Filler Content Research Articles

Novel, Fluorine-Free Membranes Based on Sulfonated Polyvinyl Alcohol and Poly(ether-block-amide) with Sulfonated Montmorillonite Nanofiller for PEMFC Applications.

Novel blend membranes containing S-PVA and PEBAX 1657 with a blend ratio of 8:2 (referred to as SPP) were prepared using a solution-casting technique. In the manufacturing process, sulfonated montmorillonite (S-MMT) in ratios of 0%, 3%, 5%, and 7% was used as a filler. The crystallinity of composite membranes has been investigated by X-ray diffraction (XRD), while the interaction between the components was evaluated using Fourier-transform infrared spectroscopy (FT-IR). With increasing filler content, good compatibility between the components due to hydrogen bonds was established, which ultimately resulted in improved tensile strength and chemical stability. In addition, due to the sulfonated moieties of S-MMT, the highest ion exchange capacity (0.46 meq/g) and water uptake (51.61%) can be achieved at the highest filler content with an acceptable swelling degree of 22.65%. The composite membrane with 7% S-MMT appears to be suitable for application in proton exchange membrane fuel cells (PEMFCs). Amongst the membranes studied, this membrane achieved the highest current density and power density in fuel cell tests, which were 149.5 mA/cm2 and 49.51 mW/cm2. Our fluorine-free composite membranes can become a promising new membrane family in PEMFC applications, offering an alternative to Nafion membranes.

Hollow hydrangea-like Mo2C/MoO2/C composites with tunable phase compositions as highly efficient microwave absorbers

With the advancement of modern electronic communication technology, the development of efficient absorbing materials has attracted great interest. Here, hollow hydrangea-like Mo2C/MoO2/C composites are synthesized by soft template method. By adjusting the pyrolysis temperature, Mo2C/MoO2/C composites with different Mo2C and MoO2 contents and degrees of graphitization can be selectively synthesized. The Mo2C/MoO2/C-800 composite with the 30 wt% filler content exhibits a minimum reflection loss of −62.9 dB at 1.6 mm and achieves a maximum absorption bandwidth of 6.2 GHz at 1.9 mm. The interaction between the dielectric properties of each component and the unique 3D hydrangea-like structure promotes microwave absorption and dissipation. Besides, CST simulation further demonstrates the effectiveness of electromagnetic wave dissipation in practical applications. The excellent properties of the hydrangea-like Mo2C/MoO2/C composites indicate their promising applications in electromagnetic wave absorbers.

Multi-shell bowl-like carbon microspheres for lightweight and broadband microwave absorption

Carbon materials have made significant progress in the field of microwave absorption (MA), but achieving wide effective absorption bandwidth (EAB) at low filler content still remains a great challenge. In this work, we design multi-shell bowl-like mesoporous carbon microspheres (MBMCs) by a facile hard template method for efficient MA. It is demonstrated that the spacing between inner and outer shell and second shell thickness play a vital role on the configuration of carbon microspheres. By controlling the second addition of silica template, the microstructure of carbon microsphere evolves from spherical to bowl shape geometry. Expanded shell spacing is beneficial for forming bowl-like microsphere. The dielectric loss and MA properties are highly associated with the configuration of MBMCs. Well-proportioned MBMCs with appropriate shell spacing present wide EAB of 7.3 GHz under a low filling ratio of 12 wt.%. This work paves a new way to broaden EAB and lower filling content of carbon materials via asymmetric multilayer microstructure design.

Thermal conductivity enhancement of epoxy by a 3D Si3N4 crystal rod/grain skeleton fabricating from photovoltaic silicon waste

