Production Of Polymer Nanocomposites Research Articles

Effects of Nanofillers and Synergistic Action of Carbon Black/Nanoclay Hybrid Fillers in Chlorobutyl Rubber

Nanocomposites based on chlorobutyl rubber (CIIR) have been made using a variety of nanofillers such as carbon black (CB), nanoclay (NC), graphene oxide (GO), and carbon black/nanoclay hybrid filler systems. The hybrid combinations of CB/nanoclay are being employed in the research to examine the additive impacts on the final characteristics of nanocomposites. Atomic force microscopy (AFM), together with resistivity values and mechanical property measurements, have been used to characterise the structural composition of CIIR-based nanocomposites. AFM results indicate that the addition of nanoclay into CIIR increased the surface roughness of the material, which made the material more adhesive. The study found a significant decrease in resistivity in CIIR–nanoclay-based composites and hybrid compositions with nanoclay and CB. The higher resistivity in CB composites, compared to CB/nanoclay, suggests that nanoclay enhances the conductive network of carbon black. However, GO-incorporated composites failed to create conductive networks, which this may have been due to the agglomeration. The study also found that the modulus values at 100%, 200%, and 300% elongation are the highest for clay and CB/clay systems. The findings show that nanocomposites, particularly clay and clay/CB hybrid nanocomposites, may produce polymer nanocomposites with high electrical conductivity. Mechanical properties correlated well with the reinforcement provided by nanoclay. Hybrid nanocomposites with clay/CB had increased mechanical properties because of their enhanced compatibility and higher filler–rubber interaction. Nano-dispersed clay helps prevent fracture growth and enhances mechanical properties even more so than CB.

Maximizing filler content and manufacturing highly thermal conductive composite materials through eutectic liquefaction of epoxy resin

We report novel research results demonstrating the production of polymer nanocomposites with high thermal conductivity. The use of diluents, a conventionally used method to reduce viscosity and increase processability, had clear limitations that could not be used for solid epoxy, but in this study, the melting point of the epoxy itself was reduced through the introduction of the eutectic system, allowing the solid epoxy to be converted into a liquid phase. By utilizing eutectic liquid (EL) derived from ketone-containing epoxy resin (DBPE) and diphenylamine (DPA), we achieved maximal filler content. Unlike DBPE’s solid form at 135 °C, EL displayed liquidity with a viscosity of 50 Pa·s at 50 °C, enabling curing with isophorone diamine (IPDA) below DBPE’s melting point. While DBPE/IPDA yielded a tensile strength of 7.2 MPa due to uneven mixing, EL/IPDA reached 44.3 MPa, marking a 520 % improvement. EL’s viscosity dropped dramatically, reaching 0.06 Pa·s at 98 °C. The EL/IPDA mixture’s viscosity at 98 °C was 150 Pa·s, allowing up to 80 wt% hexagonal boron nitride (h-BN) filler. This led to a thermal conductivity of 16 W/m·K, 20 wt% higher than DGEBA’s 60 wt% filling rate. Notably, EL/h-BN composites achieved 16 times the thermal conductivity of DGEBA/h-BN composites, which is 1 W/m·K. Lowering the melting point and viscosity expanded curing agent choices, enhanced tensile strength, increased filler content, and heightened thermal conductivity, showcasing EL’s remarkable potential.

Improving the mechanical performance of low graphene content epoxy nanocomposites: investigation of hybrid and chemically modified nanofillers

