Mohamad Bekhit

Using a solution casting technique, electron beam-irradiated polymer nanocomposite films based on polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) were successfully produced and reinforced with silver nanoparticles (AgNPs) mediated by tannic acid (TA). Tannic acid acted as a stabilizing and reducing agent at the same time in this green synthesis method, allowing well-dispersed AgNPs to develop within the polymeric matrix. To improve interfacial interactions and overall performance, the produced films were then subjected to an electron beam irradiation dose of 25 kGy as an optimum dose. FT-IR, XRD, UV/Vis, TEM, and SEM techniques have been used to investigate structural, optical, and morphological characteristics. The development of a face-centered cubic silver phase is verified by the XRD characterization, indicating that tannic acid reduction was successful in generating silver nanoparticles. The majority of the nanoparticles were spherical, with an average size of 12.5 nm, according to TEM studies. The addition of TA-Ag NPs and electron beam irradiation treatment significantly improved the tensile characteristics of the nanocomposite films, as shown by mechanical testing. This improvement was ascribed to better intermolecular contacts and irradiation-induced crosslinking. The thermal analysis results indicate that the PVA/CMC/TA-Ag nanocomposite films have enhanced thermal stability compared with pure polymeric film. This study investigated the antimicrobial activity of PVA/CMC/TA-Ag NPs films against pathogenic microbes of Staphylococcus aureus , MRSA, Proteus mirabilis , Proteus vulgaris , and Candida albicans . The PVA/CMC films containing 10 mL of TA-Ag NPs were highly effective against S. aureus and P. mirabilis with inhibition zone diameters of 25.02 ± 0.45 and 25.80 ± 1.23 mm, respectively. At 500 µg/mL, the PVA/CMC/TA-Ag NPs demonstrated a noteworthy antioxidant activity of 56.86 ± 3.54%. These findings of combination electron beam-induced crosslinking of PVA/CMC films with tannic acid-mediated green synthesis of silver nanoparticles create a multifunctional nanocomposite with improved mechanical and thermal performance, enhanced structural stability, significant antioxidant activity, and broad-spectrum antimicrobial efficacy make them appropriate for several applications such as in packaging and medical settings.

The aim of this study is to explore the impact of both gamma irradiation and hydroxyapatite nanoparticles (HAp NPs) on the performance of ethylene propylene diene monomer rubber material (EPDM). HAp NPs capped with cetyltrimethyl ammonium bromide (CTAB) were prepared with a facile chemical co-precipitation method. EPDM/HAp nanocomposites with different concentrations of hydroxyapatite nanoparticles as reinforcement nanofiller were achieved by a laboratory rubber roll mill apparatus and then subjected to ionizing radiation (gamma rays) at 50 kGy to examine the effect of the radiation dose. Nano-Filler characterization was achieved using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscope (FTIR) and X-ray diffraction (XRD) techniques. TEM image revealed that the hydroxyapatite particles are set inside the scale of nanometers (a regular size of 20–30 nm). The mechanical, thermal, morphological, and automotive brake oil resistance properties of EPDM/HAp nanocomposites have been measured. The physicochemical properties of EPDM rubber was enriched using both HAp nanoparticles and gamma radiation. The various measurements have revealed that 3 phr synthesized HAp NPs filler content provided the best results for most of the properties studied. SEM results display a regular dispersion of nanofillers into EPDM matrix at lower concentration (3 phr), whereas the agglomerations have been brought into the EPDM matrix at 5 phr loading of HAp. The TS reduction percent due to brake oil immersion of irradiated samples of EPDM nanocomposites sequenced as follows: 10.3%, 6.0%, 3.8%, and 12.5% for EPDM, EPDM/HAp (1 phr), EPDM/HAp (3 phr), and EPDM/HAp (5 phr), respectively. Moreover, the irradiated samples were not affected obviously owing to the crosslinking network produced by irradiation and EPDM/HAp (3 phr) nanocomposite have the best oil resistance. These overall findings successfully demonstrated the prepared EPDM/HAp nanocomposites had enhanced physico-chemical properties and brake oil resistance which considered promising in automotive applications.

The development of polymer nanocomposites is crucial for meeting increasing industrial demands.

Currently, there is a demand for an effective solution to address toxic pollutants in aqueous environments. Consequently, creating a cost-efficient and effective catalytic system with the added benefits of easy recovery from the medium and the ability to be reused is essential. In this study, gamma (γ) radiolysis as a simple and environmentally friendly process under ambient settings was used to successfully manufacture a nanocatalyst of cobalt ferrite nanoparticles (CoFe₂O₄ NPs) modified gum arabic (GA) as a nontoxic, biocompatible, and inexpensive biopolymer. The prepared GA-CoFe₂O₄ NPs were evaluated by using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX) mapping, and vibrating sample magnetometer analysis. XRD analysis illustrates the formation of CoFe₂O₄ NPs through the appearance of the characteristic peaks. TEM analysis shows the spherical shape of CoFe₂O₄ NPs with an average particle size diameter ranging from 20 to 30 nm. FTIR analysis of GA-CoFe₂O₄ NPs confirmed both the functionalization of GA with the CoFe₂O₄ NPs and the appearance of the specific signal of CoFe₂O₄ NPs. The atomic ratio obtained from EDX analysis matches the stoichiometric ratio of cobalt ferrite. The GA-CoFe₂O₄ NPs exhibit an excellent magnetic response of saturation magnetization of 47.619 emu g⁻¹. The prepared CoFe₂O₄NPs were then evaluated as a catalyst for the catalytic reduction of p-NP, MO dye, and a mixture of these pollutants. The results showed that CoFe₂O₄ NPs have high catalytic efficiency in the reduction of mono or mixed compounds. Furthermore, recycling of the CoFe₂O₄ NPs catalyst was also confirmed and it could be magnetically recovered and reused for at least six times with a good catalytic efficiency.

