This is an editorial article. It has no abstract.

An antibacterial natural rubber (NR) latex film was successfully prepared in this study. This was done by coating silver (Ag) nanoparticles onto the surface of the NR latex film. The Ag nanoparticles were synthesized using green tea (GT) extract as a bio-reducing agent. The corresponding Ag nanoparticles were then deposited onto the NR latex film. Before synthesis, the phenolic compounds were identified using high-performance liquid chromatography (HPLC). The Ag nanoparticles were found to be smaller than 25 nm in size. Subsequently, an experimental evaluation was conducted to determine the influence of deposition time, namely 1 to 20 min, on the film’s overall performance. Scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (SEM-EDX) confirmed that the Ag content was higher over the deposition time. The surface roughness of the samples was also screened by atomic force microscopy (AFM), where the films became rougher over the deposition time, confirming that Ag nanoparticles dispersed over the surface. As for the antibacterial activities, both qualitative and quantitative tests showed significant outputs. The clear zones of S. aureus and E. coli increased over the deposition time, and a shorter contact time was used to kill the bacteria. This study offers a scientific foundation that supports the development of future rubber products utilizing these findings.

Triboelectric nanogenerators (TENGs) offer a promising solution for self-powered sensor applications, but their viability depends on cost-effective and efficient designs. This study presents a simple, durable, low-cost, and biodegradable poly(butylene adipate-co-terephthalate)/AgFe₂O₄ (PBAT/AFO) based TENG, utilizing an innovative approach towards environmental sustainability. AgFe₂O₄ (AFO) nanoparticles, synthesized via combustion, were characterized using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Synthesized AFO nanoparticles were then incorporated into PBAT to prepare polymer nanocomposite, with scanning electron microscopy (SEM) confirming their uniform dispersion. Electrical performance evaluations demonstrated efficient charge transfer, yielding a maximum output voltage of 49.15 V and a current of 4.9 μA under hand tapping. The PBAT/AFO-TENG successfully powered LEDs and an electronic calculator, showcasing its practical utility. Additionally, it functioned as a self-powered biomechanical sensor for human body motion detection, touch security, and touch counter for laboratory entry tracking. This work highlights the simplicity, environmental sustainability, cost-effectiveness, and versatility of PBAT/AFO-TENGs, positioning them as promising candidates for future portable electronics and sensing applications.

In this study, a new plastic film with antiviral and antibacterial properties was developed using modified cassava starch with glycidyltrimethylammonium chloride (GTMAC) and reinforced by crystalline nanocellulose (CNC), called Q-CS/CNC. For comparison, a control film (Q-CS) was produced without the addition of CNC. Elemental analysis revealed a degree of substitution (DS) of 0.552, indicating the replacement of the OH groups of starch by the NR₄⁺ groups of GTMAC during the quaternization reaction. The addition of CNC resulted in significant increases (p < 0.05) of 38.9, 38.2, and 43.1% in thickness, opacity, and water vapor permeability measurements, respectively, compared to Q-CS. Incorporating CNC also contributed to an increase of 43.6% in tensile strength and 109% in stiffness but slightly decreased thermal stability. The Q-CS/CNC film demonstrated efficacy by inactivating 99% of the coronavirus in 1 min and inhibiting the growth of Staphylococcus aureus and Escherichia coli. This action is attributed to the electrostatic interaction of quaternary amino groups, grafted onto starch, with the phospholipid membrane of microorganisms, resulting in the inactivation of these microorganisms. Therefore, these results highlight the potential use of Q-CS/CNC film as antimicrobial packaging, especially against coronavirus.