Silicon nitride (Si3N4) is one of the preferred fillers for the preparation of high thermal conductivity polymer composites because of its intrinsic high thermal conductivity and good electrical insulation. To maximize the thermal conductivity enhancement effect of the fillers in the composites, it is necessary to pre-construct a three-dimensional (3D) thermally conductive filler network. Herein, surfactant foaming was applied to pre-construct a 3D Si-containing framework from photovoltaic silicon waste (PSW), which was subsequently transformed into a porous skeleton consisting of Si3N4 rods and grains by in-situ nitridation reaction sintering. And finally, thermal conductive Si3N4/epoxy (EP) composites were fabricated after infiltrating EP into the network skeleton. When the filler content of Si3N4 was 41.00 vol%, the obtained Si3N4/EP composite showed the highest thermal conductivity of 2.99 W·m-1·K-1, which was 13.95 times higher than that of pure EP. Tests on running CPU and heating table showed that the Si3N4/EP substrate had excellent heat dissipation performance compared to the pure EP substrate. The 3D continuous network formed by "bridging" between two different morphologies of Si3N4 microcrystals contributed to providing effective multi-directional heat transfer paths and thereby improving the thermal conductivity of the composites. Overall, the low cost of raw silicon source originating from industrial waste as well as the simple and practical construction of heat-conducting filler network demonstrate the promising application of the Si3N4/EP composites fabricated in our work.

Collective effect of reduced graphene oxide and Zn2U hexaferrite filler based epoxy composites on microwave absorption with improved mechanical properties

Herein, we have synthesized Ba4Zn2Fe36O60 (Zn2U) and have produced reduced graphene oxide (rGO) wrapped filler material for the preparation of epoxy composites of different weight percentages (40, 50 and 60 wt %). These rGO wrapped Zn2U hexaferrite filler was analyzed by XRD and SEM to examine the crystal structure and distribution of Zn2U hexaferrite in between/on the surface of rGO respectively. The magnetic and mechanical properties of prepared rGO@Zn2U@epoxy composites were evaluated by employing vibrating sample magnetometer and universal testing machine respectively. The investigation involved analyzing the complex permittivity and permeability, and based on this information, an assessment of the reflection loss was conducted. The results obtained indicate that epoxy composites with a filler content of 60 % rGO@Zn2U have significant promise as an advantageous choice for EMI shielding and microwave absorption applications.

Thickness-controlled HsGDY/N-doped double-shell hollow carbon tubes for broadband high-performance microwave absorption

With the increasing deterioration of the electromagnetic environment, it is important to develop new and efficient electromagnetic wave-absorbing materials. In this work, bilayer hollow HsGDY/NC nanotubes with controllable thickness are constructed by introducing high conductivity polydopamine (PDA) and hydrogen-substituted graphdiyne (HsGDY) followed by the etching and carbonization. Subsequently, the effects of the composition, coating order, and structural characteristics of nanotubes on the electromagnetic parameters are thoroughly investigated, thereby analyzing the microwave absorption mechanism. The impedance matching of HsGDY/NC is optimized by changing the thickness of NC layer, while utilizing unique multi-heterogeneous interfaces and hierarchical conductive structures that enhance the interface polarization and conductive loss. As a result, HsGDY@NC-3 displays the optimal absorbing performance with an effective absorption bandwidth (EAB) of 7.8 GHz (10.1–17.9 GHz) and a minimum reflection loss (RLmin) of −47.18 dB at the filler content of only 11 %. This work broadens the application scopes of HsGDY and provides a novel insight into the design of lightweight, high-efficiency, and wide-frequency microwave absorbers, which is expected to be a potentially effective microwave-absorbing material.

Flexible poly (vinylidene fluoride) composite with magnetite-modified graphene: Electromagnetic shielding in X-band

Electromagnetic pollution, or electromagnetic interference (EMI), is a phenomenon that has arisen due to the fast spread of electronic gadgets. To overcome EMI problem, polymer-based composites have sparked considerable attention among researchers owing to their superior qualities. Hence, this work utilizes magnetite-modified graphene (MMG) filler with polyvinylidene fluoride (PVDF) polymer to form polymer composites in various proportions ranging from 2 to 10 wt% to study the EM properties in the X-band. It was observed that the sample composite having a MMG filler content of 10 wt% possesses a relatively higher electrical conductivity of 0.65 S/cm as compared to the other prepared composites in this research work. The same sample composite also attained a total shielding efficacy of 53.04 dB at a thickness of 3 mm. Moreover, it was observed that the filler has improved the material's thermal stability and microwave absorption capacity, making it a high-efficiency EMI shielding material appropriate for usage in the electronic and aviation industries.

Valorization of Cellulosic Waste from Artichoke for Incorporation into Biodegradable Polylactic Acid Matrices.

