Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 329
Filter
Add more filters

Country/Region as subject
Publication year range
1.
Small ; : e2406160, 2024 Sep 06.
Article in English | MEDLINE | ID: mdl-39240001

ABSTRACT

Simultaneously improving the strength and toughness of polymer-inorganic nanocomposites is highly desirable but remains technically challenging. Herein, a simple yet effective pathway to prepare polymer-inorganic nanocomposite films that exhibit excellent mechanical properties due to their unique composition and structure is demonstrated. Specifically, a series of poly(methacrylic acid)x-block-poly(benzyl methacrylate)y diblock copolymer nano-objects with differing dimensions and morphologies is prepared by polymerization-induced self-assembly (PISA) mediated by reversible addition-fragmentation chain transfer polymerization (RAFT). Such copolymer nano-objects and ultrasmall calcium phosphate oligomers (CPOs) are used as dual fillers for the preparation of polymer-inorganic composite films using sodium carboxymethyl cellulose (CMC) as a matrix. Impressively, the strength and toughness of such composite films are substantially reinforced as high as up to 202.5 ± 14.8 MPa and 62.3 ± 7.9 MJ m-3, respectively. Owing to the intimate interaction between the polymer-inorganic interphases at multiple scales, their mechanical performances are superior to most conventional polymer films and other nanocomposite films. This study demonstrates the combination of polymeric fillers and inorganic fillers to reinforce the mechanical properties of the resultant composite films, providing new insights into the design rules for the construction of novel hybrid films with excellent mechanical performances.

2.
Small ; : e2310682, 2024 Aug 07.
Article in English | MEDLINE | ID: mdl-39109576

ABSTRACT

Polymer nanocomposites exhibiting remarkable mechanical properties are a focus of research for decades in structural applications. However, their practical application faces challenges due to poor interfacial load transfer, nanofiller dispersion, and processing limitations. These issues are critical in achieving stiff, strong, lightweight, and structurally integrated materials. Additionally, they often suffer from predetermined properties, which may not be effective under specific loading conditions. Addressing these challenges, the development of design strategies for mechano-responsive materials has advanced, enabling self-adaptive properties that respond to various mechanical stimuli. Drawing inspiration from natural systems, these approaches have been implemented in synthetic material systems, leveraging the design flexibility of nanocomposites as needed. Key focus areas include exploring mechanoradical reactions for dynamic mechano-responsiveness, as well as utilizing biomimetic mineralization and mechanical training for self-strengthening. This work also examines multistability, enabling on-demand deformation of materials and structures. Recent advancements in viscoelastic damping and nonreciprocal materials are discussed, highlighting their potential for directional energy absorption, transmission, and vibration control. Despite the need for significant improvements for real-world applications, mechano-responsive polymers and nanocomposites are expected to offer enormous opportunities not only in structural applications but also in other fields such as biomedical engineering, energy harvesting, and soft robotics.

3.
Nanotechnology ; 35(48)2024 Sep 17.
Article in English | MEDLINE | ID: mdl-39231463

ABSTRACT

The advancement of wearable supercapacitors (SCs) has recently garnered a lot of attention owing to their ease of fabrication into textiles, low cost, long cycle life, fast charging and discharging, high efficiency, and ability to bridge the energy and power gap between conventional capacitors and batteries. The present study focuses on the development of wearable textile-based SC electrodes using green-synthesised manganese oxide nanoparticles functionalised on poly(o-phenylenediamine) reinforced to a polymer nanocomposite. The prepared nanocomposite was characterized using spectroscopic techniques such as UV-visible spectroscopy, Fourier transform infrared spectroscopy, x-ray diffraction studies, and scanning electron microscopy to validate the incorporation of metal oxide nanoparticles into the polymer matrix. The thermal properties were studied using thermogravimetric analysis and differential scanning calorimetry. The electrochemical performance of the bare polymer and the nanocomposite was evaluated using cyclic voltammetry, galvanostatic charge-discharge, and impedance spectroscopy techniques. An impressive specific capacitance of 213 Fg-1was achieved at a current density of 1 Ag-1for the polymer nanocomposite and even after 1000 cycles a capacitance retention of 89% was observed. Enhanced antimicrobial activity was also observed for the nanocomposite against both gram-negative and gram-positive bacteria. Based on these attributes, the fabricated device can be used as an efficient antimicrobial wearable SC.

