Nanoparticles In Polymer Matrices Research Articles

Dispersion Strategy improves the mechanical properties of 3D-Printed biopolymer nanocomposite

Homogenous dispersion of nanoparticles in polymer matrices is a technical challenge that if overcome can lead to improved mechanical properties of the resulting nanocomposites. In this work, we successfully refined commercially-available nanoscale, calcium deficient, and poorly crystalline hydroxyapatite (nHA) particles and composited them with acrylate and methacrylate functionalized soybean oil (mAESO) and triethylene glycol dimethacrylate (TEGDMA) producing inks for masked stereolithography (mSLA) -based 3D printing. First, we used shear mixing and ultrasonication on nHA/ethanol mixtures to break down agglomerates and then separated the finest nanoparticles from the remaining agglomerates using centrifugation. The refined nanoparticles (termed fine) were then mixed with the resins and UV-initiator to produce inks for 3D printing. Similarly, we prepared one ink using as-purchased nHA particles (termed raw) and another ink using leftover agglomerates after refinement (termed coarse). We compared the rheological properties of the nHA-resin inks. We used mSLA to fabricate nanocomposite specimens and tested them using flexural, and Mode-I fracture toughness testing following ASTM standards. The dispersion of nanoparticles in the polymer matrix was studied by analyzing backscattered mode scanning electron microscopy images. The nHA particle refinement improved the nanoparticle dispersion in the resin matrix while also increasing the viscosity and shear yield strength of the nanocomposite ink. The flexural fracture strength, flexural modulus, and Mode-I fracture toughness of refined nHA-based nanocomposites were increased by 11 %, 71 %, and 12 %, respectively compared to the raw nHA-based nanocomposites. However, the flexural fracture strain of refined nHA-based nanocomposites was lower by 40 % compared to the raw nHA-based nanocomposites. The nanocomposites became stiffer with the incorporation of refined nanoscale nHA. The separation of nanoscale nHA particles, excellent dispersion of these nanoparticles in polymer matrix, and improved flexural strength and modulus opens a new avenue towards the 3D printing of high-performance nHA-based nanocomposites.

Two-dimensional pattern reverse Monte Carlo analysis of nanoparticles in polymer matrices using a combination of OpenACC and cuFFT

We propose a program code for reverse Monte Carlo (RMC) modeling of two-dimensional scattering patterns using a combination of OpenACC and cuFFT. The RMC method estimates the three-dimensional positions of nanoparticles (NPs) in polymer matrices to fit scattering data of NPs observed in X-ray and neutron experiments. The scattering data can be calculated as the convolution sum of the three-dimensional Fourier transform of the three-dimensional density distributions of NPs using the particle-mesh approach. To speed up the graphics processing unit (GPU) calculations, we implement a code by combining the OpenACC standard and cuFFT library and minimize the data transfer between the GPU and host. This program is publicly available and can facilitate RMC analysis of two-dimensional scattering patterns to model NP morphologies in various polymer materials. Program SummaryProgram title: on-the-fly PM-2DpRMC.CPC Library link to program files: https://doi.org/10.17632/b8dxfjc4vz.1.Licensing provisions: MIT.Programing language: C, OpenACC, cuFFT.Nature of problem: Modelling of changes of 3D positions from series of two-dimensional small angle scattering patterns.Solution method: Particle-mesh based two-dimensional pattern reverse Monte Carlo method.

Scaling Perspective on Dynamics of Nanoparticles in Polymers: Length- and Time-Scale Dependent Nanoparticle–Polymer Coupling

The motion of nanoparticles in a polymer matrix is dictated by the intricate coupling of the nanoparticles and surrounding polymers. Various length- and time-scale dependent features of nanoparticle–polymer coupling in a polymer matrix have been delineated in the past decade by combining scaling theory and molecular simulations. Representative scenarios of nanoparticle dynamics in polymers, which embody the roles of polymer matrix topology, the polymers grafted to nanoparticle surface, the anisotropic shape of nanoparticles, and an external driving force, are reviewed. The systems examined demonstrate both the richness of the physics in the nanoparticle–polymer coupling and the capability of the scaling-level description in providing unique insights into the size- and time-dependence of nanoparticle mobility. Following a review of recent work, more scenarios of nanoparticles in polymer matrices, which reflect new pieces of physics in the nanoparticle–polymer coupling, are discussed. Together with the advances in the chemical synthesis of nanoparticles and polymers as well as in the techniques of tracking nanoparticle motion and measuring nanoparticle diffusivity, the microscopic picture of nanoparticle–polymer coupling revealed theoretically and computationally is anticipated to aid in the manipulation of nanoparticles in complex polymeric environments and thus benefit many technological applications.

