Advancing multifunctional pigments that combine low-cost processing with the high-value performance of engineered materials represents a frontier in materials science. In this study, next-generation pearlescent CoO-ZnO/Mica pigments (Co.Zn/M) were engineered through a sol-gel process and designed to deliver dual functionality in two significant technological fields: anticorrosive coatings and as an activator in styrene-butadiene rubber (SBR). Two tailored compositions, 1Co.9Zn/M and 3Co.7Zn/M, were synthesized and rigorously characterized by using several spectroscopic techniques, confirming their structural integrity and compositional precision. When integrated as pearlescent pigments into epoxy resins with three ratios (e.g., 5, 10, and 15%), these pigments exhibited inherent bright colors and anticorrosive behavior, underscoring their potential as versatile materials for next-generation coatings. The corrosion measurements revealed that 3Co.7Zn/M is more protective than 1Co.9Zn/M, and the ratio of 10% is the best. Moreover, these pigments were introduced with three ratios of loading (e.g., 1, 2, and 3 phr) in SBR formulations as alternative activators to partially or entirely replace the conventional ZnO-stearic acid. The Co.Zn/M/SBR composites accelerated curing behavior and a slight reduction in tensile strength of (1.86%) compared with the blank composite, but a pronounced enhancement in elongation compared with the blank composite. Furthermore, the pigments also improved swelling resistance, cross-link efficiency, while simultaneously promoting a more uniform additive dispersion within SBR matrix.
The thermoresistive behavior of conductive polymer nanocomposites is critical for applications such as temperature sensors, thermistors, and self-regulating heaters. However, understanding how temperature influences charge transport in hybrid nanofiller systems remains challenging due to the complex interplay between matrix thermal expansion, filler geometry, and quantum tunneling. This study develops a simulation-based percolation model to investigate thermoresistivity in polymer nanocomposites containing carbon black (CB) and carbon nanotube (CNT) hybrid nanofiller. The aim is to quantitatively elucidate how temperature affects electrical resistivity by incorporating the key physical mechanisms governing thermally activated charge transport, including the temperature coefficient of resistance of conductive fillers, the thermal expansion coefficient of the polymer matrix, and temperature-dependent electron tunneling through electronic subbands. A major challenge addressed is the accurate representation of tunneling resistance as a function of temperature-dependent inter-filler distances, while accounting for confinement-induced electronic subbands in CB nanoparticles and CNTs. The model predicts that thermoresistivity increases with random nanofiller orientation and low CNT aspect ratios. Validation against experimental data reported in the literature demonstrates good agreement across a range of filler concentrations, and temperatures. The results further show that thermoresistivity can be systematically tailored by adjusting the CNT and CB properties, enabling the design of either temperature-stable conductive composites or highly sensitive thermoresistive materials.
The design of polymer composites from recycled materials requires careful control over structure at different length scales. In this work, post-consumer polyvinyl chloride (PVC) was transformed into a textile-supported electrospun nanofibrous composite reinforced with calcium carbonate (CaCO 3 ), hydroxyapatite (HAp), and carbon nanotubes (CNTs). The electrospun layer was deposited directly onto a polyester substrate, creating a mechanically integrated structure in which the fibrous network and the textile support function together. Twelve formulations were prepared to understand how gradual filler incorporation influences solution behavior, fiber formation, and mechanical response. The composition containing 15 wt% PVC with 8 wt% CaCO 3 , 2 wt% HAp, and 2 wt% CNTs provided the most stable performance, reaching a tensile strength of 42.97 ± 2.15 MPa and an elongation at break of 33.78 ± 1.75%. The improvement did not result from a single additive. CaCO 3 contributed structural rigidity, HAp introduced dispersed ceramic domains within the matrix, and CNTs enhanced load transfer while modifying surface roughness. Their combined presence led to a more cohesive fibrous architecture without noticeable embrittlement. The optimized composite maintained a highly porous structure (∼90%) with limited water uptake (∼5%) and exhibited a stable superhydrophobic surface (156.76 ± 1.00°). Under gravity-driven conditions, the membrane achieved 94% oil–water separation. During static immersion in a laboratory-prepared NaCl solution, conductivity decreased by 80.7% after 60 minutes. These results reflect how filler dispersion and hierarchical structuring influence both mechanical stability and interfacial transport behavior within the composite.
