Filler Loading Research Articles

Boosting carbon capture with CO2-Ultrapermeable molecularly imprinted membranes

Mixed matrix membrane (MMM) is one of the most promising candidates for exceeding the gas separation upper bound, while fillers can largely determine their ultimate performance. The molecular imprinting technique was first employed to prepare a layer containing rich CO2 adsorption sites on the UiO-66-NH2 surface for fabricating highly CO2-permeable PIM-1-based MMMs with higher selectivity. Transmission electron microscopy (TEM) and element mapping confirmed the successful formation of the core-shell structure for the imprinted metal-organic frameworks (MOFs). The MMMs prepared with imprinted MOFs present enhanced CO2 permeability and CO2/N2 selectivity, higher compatibility between polymers and fillers, and better mechanical strength compared to the MMMs with the pristine UiO-66-NH2. The MMMs formed with 5 wt% imprinted MOFs showed superior CO2/N2 separation performance beyond the 2019 upper bound with an ultrahigh CO2 permeability of 13,000 barrer (increased twice compared to pristine PIM-1 membrane). Moreover, with a filler content of 13 wt%, the obtained membrane maintains good mechanical properties, which indicates the benefit of the imprinted layer for the improvement of the filler loading inside a PIM-1 matrix. The membranes showed decreased CO2 permeability and CO2/N2 selectivity under the wet conditions, but stable performances over 46 hours of dynamic testing. The results indicate the presented approach for filler modification via molecular imprinting is a promising strategy for the enhancement of the MMM separation performance.

Optimizing Filler Loading and Particle Size for Enhanced PhysicoMechanical Properties in Peanut Shell

The extensive application of synthetic fiber-reinforced polymer composites is prone to dwindling due to their substantial upfront expenses, chief among them being their detrimental effects on the environment.

The effect of photoinitiator type and filler load on physicochemical and mechanical properties of experimental light-cured resin cements through lithium disilicate ceramics of different shades and thicknesses

ObjectiveThis study investigated the influence of photoinitiator types on degree of conversion (DC), rate of polymerization (RP), flexural strength (FS), flexural modulus (FM), and light transmittance (LT) of filled and unfilled light-curable resin cements through different thicknesses and shades of lithium disilicate ceramics. MethodsLithium disilicate ceramic discs (IPS Emax Press, background [0.0], 0.5, 1.0, 2.0, 3.0, and 4.0 mm, shades A1 and BL3) were prepared. Experimental resin-based cements [TEGDMA/BisGMA (50/50 mass%)] were prepared using either camphorquinone (CQ)/amine (0.44/1.85 mol%) or TPO (0.44 mol%)], and a micro and nanofiller loads of nil (unfilled); 40/10 mass%; and 50/10 mass%). Resin cements (0.2 mm thick) were placed on the lower surface of the ceramic specimens and light-activated for 30 s from the upper surface using a Bluephase Style curing light (exitance at tip: 1236 mW/cm2 ± 1.20). LT and distribution of irradiance through the ceramics were measured using a UV–vis spectrometer and a beam profile camera, respectively (n = 3). The DC and RP were measured in real-time using mid infrared spectroscopy in attenuated total reflectance (ATR) mode (n = 3). FS and FM were measured using a universal testing machine (n = 5). Statistical analyses were performed on LT, DC, RP, FS, and FM data using a general linear model, and supplementary ANOVA and post hoc Tukey multiple comparison test were also performed (α = .05). ResultsThicknesses, shades, photoinitiator type, and fillers load significantly influenced the optical and mechanical characteristics of the resin-based materials (p < 0.05). The BL3 shade ceramic provided higher values of DC, RP, FS, FM, and LT compared with the A1 shade (p < 0.05). Increasing ceramic thickness decreased the properties of the resin-based materials (p < 0.05). Generally, TPO improved mechanical properties of the resin cement compared with CQ (p < 0.05). SignificanceThe luting process of indirect restorations may be improved by using high molar absorptivity, more reactive, and more efficient photoinitiators such as TPO, as opposed to conventional CQ. The use of such initiator may allow the placement of thicker and more opaque indirect restorations.