4.
Macromol Rapid Commun ; : e2400612, 2024 Sep 18.
Article in English | MEDLINE | ID: mdl-39292818

ABSTRACT

Polymer nanocomposites have found ubiquitous use across diverse industries, attributable to their distinctive properties and enhanced mechanical performance compared to conventional materials. Elucidating the elastic-to-plastic transition in polymer nanocomposites under diverse mechanical loads is paramount for the bespoke design of materials with desired mechanical attributes. In the current work, the elastic-to-plastic transition is probed in model systems of polyethylene oxide (PEO) and silica, SiO2, nanoparticles, through detailed atomistic molecular dynamics simulations. This comprehensive, multi-scale analysis unveils pivotal markers of the elastic-to-plastic transition, highlighting the quintessential role of microstructural and regional heterogeneities in density, strain, and stress fields, featuring the polymer-nanoparticle interphase region. At the atomic level, the behavior of polymer chains interacting with nanoparticle surfaces is traced, differentiating between free and adsorbed chains, and identifying the microscopic origins of the linear-to-plastic transition. The mechanical behavior of subregions are characterized within the PEO/SiO2 nanocomposites, focusing on the interphase and bulk-like polymer areas, probing stress heterogeneities and their decomposition into various force contributions. At the inception of plasticity, a disruption is discerned in isotropy of the polymeric density field, the emergence of low-density regions, and microscopic voids/cavities within the polymer matrix concomitant with a transition of adsorbed chains to free. The yield strain also emerges as an inflection point in the local versus global strain diagram, demarcating the elastic limit, and the plastic regime shows pronounced strain heterogeneities. The decomposition of the atomic Virial stress into bonded and non-bonded interactions indicates that the rigidity of the material is primarily governed by non-bonded interactions, significantly influenced by the volume fraction of the nanoparticle. These findings emphasize the importance of the microstructural and micromechanical environment at the polymer-nanoparticle interface on the linear-to-plastic transition, which is of great importance in the design of nanocomposite materials with advanced mechanical properties.

5.
Macromol Rapid Commun ; 45(5): e2300620, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38133122

ABSTRACT

This study investigates the effect of adding oligomers on the rheological properties of polymer nanocomposite melts with the goal of enhancing the processability of nanocomposites. The scaling analysis of plateau modulus (GN ) is used in understanding the complex mechanical behavior of entangled poly(methyl acrylate) (PMA) melts upon oligomer addition. Increasing the oligomer amount led to a decrease in GN and an apparent degree of entanglement (Z) in the neat polymer melt. The particle dispersion states at two particle loadings with oligomer addition are examined in transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). The dilution exponent is found unchanged at 7 and 17 vol% particle loadings for the well-dispersed PMA-SiO2 nanocomposites compared to the neat PMA solution. These findings suggest that attractive particles with strong interfacial layers do not influence the tube dilution scaling of the polymer with the oligomer. To the contrary, composites with weak polymer-particle interfaces demonstrate phase separation of particles when oligomers are introduced and its exponent for tube dilution scaling reaches 4 at a particle loading of 17 vol%, potentially indicating that network-forming clusters influence chain entanglements in this scenario.


