Fillers In Polymer Matrix Research Articles

Aligning halloysite nanotubes in elastomer toward flexible film with enhanced dielectric constant

Naturally occurring halloysite nanotubes (HNTs) are considered electrically insulating counterparts of carbon nanotubes, and they are always randomly distributed in the reported polymer composites. With the recent optimization in advanced processing techniques for the production of muti-functional polymer composites, efficiently aligning micro-/nano-fillers in polymer matrix have been available. Here, we fabricate such aligned HNTs-silicon elastomer (PDMS) composites enabled by alternating current (AC) electric field driven alignment and report that at 7 wt% HNTs loading, the dielectric constant of aligned HNTs/PDMS composite film is almost 150 % (8.46 vs 5.71) higher than that of unaligned one at measurement frequency of 1 kHz. It is also observed that such high loading of nanoparticles brings negligible increase in dielectric loss and does not compromise much of the flexibility. This work provides a renewed understanding of the potential of aligning fillers in polymer matrix, allowing the proper utilization of the high polarization and extremely low dielectric loss predicted for HNTs in the fabrication of polymer composite dielectrics.

Polymer Composite Coatings Enhanced with Superhydrophobic Properties for Flexible Electronics Applications: A Review

ABSTRACT Flexible electronics have revolutionized various industries by offering lightweight and conformable solutions for diverse applications. However, their vulnerability to environmental factors, particularly moisture, remains a critical challenge. Polymer composite coatings enriched with superhydrophobic properties have gained considerable attention as a promising solution to safeguard flexible electronics. The present research report is a comprehensive review of the recent advancements in the development and application of superhydrophobic polymer composite coatings in flexible electronics, highlighting its potential applications in sensors and EMI shielding. The improvement in superhydrophobic characteristics hinges upon the choice of materials, fabrication techniques, surface morphology, and topographical features. This review article elaborates on the selection criteria for various organic and inorganic fillers suitable for polymers possessing innate hydrophobic or conducting properties. The different materials used as fillers in polymer matrix for fabricating superhydrophobic coating, the factors affecting the superhydrophobic properties of surfaces, and the superhydrophobic properties of fabricated surfaces using different materials have been reported.

Effect of filler orientation on mechanical and thermal properties of microwave absorbent 3D printed polycaprolactone/carbonyl iron particle composites

A thorough investigation was conducted in the present work on the mechanical and thermal characteristics of polycaprolactone/carbonyl iron particle composites. For composite fabrication, 3D printing technique was utilized. The fabricated composites were categorized as oriented, non-oriented and polycaprolactone samples based on orientation and concentration of filler particle. To evaluate the effect of orientation of carbonyl iron particle, two orientation directions, viz. parallel orientation, and perpendicular orientation with respect to loading direction were tried. The sample with parallel orientation exhibited the highest tensile strength followed by 90° orientation and pure polycaprolactone samples respectively. Oriented composites exhibited elevated dynamic modulus in comparison to the composites without orientation. The oriented composites demonstrated stiffness and tensile strength in the order of 13.66 ± 0.94 MPa and 3.79 ± 0.26 MPa respectively. The proposed methodology in the present study can be used to align carbonyl iron fillers in polymer matrix to tailor the mechanical, viscoelastic, and degradation properties.

Molecular-scale interaction between sub-1 nm cluster chains and polymer for high-performance solid electrolyte

Organic-inorganic interface in composite solid electrolyte could lead to increased ion transport for solid-state lithium batteries; however, most inorganic fillers have much larger size than polymer chains, which results in severe aggregation of inorganic fillers and poor ionic conductivity. Herein, functional sub-1 nm inorganic cluster chains were integrated with polymer chains to fabricate composite solid electrolyte with enhanced ionic conductivity. Different from all other inorganic fillers, the sub-1 nm inorganic cluster chains with diameter <1 nm have similar size and geometry compared with polymer chains, exhibiting polymer-like solution properties. A transparent sub-1 nm inorganic filler/polymer mixed solution was generated to realize monodispersion of cluster chains as functional fillers in polymer matrix. Meanwhile, abundant oxygen vacancies on cluster chains interact with polymer chains and lithium salts at molecular-scale, which decreases the complexation of polymer segments with Li+ and promote the dissociation of lithium salts, thereby improving Li+ transport. As a result, the composite solid electrolyte exhibits high ionic conductivity (0.4 mS cm−1) and large mobile Li+ distribution (50.8 %). This work pushes the size of nanofillers down to <1 nm, which is a unique approach to the molecular-scale interaction between nanofillers and polymers to boost ion transport in solid electrolytes.