A Critical Review on Nanoparticle Filled Adhesives for Structural Applications

The objective of this review paper is to highlight some of the noteworthy research that has been done on the use of nanoparticles (NPs) to improve the performance of adhesively bonded joints (ABJs) against delamination initiation and propagation. Various nanoparticle applications, such as carbon-based, ceramic-based, and mineral-based nanoparticles, are covered. Interlaminar shear strength, fracture toughness, and fracture energy are the major parameters that have been considered for enhancing FRP delamination and fatigue resistance.The reported results indicatethat the inclusion of NPs in polymeric matrices leads to improvement of various material properties,even though some discrepancies in the results have been noted. Notwithstanding, additional researchis required to address some of the issues that have not yet been tackled.

An overview of recent advances in polymer composites with improved UV‐shielding properties

AbstractOwing to their competitive price, ease of processability, and rust resistance, polymers are the most extensively used materials in everyday life. However, consistent exposure to ultraviolet (UV) radiation can lead to the degradation and discoloration of polymeric materials. Various polymer composites containing inorganic and organic nanoparticles (NPs) have been developed to improve the UV‐shielding properties of neat polymers. However, the most used UV‐shielding inorganic NPs are prone to photocatalytic processes, leading to further polymer chain degradation. To overcome this challenge, organic NPs have been used; however, they easily agglomerate, decreasing the UV‐shielding performance of the polymer composites. Herein, we critically report the fundamentals of the UV‐shielding mechanism and the synthesis methods, surface modification, and characterization of the most important inorganic and organic UV‐shielding NPs. We then summarize the various processing techniques used to disperse NPs in polymer matrices to obtain polymer composites with improved UV‐shielding properties. Finally, we propose a broader understanding of how the NP characteristics, their interaction with polymer matrices, and the various processing methods affect the UV‐shielding performance of the obtained polymer composites. In addition, various applications of inorganic and organic NPs‐containing UV‐shielding polymer composites have been reported.

Investigation of structures formed by magnetic fluid nanoparticles in polymer matrices by static light scattering

Investigation of structures formed by magnetic fluid nanoparticles in polymer matrices by static light scattering

Specific features of thermal properties of polymer composites containing conductive nanoparticles in non-conductive polymer matrices

The thermophysical properties of nanocompositions containing conducting nanoparticles of silver, gold, and fullerene C60 in nonconductive polymer matrices of various natures - chitosan, poly(vinylpyrrolidone), poly(methyl methacrylate), poly(allyl methacrylate), organic-inorganic copolymers based on hydroxyethyl methacrylate and poly(titanium oxide) are considered in detail. Gold or silver nanoparticles in polymer matrices of various natures were formed in situ by UV reduction of the corresponding precursors - HAuCl4 or AgNO3. The average size of the nanoparticles did not exceed 20 nm. Fullerene C60 was introduced either directly into the polymer matrix during the mixing process or on the synthesis of the polymer. The thermophysical properties of all polymer nanocomposites were studied by differential scanning calorimetry and dynamic mechanical analysis. In all cases, there is a significant decrease in the glass transition temperatures of the composites by an amount from 20 to 60°C relative to the glass transition temperature of the polymer matrix.

The Use of Nanocellulose in Edible Coatings for the Preservation of Perishable Fruits and Vegetables

The usage of edible coatings (ECs) represents an emerging approach for extending the shelf life of highly perishable foods, such as fresh and fresh-cut fruits and vegetables. This review addresses, in particular, the use of reinforcing agents in film-forming solutions to tailor the physicochemical, mechanical and antimicrobial properties of composite coatings. In this scenario, this review summarizes the available data on the various forms of nanocellulose (NC) typically used in ECs, focusing on the impact of their origin and chemical or physical treatments on their structural properties (morphology and shape, dimension and crystallinity) and their functionality. Moreover, this review also describes the deposition techniques of composite ECs, with details on the food engineering principles in the application methods and formulation optimization. The critical analysis of the recent advances in NC-based ECs contributes to a better understanding of the impact of the incorporation of complex nanoparticles in polymeric matrices on the enhancement of coating properties, as well as on the increase of shelf life and the quality of fruits and vegetables.