Graphene is a promising nanofiller for producing polymer nanocomposites with enhanced mechanical, electrical, thermal, electromechanical, and flame retardancy properties, leading to applications in aerospace, automotive, ballistics, medicine, electronics, and smart materials. Solvent-assisted top-down methods, including mechanical exfoliation of graphite, show great potential for scale-up and mass production of graphene dispersions for use in the fabrication of nanocomposites. However, these approaches can suffer from poor efficiency, which limits the concentrations of graphene/polymer dispersions that can be produced using in situ methods. As such, it is important to find new ways of making more effective use of these low concentrations of graphene nanofillers. Possible approaches include chemical modification of the graphene or finding synergies with other nanofillers to form hybrid nanocomposites. In this work, we demonstrate results that make use of each approach. Specifically, we demonstrate a low-cost and simple method for producing carbon nanotube dispersions and creating hybrid nanocomposites with substantial enhancements to mechanical properties. We also extend the scope of our previously reported semi-in situ exfoliation method by demonstrating its application in the production of a nanocomposite that incorporates chemically modified graphene. The superior mechanical properties exhibited by the nanocomposite are attributed to increased interaction strength between the polymer and nanofiller.

Molecular dynamics simulations for interfacial structure and affinity between carboxylic acid-modified Al2O3 and polymer melts.

Controlling the dispersion state of nanoparticles in a polymer matrix is necessary to produce polymer nanocomposites. The surface modification of nanoparticles is used to enable their dispersion in polymers. Moreover, molecular dynamics (MD) simulations are useful for revealing the interfacial properties between nanoparticles and polymers to aid in the design of materials. In this study, the effect of surface coverage, modifier length, and polymer species on the interfacial structure and affinity between surface-modified Al2O3 and polymer melts were investigated using all-atom MD simulations. Hexanoic, decanoic, and tetradecanoic acids were used as surface modifiers, and polypropylene (PP), polystyrene (PS), and poly (methyl methacrylate) (PMMA) were used as polymers. The work of adhesion Wadh and the work of immersion Wimm were selected as quantitative measures of affinity. Wadh was calculated using the phantom-wall approach, and Wimm was calculated by simply subtracting the surface tension of polymers γL from Wadh. The results showed that Wadh and Wimm were improved by surface modification with low coverage, owing to a good penetration of the polymer. The effect of modifier length on Wadh and Wimm was small. Whereas Wadh increased in the following order: PP < PS < PMMA, Wimm increased as follows: PMMA < PS < PP. Finally, the trend of Wadh and Wimm was organized using the Flory-Huggins interaction parameter χ between the modifier and the polymer. This study demonstrates that the interfacial affinity can be improved by tuning the surface coverage and modifier species depending on the polymer matrix.

Non‐covalent interactions between ionic liquid and graphene nanoplatelets as a tool to fine tune the properties of styrene butadiene rubber nanocomposites

AbstractAchieving a robust interfacial interaction between the filler and polymer matrix is crucial for the production of polymer nanocomposites with superior performance. 1‐butyl‐3‐methyl imidazolium bromide (BMIB) was used to fine‐tune the surface properties of graphene nanoplatelets (GnP) in the preparation of ionic liquid (IL)‐functionalized styrene‐butadiene rubber (SBR) nanocomposites. The combined results of Fourier transformation infrared (FTIR) spectroscopy, Raman spectroscopy, x‐ray diffraction (XRD), x‐ray photoelectron spectroscopy, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) confirmed multiple non‐covalent interactions between BMIB molecules and GnP in modified graphene (IMG). FTIR and XRD studies confirmed the role of IL as an efficient surface modifier for the uniform dispersion of GnP in the SBR matrix via secondary interactions. And the TEM micrographs revealed an even dispersion of IMG in the SBR matrix. TGA and DTG studies showed significant improvements in the thermal stability of SBR nanocomposites with IMG loading. The Cole‐Cole plot showed imperfect semicircles for all the filled systems, indicating heterogeneity. The novel SBR nanocomposites showed an improvement of 271% in tensile strength with 10‐phr IMG loading