This study presents the development of ecological compounds using polylactic acid (PLA) and artichoke flour with the aim of obtaining materials with properties like commercial PLA. PLA biocomposites with different concentrations of green artichoke (HV) and boiled artichoke (HH) (1, 3, 5, 7, 10 and 20% by weight) were manufactured through an extrusion and injection process. Structural, mechanical, physical and color tests were carried out to analyze the effect of lignocellulosic particles on the biopolymeric matrix. The Shore D hardness, elongation at break and heat deflection temperature (HDT) of the PLA/HV and PLA/HH samples showed similar values to pure PLA, indicating that high concentrations of both fillers did not severely compromise these properties. However, reductions in the tensile strength, impact strength and Young's modulus were observed, and both flours had increased water absorption capacity. FTIR analysis identified the characteristic peaks of the biocomposites and the ratio of the groups regarding the amount of added filler. The SEM revealed low interfacial adhesion between the polymer matrix and the filler. This study represents a significant advance in the valorization and application of circular economy principles to agricultural waste, such as artichoke waste. PLA/HV biocomposites make a substantial contribution to sustainable materials technology, aligning with the goals of the 2030 agenda to reduce environmental impacts and promote sustainable development.

Bamboo powders effectively reinforcing the modulus of PBAT composites and creep resistance

AbstractBamboo has a short growth cycle and exists in large quantities in nature. This paper uses bamboo powders (BP) to reinforce polybutylene adipate/terephthalate (PBAT) modulus and creep resistance. The BP was surface modified by γ‐(2,3‐epoxypropoxy)propyltrimethoxysilane (KH560), and compounded with PBAT in a twin‐screw extruder. The results showed that the specific surface area and micropores of BP were considerably higher than that of common wood powders and cellulose and contributes significantly to the modulus and the creep resistance of composites. Compared with pristine PBAT, the tensile modulus, flexural modulus of K‐BP/PBAT composites increased by 225%, 608%, respectively, at a filler content of 25 wt%. In addition, the creep resistance of K‐BP25 was improved by a factor of 3.25 compared to PBAT. The enhancement mechanism of K‐BP was discussed, the large specific surface area and micropores of K‐BP provided more anchoring sites, which effectively increased the interfacial binding force between K‐BP and PBAT, and enhanced the nucleation ability of PBAT, thus improving the modulus and creep resistance of the composites. The results of this paper broadened the scope of application of PBAT.Highlights The bamboo powders effectively reinforcing the modulus of PBAT. The bamboo powders effectively reinforcing the creep resistance of PBAT. The special feature of K‐BP can provide more anchoring sites for PBAT. The K‐BP improves the nucleation ability of PBAT.

Comparative investigation of fillers loading effect on morphological, micromechanical, and thermal properties of polyvinyl alcohol/cellulosicfillers-based composites

Polyvinyl alcohol (PVA)-based biocomposites were fabricated by the incorporation of chitosan (Ch), cellulose fibers (CS), and their mixture (1:1 ratio). Fillers with various loading (2, 4, 8, and 10 wt.-%) were incorporated into PVA employing the solution casting method. The fillers and biocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), brightfield microscopy, tensile and microindentation tests, contact angle measurement and thermogravimetric analysis (TGA). FTIR spectra revealed the removal of lignin, and intermolecular H-bonding between PVA and fillers promoting their filler–matrix interfacial interactions. Crystallographic results showed varied crystallite sizes and crystallinity of composites. Microscopic techniques revealed a uniform filler distribution, attributed to their compatibility with PVA. Tensile and microindentation tests demonstrated a decreased tensile strength (3.3–8.2 MPa of the composites compared to 15.7 MPa of the matrix) and Martens hardness (HM) of biocomposites. However, their value was increased with higher filler concentration, signifying the mechanical reinforcement. Contact angle analysis confirms the decreased wettability (hydrophilicity) of biocomposites, attributed to higher compatibility of fillers with PVA and intermolecular H-bonding between them. A slightly decreased thermal stability of biocomposites with filler incorporation is implied by TGA results despite their uniform distribution and strong matrix–filler interfacial interactions.

