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1.
Polymers (Basel) ; 16(15)2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39125250

RESUMO

Hot air, water, and glycerol were studied as foaming mediums for the production of ETPU to evaluate their influence on the behavior of the foam and compare the optimal particles for each of the foaming temperatures selected. The results showed that the times of water foaming and glycerol foaming were shorter by about 2/3 than with hot-air foaming. The best foaming temperatures for hot-air foaming, glycerol foaming, and water foaming are 110-115 °C, 75 °C, and 90 °C, respectively. The particles of glycerol foam have a matte appearance and their gloss is not very good. However, the particles in hot-air foaming are light, and the gloss is very satisfactory. The gloss of the surface of water-foaming particles is dim. At the same time, there is a faint matte appearance. Particles made with glycerol foaming and water foaming are more even than those made with hot-air foaming. The density of foaming materials from glycerol foaming, hot-air foaming, and water foaming are raised accordingly, while the hardness of foaming materials from glycerol foaming, water foaming, and hot-air foaming are successively increased.

2.
Heliyon ; 10(12): e32420, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-39183888

RESUMO

This work investigates the peculiarities of using a liquid blowing agent, namely dimethoxymethane (Methylal) to foam a thermoplastic polyurethane (TPU) in the laboratory practice of batch foaming equipment. We preliminarily measured thermodynamic properties of the polymer/gas system relevant to foaming, namely the vapor-liquid pressures at the TPU foaming temperatures. Three different paths were then explored for foaming. First, we used Methylal under its liquid-vapor equilibrium condition, in which both liquid and vapor are present. Secondly, we used Methylal in the liquid state to experiment with liquid foaming strategies. We have observed specific aspects, details, and issues related to the use of liquid blowing agents and devised strategies to deal with them. Finally, we used Methylal as a co-blowing agent together with CO2. In all cases, we examined the impact of pressure, pressure drop rate, and temperature on foam density and morphology. Overall, liquid foaming has proven to be a viable technique and Methylal an effective blowing agent, especially in cooperation with other gaseous blowing agents, where it significantly improves the expansion ratio of the final product.

3.
Nanomaterials (Basel) ; 14(15)2024 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-39120374

RESUMO

High-energy-density Li-CO2 batteries are promising candidates for large-capacity energy storage systems. However, the development of Li-CO2 batteries has been hindered by low cycle life and high overpotential. In this study, we propose a CO2-based thermoplastic polyurethane (CO2-based TPU) with CO2 adsorption properties and excellent self-healing performance to replace traditional polyvinylidene fluoride (PVDF) as the cathode binder. The CO2-based TPU enhances the interfacial concentration of CO2 at the cathode/electrolyte interfaces, effectively increasing the discharge voltage and lowering the charge voltage of Li-CO2 batteries. Moreover, the CO2 fixed by urethane groups (-NH-COO-) in the CO2-based TPU are difficult to shuttle to and corrode the Li anode, minimizing CO2 side reactions with lithium metal and improving the cycling performance of Li-CO2 batteries. In this work, Li-CO2 batteries with CO2-based TPU as the multifunctional binders exhibit stable cycling performance for 52 cycles at a current density of 0.2 A g-1, with a distinctly lower polarization voltage than PVDF bound Li-CO2 batteries.

4.
J Biomater Sci Polym Ed ; : 1-16, 2024 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-39190633

RESUMO

The treatment of recurrent genital herpes typically involves daily doses of acyclovir for extended periods. Additive manufacturing is an intriguing technique for creating personalised drug delivery systems, which can enhance the effectiveness of treatments for various diseases. The vaginal route offers a viable alternative for the systemic administration of drugs with low oral bioavailability. In this study, we produced different grades of thermoplastic polyurethane (TPU) filaments through hot-melt extrusion, with acyclovir concentrations of 0%, 10%, and 20% by weight. We used fused filament fabrication to manufacture matrix-based devices, including intrauterine devices and intravaginal rings. Our results, obtained through SEM, FTIR, and DSC analyses, confirm the successful incorporation of acyclovir into the matrix. Thermal analysis reveals that the manufacturing process alters the organization of the TPU chains, resulting in a slight reduction in crystallinity. In our in-vitro tests, we observed an initial burst release on the first day, followed by sustained release at reduced rates for up to 145 days, demonstrating their potential for long-term applications. Additionally, cytotoxicity analysis suggests the excellent biocompatibility of the printed devices, and biological assays show a remarkable 99% reduction in HSV-1 replication. In summary, TPU printed devices offer a promising alternative for long-term genital herpes treatment, with the results obtained potentially contributing to the advancement of pharmaceutical manufacturing.