Predicting effective elastic modulus of CNT metal matrix nanocomposites: A developed micromechanical model with agglomeration and interphase effects

Agglomeration and interphase region of fillers are two important factors that affect the mechanical properties of metal matrix composites reinforced with carbon nanotubes (CNT-CMMs). However, most of the existing theoretical models predict an ascending linear in strength for composites with increasing filler content, which disagrees with the experimental results, especially at high filler loading. In fact, at high CNT concentrations, agglomeration and weak interphase region bonding reduce the strength and consequently degrade the mechanical properties of composites. Based on the mean-field theory, we present a novel micromechanical model to predict the elastic modulus of CNT-CMMs by considering the effects of these two factors. Furthermore, we investigate the effect of other parameters such as CNTs aspect ratio, agglomeration amount, interphase layer thickness and modulus, and matrix modulus on the elastic modulus of CNT-CMMs. Finally, we validate our model by comparing it with numerous experimental outcomes from the literature signifies good precision. Using this model, it is possible to optimize the filler value and also maximize the elastic modulus, which can be a powerful tool for designing the CNT-CMMs.

Effect of composite processing technique on tribological properties of 3D printed PLA-graphene composites

The present study investigates the effect of processing method on the tribological behavior of 3D-printed Polylactic acid (PLA)/graphene composite samples. Two different methods, electrochemical (EG) and chemical exfoliation (HG) of graphite, are used to prepare graphene fillers. The PLA/graphene composites are processed using two different solvents, chloroform (CHCl3) and dimethylformamide (DMF). Various PLA/graphene composite combinations are prepared by varying filler type, solvent type, and filler loading. The 3D printable composite feedstock filaments are prepared using a single-screw Desktop extruder. Fused Filament Fabrication (FFF) is employed to print samples for tribological tests. The coefficient of friction (COF) and wear rate are evaluated using the ball-on-flat reciprocating sliding wear tests. It was observed that COF was reduced by 76 % with 0.5 wt% loading of filler. The wear mechanism has changed from predominant abrasive wear in neat PLA to adhesive wear for composites. Further, the interactive effect of process parameters is studied using ANOVA. The results indicate that filler type and filler loading significantly influence weight loss. The solvent type has a minimum effect.

Gravitational modulation of filler distribution in asymmetric mixed matrix membrane: Achieving high loading in skin layer

The fillers in asymmetric mixed matrix membranes (AMMMs) by phase inversion tend to distribute across the membrane, but less in the skin layer, resulting in limited enhancement of gas separation performance. In this work, an external gravity field is proposed to induce polystyrene-acrylate (PSA) modified hollow ZIF-8 nanospheres (PHZ) to settle and accumulate in the skin layer by the density difference between ZIF-8 and the polymer solution, then through phase inversion, the gravity induced AMMMs (GAMMMs) with improved ZIF-8 loading in skin layer is constructed. This is confirmed by the EDS analysis of the membrane cross-sections that more PHZ settle and accumulate in the skin layer, which enhances the filler loading by 330 % in comparison to the AMMMs without gravity sedimentation. Together with the hollow cavity of PHZ, the gas permeation can be improved greatly. Meanwhile, the PHZ can also guarantee the favorable interfacial compatibility by the hydrogen bonding interaction between the carboxyl groups in PSA with the PES polymer matrix, which is demonstrated by the slightly elevated Tg of GAMMMs over the ZIF-8/PES membrane. Consequently, the PHZ/PES GAMMMs can achieve high gas permeation while keeping sufficient selectivity at high filler loading in the skin layer. The PHZ-8d/PES GAMMM shows H2 permeance of 29.11 GPU and H2/CH4 of 83.04, which are 142.85 % and 5.99 % higher than those of ZIF-8/PES AMMM without gravity sedimentation, and exceeding the corresponding 2008 Robeson upper bound. This proposed GAMMM shows a great potential in the large-scale MMMs based gas separation.