Preparation of two–dimensional gradient fillers reinforced polymer nanocomposites for high–performance energy storage of dielectric capacitors

The serious interfacial issue between the inorganic filler and the organic matrix in the dielectric nanocomposite results in a low electric field breakdown strength (Eb) and low energy density (Ue). In this work, novel KxNa1–xNbO3@ZrO2 (KNN@ZO) nanosheets (NSs) were prepared by coating highly insulated ZO on the ferroelectric two–dimensional (2D) KNN NSs via a chemical precipitation method. As fillers, the KNN@ZO significantly improved the energy storage performances of poly (vinylidene fluoride) (PVDF)–polymethyl methacrylate (PMMA) blends. The highly insulated ZO shell restricts the carrier migration at the filler/polymer interface, thereby reducing the local electric field distortion. By sandwich structural design, a high Ue of 19.8 J/cm3, with a large difference of electrical displacement (8.5 μC/cm2), is measured in KNN@ZO/PVDF–PMMA with 5 % filler content at 528 MV/m. According to the finite element simulation, the 2D morphology and gradient structure can enhance the electric field distribution, and therefore effectively increase the Eb of nanocomposites. The results indicate that the 2D core–shell NSs fillers with gradient dielectric constant represent an effective approach to improve energy storage performance of the polymer–based nanocomposites.

Optimizing dielectric constant of noncommercial biobased fibres - Acacia Nilotica, Acacia Leucophloea and Prosopis juliflora - For composite applications with selected fillers

In recent decades, most electrical/electronic products possess non – biodegradable components. The expanding consumption of these goods and their eventual disposal pose a serious environmental threat. To cope up with this issue, biodegradable electrical/electronic components using biobased fibres can be an alternative option. The novel exploration of this research work is the usage of underutilized biobased fibres, such as Acacia Nilotica, Acacia Leucophloea and Prosopis Juliflora, as sustainable alternatives to traditional synthetic fibres in natural fibre-reinforced epoxy composites. The novelty lies in the combination of these natural fibres with ceramic fillers like Silicon Carbide, Boron Nitride and Aluminium Oxide, aiming to enhance the composite properties. The objective of the study is to optimize the type of fibre, fibre content (2 wt%, 4 wt% and 6 wt%) and types of fillers (1 wt%) combinations using the Box-Behnken Design to improve the dielectric properties of these composites. Analysis of Variance (ANOVA) is used to evaluate the relevance of each parameter on dielectric constant of the biobased fibre reinforced epoxy composite. The significant outcome is identified that Prosopis Juliflora (6 wt%) combined with Boron Nitride (1 wt%) yields an optimal dielectric constant of 1.11, highlighting the potential of these biobased fibres to serve as effective substitutes for conventional glass and carbon fibres for electrical insulating materials used in switchboards and socket pins to prevent electrical conduction and ensure safety. This research not only contributes to the field of sustainable materials but also addresses critical environmental concerns associated with electric/electronic waste.

Thermomechanical and Structural Analysis of Manufactured Composite Based on Polyamide and Aluminum Recycled Material.

The paper presents an analysis of the filler's effect on the machining process and on changes in the thermomechanical properties of polymer composites based on aluminum chips. Composite research samples with a polymer matrix in the form of polyamide 6 were made by the pressing method. Comparative studies were carried out on the changes in thermomechanical properties and structure of the obtained molders with different filler contents and different fractions after the machining process. In order to determine the changes in thermal and mechanical properties, analysis was carried out using the differential scanning calorimetry (DSC) method, thermal analysis of dynamic mechanical properties (DMTA) and a detailed stereometric analysis of the surface. After mechanical processing, roughness amplitude parameters and volumetric functional parameters were determined. In order to analyze the structure, tomographic examinations of the manufactured composite were conducted. In relation to the polymer matrix, a significant increase in the storage modulus of the composites was noted in the entire temperature range of the study. An increase in the enthalpy of melting of the matrix was noted in composites with a lower filler content and a shift in the melting range of the crystalline phase. Significant differences were noted in the study of the composite surfaces in the case of using fillers obtained after machining with different fractions. The dependencies of the functional and amplitude parameters of the surfaces after machining of composite samples prove the change in the functional properties of the surface. The use of aluminum chips in the composite significantly changed the surface geometry.

Enhanced Epoxy Composites Reinforced by 3D-Aligned Aluminum Borate Nanowhiskers.