Resin Cements in Dentistry

Even though the GIC has undergone many advances, its chemistry is fundamentally different from that of modern resin based composite direct filling products, which feature a silica or glass particle filled polymer matrix that enhances repair retention. When the restoration is etched or air abraded after the tooth has been conditioned with an adhesive resin and etched, retention becomes "micromechanical," ensuring the resin cement's high tensile strength. Cementation of the extraoral fabricated restoration is very important for the longevity of the restoration. The bond strength of resin cement to ceramic and fibre post is better than conventional cements. This article discusses about the various types of resin cements and there uses for luting indirect restorations such crowns, veneers, inlays, and onlays, etc.

High dielectric performance and thermal conductivity dielectric composite film via vertical alignment of hybrid BaTiO3 nanofibers

The arrangement of anisotropic dielectric fillers in polymer matrix can lead to a significant enhancement of dielectric properties along a specific direction, enabling the rapid development of integrated circuits and high-performance microelectronic devices. In this work, magnetic barium titanate nanofibers/polyimide composite films (mBT NFs/PI) with vertically oriented structures were constructed with the assistant of magnetic field. The dielectric constant was significantly increased from 20.8 to 39.1 at a filler content of 30 wt%, as compared to the randomly aligned films. However, the breakdown strength was affected. Addressing this issue, an optimized core-shell structure was fabricated by introducing insulated and thermo-conductive boron nitride (BN) “shell” on the surface of mBT NFs by coaxial electrospinning. The obtained mBT@BN/PI nanocomposite exhibits improved thermal conductivity and breakdown strength, while maintaining a high dielectric constant. This work highlights an effective strategy to achieve excellent dielectric properties and thermal conductivity for high-temperature dielectric capacitor materials.

Effect of small-sized modifier on boron nitride for efficient heat transfer through thermal conductive epoxy composites

Surface modification of a crystalline filler is a powerful method for increasing the thermal conductivity (κ) of filler-impregnated composites. Herein, boron nitride (BN) filler was functionalized with cationic molecules of different sizes to directly recognize the effect of an amorphous area on the filler-polymer matrix interface. Measured thermal conductivity and temperature rise for a polymer composite was up to 67.1 % and 15.3 % greater, respectively, in the sample to which the smallest molecule-modified BN was added, compared to the comparable sample with free BN. The smaller the size of the modifier molecule, the better it bonds with the resin and the smaller the non-crystalline area. Such changes improve the heat transfer at the interface by reducing interfacial thermal resistance. These findings can serve as a reference to develop alternative and effective strategies for filler modification, an alternative approach instead of focusing on functional groups and modifiers.

The effect of intra- and interphase interactions on strength of polyamide-6-based composites

The effect of filler-filler and filler-polymer matrix interactions on the strength of polyamide-6-based composites has been studied. It is shown that the strengthening of interactions of both mentioned types leads to an increase in the strength of the investigated composites. Fillers with a layered structure are preferred over dispersed ones.

Analysis of photocurrent trends in hybrid PS-BiI3 composites for direct X-ray detector via linear regression model

This study is intended to propose a non-toxic, environmentally stable, BiI3-polystyrene composite with good X-ray induced photocurrent response which are used as source for medical diagnosis purpose. Composite of different weight ratios of BiI3 as conductive filler are developed for the study. The experimental results reveals that 50:50 wt % ratio of BiI3 filler in polymer matrix gives an improved linear photo-response showed acceptable filler percentage for the composite. Further, a linear regression model to predict the photocurrent trend in composite samples synthesized with varying weight % has been developed, taking into consideration factors like constituent ratios of BiI3-polymer, distance between the electrodes and bias voltage. The photocurrent trend showed a good agreement between experimental and computational values. The developed linear regression equation that displayed a linear photo-response trend and a good correlation of 0.93 has been further validated experimentally for two test samples with high correlation maintained. The model shows great prospects to be extended to other composite materials, with in depth consideration of additional parameters and associated non linearities, for efficient development of portable X-ray detection devices.

Research advances in preparation, mechanism and application of thermally conductive and electrically insulating polymer composites in thermal management materials: A review

Today, electronic components are gradually developing towards miniaturization and multi-function. During the use of electronic components, a large amount of heat will be generated, which seriously limits the performance and service life of electronic components. Therefore, the preparation of thermal management material (TMMs) with high thermal conductivity (λ) can effectively solve the problem of thermal accumulation in electronic components. Compared with the preparation of intrinsic thermal conductive polymer composite, the method of filling thermal conductive filler in polymer matrix can better improve the λ of polymer composite. This review discusses the heat conduction mechanism of polymer and the factors affecting λ of polymer composites, including the type of filler, the shape and distribution of filler, and the functional surface treatment of filler. Then, the different methods of preparing thermally conductive and electrically insulating polymer composites (TCEIPCs) are introduced in detail. The application of polymer composites in thermal management is also introduced.