5.
Neurophotonics ; 11(3): 036601, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39193445

RESUMO

Accurate sensor placement is vital for non-invasive brain imaging, particularly for functional near-infrared spectroscopy (fNIRS) and diffuse optical tomography (DOT), which lack standardized layouts such as those in electroencephalography (EEG). Custom, manually prepared probe layouts on textile caps are often imprecise and labor intensive. We introduce a method for creating personalized, 3D-printed headgear, enabling the accurate translation of 3D brain coordinates to 2D printable panels for custom fNIRS and EEG sensor layouts while reducing costs and manual labor. Our approach uses atlas-based or subject-specific head models and a spring-relaxation algorithm for flattening 3D coordinates onto 2D panels, using 10-5 EEG coordinates for reference. This process ensures geometrical fidelity, crucial for accurate probe placement. Probe geometries and holder types are customizable and printed directly on the cap, making the approach agnostic to instrument manufacturers and probe types. Our ninjaCap method offers 2.7 ± 1.8 mm probe placement accuracy. Over the last five years, we have developed and validated this approach with over 50 cap models and 500 participants. A cloud-based ninjaCap generation pipeline along with detailed instructions is now available at openfnirs.org. The ninjaCap marks a significant advancement in creating individualized neuroimaging caps, reducing costs and labor while improving probe placement accuracy, thereby reducing variability in research.

6.
Int J Biol Macromol ; 278(Pt 3): 134842, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39159801

RESUMO

Cellulose nanocrystal is a nanomaterial that has a large specific surface area, high surface energy, and high strength. As well, it is biocompatible, environmentally friendly, nontoxic, and can be extracted from biomass resources. Because of these features, cellulose nanocrystals can be used to improve the mechanical properties of polymer matrices with a shape memory effect and as a shape memory switch. In this study, a polytrimethylene ether glycol-based thermoplastic polyurethane (TPU)/cellulose nanocrystal (CNC) composite was prepared via an in-situ polymerization process to create a self-healing polymer matrix. Also, the effect of CNC doses in low concentrations (≤2 wt%) on the different properties of the resulting bio-nanocomposite was investigated. The results showed that the introduction of CNCs affects the hydrogen bonding within the polymer matrix and provides better thermal stability in the high temperature range than pure TPU. Furthermore, the samples with 0 wt%, 0.75 wt%, 1 wt%, and 2 wt% of CNC exhibited an increasing trend in tensile strength with values of 11.71 MPa, 18.95 MPa, 17.88 MPa, and 26.18 MPa, respectively, which indicates a remarkable improvement in mechanical strength. The shape memory behavior was also notably prominent in this polymer composite, where the composite containing 2 wt% of CNC showed the fastest recovery time (240 s) at 75 °C with the highest shape retention. Moreover, their flow behavior and deformation capacity were examined through rheology tests. Besides, docking simulations were conducted in silico to assess the interaction of the TPU/CNC composite with the DNA gyrase enzyme. The interaction between CNC/TPU composite and DNA gyrase was meticulously analyzed across 10 distinct conformations, yielding docking scores ranging from -6.5 Kcal/mol to -5.3 Kcal/mol. Overall, the physico-mechanical properties of the TPU/CNC composites were substantially enhanced with the incorporation of nanofillers.


Assuntos
Celulose , Nanocompostos , Nanopartículas , Poliuretanos , Celulose/química , Nanopartículas/química , Poliuretanos/química , Nanocompostos/química , Resistência à Tração , Fenômenos Mecânicos , Ligação de Hidrogênio , Simulação de Acoplamento Molecular
7.
Polymers (Basel) ; 16(13)2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-39000692

RESUMO

The rapid development of electronic communication technology has led to an undeniable issue of electromagnetic pollution, prompting widespread attention from researchers to the study of electromagnetic shielding materials. Herein, a simple and feasible method of melt blending was applied to prepare iPP/TPU/MWCNT nanocomposites with excellent electromagnetic shielding performance. The addition of maleic anhydride-grafted polypropylene (PP-g-MAH) effectively improved the interface compatibility of iPP and TPU. A double continuous structure within the matrix was achieved by controlling the iPP/TPU ratio at 4:6, while the incorporation of multi-walled carbon nanotubes endowed the composites with improved electromagnetic shielding properties. Furthermore, by regulating the addition sequence of raw materials during the melt-blending process, a selective distribution of carbon nanotubes in the TPU matrix was achieved, thereby constructing interconnected conductive networks within the composites, significantly enhancing the electromagnetic shielding performance of iPP/TPU/MWCNTs, which achieved a maximum EMI shielding efficiency of 37.8 dB at an iPP/TPU ratio of 4:6 and an MWCNT concentration of 10 wt.%.