Subject(s)
Nanocomposites , Polymers , Silicon Dioxide , Scattering, Small Angle , Dilatation , X-Ray Diffraction
6.
Molecules ; 29(15)2024 Jul 29.
Article in English | MEDLINE | ID: mdl-39124984

ABSTRACT

As microelectronics technology advances towards miniaturization and higher integration, the imperative for developing high-performance thermal management materials has escalated. Thermal conductive polymer composites (TCPCs), which leverage the benefits of polymer matrices and the unique effects of nano-enhancers, are gaining focus as solutions to overheating due to their low density, ease of processing, and cost-effectiveness. However, these materials often face challenges such as thermal conductivities that are lower than expected, limiting their application in high-performance electronic devices. Despite these issues, TCPCs continue to demonstrate broad potential across various industrial sectors. This review comprehensively presents the progress in this field, detailing the mechanisms of thermal conductivity (TC) in these composites and discussing factors that influence thermal performance, such as the intrinsic properties of polymers, interfacial thermal resistance, and the thermal properties of fillers. Additionally, it categorizes and summarizes methods to enhance the TC of polymer composites. The review also highlights the applications of these materials in emerging areas such as flexible electronic devices, personal thermal management, and aerospace. Ultimately, by analyzing current challenges and opportunities, this review provides clear directions for future research and development.

7.
Small ; 19(39): e2302676, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37263985

ABSTRACT

Polymer nanocomposites with high loadings of nanoparticles (NPs) exhibit exceptional mechanical and transport properties. Separation of polymers and NPs from such nanocomposites is a critical step in enabling the recycling of these components and reducing the potential environmental hazards that can be caused by the accumulation of nanocomposite wastes in landfills. However, the separation typically requires the use of organic solvents or energy-intensive processes. Using polydimethylsiloxane (PDMS)-infiltrated SiO2 NP films, we demonstrate that the polymers can be separated from the SiO2 NP packings when these nanocomposites are exposed to high humidity and water. The findings indicate that the charge state of the NPs plays a significant role in the propensity of water to undergo capillary condensation within the PDMS-filled interstitial pores. We also show that the size of NPs has a crucial impact on the kinetics and extent of PDMS expulsion, illustrating the importance of capillary forces in inducing PDMS expulsion. We demonstrate that the separated polymer can be collected and reused to produce a new nanocomposite film. The work provides insightful guidelines on how to design and fabricate end-of-life recyclable high-performance nanocomposites.

8.
Small ; 19(3): e2202470, 2023 01.
Article in English | MEDLINE | ID: mdl-36449596

ABSTRACT

The increasing demand for functional materials and an efficient use of sustainable resources makes the search for new material systems an ever growing endeavor. With this respect, architected (meta-)materials attract considerable interest. Their fabrication at the micro- and nanoscale, however, remains a challenge, especially for composites with highly different phases and unmodified reinforcement fillers. This study demonstrates that it is possible to create a non-cytotoxic nanocomposite ink reinforced by a sustainable phase, cellulose nanocrystals (CNCs), to print and tune complex 3D architectures using two-photon polymerization, thus, advancing the state of knowledge toward the microscale. Micro-compression, high-res scanning electron microscopy, (polarised) Raman spectroscopy, and composite modeling are used to study the structure-property relationships. A 100% stiffness increase is observed already at 4.5 wt% CNC while reaching a high photo-polymerization degree of ≈80% for both neat polymers and CNC-composites. Polarized Raman and the Halpin-Tsai composite-model suggest a random CNC orientation within the polymer matrix. The microscale approach can be used to tune arbitrary small scale CNC-reinforced polymer-composites with comparable feature sizes. The new insights pave the way for future applications where the 3D printing of small structures is essential to improve performances of tissue-scaffolds, extend bio-electronics applications or tailor microscale energy-absorption devices.