Mechanical and Three Body Abrasive Wear Behaviour of Nano-Filler Filled, Chopped Glass Fiber Filled Hybrid Composites

Polymer matrix composites are developed for tribological applications due to the possibility of optimizing the properties with the addition of special filler materials as reinforcement. Filler filled polymer matrix composite systems are used in many automotive parts and components like brake pads or clutches which require high coefficient of friction coupled with low wear. However, in most cases it is the primary concern to develop polymer composites that posses low friction and low wear properties under dry sliding conditions against smooth metallic counterparts e.g., gears or bearings, chute liners and coal handling equipments in power plants, gear pumps handling industrial fluids, agricultural machine components. Polymer composites operate in applications where fluid and grease lubricants fail, and have superior tribological performance to traditional polymer composites. Particulate fillers or fibres or solid lubricants have been a part of notable reductions in the wear rate of the polymer matrix at very low loading, and there exists a wide scope on the development of polymer composites on the tribological behaviour. The incorporation of fillers in polymer could provide a synergism in terms of improving mechanical properties and wear performance, which has not been adequately explored so far. The research on nano fillers such as nano clay, Glass fiber and Titanium di-oxide (TiO2) in epoxy system is scarcely reported and further they focus on a few specific issues only. The present study was focused on investigating Mechanical - Tensile, Hardness, and three body abrasive wear characteristics of thermosetting based Epoxy composites and the effect of incorporation of nano clay, TiO2 nanoparticles and chopped glass fiber on microstructure, hardness, friction and abrasive wear are determined and analyzed. The main aim was to investigate the effect of applied load, sliding distance /abrading distance, sliding speed and percentage of filler. The surface morphology of the worn out surfaces were examined using SEM, to get a better understanding of the wear mechanisms.

Piezo-triboelectric hybridized nanogenerator embedding MXene based bifunctional conductive filler in polymer matrix for boosting electrical power

With an emerging energy crisis and global warming, energy harvesting technologies have attracted an attention as an alternative to replace the fossil fuel-based energy generation methods because they can generate the carbon-free and sustainable energy. Among various energy harvesting technologies, mechanical energy harvesters are regarded as an attractive harvesting method because they can convert the abundant mechanical energy surrounding us to electrical energy. However, the low electrical performance of the mechanical energy harvester is hindering its practical utilization. Hybridization of the two different mechanical energy harvesters can provide the solution for this issue because the electrical performance of the energy harvester can be improved by harvesting the applied mechanical energy in two harvesters, simultaneously. Herein, a triboelectric and piezoelectric hybridized generator is fabricated by embedding MXene and barium titanate ceramic filler in the polydimethylsiloxane matrix (HG-MBP). The role of MXene as the bifunctional conductive filler is theoretically and experimentally investigated and the optimum point of MXene content is investigated and the high open-circuit voltage of 80 V, short-circuit current of 14 μA, and a power density of 13.5 W/m2 are obtained. As an application, a 3D printer modeled robot hand is successfully controlled based on finger joint movements of a real hand to which the HG-MBPs are attached. Moreover, the object detection system is developed with the aid of k-mean clustering method and different materials are distinguished with a high classification accuracy of 93.33%. These results reveal the excellent potential of the proposed HG-MBP as a human gesture manipulation system and as a material detection sensor, which can be expected to be utilized as a next-generation e-skin in the human–machine interface.

High-Dielectric PVP@PANI/PDMS Composites Fabricated via an Electric Field-Assisted Approach.

Polymer-based composite films with multiple properties, such as low dielectric loss tangent, high dielectric constant, and low cost are promising materials in the area of electronics and electric industries. In this study, flexible dielectric films were fabricated via an electric field-assisted method. Polyaniline (PANI) was modified by polyvinylpyrrolidone (PVP) to form a core–shell structure to serve as functional particles and silicone rubber polydimethylsiloxane (PDMS) served as the matrix. The dielectric constant of the composites prepared under electric fields was improved by the micro-structures formed by external electric fields. With the addition of 2.5 wt% PVP@PANI, the dielectric constant could be significantly enhanced, up to 23; the dielectric loss tangent is only 1, which is lower than that of the aligned PANI samples. This new processing technology provides important insights for aligning fillers in polymer matrix to form composites with enhanced dielectric properties.