Recently, the durability of high-performance and multifunctional portable electronic devices such as smartphones and tablets, has become an important issue. Electronic device housing, which protects internal components from external stimuli, such as vibration, shock, and electrical hazards, is essential for resolving durability issues. Therefore, the materials used for electronic device housing must possess good mechanical and electrical insulating properties. Herein, we propose a novel high-strength polymer nanocomposite based on 3D-aligned aluminum borate nanowhisker (ABOw) structures. ABOw was synthesized using a facile hydrothermal method, and 3D-aligned ABOw structures were fabricated using a freeze-casting process. The 3D-aligned ABOw/epoxy composites consist of repetitively layered structures, and the microstructures of these composites are controlled by the filler content. The developed 3D-aligned ABOw/epoxy composite had a compressive strength 56.72% higher than that of pure epoxy, indicating that it can provide high durability when applied as a protective material for portable electronic devices.

Study of Polymer Ceramic-Inorganic Composites for Electromagnetic Radiation Absorption

The aim of the presented work is to study polymer ceramic-inorganic composites for electromagnetic radiation absorbing. Epoxy-based polymer composites modified with ceramic-inorganic graphite-ferromagnetic (CIGF) fillers were first obtained: silicon carbide, chromium oxide Cr2O3, graphite, humic substances and potassium titanate. As polymer matrix epoxy resin based on Epikote Resin MGS LR 285 and Epikure Curing Agent MGS LH 285 was studied. Primary research was directed to study humic substance, silicon carbide SiC, chromium oxide Cr2O3, graphite and potassium titanate nanoparticles introduction impact on polymer ceramic-inorganic composites strength and technological properties. Complex of technological and strength characteristics were researched and compositions with humic substances 0.5 wt%, a higher silicon carbide SiC – 10 wt% content were studied, while chromium oxide Cr2O3, graphite content in 5–25 % wt. range was optimized. Results shows, that addition of humic substances, silicon carbide SiC, chromium oxide Cr2O3, graphite and potassium titanate nanoparticles into the epoxy resin up to 20 wt% filler content increases the composite impact strength and breaking stress during bending. The CIGF fillers complex system using advantage is proven by studying the nature of modification effect on ceramic-ferromagnetic-graphite polymer composites for electromagnetic radiation absorption.

Three-Dimensionally Printed Ternary Composites of Polyamide: Effect of Gradient Structure on Dimensional Stability and Mechanical Properties

Fused deposition modeling (FDM) 3D printing has the advantages of a simple molding principle, convenient operation, and low cost, making it suitable for the production and fabrication of complex structural parts. Moving forward to mass production using 3D printing, the major hurdle to overcome is the achievement of high dimensional stability and adequate mechanical properties. In particular, engineering plastics require precise dimensional accuracy. In this study, we overcame the issues of FDM 3D printing in terms of ternary material compounds for polyamides with gradient structures. Using multi-walled carbon nanotubes (MWCNTs) and boron nitride (BN) as fillers, polyamide 6 (PA6)-based 3D-printed parts with high dimensional stability were prepared using a single-nozzle, two-component composite fused deposition modeling (FDM) 3D printing technology to construct a gradient structure. The ternary composites were characterized via DSC and XRD to determine the optimal crystallinity. The warpage and shrinkage of the printed samples were measured to ensure the dimensional properties. The mechanical properties were analyzed to determine the influence of the gradient structures on the composites. The experimental results show that the warpage of pure polymer 3D-printed parts is as high as 72.64%, and the introduction of a gradient structure can reduce the warpage to 3.40% by offsetting the shrinkage internal stress between layers. In addition, the tensile strength of the gradient material reaches up to 42.91 MPa, and the increasing filler content improves the interlayer bonding of the composites, with the bending strength reaching up to 60.91 MPa and the interlayer shear strength reaching up to 10.23 MPa. Therefore, gradient structure design can be used to produce PA6 3D-printed composites with high dimensional stability without sacrificing the mechanical properties of PA6 composites.