Advanced thermoset composite materials are widely used due to their high specific strength, corrosion resistance, good fatigue life, light-weight nature, and design flexibility; however, they exhibit limitations such as poor recyclability, weak out-of-plane strength, and low damping capacity. Since mechanical vibrations lead to energy loss, fatigue failure, and noise, materials with enhanced damping properties are required for vibration control applications. In this study, pure thermoplastic polyurethane (TPU) and aluminum powder-filled TPU composites (1,2,5, and 10 wt%) were fabricated using injection molding for tensile and free vibration analysis. The first three natural frequencies were evaluated theoretically using Euler-Bernoulli beam theory, numerically via ANSYS following ASTM E756 standards, and experimentally through impact hammer testing using an ACC 103 accelerometer sensor. Mechanical properties were determined using tensile testing, while dynamic responses were analyzed in terms of natural frequencies and damping ratios. The results indicate that natural frequencies are directly dependent on elastic modulus, while the aluminum filler in the corporation reduces natural frequencies and significantly improves damping performance. SEM analysis revealed that filler dispersion, agglomeration, and interfacial adhesion strongly affect both mechanical and dynamic properties. The maximum damping ratio of 2.44 was achieved for 10 wt% aluminum-filled TPU with 65% improvement compared to pure TPU, demonstrating its potential for applications such as sandwich composite cores, vibration isolation systems, and structures requiring effective vibration suppression.
In this study, ZnS nanoparticles (NPs) were immobilized on a carbon black/phosphorylated butadiene rubber (CB-PhBR) matrix using the successive ionic layer adsorption and reaction (SILAR) method to develop multifunctional polymer nanocomposites. The novelty of this work lies in the cycle-controlled deposition of ZnS NPs on a conductive, phosphate-functionalized elastomer matrix and the evaluation of the resulting structural, optical, electrical, and dielectric responses. XRD confirmed cubic ZnS formation, while SEM, FTIR, and BET supported its immobilization and the resulting morphological/porous-structure changes. The immobilization of ZnS NPs reduced the electrical conductivity and dielectric permittivity, indicating disruption of the CB percolation network and suppression of interfacial polarization. UV-vis analysis showed an increase in the optical band gap from 2.29 eV for CB-PhBR to 3.82 eV for ZnS NPs/CB-PhBR. These results demonstrate that SILAR-assisted immobilization of ZnS NPs effectively modifies the functional properties of CB-PhBR-based nanocomposites, indicating their potential for dielectric, optoelectronic, and functional polymer applications.
This study reports the successful synthesis and characterization of a novel TiO 2 /TeO 2 /B 2 O 3 ternary glass system prepared via the sol-gel method. Comprehensive analysis using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM) confirmed a uniform, predominantly amorphous structure in the as-prepared state. Optical characterization by UV-Vis spectroscopy revealed a significant reduction in the optical band gap compared to pure TiO 2 , effectively shifting the absorption edge into the visible light region. A critical finding of this research is the material’s dose-dependent radiation stability. The ternary glass maintained its amorphous network after exposure to gamma radiation doses of 50 kGy and 75 kGy, demonstrating exceptional structural robustness. A radiation-induced structural evolution from the amorphous phase to the crystalline anatase phase of TiO 2 was only observed at a higher absorbed dose of 100 kGy. This evolution, coupled with a further reduction in the optical band gap to 2.9 eV, highlights the potential of this ternary glass for advanced applications in visible-light photocatalysis and optoelectronics where durability in high-radiation environments is essential.