Subject(s)
Nanocomposites , Nanoparticles , Polymers/chemistry , Cellulose/chemistry , Nanoparticles/chemistry , Nanocomposites/chemistry , Printing, Three-Dimensional
9.
Nanotechnology ; 34(24)2023 Mar 24.
Article in English | MEDLINE | ID: mdl-36753754

ABSTRACT

The mechanical properties of polymer nanocomposites can be improved by incorporating various types of nanofillers. The hybridization of nanofillers through covalent linkages between nanofillers with different dimensions and morphology can further increase the properties of nanocomposites. In this work, aramid nanofibers (ANFs) are modified using chlorinated cellulose nanocrystals (CNCs) and functionalized with 3-glycidoxypropyltrimethoxysilane to improve the chemical and mechanical interaction in an epoxy matrix. The integration of CNC functionalized ANFs (fACs) in the epoxy matrix simultaneously improves Young's modulus, tensile strength, fracture properties, and viscoelastic properties. The test results show that 1.5 wt% fAC reinforced epoxy nanocomposites improve Young's modulus and tensile strength by 15.1% and 10.1%, respectively, and also exhibit 2.5 times higher fracture toughness compared to the reference epoxy resin. Moreover, the glass transition temperature and storage modulus are found to increase when fACs are incorporated. Thus, this study demonstrates that the enhanced chemical and mechanical interaction by the CNC functionalization on the ANFs can further improve the static and dynamic mechanical properties of polymer nanocomposites.

10.
Anal Bioanal Chem ; 415(8): 1559-1570, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36807994

ABSTRACT

A novel voltammetric platform based on pencil graphite electrode (PGE) modification has been proposed, containing bimetallic (NiFe) Prussian blue analogue nanopolygons decorated with electro-polymerized glyoxal polymer nanocomposites (p-DPG NCs@NiFe PBA Ns/PGE). Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square wave voltammetry (SWV) were utilized to investigate the electrochemical performance of the proposed sensor. The analytical response of p-DPG NCs@NiFe PBA Ns/PGE was evaluated through the quantity of amisulpride (AMS), one of the most common antipsychotic drugs. Under the optimized experimental and instrumental conditions, the method showed linearity over the range from 0.5 to 15 × 10-8 mol L-1 with a good correlation coefficient (R = 0.9995) and a low detection limit (LOD) reached, 1.5 nmol L-1, with excellent relative standard deviation for human plasma and urine samples. The interference effect of some potentially interfering substances was negligible, and the sensing platform demonstrated an outstanding reproducibility, stability, and reusability. As a first trial, the proposed electrode aimed to shed light on the AMS oxidation mechanism, where the oxidation mechanism was monitored and elucidated using the FTIR technique. It was also found that the prepared p-DPG NCs@NiFe PBA Ns/PGE platform had promising applications for the simultaneous determination of AMS in the presence of some co-administered COVID-19 drugs, which could be attributed to the large active surface area, and high conductivity of bimetallic nanopolygons.


Subject(s)
COVID-19 , Graphite , Humans , Electrochemical Techniques/methods , Amisulpride , Polymers/chemistry , Reproducibility of Results , Electrodes , Graphite/chemistry
11.
Macromol Rapid Commun ; 44(1): e2200227, 2023 Jan.
Article in English | MEDLINE | ID: mdl-35642732

ABSTRACT

Superionic anhydrous proton conductors can be obtained from the complexation of nanoscale polyoxometalates (POMs) and poly(ethylene glycol) (PEG) in the "polymer in salt" regime. The reduced energy barrier of H+ hopping is facilitated from the increased H+ concentration and shortened inter-POM distances. POMs with identical structure/size (≈1 nm) but different charge densities are complexed with PEG, respectively, with concentrations ranging from 10 to 60 % wt. Increasing trends of viscosities can be observed with the rising charge densities of POMs due to the increasing confinement strength on PEG substrate from POMs. Fractional Walden rule is further applied to analyze the viscosity and proton conductivity correlations, and microscopic mechanisms of proton conduction for PEG-POM nanocomposites are revealed: 1) ion transport is highly associated with polymer chain dynamic for POMs concentrations ranging from 10 to 30 % wt.; 2) ionic conduction is largely decoupled from chain dynamic of polymer matrix for concentrations ranging from 40 to 60 % wt. with Walden plots shifted to the superionic regime. The decoupling of proton transport from polymer segment dynamics allows the simultaneous enhancements of the nanocomposites' mechanical properties and proton conductions, providing guidelines for the rational design of anhydrous proton conductors with integrated functionalities.