8.
Materials (Basel) ; 17(13)2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38998443

RESUMO

Increased usage of selective laser sintering (SLS) for the production of end-use functional components has generated a requirement of developing new materials and process improvements to improve the applicability of this technique. This article discusses a novel process wherein carbon black was applied to the surface of TPU powder to reduce the laser reflectivity during the SLS process. The printing was carried out with a preheating temperature of 75 °C, laser energy density of 0.028 J/mm2, incorporating a 0.4 wt % addition of carbon black to the TPU powder, and controlling the powder layer thickness at 125 µm. The mixed powder, after printing, shows a reflectivity of 13.81%, accompanied by the highest average density of 1.09 g/cm3, hardness of 78 A, tensile strength of 7.9 MPa, and elongation at break was 364.9%. Compared to commercial TPU powder, which lacks the carbon black coating, the reflectance decreased by 1.78%, mechanical properties improved by 33.9%, and there was a notable reduction in the porosity of the sintered product.

9.
Technol Cancer Res Treat ; 23: 15330338241266479, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39043036

RESUMO

Objective: In external radiotherapy, dose boluses and compensators are used for treatment of irregular facial topography surfaces. In such cases, skewed isodose curves need to be addressed using a bolus that gives the deep dose distribution a shape adapted to the anatomical structures to be protected or irradiated. The combination of 3D modeling and printing technologies is a promising alternative to the conventional inaccurate and uncomfortable bolus fabrication technique. In this work, the proposed technologies will be used in the design and fabrication of high-performance and high-accuracy boluses that respond to the main constraints on metrology, adhesion to the patient's surface, comfort, and dose delivery. Methods: As a first phase in the implementation of the proposed solution, 3D printing materials, to be used in the fabrication of radiotherapy boluses, were selected and characterized to check how they respond to the required criteria on functionality, safety, and quality. Results: The obtained results show that among the studied materials, thermoplastic polyurethane (TPU) was found to be slightly more suitable than polylactic acid (PLA) for the fabrication of 3D printing boluses but for some kinds of treatments, PLA may be preferred despite its relative rigidity. Conclusion: In this work, procedures for dose bolus fabrication were proposed, and necessary data were obtained for some available 3D printing materials (TPU and PLA) that can be used for targeted applications. This achievement is a major step toward the final implementation of 3D modeling and printing technologies for the efficient fabrication of radiotherapy dose boluses.


Assuntos
Impressão Tridimensional , Dosagem Radioterapêutica , Humanos , Planejamento da Radioterapia Assistida por Computador/métodos , Poliésteres/química , Poliuretanos/química
10.
Int J Artif Organs ; : 3913988241261817, 2024 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-39066643

RESUMO

Reconstruction of mandible implants to address segmental abnormalities is still a challenging task, both in vitro and in vivo. The mechanical strength of the materials used is a critical factor that determines how well bone is regenerated. The reconstruction technique of mandibular abnormalities widely uses polymeric implants. It is critical to evaluate the mechanical resilience under different load cases, including axial, combined, and flexural loading conditions. This study developed implants for mandibular defects using a combination of four materials: polylactic acid (PLA), polyethylene terephthalate glycol (PETG), thermoplastic polyurethane (TPU), and polycaprolactone (PCL), with the aim of mimicking the inherent characteristics of cortical and cancellous bone structures and evaluating their mechanical properties to support bone Osseo integration. The eleven of these combinations of structures result below the micro strain threshold level of <3000 µÎµ, and the five combinations of the structures result in micro strain above the threshold value. The intact bone study results show that the stress under axial, combined, and flexural loading conditions is 27.6, 38.9, and 64.9 MPa, respectively. This study's stress results are lower than those from the intact bone study. The study found that the combinations of PLA and TPU material were most preferred for the cortical and cancellous bone regions of polymeric implants. These materials are also compatible with 3D printing. The results of this study can be used to find multi-material combinations that are strong and flexible.