This study investigates the influence of cenosphere and graphene nanoplatelet (GNP) reinforcements on the physical, mechanical, and dimensional accuracy characteristics of PLA-based composites fabricated using Fused Filament Fabrication (FFF). The incorporation of cenospheres effectively reduced the composite density from 1.25 g/cm 3 for neat PLA to 1.19 g/cm 3 and 1.14 g/cm 3 for 5 wt% and 10 wt% cenosphere additions, respectively, demonstrating the lightweighting capability of hollow ceramic fillers. The void content increased progressively with reinforcement loading due to increased melt viscosity, particle agglomeration, and localized air entrapment during processing, with values ranging from 2.14% to 8.09% for the reinforced composites. Despite the increase in porosity, graphene nanoplatelets improved the overall stiffness and stress transfer efficiency of the composites through enhanced interfacial interaction and restriction of polymer chain mobility. Mechanical characterization revealed substantial enhancement in hardness, reaching a maximum value of 91.5 Shore D for the hybrid PCG-5 composite, attributed to the synergistic reinforcement effect of rigid cenospheres and high-stiffness graphene nanoplatelets. Dimensional accuracy analysis identified layer thickness as the most influential processing parameter, contributing nearly 79% of the total variation, with lower layer heights consistently improving geometric fidelity. Statistical analyses using Taguchi design, ANOVA, contour mapping, and regression modeling confirmed this trend, while Random Forest regression further validated the experimental findings with a high prediction accuracy (R 2 = 0.94) and minimal prediction error. Feature importance analysis also established layer thickness as the dominant governing factor, followed by printing speed and raster angle. Overall, the integration of experimental optimization and machine learning provides an effective framework for improving dimensional precision and mechanical performance in additively manufactured PLA hybrid composites intended for lightweight engineering applications.
The way polymers are being designed for protection is changing. Instead of relying on heavy metals or dense composites, researchers are now creating architected polymer shields that block both electromagnetic interference (EMI) and ionizing X/γ - rays while staying light, flexible, and multifunctional. This review takes a structural view of how form dictates function. It highlights three design families that define current progress: multilayers that grade impedance and trap waves through cascaded absorption; segregated networks that build efficient conductive paths along polymer interfaces; and porous or foamed frameworks that scatter radiation through microcellular pathways, achieving strong attenuation with minimal weight. By linking architecture, filler chemistry (graphene, MXenes, ferrites, BaTiO 3 , Bi 2 O 3 , WO 3 ) and processing strategies (solution or melt mixing, magnetic alignment, additive manufacturing) to measurable outcomes—shielding effectiveness, specific efficiency, and attenuation coefficients—we show where performance gains truly come from. The review also exposes the hidden compromises between conductivity, impedance matching, mechanical strength, and durability, while offering design “playbooks’’ for three front - line needs: low - reflectance EMI absorbers, flexible medical aprons, and structural aerospace panels . Finally, it looks ahead to the next breakthroughs: corrosion - proof 2D interfaces, scalable filler dispersion, frequency - tuned architectures, and data - guided materials discovery that could make polymer shielding a mainstream multifunctional technology.
Welding of polymer composites, for like-material (composite/composite) and dissimilar (composite/metal) combinations, is a promising alternative to conventional joining methods in sectors such as aerospace and automotive, yet achieving robust joints is critically dependent on optimal interfacial bonding. The primary objective of this systematic review is to evaluate the comparative effectiveness of surface treatment strategies applied prior to welding, based on material properties, process variables, and application contexts. Employing a bibliometric and SWOT analysis, this study categorizes techniques into seven main groups: abrasive, laser texturing, plasma, etching, chemical oxidation, intermediate film application, and nanofiller incorporation. These methods are assessed by how they modify surface properties to enhance mechanical anchoring and chemical interactions. The analysis reveals a multifaceted choice of treatment, highly dependent on the specific materials and welding process, with recurring effective strategies: for like-material joints, robust performance is achieved through compatible thermoplastic films, often combined with plasma or nanofillers, whereas for dissimilar joints, an effective combination strategy frequently involves abrasive preparation, oxide layer growth, and silane deposition to increase roughness and chemical compatibility. This review establishes that engineered surface treatments and their strategic combinations are fundamental for enabling reliable, high-performance welded joints, thereby advancing the application of lightweight composite structures.