Subject(s)
Nanocomposites , Polyethylene Glycols , Polyethylene Glycols/chemistry , Protons , Polymers/chemistry , Nanocomposites/chemistry
12.
Environ Res ; 220: 115212, 2023 03 01.
Article in English | MEDLINE | ID: mdl-36623680

ABSTRACT

Mechanically-robust nanocomposite membranes have been developed via crosslinking chemistry and electrospinning technique based on the rational selection of dispersed phase materials with high Young's modulus (i.e., graphene and multiwalled carbon nanotubes) and Cassie-Baxter design and used for oil and water separation. Proper selection of dispersed phase materials can enhance the stiffness of nanocomposite fiber membranes while their length has to be larger than their critical length. Chemical modification of the dispersed phase materials with fluorochemcials and their induced roughness were critical to achieve superhydrophobocity. Surface analytic tools including goniometer, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, atomic force microscopy (AFM) and scanning electron microscope (SEM) were applied to characterize the superhydrophobic nanocomposite membranes. An AFM-based nanoindentation technique was used to measure quantitativly the stiffness of the nanocomposite membranes for local region and whole composites, compared with the results by a tensile test technique. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques were used to confirm composition and formation of nanocomposite membranes. These membranes demonstrated excellent oil/water separation. This work has potential application in the field of water purification and remediation.


Subject(s)
Nanocomposites , Nanotubes, Carbon , Nanotubes, Carbon/chemistry , Nanocomposites/chemistry , Spectroscopy, Fourier Transform Infrared
13.
Microsc Microanal ; 29(5): 1557-1565, 2023 Sep 29.
Article in English | MEDLINE | ID: mdl-37639375

ABSTRACT

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a versatile surface-sensitive technique for characterizing both hard and soft matter. Its chemical and molecular specificity, high spatial resolution, and superior sensitivity make it an ideal method for depth profiling polymeric systems, including those comprised of both inorganic and organic constituents (i.e., polymer nanocomposites, PNCs). To best utilize ToF-SIMS for characterizing PNCs, experimental conditions must be optimized to minimize challenges such as the matrix effect and charge accumulation. Toward that end, we have successfully used ToF-SIMS with a Xe+ focused ion beam to depth profile silica nanoparticles grafted with poly(methyl methacrylate) (PMMA-NP) in a poly(styrene-ran-acrylonitrile) matrix film by selecting conditions that address charge compensation and the primary incident beam angles. By tracking the sputtered Si+ species and fitting the resultant concentration profile, the diffusion coefficient of PMMA-NP was determined to be D = 2.4 × 10-14 cm2/s. This value of D lies between that measured using Rutherford backscattering spectrometry (6.4 × 10-14 cm2/s) and the value predicted by the Stokes-Einstein model (2.5 × 10-15 cm2/s). With carefully tuned experimental parameters, ToF-SIMS holds great potential for quantitatively characterizing the nanoparticles at the surfaces and interfaces within PNC materials as well as soft matter in general.

14.
Int J Mol Sci ; 24(13)2023 Jun 23.
Article in English | MEDLINE | ID: mdl-37445729

ABSTRACT

Photopolymerization is a growing field with an extensive range of applications and is environmentally friendly owing to its energy-efficient nature. Such light-assisted curing methods were initially used to cure the coatings. However, it has become common to use photopolymerization to produce 3D objects, such as bridges or dental crowns, as well as to cure dental fillings. In this study, polymer nanocomposites containing inorganic nanofillers (such as zinc nano-oxide and zinc nano-oxide doped with two wt.% aluminum, titanium nano-oxide, kaolin nanoclay, zirconium nano-oxide, aluminum nano-oxide, and silicon nano-oxide) were fabricated and studied using Real Time FT-IR to investigate the effects of these nanoadditives on the final conversion rates of the obtained nanocomposites. The effects of the fillers on the viscosity of the produced nanocomposites were also investigated, and 3D prints of the selected nanocomposites were presented.