A brief review on polymer nanocomposites: current trends and prospects

Abstract Nanoparticles (NPs) are being incorporated into pristine polymeric matrices as well as recycled waste polymers to prepare new materials with enhanced properties called polymer nanocomposites (PNCs). There has been an accelerating growth in the field of polymer nanocomposites in the last two decades owing to their tunable and enhanced optical, thermal, electrical, magnetic, and mechanical properties, which make them viable and well-suited for various applications. The addition of nanoparticles in the form of nanosheets, nanotubes, nanospheres, quantum dots, etc., to the polymer matrices reduces the drawbacks of polymers like low mechanical strength, weaker chemical resistivity, etc. due to the large surface area to volume ratio of NPs. Moreover, the interaction of nanoparticles with the polymer chain lowers the permeability of gases and increases the water resistance of the polymer. Due to their remarkable capabilities, polymer nanocomposites have attracted significant theoretical interest as well as a large number of practical applications in a variety of scientific and technological domains. This article provides an overview of the various classes of nanoparticles and different fabrication methods used to produce polymer nanocomposites. Additionally, an effort is made to comprehend the properties and applications of polymer nanocomposites in different areas like wastewater treatment, dye removal, heavy metal and gas sensing, optoelectronics, etc.

Poly(acrylic acid-co-acrylamide)/Polyacrylamide pIPNs/Magnetite Composite Hydrogels: Synthesis and Characterization

Novel composite hydrogels based on poly(acrylic acid-co-acrylamide)/polyacrylamide pseudo-interpenetrating polymer networks (pIPNs) and magnetite were prepared via in situ precipitation of Fe3+/Fe2+ ions within the hydrogel structure. The magnetite formation was confirmed by X-ray diffraction, and the size of the magnetite crystallites was shown to depend on the hydrogel composition: the crystallinity of the magnetite particles increased in line with PAAM content within the composition of the pIPNs. The Fourier transform infrared spectroscopy revealed an interaction between the hydrogel matrix, via the carboxylic groups of polyacrylic acid, and Fe ions, which strongly influenced the formation of the magnetite articles. The composites' thermal properties, examined using differential scanning calorimetry (DSC), show an increase in the glass transition temperature of the obtained composites, which depends on the PAA/PAAM copolymer ratio in the pIPNs' composition. Moreover, the composite hydrogels exhibit pH and ionic strength responsiveness as well as superparamagnetic properties. The study revealed the potential of pIPNs as matrices for controlled inorganic particle deposition as a viable method for the production of polymer nanocomposites.

Thermoset/graphene polymer composites—A review of processing and properties

AbstractPolymer‐carbon nanocomposites incorporate the exceptional properties of both the polymer matrices, such as low cost and simple processing, with the distinctive features of the carbon‐based fillers, such as high electrical and thermal conductivities, and excellent mechanical properties. Various fillers like carbon black (CB), graphite, expanded graphite (EG), and carbon nanotubes (CNTs) are being used to produce materials with advanced properties. However, at high filler loading, these filler materials have some major challenges such as filler agglomeration. Recently, graphene has gained increased interest as an alternative filler to produce polymer nanocomposites with advanced characteristics. Thermosetting polymer composites with graphene fillers are being considered for multiple applications and are a subject of interest for researchers because of enhanced properties like excellent corrosion resistance and low density. This review outlines studies to improve the mechanical, electrical, and thermal properties of thermoset/graphene composites.

A long chain-induced depletion effect for abnormal grafting in the preparation of bimodal bidisperse polymer-grafted nanoparticles.

One of the challenging problems in the research field of polymer nanocomposites is how to prepare nanocomposites with high grafting density and strong ability of dispersion at the same time. For nanocomposites composed of bimodal bidisperse polymer chains and nanoparticles, the above requirements can be met by rationally adjusting the ratio of long and short polymer chains. In this study, the process of grafting bimodal bidisperse polymer chains onto the surface of nanoparticles in a grafting-to manner was investigated via computer simulation and theoretical methods. Three grafting strategies were designed: first short then long (SL) system, both short and long (Both) system and first long then short (LS) system. An abnormal phenomenon for the Both system was found by analyzing the grafting density of long and short polymer chains on the surface of nanoparticles. We speculate that the reason for this anomalous phenomenon is the "depletion effect" brought about by the long chains in the Both system. We employ the Polymer Reference Interaction Site Model (PRISM) theory to investigate this anomaly in-depth. By comparing the radial distribution function (RDF) predicted by the PRISM theory with the RDF results obtained by the molecular dynamics (MD) simulation, we found that with the increase of the number of long chains in the system, the grafting density of short polymer chains on the nanoparticle surface showed an obvious upward trend. The "depletion effect" brought by long chains was the main reason for higher short chains' grafting density of the Both system compared to the SL system. Our findings provide effective guidance for the design of nanoparticle-grafted bimodal bidisperse polymer chains and provide a theoretical basis for experimentation and production of polymer nanocomposites with better performance.