3D-Positioning of Nanoparticles in High-Curvature Block Copolymer Domains.

The defined assembly of nanoparticles in polymer matrices is an important precondition for next‐generation functional materials. Here we demonstrate that a defined three‐dimensional nanoparticle assembly within the unit cells can be realized by directly linking the nanoparticles to block copolymers. We show that for a range of nearly symmetric to unsymmetric block copolymers there are only two formed structures, a hexagonal lattice of P6/mmm‐symmetry, where the nanoparticles are located in 1D‐arrays within the cylindrical domains, and a cubic lattice of Im3m‐symmetry, where the nanoparticles are located in the octahedral voids of a BCC‐lattice, corresponding to the structure of ferrite steel. We observe the block length ratio and thus the interfacial curvature to be the most important parameter determining the lattice type. This is rationalized in terms of minimal chain extension such that domain topologies with large positive curvature are highly preferred. Already volume fractions of only one percent are sufficient to destabilize a lamellar structure and favor the formation of highly curved interfaces. The study thus demonstrates how nanoparticles can be located on well‐defined positions in three‐dimensional unit cells of block copolymer nanocomposites. This opens the way to functional 3D‐nanocomposites where the nanoparticles need to be located on defined matrix positions.

3D‐Positioning of Nanoparticles in High‐Curvature Block Copolymer Domains

AbstractThe defined assembly of nanoparticles in polymer matrices is an important precondition for next‐generation functional materials. Here we demonstrate that a defined three‐dimensional nanoparticle assembly within the unit cells can be realized by directly linking the nanoparticles to block copolymers. We show that for a range of nearly symmetric to unsymmetric block copolymers there are only two formed structures, a hexagonal lattice of P6/mmm‐symmetry, where the nanoparticles are located in 1D‐arrays within the cylindrical domains, and a cubic lattice of Im3m‐symmetry, where the nanoparticles are located in the octahedral voids of a BCC‐lattice, corresponding to the structure of ferrite steel. We observe the block length ratio and thus the interfacial curvature to be the most important parameter determining the lattice type. This is rationalized in terms of minimal chain extension such that domain topologies with large positive curvature are highly preferred. Already volume fractions of only one percent are sufficient to destabilize a lamellar structure and favor the formation of highly curved interfaces. The study thus demonstrates how nanoparticles can be located on well‐defined positions in three‐dimensional unit cells of block copolymer nanocomposites. This opens the way to functional 3D‐nanocomposites where the nanoparticles need to be located on defined matrix positions.

Nanoparticles Filled Polymer Nanocomposites: A Technological Review

Incorporation of nanoparticles in polymeric matrices to develop polymer nanocomposite with an idea to maximize the “nano-effect” derived out of the nanoparticles and to minimize the disadvantages o...

Assembly of Polymer-Grafted Nanoparticles in Polymer Matrices.

Leibler pioneered the idea that long enough matrix polymers of length P will spontaneously dewet a chemically identical polymer layer, comprising chains of length N, densely end-grafted to a flat surface ("brush"). This entropically driven idea is routinely used to explain experiments in which 10-20 nm diameter nanoparticles (NPs) densely grafted with polymer chains are found to phase separate from chemically identical melts for P/N ≳4. At lower grafting densities, these effects are also thought to underpin the self-assembly of grafted NPs into a variety of structures. To explore the validity of this picture, we conducted large-scale molecular dynamics simulations of grafted NPs in a chemically identical polymer melt. For the NPs we consider, in the ≈5 nm diameter range, we find no phase separation even for P/N = 10 in the absence of attractions. Instead, we find behavior that more closely parallels experiments when all of the chain monomers are equally attractive to each other but repel the NPs. Our results thus imply that experimental situations investigated to date are dominated by the surfactancy of the NPs, which is driven by the chemical mismatch between the inorganic core and the organic ligands (the graft and free chains are chemically identical). Entropic effects, that is, the translational entropy of the NPs and the matrix, the entropy of mixing of the grafts and the matrix, and the conformational entropy of the chains appear to thus have a second-order effect even in the context of these model systems.