In this work, the effect of surface modification of palygorskite (Pal) on its dispersion and on the morphological, thermal, wettability, mechanical, optical, and gas transport properties of blown polypropylene (PP)/Pal films was investigated. PP/PPma/Pal composites containing 1 wt% modified Pal were prepared via twin-screw extrusion, followed by blown film processing. The results demonstrated that surface modification significantly improved filler dispersion within the polymer matrix, leading to a reduction of approximately 15% in crystallinity, as confirmed by SEM and XRD analyses respectively. In addition, the films exhibited enhanced thermal stability, with an increase of similar to 25% in the onset degradation temperature, and improved wettability, while maintaining mechanical performance. The films showed high transparency (>91%) and reduced haze (32-37%), attributed to changes in crystallinity that increased the amorphous fraction and improved optical clarity. Notably, in contrast to the typical barrier effect reported for layered clays, the incorporation of fibrous Pal led to a substantial increase in gas permeability, with O-2 and CO2 permeability rising by 190% and 220%, respectively. This behavior is attributed to reduced polymer chain packing and the presence of polar functional groups introduced during surface modification. These findings demonstrate a novel strategy for tuning gas transport properties in polymer films and highlight their potential for agricultural applications, particularly as greenhouse covering materials where enhanced gas exchange can promote plant growth and productivity.
The use of multilayer flexible food packaging has fundamentally revolutionized the global food system by allowing the product to have an extended shelf life, safer storage and highly efficient distribution of packaged foods on a scale never experienced before. However, the complexity of material that makes such performance in service creates immense difficulties at the end of the service since the combination of several polymers, barrier layers, adhesives, and inks place harsh demands on recyclability. Because of this, bulk post-consumer packaging of snacks is often not recycled through standard recycle streams and instead goes to landfills, incineration, or scattered about in nature. This review critically examines the main recycling options that can be used in the recycling of packaging waste, and they include mechanical recycling, chemical recycling and newer upcycling avenues. The most practical but least energy-intensive recycling method is mechanical recycling, which has limitations due to polymer incompatibility, contamination and degradation of material during recycling. Another path that is provided through chemical recycling is the production of complex laminates into fuels, monomers and virgin-equivalent polymers, though barriers in terms of energy requirements, expenses, and integration of the process still exist. Also, increased upcycling and hybrid recycling designs are addressed as a possible measure of producing functionalized polymers, customized blends and specialty materials with previously unrecyclable waste. The review also explores diverse applications in infrastructure and high-value polymers while establishing a rigorous framework to evaluate the Technology Readiness Levels (TRL) and Operational Expenditure (OPEX) of recycling routes. It identifies the industrial shift toward mono-material design-for-recycle structures as a primary solution to material incompatibility. Ultimately, the study highlights the role of integrated systems and policy in fostering a circular economy and reducing the environmental impact of multilayer packaging.
The engineering application of carbon fiber-reinforced polymers (CFRP) in lightweight structural systems is constrained by joining defects in friction stir welding (FSW). Current research lacks systematic comparison and mechanism analysis of different auxiliary media for CFRP FSW. This study comparatively investigates the regulation mechanism of aqueous medium and cutting fluid on defect evolution and mechanical properties of CFRP FSW joints. Results demonstrate that cutting fluid achieves a precise balance between welding heat input and cooling rate via synergistic cooling–lubrication effects, overcoming the defect sensitivity caused by the single cooling function of aqueous medium. The intrinsic regulation mechanism of auxiliary media on defect formation is revealed, and cutting fluid is verified to significantly improve joint compactness, suppress interfacial degradation, and enhance mechanical performance. These findings fill the knowledge gap in medium-assisted CFRP FSW and support high-quality joining of high-performance CFRP components.
