Doaa Essamey El-Nashar

This study focuses on fabricating and evaluating novel, ecofriendly, green, flexible, antimicrobial Styrene Butadiene Rubber vulcanizates for producing safety products. Styrene butadiene rubber (SBR) was compounded with ginger extract, a plant rich in bioactive phenolic compounds, and the conventional drugs, berberine and chitosan, in the ordinary mixer of rubber. Ginger ( Zingiber officinale ) extract was analyzed using HPLC. The rheological properties of the SBR mixes were analyzed to determine the optimal curing time. The compounded rubber mixes were then vulcanized at 152 °C. The prepared vulcanizates were evaluated using Fourier-transform infrared spectroscopy (FTIR), specific surface area measurements, mechanical, swelling, antimicrobial properties, and cytotoxicity analysis. The results showed that the physicochemical and mechanical properties of all vulcanizates remained robust, i.e., no significant degradation, even after exposure to thermal oxidative aging at 90 °C for seven days. Therefore, the change of tensile strength percentage after aging was 25, 5.56, 13, and 10% for free SBR, SBR/30 phr chitosan, SBR/20 phr ginger, and SBR/7 phr berberine, respectively. The cytotoxicity tests confirmed the safety of the investigated vulcanizates due to the negative results against the normal human fibroblast cell line (BJ1). Furthermore, the antimicrobial activity results demonstrated that the release of the various antimicrobial agents successfully inhibited the growth of different bacteria and fungi on the SBR rubber surface. The dielectric and electric findings highlighted the ability of the presence of bioactive agents to modify dielectric relaxation and conductivity in the investigated SBR vulcanizates and confirmed the utility of SBR composites contained 30 phr chitosan, 20 phr ginger, and 7 phr berberine as a good viable choice for antistatic and flexible electronic applications.

Magnetic carbon dots (Fe ₃ O ₄ /N–CQDs) were synthesized via a one-step microwave-assisted method using sugarcane bagasse as the carbon precursor. The synthesized materials were thoroughly characterized via thermogravimetric analysis (TGA/DTG), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) to examine their thermal behavior, nanoscale morphology, and phase composition. These Fe ₃ O ₄ /N–CQDs were incorporated into acrylonitrile butadiene rubber (NBR) at varying concentrations (0–11 phr), and the resulting composites were evaluated for their structural characteristics (FTIR, SEM), thermal stability, curing behavior, mechanical performance, swelling resistance, thermal aging resistance, as well as magnetic, and dielectric properties. Among the formulations studied, the composite containing 8 phr Fe ₃ O ₄ /N–CQDs showed the most balanced performance, with tensile strength increasing from 2.3 to 4.2 MPa and hardness from 54 to 65 Shore A. Post-aging analysis revealed improved tensile strength and reduced swelling, attributed to enhance crosslinking. The composites demonstrated superior thermal aging resistance under accelerated aging at 110°C for 10 days. Magnetic measurements indicated soft magnetic behavior, with saturated magnetization increasing from 29.05x 10 ⁻³ emu/g (0 phr) to 91.32 × 10 ⁻³ emu/g (11 phr) and coercivity below 120 G, while dielectric and conductivity studies showed frequency-dependent permittivity and conductivity consistent with interfacial polarization and hopping mechanisms. These results demonstrate that Fe ₃ O ₄ /N–CQDs can simultaneously enhance the thermal, mechanical, antiaging, magnetic, and dielectric properties of NBR compounds.

This study developed novel EPDM rubber composites filled with tungsten powder as a safer alternative to radiation shielding materials. The composites rheological, mechanical, and radiation shielding properties were investigated. The results showed that adding tungsten powder up to 30 phr improved the composites’ mechanical properties and radiation shielding effectiveness. The tensile strength increased from 5.1 MPa (unfilled EPDM) to 16.5 MPa at 30 phr, with elongation at break rising from 750% to 1350%, and hardness from 48 to 73 Shore A. Under γ-irradiation, EPDM/W composites maintained superior stability, with 30 phr showing the highest resistance to degradation compared to other loadings. The linear attenuation coefficient increased with tungsten content, reaching 2.6 cm⁻¹ at 40 phr and 80.99 keV, and 0.1702 cm⁻¹ at 661.64 keV. The composites demonstrated promising properties for gamma-ray shielding applications, making them a potential candidate for replacing lead-based materials in nuclear facilities. The findings suggest that EPDM/W composites could provide a safer and more effective solution for radiation protection.

Injuries are common in daily life and may result in severe complications if not properly treated. In recent years, extensive efforts have been devoted to developing effective wound dressings that reduce infection risk and accelerate the healing process.In this study, a novel polymeric wound dressing patch was fabricated by integrating sulfathiazole (SF), an antimicrobial agent, into a chitosan (CS) and polydimethylsiloxane (PDMS) matrix using the solvent casting technique. Two different concentrations of SF, 10% and 20% relative to the weight of CS, were used. The chemical structure of the prepared patches was confirmed using Fourier Transform Infrared Spectroscopy (FT-IR), which revealed characteristic peaks for CS, PDMS, and SF. Scanning Electron Microscopy (SEM) images showed a uniform and smooth surface for the CS–PDMS blend, while SF-loaded patches exhibited even dispersion of the drug within the polymeric matrix. Thermogravimetric analysis (TGA) demonstrated that blending PDMS with CS enhanced thermal stability; however, the incorporation of SF slightly reduced this stability. Mechanical testing indicated that the CS–PDMS patch had improved tensile strength and elongation at break compared to CS alone, whereas these properties decreased upon SF incorporation. In the animal experiment, the SF-loaded CS–PDMS patch containing 20% SF demonstrated a significantly greater wound size reduction (83.1%) compared to the control group. These findings were further confirmed by histological analysis. Moreover, the patch exhibited strong antimicrobial activity against a wide range of pathogens, including Escherichia coli , Staphylococcus aureus (ATCC), Candida albicans (ATCC), Aspergillus flavus (clinical isolate), and methicillin-resistant Staphylococcus aureus (MRSA). These findings suggest that the CS–PDMS–SF patch is a promising multifunctional wound dressing with both healing-promoting and antimicrobial properties.

