the aC hard mask, all-organic materials are preferable to organic-inorganic hybrid materials because they leave no residue. In this work, area-selective molecular layer deposition (MLD) was developed for the all-organic polyamide nylon 6,2. The monomer reactants for nylon 6,2 MLD were ethylene diamine and adipoyl chloride. Nylon 6,2 MLD was studied in the homogeneous, steady-state growth regime and during nucleation on various starting surfaces utilizing in situ spectroscopic ellipsometry. Area-selective MLD of nylon 6,2 was achieved on the “growth” carbon surface in the presence of silica by functionalizing aC via mild oxidation. In addition, a surface passivant was selectively attached to silica by using an amine-catalyzed coupling chemistry. The passivant inhibited the nylon 6,2 MLD on the “nongrowth” silica surface. A single passivation pretreatment was sufficient to restrict the MLD on the silica surface. The passivant, however, did not substantially impact the MLD nucleation and growth on the aC surface. This strategy yielded area selectivity with exceptionally high quality and over a wide range of MLD cycles. The area-selective MLD of nylon 6,2 was further applied on industrial test features with aC patterns masking trenches in silica. This demonstration illustrated the capability of area-selective MLD to repair RIE-eroded aC hard masks and to maintain the critical dimension.

Strengthening of tensile zone of the reinforced concrete beams with composite fabrics

A fabric, tapes, that are glued to the outer tensile surface, which are considered as the external composite reinforcement with tensile steel reinforcement, are currently used to strengthen reinforced concrete beams. The results of the experimental studies presented in this article have shown the possibilities of effective application of technical polyamide (nylon) fabric produced by «Khimvolokno Plant» JSC «Grodno Azot», and glass fabrics, produced by JSC «Polotsk-Steklovolokno» for strengthening the reinforced concrete beams. Experimental studies have shown that the external reinforcing of the tensile zone with technical polyamide (nylon) fabric and fiberglass changes the beam failure mode, increases the bearing capacity of reinforced concrete beams in comparison with beams without strengthening by 16% – 38%, depending on the material and the method of strengthening.

MANUFACTURING OF FULL REMOVABLE LAMINAR DENTURES USING DIFFERENT GROUPS OF MATERIALS FOR DENTURE BASES AND THEIR COMPARATIVE CHARACTERISTICS

Restoration of complete maxillary or mandibular adentia, despite the advances of dentistry nowadays, has always been and is still remaining one of the most challenging among the clinical issues of orthopedic dentistry. The effectiveness of a high-quality complete removable denture is largely predetermined by the properties of the denture base material. However, long experience in manufacturing the dentures has revealed a number of their disadvantages. The development of new denture base materials and their studies have been being carried out for many years. The aim of this work was to investigate the effectiveness of thermoplastic base material "Vertex ThermoSense" (Netherlands) and fluorine-containing acrylic plastic "Ftoraks" (Ukraine) used in manufacturing the dentures for edentulous patients who previously worn full removable dentures made of acrylic plastic over the past 3- 5 years. We examined and treated 43 patients with complete anodontia who went to the orthodontic clinic to order a new denture. We used fluorine-containing acrylic co-polymers "Ftorax" (Ukraine) and polyamide (nylon) "Vertex ThermoSense" (Netherlands), recommended by manufacturers for making removable dentures. We assessed the level subjective satisfaction with new dentures in different follow-up time intervals, checked the restoration of the chewing function in the patients using electromyographic techniques. Clinical findings obtained supported the superiority of Vertex ThermoSense thermoplastic material over fluorine-containing acrylic resins in terms of high functional quality and strength that facilitate the durability of these complete dentures. In addition, the denture base made of "Vertex ThermoSense" does not contain residual monomer, thereby preventing the occurrence of allergic reactions. The results of our work allow us to strongly recommend the material "Vertex ThermoSense" to implement into prosthodontic practice for manufacturing complete removable dentures.