To enhance CFRP-aluminum alloy thin plate joint strength, this study proposes a novel hybrid riveting method. It involves 3D-printing multi-row micro-metal rivets on aluminum substrate, embedding them into carbon fiber fabric, and co-curing via vacuum-assisted resin transfer molding to form a joint integrating mechanical interlocking and adhesive bonding. Single-factor experiments with rivet row number (0, 1, 2, 3) as the variable evaluated mechanical performance and failure mechanisms. The single-row configuration achieved 7.54 MPa lap shear strength, 650.2% and 408.7% higher than adhesive-only (1.01 MPa) and surface-treated adhesive (1.43 MPa) groups, respectively. Strength showed a non-linear trend (1 > 3 > 2), while elongation increased with row number. Failure analysis revealed interfacial debonding for rivet-free specimens and aluminum substrate fracture for riveted ones. The non-linear strength behavior stems from multi-row rivet bridging and localized bending. This technique significantly improves CFRP-aluminum bonding.
This study systematically investigates the effects of graphene oxide (GO) and reduced graphene oxide (rGO) on the structural, thermal, mechanical, rheological, and morphological properties of polypropylene (PP). PP/GO and PP/rGO composites containing 1–10 wt% filler were fabricated via melt blending using a twin-screw extruder, followed by injection molding. FTIR analysis confirmed the presence of oxygen-containing functional groups in GO and rGO, while the reduced peak intensity in rGO-filled samples, suggesting improved compatibility with the non-polar PP matrix. XRD and DSC results showed that both fillers acted as nucleating agents; however, rGO exhibited a significantly stronger effect, evidenced by a 17°C increase in crystallization onset temperature (Tc,onset) at 10 wt% loading and the formation of more stable α-phase crystallites. SEM observations revealed agglomeration and weak interfacial bonding in GO composites, whereas rGO provided uniform dispersion, strong interfacial interaction, and crack-deflection behavior. Mechanical testing confirmed the superior reinforcing effect of rGO, with increases of 37.6% in tensile strength (PP/rGO5) and 67.1% in impact strength (PP/rGO10). Rheological and TGA analyses further demonstrated enhanced chain restriction and thermal stability with rGO. Overall, this study provides clear evidence that rGO is a more effective nanofiller for PP than GO.
The casting method was used to produce new inexpensive optoelectronic nanocomposite films containing strontium titanate (SrTiO 3 ) and cobalt oxide (Co 2 O 3 ) nanoparticles in a polyvinyl alcohol (PVA) host polymer matrix. According to the images taken with the optical microscope, the nanoparticles were evenly dispersed throughout the polymer matrix. Looking at the FTIR spectra in comparison to PVA shows that certain peaks have changed intensity and others have moved locations. Results show that the optical constants are proportional to the concentration of (SrTiO 3 -Co 2 O 3 ) nanoparticles (NPs), indicating that optical constants increase with concentration and transmittance decreases with further concentration. With a rise in (SrTiO 3 -Co 2 O 3 ) nanoparticle concentration. The optical band gap significantly decreased from 4.1 eV to 3.4 eV, facilitating indirect transitions, as the concentration of SrTiO 3 –Co 2 O 3 increased. This indicates that localized states improved, resulting in enhanced optoelectronic performance. At a loading of 6 wt% of SrTiO-Co 2 O 3 , the dielectric constant, dielectric loss, and AC electrical conductivity increased to 1.187, 0.523, and 2.90 × 10 −11 S/cm, respectively. This indicates an improvement in charge transfer and interfacial polarization. The antibacterial assays indicated that Staphylococcus aureus had inhibition zones measuring up to 34 mm, while Escherichia coli displayed inhibition zones of up to 26 mm. This confirmed that the antibacterial activity intensified with increasing nanoparticle concentration. The pressure sensing performance was markedly enhanced, with the nanocomposite exhibiting a peak sensitivity of 72.66% at a 6 wt% nanoparticle concentration, highlighting its suitability for flexible pressure sensor applications. In general, the addition of SrTiO 3 –Co 2 O 3 nanoparticles altered the optical band gap, enhanced the dielectric and electrical properties, and rendered the material significantly more sensitive to pressure and more effective in the elimination of bacteria. The combined functions of PVA/SrTiO 3 –Co 2 O 3 nanocomposite films suggest that they may be beneficial for antimicrobial applications, flexible pressure sensors, and optoelectronic devices.