Enhanced thermal conductivity of reduced graphene oxide reinforced polymer films through a novel GO reduction mechanism

AbstractGraphene's remarkable thermal conductance characteristics makes it a very promising thermal interface material for polymeric composites. In this study, we propose an innovative approach aimed at augmenting the thermal conductivity of flexible composite films, employing reduced graphene oxide (rGO) and polyvinyl alcohol (PVA) as the constituent materials. The fabrication process involves the utilization of solution casting coupled with a low‐temperature chemical reduction method for graphene oxide (GO). Given that the high thermal conductivity of polymer nanocomposites typically correlates with increased crystallinity and reduced defects, our primary objective is to investigate the impact of reduction of GO in order to associate enhance crystallinity within the graphene oxide‐polymer system, with the overall increased thermal conductivity of the resulting GO/PVA films. The diethylene glycol‐GO/PVA films thus, generated through this methodology exhibit an exceptional thermal conductivity of approximately 5.1 W/mK, achieved with a mere 10 wt.% filler loading. This surpasses the thermal conductivity observed in films comprised solely of GO/PVA. The notable enhancement in thermal conductivity can be attributed to several factors, including improved crystallinity and reduced defects of GO with effective polymeric bridging facilitated by the rGO with PVA. Collectively, these advancements contribute to the overall thermal performance of the material, presenting a promising methodology for future developments in the field of thermal conductivity materials.Highlights Reduction of GO through a streamlined and facile methodology. Orchestrated a controlled reduction process at lower temperatures and simultaneously enhancing the crystallinity and decreasing the defects of GO. Fabricated reduced GO/PVA polymer films exhibited an exceptional thermal conductivity of approximately 5.1 W/mK with just a 10 wt.% filler loading.

ZIF‐67‐Derived Co@Carbon Polyhedra Anchored on Reduced Graphene Oxide with Multiple Attenuation Abilities for Full X‐ and Ku‐Band Microwave Absorption

High‐performance microwave absorption (MA) materials are attracting growing attention to solve the expanded electromagnetic interference problems. Herein, zeolitic imidazolate organic frameworks (MOF)‐67 (ZIF‐67) are grown in situ on the sheet of graphene oxide (GO) through the coordination of Co2+ with oxygen functional groups. Through carbonization in an inert atmosphere, Co@carbon polyhedra (Co@CP)‐decorated reduced GO composites (Co@CP‐rGO) with a large number of heterogeneous interfaces are successfully obtained. The composites demonstrate excellent MA performance. With a filler loading of 10 wt%, the optimal minimum reflection loss (RL) of the composite can reach −54.6 dB. More importantly, the composites with thickness of 3.5 and 2.5 mm show the effective absorption bandwidth (RL &lt; −10 dB) of 4.75 GHz (8.18–12.93 GHz) and 6.56 GHz (11.44–18 GHz), fully covering the X‐ and Ku‐band. It is proposed that the synergistic effect of multiple dielectric loss, magnetic loss, reflections and scattering contributes to the high MA performance.

A wood-inspired epoxy-based electronic packaging material with vertically aligned thermally conductive channels for electromagnetic waves absorption and thermal management

Multifunctional materials integrating electromagnetic waves absorption (EMA) and heat conductivity functions are urgently desirable to tackle the heat emission and electromagnetic interference issues of advanced electronics. However, simultaneously mustering these features into one material remains a formidable challenge as the incompatibility between high thermal conductivity and excellent EMA performance. Herein, inspired by the water transport process of trees in nature, an epoxy-based electronic packaging material (CFS/EB) with vertical thermal conduction channels is fabricated by encapsulating high thermal conductivity boron nitride/epoxy hybrids into aerogel skeleton with good electromagnetic features. This ingenious design not only can defuse the issue of difficult coexistence of outstanding EMA and thermal conduction performance, but also delivers high through-plane thermal conductivity arised from vertical aligned channels. The resulting CFS/EB composite exhibits strong EMA performance with minimum reflection loss value of −59.2 dB and broad effective absorption bandwidth of 5.82 GHz. Synchronously, the composite also holds the high through-plane thermal conductivity of 1.51 W m−1 K−1 (655 % higher than pure epoxy resin) at low filler loading of 13.15 wt% as well as electrical insulation of 1.43 × 1012 Ω·cm. Such a superior comprehensive performance endows CFS/EB composite a great application prospects in electronic packaging fields, whilst the orientation structure design triggered by this bioinspired strategy offer facile yet feasible alternatives to address heat accumulation and electromagnetic interference problems for integrated electronics.