A nanocomposite of styrene butadiene rubber (SBR) and multi-walled carbon nanotubes (MWCNT) was fabricated using an internal melt mixer. Systematically investigated the role of MWCNT loading on the mechanical, dielectric, electrical and Electromagnetic interference (EMI) shielding characteristics of developed nanocomposites. The fine dispersion of MWCNTs in the SBR matrix was clearly observed from high-resolution transmission electron microscope images. The nanocomposites exhibited outstanding electrical, dielectric and EMI shielding behaviours (~45 dB at 20 phr of MWCNT). A high conductivity of 0.92 S/cm was attained in the nanocomposites and is attributable to the establishment of percolation networks of MWCNT in the SBR matrix. These composites displayed reasonably good mechanical properties because of the reinforcing effect of MWCNT. The economically viable and easy fabrication protocol of this nanocomposite can act as a platform for the synthesis of low-cost and highly effective composite for EMI shielding applications.

In this study, we investigated the influence of processing parameters on the cellular structure and density of specimens fabricated using in-situ foam 3D printing. First, we conducted a comprehensive analysis to examine how the combined effects of printing temperature and speed influence the four key stages of the foaming process: gas dissolution, cell nucleation, cell growth, and stabilization. By evaluating the structural characteristics of the printed foams, we identified the dominant mechanisms governing each stage. Next, we explored the effect of nozzle diameter, an aspect previously unexamined in the literature. We found that smaller nozzle diameters promote higher cell density due to enhanced pressure drop and shear-induced nucleation, resulting in a 36.78% reduction in density and a 60.31% increase in cell density when using a 0.4 mm nozzle instead of 0.8 mm (at 240°C, 60 mm/sec). Finally, we fabricated functionally graded four-layer structures by adjusting the printing temperature for each layer to control porosity distribution. To evaluate the mechanical performance of these graded structures, we performed three-point bending and drop-weight impact tests, allowing us to assess how layer order influences mechanical properties. Our results showed that proper layer sequencing can increase flexural strength by up to 69.35% and improve perforation energy by more than 94.82% compared to homogeneous structures.

Biocomposites have recently received more attention because of raising environmental awareness and the drive toward sustainable technologies. The most common biodegradable polymer is poly(lactic acid) (PLA), which has an excellent balance of physical and rheological properties, but there is some limit to its usage. PLA properties can be improved by adding different types of fibers or fillers that come from agricultural waste. In this study, corn cob and lavender stem were used to reinforce PLA without any coupling agent, and the properties of the composites were investigated. The melt flow rate (MFR) values decreased with the corn cob content and increased with the addition of lavender stem. Mechanical tests showed that the tensile and flexural modulus of the composites increased and the strengths decreased with the reinforcement material content. The rigidness of PLA slightly decreased with the addition of fillers. There was no significant effect on the thermal properties. The unremarkable improvement of the reinforcement was due to the lack of appropriate adhesion of the two phases. The structure of the compounds was found to be homogenous on the scanning electron microscopy (SEM) micrographs. The incorporation of corn cob and lavender stem can reduce the production cost of materials.

The electrical and electrothermal de-icing performance of graphene/polyhydroxyalkanoates (PHA) and graphene/polylactic acid (PLA) composites with different thicknesses were systematically compared and investigated. Graphene/PHA with 1 mm thickness shows a slightly lower electrical resistivity than graphene/PLA. However, the results are contrary for 0.1 mm-thick samples, likely due to poorer interfacial adhesion between graphene and PHA. Besides, all 0.1 mm-thick samples show higher electrical resistivity than 1 mm-thick samples, likely attributed to the alignment of graphene. The current-voltage curves of graphene/PHA exhibit nonlinear behavior with fluctuations, whereas all graphene/PLA samples show linear behavior. This result enables the graphene/PLA to exhibit superior electrothermal stability than graphene/PHA. An excellent electrothermal performance is obtained for these composites. The temperature increases from –40.2 to 95 °C within 17 s under 7 V. While these composites cannot be self-heated and utilized above 95 °C, this is because the composites would undergo electrical breakdown when heated to temperatures above 95°C for 5~10 s. The composite can melt ice within 550 s at –40 °C and within 447 s at –20 °C. These findings suggest that graphene/PHA and graphene/PLA composites hold significant potential for de-icing applications.