Subject(s)
Aluminum , Silicon Dioxide , Spectroscopy, Fourier Transform Infrared , Printing, Three-Dimensional , Dentistry , Zinc
15.
Molecules ; 28(21)2023 Oct 30.
Article in English | MEDLINE | ID: mdl-37959762

ABSTRACT

The thermal conductivity of epoxy nanocomposites filled with self-assembled hybrid nanoparticles composed of multilayered graphene nanoplatelets and anatase nanoparticles was described using an analytical model based on the effective medium approximation with a reasonable amount of input data. The proposed effective thickness approach allowed for the simplification of the thermal conductivity simulations in hybrid graphene@anatase TiO2 nanosheets by including the phenomenological thermal boundary resistance. The sensitivity of the modeled thermal conductivity to the geometrical and material parameters of filling particles and the host polymer matrix, filler's mass concentration, self-assembling degree, and Kapitza thermal boundary resistances at emerging interfaces was numerically evaluated. A fair agreement of the calculated and measured room-temperature thermal conductivity was obtained.

16.
Small ; 18(28): e2202421, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35695338

ABSTRACT

Polymer dielectrics with excellent thermal stability are the essential core material for thin film capacitors applied in a harsh-environment. However, the dielectric and mechanical properties of polymers are commonly deteriorated with temperature rising. Herein, polyetherimide (PEI)-based nanocomposites contained with SiO2 nanoparticles (SiO2 -NPs) are fabricated by a solution casting method. It is found that the introduction of SiO2 -NPs decreases the electric conductivity and significantly enhances the breakdown strength of the nanocomposites, especially under high temperatures. As a result, the 5 vol% PEI/SiO2 -NPs nanocomposite film displays a superior dielectric energy storage performance, e.g., a discharged energy density of 6.30 J cm-3 and a charge-discharge efficiency of 90.5% measured at 620 MV m-1 and 150 °C. In situ scanning Kelvin probe microscopy characterization indicates that the charge carriers can be trapped in the interfacial regions between the polymer matrix and the SiO2 -NPs till the temperature reaches as high as 150 °C. This work demonstrates an effective strategy to fabricate high-temperature dielectric polymer nanocomposites by embedding inorganic nanoparticles and provides a method for directly detecting charge behavior at the nanoscale inside the matrix.

17.
Macromol Rapid Commun ; 43(19): e2200221, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35686731

ABSTRACT

Polymer welding has received numerous scientific attention, however, the welding of polymer nanocomposites (PNCs) has not been studied yet. In this work, via coarse-grained molecular dynamics simulation, the attention on investigating the welding interfacial structure, dynamics, and strength by constructing the upper and lower layers of PNCs, by varying the polymer-nanoparticle (NP) interaction strength εNP-p is focused. Remarkably, at low εNP-p , the NPs gradually migrate into the top and bottom surface layer perpendicular to the z direction during the adhesion process, while they are distributed in the middle region at high εNP-p . Meanwhile, the dimension of polymer chains is found to exhibit a remarkable anisotropy evidenced by the root-mean-square radius of gyration in the xy- (Rg,xy ) and z- (Rg,z ) component. The welding interdiffusion depth increases the fastest at low εNP-p , attributed to the high mobility of polymer chains and NPs. Lastly, although the mechanical properties of PNCs at high εNP-p is the strongest because of the presence of the NPs in the bulk region, the welding efficiency is the greatest at low εNP-p . Generally, this work provides a fundamental understanding of the interfacial welding of PNCs, in hopes of guiding to design and fabricate excellent self-healable PNCs.