Core-shell engineering of graphite nanosheets reinforced PVDF toward synchronously enhanced dielectric properties and thermal conductivity

Polymer composites integrating high dielectric permittivity (ε′) but low loss, large breakdown strength (Eb) and thermal conductivity (TC), have attracted widespread attention in electronic devices and power systems. To simultaneously achieve these properties in graphite nanosheet (GNS)/poly(vinylidene fluoride, PVDF), the GNS were first encapsulated by a layer of aluminum oxide (Al2O3), and then incorporated into PVDF, and the resulting PVDF nanocomposites’ dielectric properties and TC were explored in terms of the Al2O3 shell thickness and filler loading. The insulating Al2O3 shell serves as a barrier layer for the formation of leakage current and long-distance electron migration thus resulting in much lower dielectric loss and conductivity of the GNS@Al2O3/PVDF. It effectively mitigates the dielectric mismatch between the filler and host matrix, further introduces more traps that can capture charge carriers, and increases the barrier height for electron detrapping subsequently preventing the growth of electric trees and elevating the Eb. Moreover, the Al2O3 interlayer alleviates both the phonon density state and phonon impedance mismatches between the filler and matrix and facilitates the interfacial phonon transport thus leading to improved TC. The dielectric parameters and TC of the GNS@Al2O3/PVDF can be simultaneously modulated by optimizing the Al2O3′s thickness. This work offers an effective approach for designing and fabricating the polymeric nanodielectrics concurrently integrating high ε′ but low loss, enhanced Eb, and TC for prospective applications in power equipment and microelectronic devices.

Fluorinated ZIF-71 with adjusted pore size to enhance separation performance of mixed matrix membrane for recovering R32 from R410A

Due to the high Global Warming Potential (GWP) of hydrofluorocarbons (HFCs), the Kigali Amendment to the Montreal Protocol explicitly calls for the phase-out or limited use of HFCs, and the replacement of HFCs by hydrofluoroolefins (HFOs) is imminent. Therefore, it is particularly significant to develop new technology to separate valuable difluoromethane (R32, GWP = 675) from the near-azeotropic refrigerant blend R410A (GWP = 2088), because the traditional distillation is not applicable. In this work, aiming to enhance the separation performance of mixed matrix membrane (MMMs) for R410A, 5-fluorobenzimidazole was introduced into ZIF-71 by the solvent assisted linker exchange (SALE) method for the first time to reduce the pore size of fluorinated ZIF-71 by benzene rings and form hydrogen bonds between R32 with ZIF-71. A novel series of MMMs consisting of fluorinated ZIF-71 and Poly(ether-block-amide) ®1657 (Pebax®1657) polymer were prepared to separate the components of the R410A. The separation performance of the MMMs was investigated at different feed pressures and filler loading. The results showed that the introduction of 5-fluorobenzimidazole contributed to a significant increase in R32 permeability and R32/R125 selectivity of the MMMs compared to pure Pebax membrane. The 15 wt% ZIF-71-F/Pebax MMM showed the best separation performance with R32/R125 selectivity up to 26.6, four times that of pure Pebax membrane and twice that of ZIF-71/Pebax MMM. The ZIF-71-F/Pebax MMM have outstanding data on R32/R125 selectivity and no significant disadvantage in permeability, far exceeding the reported separation performance of membranes for R410A. This confirms that the application of fluorinated metal organic frameworks (MOFs) to the separation of refrigerant blends is a promising strategy.

Compliant composite elastomers via grafting short dangling chains for promoting thermal transport performance

AbstractThe multifunctional composite elastomers serve as thermal interface materials for heat dissipation in electronic devices when their thermal transport performance is enhanced. The common method for enhancement, continuously raising the thermal conductive filler loading only can improve thermal conductivity of composite elastomers but reduces compliance, resulting in elevated contact thermal resistance with solid surfaces, compromising thermal transport. To address this, we propose grafting short dangling chains onto the composite elastomer matrix to further promote compliance under a certain filler loading. Characterization results demonstrate that the grafted chains effectively reduce relaxation time, enabling faster deformation for the material under pressure. This approach enhances interfacial compatibility, widening the thermal transport path at contact interfaces to contact thermal resistance by 94% (from 17.8 to 1.07 mm2W/K), significantly improving overall thermal transport. Additionally, we discussed the feasibility of employing composite elastomers as thermal interface materials for efficient chip heat dissipation.Highlight The grafted dangling chains can promote the composite elastomers softness. The softness promotion can help reduce thermal contact resistance. A series of theories are employed to learn the mechanisms of the promotion. The resulting composite elastomers can be used as thermal interface materials.