This study developed novel EPDM rubber composites filled with tungsten powder as a safer alternative to radiation shielding materials. The composites rheological, mechanical, and radiation shielding properties were investigated. The results showed that adding tungsten powder up to 30 phr improved the composites mechanical properties and radiation shielding effectiveness. The linear attenuation coefficient increased with tungsten content, reaching 2.6 cm ^-1 at 40 phr and a photon energy of 80.99 keV. The composites demonstrated promising properties for gamma-ray shielding applications, making them a potential candidate for replacing lead-based materials in nuclear facilities. The findings suggest that EPDM/W composites could provide a safer and more effective solution for radiation protection.

The goal of this work is to prevent environmental pollution resulted from burned agriculture waste, offering a pathway with the potential to reduce CO₂ emissions compared to direct combustion of sugarcane bagasse. Cellulose nanocrystals (CNC) are produced by acid hydrolyzing cellulose obtained from sugarcane bagasse. It serves as a reinforcing filler within the ethylene propylene diene monomer (EPDM) rubber matrix. Transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) were employed to examine morphology, thermal properties and crystallinity respectively. The empirical crystallinity (LOI) and average hydrogen bond strength (MHBS) were determined using Fourier transform infrared spectroscopy (FTIR) for cellulose and cellulose nanocrystals (CNC). It was discovered that (CNC) is lower than CNC for both LOI and MHBS, demonstrating the breakdown of cellulose into CNCs. Two roll-mill was used to prepare EPDM/cellulose nanocrystals (CNC) nanocomposites. Two to ten parts of CNC per hundred rubbers were used. Curing characteristics, mechanical testing, thermogravimetric analysis (TGA), equilibrium swelling, and scanning electron microscopy (SEM) were used to assess the EPDM/(CNC) nanocomposites. SEM pictures, show that some clumping, particularly at higher percentages of (CNC), and a uniform dispersion of (CNC) at 8 phr. It has been demonstrated that when the loading of CNCs increases, the cure time lowers and cure rate index increased, simulating a shorter industrial production cycle. In comparison to EPDM at 8 phr (CNC) loading, Additionally, the results showed an increase in tensile strength from 2.68 to 10.82 MPa i.e. increased by 403.7% and increasing in elongation at break by 233.47%. Also the hardness increased to about 83.33%. The modulus at 50, 100, and 200%, as well as a decrease in equilibrium swelling that confirm the mechanical testing. So, the prepared (CNC) may be enhanced the mechanical properties of the evaluated nanocomposites comparing to EPDM vulcanizates free.

This study investigates the incorporation of recycled nano‐tungsten oxide (WO ₃ ) into ethylene propylene diene monomer (EPDM) rubber to enhance its mechanical properties and gamma shielding capabilities. Utilizing a conventional two‐roll mill, EPDM composites filled with varying WO ₃ concentrations (0–20 parts per hundred rubber, phr) were prepared and analyzed. The mechanical test results revealed significant improvements in tensile strength, elongation at break, and hardness, with optimal performance observed at 15 phr WO ₃ . Gamma attenuation properties were assessed through theoretical and experimental methods, demonstrating enhanced shielding performance proportional to WO ₃ content, particularly at low to medium energy levels. Scanning electron microscopy confirmed a uniform dispersion of WO ₃ at 15 phr, while rheometric analysis highlighted improvements in curing behavior and crosslinking density at this concentration. These findings underscore the potential of recycled nano‐WO ₃ as a sustainable filler, providing a lead‐free alternative for applications requiring enhanced mechanical and radiation shielding properties. Future work will explore the long‐term durability and application‐specific performance of these composites.

Naturally occurring inexpensive substance is useful as a raw material like graphite. Graphene oxide (GO) is made from sugarcane bagasse (SB) to create nano graphene oxide (GO‐SB). Nitrile rubber (NBR) was used as base matrix while (GO‐SB) filler was combined at various loadings [2, 4, 6, 8, and 10 Part per hundred part of rubber (phr)]. The impact of the prepared (GO‐SB) loading on the physicomechanical and curing characteristics of NBR nanocomposites was examined and evaluated. Transmission Electron Microscopy (TEM), x‐ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT‐IR) were used to estimate and characterize the prepared investigated rubber samples. Excellent dispersion of (GO‐SB) (8 phr) in the NBR matrix was observed using scanning electron microscopy (SEM). The filler agglomerations in the matrix were found to be a heterogeneous dispersion of (GO‐SB) (10 phr). Curing characterizations showed that the compounded rubber with (GO‐SB) had larger maximum and minimum torques, a torque difference at 8 phr, and a faster cure rate than the unfilled NBR compound. The equilibrium swelling and mechanical characteristics demonstrated that reinforcing effect of the prepared nanocomposites contained 8 phr (GO‐SB). When the filler content increased up to 10 phr, Shore A hardness values increased.Highlights: Graphene oxide nanosized prepared from sugarcane bagasse. Transmission electron microscopy verified the nanoscale of Graphene oxide. Nano Graphene oxide and ingredients are incorporated in NBR by rubber mixer. Effect of Nano Graphene oxide on mechanical properties of NBR evaluated. The products have better physico mechanical properties.