11.
Biomaterials ; 311: 122669, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38906013

RESUMO

Biohybrid tissue-engineered vascular grafts (TEVGs) promise long-term durability due to their ability to adapt to hosts' needs. However, the latter calls for sensitive non-invasive imaging approaches to longitudinally monitor their functionality, integrity, and positioning. Here, we present an imaging approach comprising the labeling of non-degradable and degradable TEVGs' components for their in vitro and in vivo monitoring by hybrid 1H/19F MRI. TEVGs (inner diameter 1.5 mm) consisted of biodegradable poly(lactic-co-glycolic acid) (PLGA) fibers passively incorporating superparamagnetic iron oxide nanoparticles (SPIONs), non-degradable polyvinylidene fluoride scaffolds labeled with highly fluorinated thermoplastic polyurethane (19F-TPU) fibers, a smooth muscle cells containing fibrin blend, and endothelial cells. 1H/19F MRI of TEVGs in bioreactors, and after subcutaneous and infrarenal implantation in rats, revealed that PLGA degradation could be faithfully monitored by the decreasing SPIONs signal. The 19F signal of 19F-TPU remained constant over weeks. PLGA degradation was compensated by cells' collagen and α-smooth-muscle-actin deposition. Interestingly, only TEVGs implanted on the abdominal aorta contained elastin. XTT and histology proved that our imaging markers did not influence extracellular matrix deposition and host immune reaction. This concept of non-invasive longitudinal assessment of cardiovascular implants using 1H/19F MRI might be applicable to various biohybrid tissue-engineered implants, facilitating their clinical translation.


Assuntos
Prótese Vascular , Imageamento por Ressonância Magnética , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Engenharia Tecidual , Alicerces Teciduais , Animais , Alicerces Teciduais/química , Engenharia Tecidual/métodos , Imageamento por Ressonância Magnética/métodos , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Ratos , Humanos , Masculino , Ácido Poliglicólico/química , Ácido Láctico/química , Poliuretanos/química , Miócitos de Músculo Liso/citologia , Materiais Biocompatíveis/química , Ratos Sprague-Dawley , Nanopartículas Magnéticas de Óxido de Ferro/química
12.
Polymers (Basel) ; 16(12)2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38932034

RESUMO

Recently, clothing development 3D printing and the evaluation of its physical characteristics have been explored. However, few studies have tackled thermal comfort, which is a major contributor to the wearers' comfort. Therefore, this study was designed to suggest effective materials and hole sizes for clothing obtained by 3D printing to maintain a comfortable clothing environment. In particular, two main variables, namely five different materials and three-hole sizes, were analyzed. All samples were placed on a hot plate (36 °C), and their surface temperature and humidity were measured for 10 min. The samples with only thermoplastic polyurethane (TPU) achieved the largest temperature change of 3.2~4.8 °C, whereas those with ethylene-vinyl acetate (EVA) foam exhibited the lowest temperature change of -0.1~2.0 °C. Similarly, the samples with only TPU showed the greatest humidity change of -0.7~-5.5%RH. Moreover, the hole size had a larger effect on humidity change than material type. The samples with large holes achieved the largest humidity change of -4.4%RH, whereas the samples without holes had the smallest humidity change of -1.5%RH after 10 min (p < 0.001). Based on these results, various combinations of materials and hole sizes should be considered to fit the purpose of 3D printing clothing.

13.
Adv Sci (Weinh) ; 11(36): e2404154, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38925613

RESUMO

The global climate change is mainly caused by carbon dioxide (CO2) emissions. To help reduce CO2 emissions and conserve thermal energy, sustainable materials based on flexible thermal insulation are developed to minimize heat flux, drawing inspiration from natural systems such as polar bear hairs. The unique structure of hollow double-shell fibers makes it possible to achieve low thermal conductivity in the material while retaining exceptional elasticity, allowing it to adapt to insulation systems of any shape. The layered system of porous mats reaches a thermal conductivity coefficient of 0.031 W∙m⁻¹âˆ™K⁻¹ and enables to reduce the heat transfer. The results achieved using scanning thermal microscopy (SThM) correlate with the simulated heat flow in the case of individual fibers. This research study brings new insights into the energy efficiency of domestic environments, thereby addressing the growing demand for sustainable and high-performance insulation materials for saving energy loss and reducing pollution footprint.