Freestanding cellulose acetate/ZnO flowers composites for solar photocatalysis and controlled zinc ions release

The versatile properties of ZnO micro- and nano- structures have resulted in many applications in piezotronics, biosensors and photocatalysis. However, ZnO can easily dissolve in aqueous fluids, potentially resulting in the release of reactive oxygen species and zinc ions at toxic concentrations. Such an issue can be solved by dispersing ZnO within biocompatible polymeric matrices to reduce the direct exposure to the aqueous fluid and control the release of zinc ions. Herein, this work explores tailored ZnO flowers/cellulose acetate photocatalytic composites at different ZnO weight percentages (1–15 wt%). The photocatalytic degradation of methylene blue dye under simulated solar light is studied, finding an optimal value of ZnO filler loading in the polymer (10 wt%), resulting from a compromise between the photodegradation efficiency and the hydrophobicity induced by ZnO flowers. The reusability of the composites is investigated, finding a surprising improvement in the photodegradation efficiency after the first cycle. Simulated solar light stimulation induces the controllable release of zinc ions in aqueous solution at ppm-levels from the composites at the optimal ZnO filler loading. Finally, the release of ionic species in the absence of light stimulation is found to be directly proportional to the ZnO-loading in the composite, as a result of its degradation in aqueous environments.

Effect of graphene nanoplatelets and nano zinc oxide on gas barrier and antibacterial properties of thermoplastic nanocomposites

AbstractGraphene‐loaded thermoplastic nanocomposite films must be evaluated for antibacterial activity, mechanical, and barrier properties before being utilized as food packaging. Herein, economically feasible linear low‐density polyethylene (LLDPE)‐based flexible packaging materials were developed via the melt compounding technique at 170°C temperature by taking advantage of both graphene nanoplatelets (GNP) and nano zinc oxide (ZnO) fillers. Morphological studies reveal that in composites loaded with GNP/ZnO hybrid fillers, ZnO nanoparticles form a network‐like structure throughout the polymer matrix. Simultaneously, GNPs are uniformly dispersed. The inclusion of hybrid nanofiller considerably reduces both the oxygen transmission rate and the water vapor transmission rate (WVTR) in LLDPE nanocomposites. A maximum decrease of 36% and 67%, respectively, in both oxygen transmission rate and WVTR is observed for 3 wt% of hybrid filler loading in a thermoplastic matrix containing 1 wt% of nano ZnO. The antibacterial efficacy of the derived nanocomposite films is obvious against gram‐positive (Bacillus subtilis) and gram‐negative (Escherichia coli) bacterial strains. These nanocomposite films have the potential to be successfully utilized as flexible packaging materials owing to their improved thermal, barrier, and antibacterial effectiveness.Highlights GNP/ZnO was used as a hybrid reinforcing filler in the LLDPE matrix. ZnO nanoparticles establish a network‐like morphology. LLDPE nanocomposite films exhibited excellent antibacterial activity. Oxygen and water vapor barrier properties were significantly improved. The thermoplastic composite films could be used as food packaging materials.

Preparation of Al-doped mesoporous silica spheres (Al-MSSs) for the improvement of mechanical properties and aging resistance of dental resin composites