Characterizing the Self‐Healing Asphalt Materials: A Neutron Imaging Study

Given the significant role of asphaltic pavement in surface transportation systems, even minor enhancements in asphalt materials hold the potential for cost savings and reduced environmental impacts. The healing properties of asphalt have drawn interest for sustainability, yet much remains unknown about the causes and influencing factors. To leverage self‐healing for extending pavement life, understanding the mechanisms and conditions that stimulate microcrack healing is essential. This study aims to investigate the dynamic progress of microcrack closure in asphalt mastics. The time‐series evolution of crack closure led by self‐healing is tracked by neutron computed tomography, with image processing facilitating volumetric analysis over a 7 h period. The study examines the healing process in mastic samples with three different sand filler contents (10, 20, and 30%). Results show that for all the investigated samples, the healing rate declines exponentially over time, with 100% recovery not achieved after 7 h at room temperature. Filler content‐influenced healing speed and 20% sand demonstrate the best performance. Meanwhile, the healing performance varies within the 10% and 30% groups, depending on initial crack size. Additionally, the study finds that initial crack size influences healing behavior in the samples.

Optimizing the dielectric properties of polymer composites by constructing multi-dimensional fillers

The construction of multidimensional fillers provides new ideas for the development of composite materials. In this study, one-dimensional (La0.5Nb0.5)xTi1-xO2 ceramic nanorods (x-LNTO NRs) and 1-LNTO ceramic materials with three-dimensional fiber structure network (3D-1-LNTO) were prepared by electrospinning. These materials were used as fillers to prepare x-LNTO NRs/PVDF composites and 3D-1-LNTO/PVDF composites. Compared with the 1-LNTO NPs/PVDF composites, the 1-LNTO NRs/PVDF composites showed better dielectric properties, with a dielectric constant of 40 and a dielectric loss of 0.12 at a fill content of 60 wt%. The 3D-1-LNTO/PVDF composites achieved a high dielectric constant at a low filler content, the composite achieved a dielectric constant of 25 at a fill content of only 10 wt%, which is 2.5 times higher than that of pure PVDF. Compared with x-LNTO NRs, 3D-1-LNTO is more obvious for improving the dielectric properties of composites. The construction of continuous fiber network is the main reason for the enhancement of dielectric constant, and this study provides a new experimental idea for the construction of multi-dimensional high dielectric fillers.

Coniferous Bark as Filler for Polylactic Acid-Based Biocomposites.

This study explores the possibilities of utilisation of coniferous bark as a filler in wood-polymer composites (WPCs), its impact on properties such as the modulus of rupture (MOR), modulus of elasticity (MOE), thickness swelling (TS) and water absorption (WA) after 2 h and 24 h of immersion in water and the significance of this impact compared to other factors. Six variants of bark-polylactic acid (PLA) WPCs were manufactured, differentiated by their filler content and filler particle size. As a comparison, analogous composites filled with coniferous sawdust were also manufactured. Bark-filled composites were characterised by lower TS and WA after both 2 h and 24 h of immersion, as well as lower water contact angles and surface free energy. The bark filler decreased the composites' MORs and MOEs, while greater differences were noticed for variants filled with small particles. The type of filler was the second most important factor contributing to variance in this study, with the filler content being the most important one.

A critical review of composite filaments for fused deposition modeling: Material properties, applications, and future directions

This review paper provides a comprehensive analysis of recent advancements in the development and application of composite filaments for fused deposition modeling (FDM) 3D printing technology. Focusing on the integration of various materials such as nano-fillers, fibers, and bio-based polymers into polylactic acid (PLA) and other thermoplastics, this study delves into how these composites enhance mechanical, thermal and functional properties of the printed objects. We critically assess studies that investigate the impact of raster orientation, filler content, and material composition on tensile, bending, and impact strength, as well as on the thermal stability and degradation behavior of composite filaments. The review highlights key findings from the literature, including the optimization of filament formulations to achieve superior mechanical performance, improved thermal resistance, and specific functional characteristics suitable for a wide range of applications from biomedical to structural components. Moreover, this paper discusses the challenges associated with composite filament production, including material compatibility, dispersion of nano-fillers, and the need for printer hardware adjustments. Future directions for research in the field are identified, emphasizing the potential for new material combinations, sustainability considerations, and the development of filaments designed for specific industrial applications. An effective way to better meet designers’ expectations for qualified materials is composite filaments. This review focuses on how these elements can be applied to improve both product design and functionality. A guide is presented in choosing composite filaments that can meet the features expected from the designed product.