Dynamics and morphology of self‐assembly behavior of polymer‐grafted nanoparticles: a dissipative particle dynamics simulation study

AbstractThe self‐assembly of polymer‐grafted nanoparticles is increasingly applied in the field of functional materials. However, the corresponding relationship between the intrinsic dynamic transition path and microstructure is still not clear enough, which will lead to an inability to achieve further precise regulation and directional design in experiments and industrial production. In this study, by constructing a coarse‐grained model of polymer‐grafted nanoparticles, the dissipative particle dynamics (DPD) simulation method is used to study the effects of the following three factors on the self‐assembly behavior and structure of polymer‐grafted nanoparticles: solvophobic polymer chain length, solvophilic–solvophobic chain ratio and solvent selectivity. The simulation results show that with an increase of the chain length of the solvophobic chain, the self‐assembled morphological structure presents a process of changing from an onion‐like vesicle structure to a unilamellar vesicle structure; the morphology gradually changes from a higher‐order morphology to a lower‐order morphology with an increase of the ratio of solvophilic to solvophobic chains. In addition, solvent selectivity can also tune the aggregated morphology of polymer‐grafted nanoparticles. When the compatibility of the solvent with solvophobic polymers and solvophilic polymers is quite different, polymer‐grafted nanoparticles tend to form unilamellar vesicles; when the compatibility of the solvent with solvophobic polymer and solvophilic polymer is close, the polymer‐grafted nanoparticles tend to form a multilamellar micelle structure. The use of coarse‐grained DPD simulations to study the effect of various factors on the self‐assembly behavior of polymer‐grafted nanoparticles can achieve precise regulation of specific polymer structures, thereby providing reliable theoretical guidance for laboratory and industrial production of polymer nanocomposites with fewer defects and better performance. © 2022 Society of Industrial Chemistry.

Polymer-Magnetic Semiconductor Nanocomposites for Industrial Electronic Applications.

Nanocomposite materials have acquired great importance, as have similar composite materials on a macroscopic scale, because the reinforcement complements the defects in the properties of the matrix, thus obtaining materials with better mechanical, thermal, and electrical properties, among others. At the same time, the importance and research of polymeric nanocomposites reinforced with nanoparticles of various types have grown. Among those that have stood out the most in the electronics industry are polymeric matrices reinforced with nanoparticles that present dual behavior, that is, both magnetic and semiconductor. This property has been very well used in developing electronic devices such as televisions, computers, and smartphones, which are part of everyday life. In this sense, this review presents a compilation of the synthetic methods to produce polymer nanocomposites with dual magnetic and semiconductor behavior and their potential applications within electronic fields and new relevant trends.

Improving Latex‐Based Pressure‐Sensitive Adhesive Properties Using Carboxylated Cellulose Nanocrystals

AbstractCellulose nanocrystals (CNCs) are becoming a popular option when producing polymer nanocomposites because they are a green alternative to petroleum‐based performance enhancers and provide significant matrix reinforcement at low loadings. DextraCel is a commercial grade CNC with carboxylate surface groups that can be dispersed in water without sonication. These carboxylated CNCs (cCNCs) can be incorporated in situ via seeded semi‐batch emulsion polymerization to produce latexes for adhesive applications. The resulting nanocomposite films exhibit 26x higher peel strength, 4.5x higher tack, and 7.7x higher shear strength relative to base case films. Curiously, adhesives produced from latexes containing cCNCs that do not undergo ultrasonication display greater adhesive property improvements relative to films produced with cCNCs that are ultrasonicated. Atomic force microscopy images reveal that cCNCs have stronger self interactions than their sulfated CNCs counterparts; cCNCs display side‐by‐side and end‐to‐end association in films when they are not ultrasonicated, which increases their “apparent” aspect ratio—an important characteristic attributed to matrix reinforcement. Omitting ultrasonication preserves cCNC‐cCNC interactions that cause them to behave like nanofibers rather than discrete nanocrystals; this allows them to display greater mechanical enhancements, similar to reinforcements provided by nanofibrils, without the technical challenges associated with producing composite latexes with nanofibrils.