ObjectiveThe purpose of this study was to synthesize Al-doped mesoporous silica spheres (Al-MSSs) and evaluate the effect of them as functional fillers on the mechanical properties and aging resistance of dental resin composites. MethodsAl-MSSs were prepared by a two-step method. The effect of Al-MSSs on the performance of the composites was evaluated using neat resin matrix, commercial composites 3M Z350XT and samples containing mesoporous silica spheres (MSSs) and nonporous silica spheres (NSSs) as control. The neat resin matrix consisted of resin monomer (Bisphenol A glycerolate dimethacrylate/triethylene glycol dimethacrylate, 49.5/49.5, wt%) and photoinitiator (camphor quinone/Ethyl-4-dimethylaminobenzoate, 0.2/0.8, wt%). The mechanical properties (flexural strength, flexural modulus, compressive strength and microhardness) of them were evaluated by a universal testing machine and microhardness tester. The mechanical stabilities of the prepared composites in wet environment were evaluated by immersing them in deionized water at 37 °C. In addition, we evaluated the effect of Al-MSSs on other properties of the dental resin composites such as polymerization shrinkage, degree of conversion, curing depth, contact angle, water sorption and solubility according to ISO 4049: 2019. ResultsThe synthesized Al-MSSs possessed good dispersibility with an average particle size of about 505 ± 16 nm. The mechanical properties of resin composites gradually increased with the increase of the loading amounts of inorganic fillers. The reinforcing effect of Al-MSSs was similar to that of MSSs and better than that of the NSSs groups at the same filler loading. After aging in deionized water at 37 °C for 30 days, the mechanical properties of all resin composites decreased. However, the decrease percentage of the composites filled with Al-MSSs was significantly lower than the other groups, indicating that the stability of the dental composites in wet environments was significantly improved by the Al-MSSs fillers. Furthermore, Al-MSSs had no obvious influence on the biocompatibility and other properties of dental resins. SignificanceThe prepared Al-MSSs could effectively improve the mechanical properties and aging resistance without sacrificing other physic-chemical properties of dental resin composites.

Biochar for sustainable additive manufacturing: Thermal, mechanical, electrical, and rheological responses of polypropylene-biochar composites

The utilization of eco-friendly reinforcing materials and the fabrication of sustainable composites with enhanced mechanical and electrical properties are a subject of great scientific interest. Such research is aiming to be applied in a variety of industrial applications. In this study, polypropylene (PP) was used as a matrix material and combined with biochar (BC) as a filler at different loadings (2.0, 4.0, 6.0, 8.0, and 10.0 wt %) to produce reinforced composites. Biochar was produced from olive tree prunings. Additively manufactured specimens underwent a variety of tests (fourteen in total) regarding their thermal, structural, mechanical, morphological, and electrical properties. The mechanical properties of the PP were improved by the addition of 4.0 wt % biochar, as the tensile strength and modulus of elasticity, presented a 28.4 % and 24.3 % increase compared to that of pure PP. Overall, the 6 wt % was the optimum loading considering all the tests conducted. The thermal stability of the PP/BC composites was significantly improved compared to that of pure PP. At a filler loading of 8.0 wt %, the dc-conductivity of PP/biochar composite increased by more than 9 orders of magnitude, suggesting the existence of a percolation threshold, above which the polymer composite switches from insulating behavior to a conductive state. Overall, biochar addition had a positive impact on all measured quantities and proved to be an eco-friendly material suitable for use in various applications of additive manufacturing (AM).

Regulating microstructure and composition by carbonizing in-situ grown metal-organic frameworks on cotton fabrics for boosting electromagnetic wave absorption

High-temperature carbonized metal-organic frameworks (MOFs) derivatives have demonstrated their superiority for promising electromagnetic wave (EMW) absorbers, but they still suffer from limited EMW absorption capacity and narrow bandwidth. Considering the advantage of microstructure and chemical composition regulation for the design of EMW absorber, hierarchical heterostructured MoS2/CoS2-Co3O4@cabonized cotton fabric (CF) (MCC@CCF) is prepared by growing ZIF-67 MOFs onto CF surface, chemical etching, and carbonization. Aside from the dual loss mechanism of magnetic-dielectric multicomponent carbonized MOFs, chemical etching and carbonization process can effectively introduce abundant micro-gap structure that can result in better impedance matching and stronger absorption capacity via internal reflection, doped heteroatoms (Mo, N, S) to supply additional dipolar polarization loss, and numerous heterointerfaces among MoS2, CoS2, Co3O4, and CCF that produce promoted conduction loss and interfacial polarization loss. Thus, a minimal reflection loss of −52.87 dB and a broadest effective absorption bandwidth of 6.88 GHz were achieved via tunning the sample thickness and filler loading, showing excellent EMW absorption performances. This research is of great value for guiding the research on MOFs derivatives based EMW absorbing materials.