18.
Macromol Rapid Commun ; 43(15): e2100879, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35298868

ABSTRACT

Synthesis of light polymer nanocomposites with high strength and toughness has been a significant interest for its potential applications in industry. Herein, the authors have synthesized polymerization-induced self-assembly (PISA) derived nanodimensional polymeric worm (fiber) reinforced polymer nanocomposites by a simple and environmentally friendly synthesis process without the addition of volatile organic compounds. PISA-derived worms with a core-forming block of low glass transition temperature (Tg  ≈ 27.1 °C) comprising poly(styrene-stat-n-butyl acrylate) have been employed as reinforcing filler. The influence of core-segment cross-linking on reinforcement efficiency has been explored by comparing noncross-linked worms, and worms cross-linked with a small amount of ethylene glycol diacrylate introduced at t = 0 h or t = 2 h of polymerization. Upon addition of 1 wt% of noncross-linked, t = 0 h cross-linked, and t = 2 h cross-linked worms, toughness of polymer nanocomposites can be enhanced by 62%, 114%, and 120%, respectively. The results suggest that the reinforcement efficiency of worms is significantly influenced by the cross-linking of core-segments regardless of cross-linking methods. This work broadens the understanding in application of PISA-derived worms as reinforcing filler by demonstrating the efficient reinforcement with low Tg worms.


Subject(s)
Nanocomposites , Nanofibers , Acrylates , Polymers , Styrene , Tensile Strength
19.
Environ Res ; 203: 111842, 2022 01.
Article in English | MEDLINE | ID: mdl-34363804

ABSTRACT

Nickel oxide (NiO) nanoparticles (NPs) and graphene quantum dots (GQDs) reinforced polyvinyl alcohol (PVA) nanocomposite films were prepared using a solution casting technique. The physicochemical characteristics of PVA/NiO/GQDs (PNG) nanocomposite films were studied using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM). The obtained PNG nanocomposite films showed good mechanical flexibility and improved tensile strength. The influence of nanofiller concentrations on PNG nanocomposite film. The obtained results demonstrate an increase in the activation energy (Ea) up to PNG3 upon increasing the GQDs concentration and thereafter, its decreases. The fundamental interactions of the constituents of PNG nanocomposite film were investigated using density functional theory (DFT). This study on electronic structure reveals that the PVA model indirectly interacts with GQDs through the NiO model. This configuration is favoured in terms of interaction energy (-78 kJ/mol) compared to the one in which PVA interacts directly with the GQDs model.


Subject(s)
Graphite , Nanocomposites , Nanoparticles , Quantum Dots , Nickel , Polyvinyl Alcohol , Spectroscopy, Fourier Transform Infrared
20.
Int J Mol Sci ; 23(18)2022 Sep 07.
Article in English | MEDLINE | ID: mdl-36142201

ABSTRACT

Polymethyl methacrylate (PMMA), a well-known polymer of the methacrylate family, is extensively used in biomedicine, particularly in odontological applications including artificial teeth, dentures and denture bases, obturators, provisional or permanent crowns, and so forth. The exceptional PMMA properties, including aesthetics, inexpensiveness, simple manipulation, low density, and adjustable mechanical properties, make it a perfect candidate in the field of dentistry. However, it presents some deficiencies, including weakness regarding hydrolytic degradation, poor fracture toughness, and a lack of antibacterial activity. To further enhance its properties and solve these drawbacks, different approaches can be performed, including the incorporation of nanofillers. In this regard, different types of metallic nanoparticles, metal oxide nanofillers, and carbon-based nanomaterials have been recently integrated into PMMA matrices with the aim to reduce water absorption and improve their performance, namely their thermal and flexural properties. In this review, recent studies regarding the development of PMMA-based nanocomposites for odontology applications are summarized and future perspectives are highlighted.


Subject(s)
Nanocomposites , Polymethyl Methacrylate , Anti-Bacterial Agents , Carbon , Denture Bases , Materials Testing , Methacrylates , Oxides , Polymers , Surface Properties , Water
SELECTION OF CITATIONS
SEARCH DETAIL