The integration of natural fibers into 3D-printed polymer composites has gained significant attention due to the growing demand for sustainable and high-performance materials. This review comprehensively examines the material selection, processing methods, property enhancement techniques, 3D printability, challenges, and future prospects of natural fiber-reinforced polymer composites in additive manufacturing or 3D printing of polymer composites. Natural fibers, categorized into plant-based (bast, leaf, grass, seed/fruit, and wood fibers) and animal-based (silk, keratin, and secreted protein/shell-based biofillers), offer biodegradability, renewability, and enhanced mechanical properties, making them promising reinforcements for polymer matrices such as polylactic acid (PLA) and polycaprolactone (PCL). However, challenges such as fiber hydrophilicity, thermal degradation, and poor interfacial bonding necessitate surface treatments, fiber modifications, and process optimizations to improve printability and composite performance. While additive manufacturing techniques, particularly fused deposition modeling (FDM) and stereolithography (SLA), enable the fabrication of complex geometries with reduced material waste, factors like nozzle clogging, fiber alignment, and anisotropic mechanical properties remain key limitations. Future research should focus on novel fiber-polymer combinations, advanced printing techniques, life cycle analysis, and expanding applications into fields such as construction. By addressing these challenges, 3D printing of natural fiber-reinforced polymer composites can advance the area of sustainable manufacturing of biocomposites while maintaining structural integrity and functional performance.
This study offers a systematic review of the methodology surrounding the use of thermoplastics in three-dimensional (3D) printing for medical applications. Despite 3D printing not being extensively adopted for the creation of clinical medical devices due to safety and legal concerns, recent developments in materials, printing technology, and professional skills have broadened its clinical uses. The use of thermoplastics in 3D printing allows for the creation of economical components with diverse properties and potential applications. For example, literature consistently reports that while PLA-based structures typically exhibit tensile strengths in the range of 50–65 MPa, PEEK-based printed components achieve substantially higher strengths of 90–100 MPa, alongside superior fatigue resistance and long-term biocompatibility, making PEEK more suitable for load-bearing orthopedic applications. By employing design tactics such as thermoplastic layering, it is possible to reconcile competing demands, such as the mechanical strength and biological compatibility required for tissue structures. Consequently, this review summarizes the research efforts aimed at identifying appropriate thermoplastics, including polylactic acid (PLA), polypropylene (PP), polycarbonate (PC), polyurethane (PU), Acrylonitrile Butadiene Styrene (ABS), polyetheretherketone (PEEK), and polyvinyl alcohol (PVA), for the production of biomedical parts through 3D printing. It covers a range of produced items, including bones, high-quality prosthetics, intervertebral discs, medical devices, heart valves, and tissues containing blood vessels. Additionally, this review examines various 3D printing techniques, the challenges faced, and the future prospects for thermoplastic biomedical components.
This article examines the mechanics, environmental aspects, and effects of biopolymer degradation as sustainable substitutes for conventional plastics. To maximize their environmental performance, it is important to understand degradation processes and the biological, abiotic, and environmental factors such as temperature, moisture, microbial activity, oxygen, pH, and UV exposure. The review emphasizes both the possible hazards, such as microplastic production, toxicity, and ecological disruptions, and the positive environmental advantages, such as pollution reduction and microplastic mitigation. It also addresses contemporary issues such as legislative gaps, lack of standardized testing, delayed degradation in natural environments, and financial constraints. In order to promote sustainable, biodegradable materials that support global environmental and societal goals, future approaches will concentrate on cutting-edge monitoring technologies, circular economy principles, policy development, and public awareness. In conclusion, biopolymers have a lot to offer the environment, but in order to fully realize their potential in sustainable development, further study, technological progress, and international collaboration are needed.