Facile and scalable preparation of Ni/NiO/SiO2@porous carbon network with strong and wide bandwidth microwave absorption

Researchers are exploring high-performance electromagnetic wave absorbing materials to mitigate electromagnetic interference, focusing on minimizing surface reflection and enhancing attenuation capability. However, one single component and structure struggle to meet the aforementioned requirements. Here, a Ni/NiO/SiO2@porous carbon network (Ni/NiO/SiO2@PCN) with porous structures is synthesized via a pyrolysis process. The magnetic Ni/NiO and dielectric SiO2 nanoparticles are uniformly dispersed within the PCN matrix. The absorption capability of the material can be controlled by adjusting the SiO2 content in Ni/NiO/SiO2@PCN. Particularly, when the SiO2 loading is 0.5 wt%, the resulting Ni/NiO/SiO2@PCN-0.05 demonstrates outstanding EMW absorption properties, exhibiting strong broadband absorption attributed to its 3D porous architectures, the hybrid composition of Ni/C, NiO/C, and SiO2/C, and good impedance matching. At a filler loading of 20 wt%, the Ni/NiO/SiO2@PCN-0.05 achieves remarkable EMW absorption performance, with a minimal reflection loss reaching −71.42 dB at 2.6 mm and 11.18 GHz, and an effective absorption band extending over 6.24 GHz within the frequency range of 11.52 to 18.0 GHz at a thickness of 2.25 mm, effectively covering the entire Ku band. This study introduces a cost-effective and efficient fabrication approach for producing high-performance microwave absorbers, thereby offering promising prospects for applications in the field of microwave telecommunications.

Characterization of cellular uptake, anti-colorectal cancer effects and pharmacokinetics of curcumin-loaded polypropylene/rice husk composites filled with nano-SiO2

Curcumin-loaded polypropylene/rice husk/SiO2 composites were fabricated with tunable nano-SiO2 filler loadings (0–10 wt%) via melt-blending and injection molding. XRD analysis revealed effective intercalation of nanoparticles and interaction with the polymer chains up to 6 wt% loading. Incorporation of SiO2 fillers significantly enhanced mechanical strength with 6 % nano-SiO2 formulation demonstrating 27 % higher tensile strength, 52 % increased flexural modulus and 51 % greater impact resistance. The silica nanoparticles also reduced heat release rate through protective charring and decreased moisture absorption by over 8 % due to hydrophilic surface groups. In vitro studies showed that curcumin nano-composites with 6 % nano-SiO2 exhibited maximal cytotoxicity against HT-29 and HCT-116 colon cancer cells with CC50 values of 12.4±1.1 μg/ml and 10.3±0.9 μg/ml respectively, attributed to optimal drug release profile. The formulation arrested 22.1% cells in sub-G1 phase inducing apoptosis. Oral administration in tumor-bearing mice led to 3-fold increase in plasma exposure (Cmax 186±14 ng/ml) and relative bioavailability versus free curcumin, indicating capacity to evade presystemic clearance. The composites also enabled 3 times higher tumor accumulation highlighting potential for targeted colorectal cancer therapy via improved pharmacokinetics and site-specific action. Overall, precise tuning of nanostructured fillers augments mechanical and transport properties while potentiating anticancer performance.

Synergistic effect of amino and hydroxyl bifunctional modified h-BN on interfacial thermal conductivity in polydimethylsiloxane matrix: Simulations and experiments

As a widely used thermal conductive matrix material, the interface problem between polydimethylsiloxane (PDMS) and thermal conductive fillers needs to be solved urgently. The interfacial heat transfer mechanism between PDMS and hexagonal boron nitride (h-BN) modified by different groups was studied by combining density functional theory (DFT) simulation and molecular dynamics (MD) simulation. The bi-functionalization of h-BN was achieved by the environmentally friendly 6-aminocaproic acid (ACA) additive-assisted water ball milling process. The h-BN/PDMS composite thermal interface materials were prepared using a simple rolling method. The thermal conductivity of the obtained sample reached 1.256 W m−1 K−1 at a filler loading of 15 wt%. The proposed bifunctional synergistic heat transfer mechanism is expected to provide theoretical guidance for the preparation of high thermal conductivity and insulating PDMS used in electronic communications.