Enhancement of thermal conductivity of BN-Ni/epoxy resin composites through the orientation of BN-Ni fillers by magnetic field and hot-pressing

The construction of high thermal conductivity polymer composites by the orientation of fillers is of great significance in electronic devices. Herein, a novel strategy to prepare boron nitride-Ni nanoparticles/epoxy resin composites (hmBN-Ni/EP) through the synergistic effect of magnetic field and hot-pressing on the orientation of BN-Ni fillers has been reported. hmBN-Ni/EP composites have better BN orientation in the in-plane direction than other BN-based/EP composites obtained by hot-pressing or magnetic field orientation only. The thermal conductivity of hmBN-Ni/EP reached 2.42 W m−1 K−1 at 30 wt% BN-Ni loading, which was 1145% higher than pure EP. The enhancement of thermal conductivity of hmBN-Ni/EP was attributed to the high in-plane orientation of BN-Ni through the synergistic effect of magnetic field orientation and hot-pressing. Meanwhile, the as-prepared hmBN-Ni/EP composites showed good insulation and mechanical properties which were facilitated to its industrial application in electronic packaging. This work provided a new strategy for better orientation of BN-Based fillers in polymer matrix by combining the magnetic field orientation and hot-pressing.

Bioactive Propolis-Silane System as Antifungal Agent in Lignocellulosic-Polymer Composites

Polymer composites with renewable lignocellulosic fillers, despite their many advantages, are susceptible to biodegradation, which is a major limitation in terms of external applications. The work uses an innovative hybrid propolis-silane modifier in order to simultaneously increase the resistance to fungal attack, as well as to ensure good interfacial adhesion of the filler–polymer matrix. Polypropylene composites with 30% pine wood content were obtained by extrusion and pressing. The samples were exposed to the fungi: white-rot fungus Coriolus versicolor, brown-rot fungus Coniophora puteana, and soft-rot fungus Chaetomium globosum for 8 weeks. Additionally, biological tests of samples that had been previously exposed to UV radiation were carried out, which allowed the determination of the influence of both factors on the surface destruction of composite materials. The X-ray diffraction, attenuated total reflectance–Fourier transform infrared spectroscopy, and mycological studies showed a significant effect of the modification of the lignocellulose filler with propolis on increasing the resistance to fungi. Such composites were characterized by no changes in the supermolecular structure and slight changes in the intensity of the bands characteristic of polysaccharides and lignin. In the case of systems containing pine wood that had not been modified with propolis, significant changes in the crystalline structure of polymer composites were noted, indicating the progress of decay processes. Moreover, the modification of the propolis-silane hybrid system wood resulted in the inhibition of photo- and biodegradation of WPC materials, as evidenced only by a slight deterioration in selected strength parameters. The applied innovative modifying system can therefore act as both an effective and ecological UV stabilizer, as well as an antifungal agent.

Monte Carlo simulations of nanotube filler in composite material: code optimization

The electrically conductive polymer composites (CPCs) have attracted intensive attention for several decades due to their flexibility and unique electrical properties. CPCs are potentially used in many applications such as flexible electrodes, batteries, and strain sensors. The percolated conductive pathways are formed by conductive filler in polymer matrix which is a major effect on the electrical behavior of CPCs. Computational simulations have been used to study the percolation phenomena of CPCs. The simulation algorithms need to be developed and optimized for reducing the simulation time-consuming. In this study, the in-house Monte Carlo simulation that used to estimate percolation threshold is optimized. To simulate in the large-scale system, cut-off distance will be defined to avoid unnecessary complex calculations. The calculation sequence within the code has been rearranged to omit the unnecessary calculation processes. Results show that the optimized software takes less processing time than the previous version around 5 times. Therefore, we can perform the large system to investigate the percolation phenomenon with less lattice confinement effect.