Перколяционная модель формирования высокомодульных нанокомпозитов полимер/углеродные нанотрубки

Production of the high-modulus nanocomposites polymer/carbon nanotubes and polymer/graphene at present is actual task and its solution is obviously important for such innovational industry sectors as air-, automobile industry, astronautics a.a. The general theoretical criterions of production of the indicated nanomaterials studied within the frameworks of percolative models of polymer nanocomposites reinforcement. These models assumed, that reinforcement degree or relative modulus of elasticity of polymer nanocomposites is defined by nanofiller structure in polymer matrix of nanocomposites. The structure of nanofiller (more exactly, its aggregates) can be characterized by fractal dimension of these aggregates. A various variants of percolative model of polymer nanocomposites reinforcement allow to taken into account such important for this class of nanomaterials parameters as the level of interfacial adhesion, relative content of interfacial regions (which are in the case of polymer nanocomposites the same reinforcing element of their structure as and actually nanofiller), aggregation degree of nanofiller a.a. Such approach allows to obtain functional interrelation between these characteristics and define conditions, which are necessary of production of high-modulus polymer nanocomposites. It was been found that for this goal achievement is necessary performance of the following conditions: realization of negative values of percolative index. Mathematically this condition is realized in the case, when aggregation degree is smaller, than volume content of nanofiller. Further, the usage of volume content of nanofiller larger than its percolation threshold and achievement of nanoadhesion effect are two following conditions. In the case of the indicated conditions performance percolative model predicts the possibility of production of polymer nanocomposites of the considered classes, which have mechanical characteristics, compared by its value with similar parameters for steel, but essentially smaller by weight.

Fabrication techniques of polymeric nanocomposites: A comprehensive review

Nanotechnology is the key solution for many human problems such as energy conversion, water treatment, and material science. In composite materials, nanoparticles are dispersed in a matrix material such as metals, ceramics, or polymers to enhance their mechanical and thermophysical properties. Polymer nanocomposite materials found their applications in vital fields such as the automotive and aircraft industries. There are many techniques adopted to produce polymer nanocomposites, and they are summarized and discussed according to our best known in this paper. All techniques aim to produce nanocomposite materials with uniform dispersion and without aggregations. Melt-mixing, mixing, in-situ polymerization, electrospinning, and selective laser sintering techniques are the most commonly used techniques to produce polymer nanocomposite. The utilization of water, atomic layer deposition, and plasma-assisted mechanochemistry are found to eradicate the issue of nanoparticles aggregation for melt-mixing technique. Also, sonication with high frequencies plays the same role for mixing techniques. In-situ polymerization provides fabrication of nanocomposites that are thermodynamically stable. Electrospinning represents an effective method which is suitable for producing porous structures. In addition, fabrication of nanocomposites via selective laser sintering has obvious benefits to overcome the problem of aggregation. The working principles of each technique, including the advantages and disadvantages, are discussed.

Pathways to Green Perspectives: Production and Characterization of Polylactide (PLA) Nanocomposites Filled with Superparamagnetic Magnetite Nanoparticles.