14.
Polymers (Basel) ; 16(7)2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38611158

RESUMO

Synthetic biomaterials play a crucial role in developing tissue-engineered heart valves (TEHVs) due to their versatile mechanical properties. Achieving the right balance between mechanical strength and manufacturability is essential. Thermoplastic polyurethanes (TPUs) and elastomers (TPEs) garner significant attention for TEHV applications due to their notable stability, fatigue resistance, and customizable properties such as shear strength and elasticity. This study explores the additive manufacturing technique of selective laser sintering (SLS) for TPUs and TPEs to optimize process parameters to balance flexibility and strength, mimicking aortic valve tissue properties. Additionally, it aims to assess the feasibility of printing aortic valve models with submillimeter membranes. The results demonstrate that the SLS-TPU/TPE technique can produce micrometric valve structures with soft shape memory properties, resembling aortic tissue in strength, flexibility, and fineness. These models show promise for surgical training and manipulation, display intriguing echogenicity properties, and can potentially be personalized to shape biocompatible valve substitutes.

15.
Polymers (Basel) ; 16(7)2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38611246

RESUMO

Currently, metal is the most common exterior material used in robot development due to the need to protect the motor. However, as soft, wearable, and humanoid robots are gradually being developed, many robot parts need to be converted into artificial skin using flexible materials. In this study, in order to develop soft exterior parts for robots, we intended to manufacture exterior robot arm parts via fused filament fabrication (FFF) 3D printing according to various structural and thickness conditions and analyze their mechanical properties. The exterior parts of the robot arms were manufactured utilizing Shore 95 A TPU (eTPU, Esun, Shenzhen, China), which is renowned for its softness and exceptional shock absorption characteristics. The exterior robot arm parts were modeled in two parts, the forearm and upper arm, by applying solid (SL) and re-entrant (RE) structures and thicknesses of 1, 2, and 4 mm. The mechanical properties were analyzed through the use of three-point bending, tensile, and compression testing. All of the characterizations were analyzed using a universal testing machine (AGS-X, SHIMADZU, Kyoto, Japan). After testing the samples, it was confirmed that the RE structure was easily bendable towards the bending curve and required less stress. In terms of the tensile tests, the results were similar to the bending tests; to achieve the maximum point, less stress was required, and for the compression tests, the RE structure was able to withstand the load compared to the SL structure. Therefore, after analyzing all three thicknesses, it was confirmed that the RE structure with a 2 mm thickness had excellent characteristics in terms of bending, tensile, and compressive properties. Therefore, the re-entrant pattern with a 2 mm thickness is more suitable for manufacturing a 3D-printed humanoid robot arm.

16.
ChemistryOpen ; : e202300301, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38666528

RESUMO

Direct 3D printing of liquid metal is difficult to form and easy to destroy. In this paper, we developed a 3D printed composite material consisting of a thermoplastic polyurethane (TPU) matrix and liquid metal (LM) dispersed droplets, and introduced the method for realizing 3D printed devices with this composite material: First, the LM is added to 10~50wt %TPU at 190~200 °C through ultrasonic blending to prepare blended ink. After solid cooling, the LM-TPU composite fiber with a diameter of 600 µm was prepared by Wellzoom desktop extruder at 190 °C at an extrusion speed of 400 mm/min. It has excellent elasticity, with a tensile limit of 0.637 N/m2, and the TPU could evenly wrap LM droplets. Finally, the LM-TPU fiber is 3D printed at 240 °C by using a 3D printer, and 2D/3D flexible electronic devices with heating and conductive functions could be prepared. The microcircuit has good electrical conductivity; after adding voltage, the circuit has heat release; it could be used as heating equipment to keep warm and used in various flexible wearable electronic products.

17.
J Exp Bot ; 75(10): 2994-3008, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38436737

RESUMO

Triose phosphate utilization (TPU) limitation is one of the three biochemical limitations of photosynthetic CO2 assimilation rate in C3 plants. Under TPU limitation, abrupt and large transitions in light intensity cause damped oscillations in photosynthesis. When plants are salt-stressed, photosynthesis is often down-regulated particularly under dynamic light intensity, but how salt stress affects TPU-related dynamic photosynthesis is still unknown. To elucidate this, tomato (Solanum lycopersicum) was grown with and without sodium chloride (NaCl, 100 mM) stress for 13 d. Under high CO2 partial pressure, rapid increases in light intensity caused profound photosynthetic oscillations. Salt stress reduced photosynthetic oscillations in leaves initially under both low- and high-light conditions and reduced the duration of oscillations by about 2 min. Besides, salt stress increased the threshold for CO2 partial pressure at which oscillations occurred. Salt stress increased TPU capacity without affecting Rubisco carboxylation and electron transport capacity, indicating the up-regulation of end-product synthesis capacity in photosynthesis. Thus salt stress may reduce photosynthetic oscillations by decreasing leaf internal CO2 partial pressure and/or increasing TPU capacity. Our results provide new insights into how salt stress modulates dynamic photosynthesis as controlled by CO2 availability and end-product synthesis.