Incorporation of ZnO nanoparticles in polymeric matrices as UV protector

At present there is great interest in the development of new nanomaterials that can be applied in different areas of study such as chemistry, physics, medicine, among others. In many polymeric materials, especially when used in coatings exposed to sunlight, they cause photolysis and photooxidation reactions, leading to the degradation of their physical-mechanical, optical and other properties. Therefore, the need to look for new materials capable of resisting radiation for prolonged periods, while retaining its original characteristics, such as hue and brightness, is imperative. Zinc oxide nanoparticles have attracted great interest in this aspect as they are used in most commercial sunscreens that use inorganic pigments, for their ability to adsorb ultraviolet rays. In the present work, the incorporation of the Np-ZnO in situ during the polymerization by the emulsion process of butyl acrylate was carried out. ZnO nanoparticles are incorporated into butyl polyacrylate in different concentrations of 0.3%, 0.5%, and 1% W, in which it is observed that at 1% there is greater agglomeration and in the others it does not affect the morphology of our polymer.

Mechanical and Optical Properties of Stretchable Silicon Nanocrystal/Polydimethylsiloxane Nanocomposites

Nanoparticle‐infused polymer composites have long been an area of interest due to the typically stabilizing effects they have on the mechanical behavior of the composites, as well as added functionalities such as reduced surface resistance. Newer applications of these nanocomposites include dispersing optoelectronically functional nanoparticles in polymer matrices, for example, including luminescent nanocrystals in rigid slabs for luminescent solar concentrating photovoltaics and electrochromic panels. Dispersion of luminescent nanocrystals in stretchable polymers adds novel possibilities for applications, such as wearable health monitoring systems, flexible communications devices, and more. To leverage the exciting combined properties that these nanocomposites promise, there is a pressing need to evaluate and understand the interconnections between the optical effects, mechanical behavior, and the properties of the constituents. Herein, the optical and mechanical behavior of brightly emissive silicon nanocrystal/polydimethylsiloxane (PDMS) nanocomposites are investigated as a function of nanocrystal concentration and nanocrystal surface functionality. Mechanically, incorporating the nanocrystals at higher concentration leads to a dramatic reduction in the mechanical properties of the nanocomposite. The results suggest that the nanocrystal inclusions interfere with polymer cross‐linking, changing the mechanical behavior of the host PDMS as compared to the control.

Self‐Assembled PMMA Porous Membranes Decorated with In Situ Synthesized ZnO Nanoparticles with UV‐Tunable Wettability

AbstractThis study reports a simple approach to fabricate porous poly(methyl methacrylate) (PMMA) membranes homogeneously decorated with exposed zinc oxide (ZnO) nanoparticles (NPs). This fabrication method significantly overcomes the disadvantages of both conventional foaming processes and incorporation of inorganic NPs in polymeric matrices. In particular, the porous structure is simply self‐assembled by slowly evaporating a suitable solvent. The ZnO NPs are in situ formed by a thermally activated conversion of the zinc acetate precursor, previously embedded in the polymeric matrix. Scanning and transmission electron microscopy investigations show the formation of the desired self‐assembled highly porous structure and ZnO NPs with branched morphology, respectively. The wetting behavior of the membranes surface is studied as a function of the ZnO content and UV irradiation, exploiting the switchable wettability of ZnO. The obtained unexpected results are then tentatively rationalized taking into account the surface chemistry and the roughness that arises from both porous structure and the different NPs dimensions and content.

Antifungal susceptibility of Candida species to copper oxide nanoparticles on polycaprolactone fibers (PCL-CuONPs).