Poly(lactic acid)/carbon nanotube composites with enhanced electrical conductivity via a two-step dispersion strategy

Conductive polymer composites (CPCs) prepared by melt blending techniques display promising shielding properties, and could help address the growing challenges posed by electromagnetic interferences. However, it remains challenging with current processing techniques to achieve high electrical conductivity in CPCs owing to the poor dispersion of conductive fillers in polymer matrix. Herein, we propose a “two-step dispersion strategy” to enhance the electrical conductivity of poly (lactic acid) (PLA)/carbon nanotubes (CNTs) composites by employing Pickering emulsion templating and masterbatch blending method. The CNTs were dispersed uniformly via regenerated cellulose-assisted assembly on the surface of Pickering emulsions to yield PLA/CNT masterbatch. This was followed by melt blending with PLA granules to form an interconnected CNTs network within the PLA matrix. The resulting PLA/CNT composite exhibited a low percolation threshold of 0.46 vol%, and a high electrical conductivity of 72.2 S/m at 5.6 wt% CNT loading. Materials produced using this method outperformed PLA/CNT composites obtained by direct melt blending. Furthermore, the composite exhibited a maximum EMI shielding effectiveness of 31.1 dB, and superior tensile strength of 71.4 MPa. The “two-step dispersion strategy” provides an effective and versatile route to solve the dispersion problem of CNT and fabricate high performance CPCs.

Mixed Manganese Dioxide on Magnetite Core MnO2@Fe3O4 as a Filler in a High-Performance Magnetic Alginate Membrane.

The process of ethanol dehydration via pervaporation was performed using alginate membranes filled with manganese dioxide and a mixed filler consisting of manganese dioxide on magnetite core MnO2@Fe3O4 particles. The crystallization of manganese dioxide on magnetite nanoparticle surface resulted in a better dispersibility of this mixed filler in polymer matrix, with the preservation of the magnetic properties of magnetite. The prepared membranes were characterized by contact angle, degree of swelling and SEM microscopy measurements and correlated with their effectiveness in the pervaporative dehydration of ethanol. The results show a strong relation between filler properties and separation efficiency. The membranes filled with the mixed filler outperformed the membranes containing only neat oxide, exhibiting both higher flux and separation factor. The performance changed depending on filler content; thus, the presence of optimum filler loading was observed for the studied membranes. The best results were obtained for the alginate membrane filled with 7 wt.% of mixed filler MnO2@Fe3O4 particles. For this membrane, the separation factor and flux equalled to 483 and 1.22 kg·m−2·h−1, respectively.

Simultaneous degumming and deacidification of crude palm oil using mixed matrix PVDF membrane

The research work aimed to investigate the compatibility of polyvinylidene difluoride (PVDF) membrane embedded with various inorganic adsorbents for producing a mixed matrix membrane (MMM) and to examine the capability of mixed matrix PVDF membrane (PVDF-MMM) for simultaneous degumming and deacidification of crude palm oil (CPO). Four different adsorbent were tested which includes calcium silicate (CaS), magnesium silicate (MagS), ZSM-zeolite (ZSM) and activated carbon (AC). The in-house made PVDF-MMM was fabricated according to the dry-jet wet spinning method. The performances of these PVDF-MMMs were assessed with respect to the removals of phosphorus, FFA and colour. Based on finding showed that the combination of 18PVDF embedded with 3 wt% MagS showed the most compatible polymer-inorganic hybrid MMM to perform pre-treatment of CPO. Increasing the MagS concentration from 3 to 8 wt% in the polymer matrix recorded the highest removals of FFA at 16.51 %, phospholipid at 93.31 % and colour at 18.8 %, respectively. Nevertheless, high amount of MagS added to the polymer matrix affected the spinnability and reproducibility performance of MMM. Future work, surface modifications of inorganic adsorbent can be evaluated to facilitate good dispersion of filler in polymer matrix during membrane fabrication to maintain good membrane reproducibility.

Determination of Mechanical and Tribological Properties of Silicone-Based Composites Filled with Manganese Waste.

High-tonnage industrial processes generate high amount of waste. This is a growing problem in the whole world. Neutralizing such waste can be time consuming and costly. One of the possibilities of their reuse is to use them as fillers in polymer composites. Introduction of the filler in polymer matrix causes change in its mechanical and tribological properties. In the article, the effect of introducing fillers from post-production waste, and its effect on changing the physical properties of silicone-based composites filled with manganese (II) oxide and waste manganese residue was investigated. The composites were made by gravity casting. Composites with 2.5, 5, 7.5, and 10 wt% of the fillers were examined. The composite materials were subjected to tests such as: density, hardness, resilience, tensile test, abrasion resistance, and ball-on-disc. Microscopic images showed that, the particles of the fillers are uniformly distributed in silicone matrix with the formation of smaller agglomerates. Such agglomerates introduced a discontinuity in the structure of the polymer material, which caused a decrease in the tensile strength and elongation at break for all tested compositions in comparison with the mechanical properties of the silicone used as the matrix. However, it was found that all silicone-based composites filled with manganese (II) oxide and manganese residue showed a reduction in abrasive wear, compared to the reference sample.