Assuntos
Fotossíntese , Estresse Salino , Solanum lycopersicum , Solanum lycopersicum/fisiologia , Solanum lycopersicum/metabolismo , Solanum lycopersicum/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Trioses/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Folhas de Planta/efeitos dos fármacos , Dióxido de Carbono/metabolismo , Fosfatos/metabolismo , Luz , Cloreto de Sódio/farmacologia
18.
Polymers (Basel) ; 16(3)2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38337302

RESUMO

Antioxidants are essential to the polymer industry. The addition of antioxidants delays oxidation and material degradation during their processing and usage. Sustainable phenolic acids such as 4-hydroxybenzoic acid or 3,4-dihydroxybenzoic acid were selected. They were chemically modified by esterification to obtain various durable molecules, which were tested and then compared to resveratrol, a biobased antioxidant, and Irganox 1076, a well-known and very efficient fossil-based antioxidant. Different sensitive matrices were used, such as a thermoplastic polyolefin (a blend of PP and PE) and a purposely synthesized thermoplastic polyurethane. Several formulations were then produced, with the different antioxidants in varying amounts. The potential of these different systems was analyzed using various techniques and processes. In addition to antioxidant efficiency, other parameters were also evaluated, such as the evolution of the sample color. Finally, an accelerated aging protocol was set up to evaluate variations in polymer properties and estimate the evolution of the potential of different antioxidants tested over time and with aging. In conclusion, these environmentally friendly antioxidants make it possible to obtain high-performance materials with an efficiency comparable to that of the conventional ones, with variations according to the type of matrix considered.

19.
ACS Appl Mater Interfaces ; 16(2): 2814-2824, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38181326

RESUMO

High-performance flexible strain sensors have tremendous potential applications in wearable devices and health monitoring. However, developing a flexible strain sensor with high sensitivity over a wide strain range remains a significant challenge. In this study, a fibrous membrane with a porous and crimped structure was designed as the substrate material for TPU/GNPs flexible strain sensors. This structural design effectively balances sensitivity with the strain range. The TPU-PEO fibrous membrane prepared using electrospinning with water washing, resulted in a porous fibrous membrane with a TPU framework. Subsequently, the fibrous membrane was subjected to anhydrous ethanol stimulation to obtain a porous and crimped network structure. GNPs were modified on the TPU fibrous membrane through ultrasonic treatment. The produced flexible strain sensor exhibited high sensitivity (GF = 4047.5) within a large strain range (350%) and demonstrated excellent sensing performance, stability, and durability (>10,000 cycles). It not only captured basic movements but also efficiently recognized and measured bending angles, enabling a more sophisticated human-machine interaction experience. This advancement opens up possibilities for future intelligent wearable technology and human-machine interaction, contributing to the evolution of these fields.

20.
J Funct Biomater ; 15(1)2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38248691

RESUMO

Thermoplastic polyurethane (TPU) is a polymer used in a variety of fields, including medical applications. Here, we aimed to verify if the brush and bar coater deposition techniques did not alter TPU properties. The topography of the TPU-modified surfaces was studied via AFM demonstrating no significant differences between brush and bar coater-modified surfaces, compared to the un-modified TPU (TPU Film). The effect of the surfaces on planktonic bacteria, evaluated by MTT assay, demonstrated their anti-adhesive effect on E. coli, while the bar coater significantly reduced staphylococcal planktonic adhesion and both bacterial biofilms compared to other samples. Interestingly, Pearson's R coefficient analysis showed that Ra roughness and Haralick's correlation feature were trend predictors for planktonic bacterial cells adhesion. The surface adhesion property was evaluated against NIH-3T3 murine fibroblasts by MTT and against human fibrinogen and human platelet-rich plasma by ELISA and LDH assay, respectively. An indirect cytotoxicity experiment against NIH-3T3 confirmed the biocompatibility of the TPUs. Overall, the results indicated that the deposition techniques did not alter the antibacterial and anti-adhesive surface properties of modified TPU compared to un-modified TPU, nor its bio- and hemocompatibility, confirming the suitability of TPU brush and bar coater films in the biomedical and pharmaceutical fields.

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