In the category of biopolymers, polylactide or polylactic acid (PLA) is one of the most promising candidates considered for future developments, as it is not only biodegradable under industrial composting conditions, but it is produced from renewable natural resources. The modification of PLA through the addition of nanofillers is considered as a modern approach to improve its main characteristic features (mechanical, thermal, barrier, etc.) and to obtain specific end-use properties. Iron oxide nanoparticles (NPs) of low dimension (10–20 nm) such as magnetite (Fe3O4), exhibit strong magnetization in magnetic field, are biocompatible and show low toxicity, and can be considered in the production of polymer nanocomposites requiring superparamagnetic properties. Accordingly, PLA was mixed by melt-compounding with 4–16 wt.% magnetite NPs. Surface treatment of NPs with a reactive polymethylhydrogensiloxane (MHX) was investigated to render the nanofiller water repellent, less sensitive to moisture and to reduce the catalytic effects at high temperature of iron (from magnetite) on PLA macromolecular chains. The characterization of nanocomposites was focused on the differences of the rheology and morphology, modification, and improvements in the thermal properties using surface treated NPs, while the superparamagnetic behavior was confirmed by VSM (vibrating sample magnetometer) measurements. The PLA−magnetite nanocomposites had strong magnetization properties at low magnetic field (values close to 70% of Mmax at H = 0.2 T), while the maximum magnetic signal (Mmax) was mainly determined by the loading of the nanofiller, without any significant differences linked to the surface treatment of MNPs. These bionanocomposites showing superparamagnetic properties, close to zero magnetic remanence, and coercivity, can be further produced at a larger scale by melt-compounding and can be designed for special end-use applications, going from biomedical to technical areas.

Optimization of graphene nanoplatelets dispersion and nano-filler loading in bio-based polymer nanocomposites based on tensile and thermogravimetry analysis

The incorporation of graphene nanoplatelets (GNPs) has attracted massive attention in polymer nanocomposite production. In this work, GNPs reinforced nanocomposites of liquid natural rubber (LNR) toughened poly (lactic acid) (PLA)/poly (aniline) (PANi) were fabricated through melt-mixing using internal mixer. The effects of ultrasonic treatment period, mixing rotor speed and GNPs loadings in PLA-LNR/PANi was investigated. A premix ultrasonication of LNR/PANi with GNPs for 1 h was found to be the most effective period as compared to the longer sonication time. The best melt-mixing of the materials was achieved at 100 rpm, in accordance to the tensile properties as well as homogeneous dispersion and distribution of nano-filler as shown in thermogravimetry analysis. Results revealed that the optimum loading was found at 0.4 wt.% of GNPs with excellent enhancement in tensile strength (25 MPa), tensile modulus (1188.9 MPa) and thermal stability of the nanocomposite, as proven by ANOVA statistical analysis.

Characterizations of Polypropylene/Single-Walled Carbon Nanotube Nanocomposites Prepared by the Novel Melt Processing Technique with a Controlled Residence Time

Melt processing is considered one of the favored techniques to produce polymer nanocomposites with various inorganic fillers such as graphene and carbon nanotubes (CNTs). Due to their superior conductivity and tensile properties, among others, CNTs have been applied in broad applications. When a low filler fraction is desired, a high degree of dispersion is required in order to benefit from the intrinsic properties of CNTs. However, due to their high cohesive energy, dispersing CNTs in polymer melts is a difficult task. This study employed the melt mixing technique with a controlled residence time of 20 min to disperse single-walled carbon nanotubes (SWNTs) into a polypropylene matrix. The composites were prepared by using a corotating twin-screw extruder equipped with a back-conveying element with varying amounts of SWNTs from 0.29 to 6.56 wt.%. Mechanical, electrical, morphological, and rheological properties were evaluated. Due to the filler effect, storage, loss modulus, and complex viscosity increased with the SWNT content. Based on the van Gurp–Palmen plot, 0.29 wt.% SWNTs was the rheological percolation threshold, and the electrical property measurement revealed a 1.4 wt.% SWNT electrical percolation threshold based on the statistical percolation theory. Relatively large agglomerates were found when the SWNT content increased more than 1.28 wt.%.