The integration of metallic or ceramic nanoparticles in polymer matrices has improved the antimicrobial and antifungal behavior, resulting in the search for composites with increased bactericidal and antimycotic properties. A polycaprolactone fibers with copper oxide nanoparticles was prepared. Polycaprolactone-copper fibers (PCL- CuONPs) were prepared into two major steps in situ method: (a) Synthesis of CuO particles, then (b) incorporation of polycaprolactone to electrospun process. The first step is the reduction of Cu+2 ions by gallic acid in N,N-dimethylformamide and tetrahydrofuran solution with the simple addition of polycaprolactone in the solution for the second electrospun step. Raman spectra provide information about the nature of the copper oxide synthesized. There are three Raman peaks in the sample, at 294 and 581 cm-1 and a very broad band from 400 to 600 cm-1 which are characteristics bands for CuO. Scanning electron microscopy (TEM) revealed copper oxide nanoparticles with semispherical shapes with diameter 35 ±11 nm. Dynamic light scattering (DLS) analysis showed uniform CuONPs in a range of 88±11 nm. Scanning electron microscopy (SEM) of PCL-CuONps reveled fibers with diameters ranging from 925 to 1080 nm were successfully obtained by electrospinning technique. Orientation, morphology and diameter were influenced by the increment on CuONPs concentration, with the smaller diameter present in samples prepared from low concentrated solutions. The antimycotic applicability of the composite was evaluated to determine the antifungal activity in three species of the genus Candida (Candida albicans, Candida glabrata and Candida tropicalis). PCL-CuONPs exhibit a considerable antifungal effect on all species tested. The preparation of PCL-CuONPs was simple, fast and low-cost for practical application as an antifungal dressing.

Azo functionalized polystyrene supported Copper nanoparticles: An economical and highly efficient catalyst for A[formula omitted] and KA[formula omitted] coupling reaction under microwave irradiation

The combination of polymeric support and metal nanoparticles were always leading towards better catalytic systems. Herein, we report Cu supported on azo functionalized polystyrene. The synthesized catalyst was characterized by (SEM, HR-TEM, EDX, RAMAN, XPS, and IR). Active Cu species stabilized by azo linkages present in the polymer matrices is responsible for the catalytic activity. We enrolled in the catalyst in A3 (aldehyde, amine, and acetylene) and KA2 (cyclic ketone, amine, acetylene) coupling reaction. Synthesized catalyst performs much better under microwave irradiation as compared to the conventional method. The better activity of the catalyst may be due to the presence of azo linkages which stabilized the copper nanoparticles in polymer matrices. We achieved 98% yield in both the coupling reactions and time ranges between 15–20 min. We synthesized six derivatives of tetra substituted propargylamine and twenty two derivatives of propargylamines by utilizing optimized conditions. Furthermore, the synthesized catalyst and the reaction conditions were environmentally friendly. In the reusability scan, we found that catalyst was reuse more than seven times with a slight loss in its activity.

3D-Printed Diamond-Titanium Composite: A Hybrid Material for Implant Engineering.

Diamond-based implant materials make up an emerging research area where the materials could be prepared to promote cellular functions, decrease bacteria attachment, and be suitable for potential in situ imaging. Up until now, diamond implants have been fabricated using coating technologies or embedding diamond nanoparticles in polymer matrices. Here we demonstrated a method of manufacturing diamond implants using laser cladding technology to 3D print a composite of diamond and fused titanium material. Using this method, we could prepare composite scaffolds of up to 50% diamond, which has never been achieved before. We next investigated the interfacial properties of these scaffolds for potential applications in implants. The addition of diamond to the biomaterial results in a 30% decrease in the water contact angle, making the scaffolds more hydrophilic and improving cellular adhesion and proliferation.

Synthesis of Metal-Polymer Complexes and Functional Nanostructures in Films and Coatings of Interpolyelectrolyte Complexes

Interpolyelectrolyte complexes possess high ion-exchange capacity, which makes it possible to obtain metal-polymer compounds on their basis and allows their use for the extraction of metal ions from dilute aqueous solutions. The deposition and reduction of metal ions is the main method of obtaining nanoparticles in polymer matrices. Tuning the interaction of functional groups of polyanions and polycations with ions/metal surfaces provides wide opportunities to control the structure and size of nanoparticles and to obtain nanocomposites. The review discusses the work of A.B. Zezin devoted to the structure and mechanisms of the formation of metal-polymer complexes in films and coatings of interpolyelectrolyte complexes, which were the starting point for the development of methods for producing nanocomposites.

Optically detected magnetic resonance study of relaxation/emission processes in the nanoparticle-polymer composite

Two nanocomposites containing CdS nanoparticles in polymeric matrices were studied using the photoluminescence (PL) and optically detected magnetic resonance (ODMR) methods. Due to equal sizes of N ...