Interface adjustment between poly(ethylene terephthalate) and graphene oxide in order to enhance mechanical and thermal properties of nanocomposites

AbstractThere is great interest in the use of graphene and derivatives in the production of polymer nanocomposites as it provides improvements in the properties of the materials to which they are associated. Such improvements depend heavily on filler dispersion and the interaction between the nanomaterials and the matrix. This work aimed to study the compatibility of graphene oxide (GO) with a poly(ethylene terephthalate) matrix. For this, graphite was modified using Hummers method, using reaction times of 3 and 6 h. The obtained GO was functionalized with amine, amide, and magnetite groups (FGO). The effects of the oxidation degree, functionalization and concentration of the nanofillers on the dispersion and consequently on the properties of the polymer nanocomposites were evaluated. The nanocomposites were synthesized by the solid–solid deposition method followed by the melt mixing technique. It was observed that lower concentrations of nanofiller associated with the lower degree of oxidation and functionalization improved the interaction of the nanofillers with the matrix, which resulted in better mechanical properties under tensile stresses for strain at break, maximum stress, Young's modulus and toughness. It was also observed that the glass transition and crystallization of nanocomposites increased due to a nucleating effect of the nanofillers.

Improving the dispersion of MWCNT and MMT in PVDF melts employing controlled extensional flows

AbstractPoly (vinylidene fluoride) (PVDF) has been widely explored to produce polymer nanocomposites possessing outstanding combinations of properties. In this work, the impact of extensional melt flows on the dispersion, relaxation and crystallinity of PVDF nanocomposites filled with multiwalled carbon nanotubes (MWCNT) and montmorillonites (MMT) was studied. Extrusion was employed to produce nanocomposites containing 3 wt% of fillers, named: (i) PVDF/3 wt% MWCNT, (ii) PVDF/3wt%MMT, and (iii) PVDF/1.5wt%MWCNT/1.5 wt% MMT. The results showed that applying a sequence of extensional flows through the melts improved the dispersion of both fillers in the PVDF matrix. Moreover, extensional flows significantly enhanced the viscosity and relaxation of MWCNT nanocomposite, but had marginal effects on MMT nanocomposite. On the other hand, MMT favored the crystallization of the β piezoelectric phase of PVDF over the α phase and the extensional flow enhanced its crystallinity content. Therefore, these new insights prospect a vast horizon toward the use of extensional flows for tailoring synergic combinations of properties in hybrid PVDF/MWCNT/MMT systems.

In-situ synthesis of 3D printable mono- and Bi-metallic (Cu/Ag) nanoparticles embedded polymeric structures with enhanced electromechanical properties

The interest of additive manufacturing with 3D printing increases day by day, which provides improved mechanical, electrical, magnetic and thermal properties of 3D parts. The production of 3D parts with the stereolithography (SLA) method, which allows it to be produced with high precision, resolution and complex geometries, distinguishes itself from other alternative additive manufacturing methods (FDM. SLS. LOM. LMD etc.). However, studies on the preparation of functional 3D polymer nanocomposites with the SLA method are quite limited. This study aims to produce silver (Ag) and/or copper (Cu) based 3D polymer nanocomposites for enhancing its mechanical strength, thermal stability and electrical conductivity. Mono and bimetallic (Cu/Ag) nanoparticles have been in-situ synthesized by selective irradiation of laser beam method using a commercial SLA device. In this method, metal (Cu/Ag) acrylate containing photocurable resin is not only cured but also leads to thermal decomposition of metal ions into nanoparticles to form functional 3D structures. The mechanical, electrical and thermal properties of polymer nanocomposites are characterized in detail. As a result of the analysis, the nanoparticles, with an average diameter of 25–55 nm, are well dispersed in the polymer matrix without agglomeration. The temperature at which 5% weight loss of Ag and Cu based polymer structures is measured as 179.3 °C while the glass transition temperature is found to be 223.81 °C. Most importantly, the resistance values are significantly decreased from 456.62 GΩ (Gigaohm) to 1.50 GΩ by increasing the amount of Ag addition at 3D polymeric structures. Therefore, this study allows the production of polymer nanocomposites not only in complex structures but also in desired properties especially for electrically conductive materials, capacitors and electronic applications.