Conductive polymer nanocomposites for electromagnetic interference (EMI) shielding are important materials that can be combat the increasingly dangerous radiation pollution arising from electronic equipment and our surrounding environment. In this work, we have synthesized polyaniline-copper nanoparticles (PANI-Cu NPs) by the copper salt based oxidative polymerization method at room temperature and then added with different concentration (0, 1, 3 and 5 wt%) in polystyrene polymer forming PS/ PANI-Cu nanocomposites films by means of the traditional solution casting technique. The formed PANI-Cu NPs were investigated by UV/Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and SEM/EDX elemental mapping techniques. On the other hand, the prepared PS/PANI-Cu nanocomposites films were evaluated by UV and SEM, the mechanical properties of the nanocomposites films were evaluated and showed an improvement by added PANI-Cu NPs up to 3 wt% and 50 kGy gamma exposure dose. The PS/PANI-Cu nanocomposites films were examined as electromagnetic interference shielding material. Electromagnetic shielding effectiveness of the produced nanocomposites were tested in the X-band of the radio frequency range namely from 8 to 12 GHz using the vector network analyzer (VNA) and a proper wave guide. All samples were studied before and after 50 kGy gamma-ray irradiation under the same condition of pressure and temperature. The results showed that the nanocomposites have improved shielding properties.

This article evaluates the physicochemical and antimicrobial properties when silver-coated silica (SiO₂-Ag) nanoparticles as active nanofiller are incorporated into the polypropylene (PP) thermoplastic matrix. The silica (SiO₂) nanoparticles were prepared by precipitation method using sodium silicate. After that, silver-coated silica (SiO₂-Ag) nanoparticles were synthesized by gamma radiation technique. X-ray diffraction (XRD), Infrared spectroscopy analysis (FTIR) and Transmission electron microscopy (TEM) analysis clarified the formation of SiO₂-Ag nanoparticles. SiO₂-Ag nanoparticles has a particle size with an average of 70 nm. The melt mixing procedure operated to fabricate PP thermoplastic nanocomposites with various ratios of 1.0, 2.0, and 3.0 part per hundred resin (phr) of the SiO₂-Ag nanoparticles. To examine the effect of ionizing radiation on the prepared PP/SiO₂-Ag nanocomposites, the samples were exposed to 20 kGy of gamma-irradiation. FTIR, XRD, mechanical analysis, thermogravimetric analysis (TGA), and scanning electron microscope (SEM) were utilized to characterize the physico-chemical alterations of the PP when loaded with SiO₂-Ag nanoparticles. It is found that PP/1.0 phr SiO₂-Ag nanocomposite revealed superior physico-chemical characteristics than the other two components. The irradiated specimens revealed superior tensile strength (TS) and elastic modulus (EM) over unirradiated ones, whereas inverse effects were predominant in case elongation at break (E%). Tmax of the native PP increased from 335°C to nearly 370°C of PP/1.0 phr SiO₂-Ag nanocomposite. It is established that the fabricated PP/SiO₂-Ag nanocomposites exhibited potent antimicrobial activity and can be a good candidate for food packaging applications.

In the current work, cuprous oxide (Cu₂O) nanoparticles coated with Tween 80 were successfully synthesized via the chemical reduction method. Nanocomposites composed of low-density polyethylene (LDPE) and different ratios of Cu₂O nanoparticles were fabricated by the melt mixing process. 10% of ethyl vinyl acetate (EVA) as a compatibilizing agent was added to the molten LDPE matrix and the mixing process continued until homogenous nanocomposites were fabricated. To study the influence of ionizing radiation on the fabricated samples, the prepared species were exposed to 50 and 100 kGy of gamma rays. The synthesized Cu₂O nanoparticles were investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). XRD and TEM analysis illustrated the successful formation of spherical Cu₂O nanoparticles with an average size of 16.8 nm. The as-prepared LDPE/Cu₂O nanocomposites were characterized via different techniques such as mechanical, thermal, morphological, XRD, and FTIR. Electromagnetic interference shielding (EMI) of the different nanocomposite formulations was performed as a promising application for these materials in practical life. The electromagnetic shielding effectiveness (SE) of the produced samples was measured in the X-band of the radio frequency range from 8 to 12 GHz using the vector network analyzer (VNA) and a proper waveguide. All the samples were studied before and after gamma-ray irradiation under the same conditions of pressure and temperature. The shielding effectiveness increased significantly from 25 dB for unirradiated samples to 35 dB with samples irradiated with 100 kGy, which reflects 40% enhancement in the effectiveness of the shielding.

The purpose of this research is to investigate the effect of gamma irradiation, concentration of microcrystalline newsprint fibers (MNF) and maleic anhydride as coupling agent for treating microcrystalline newsprint fibers (MA–MNF) on the mechanical and thermal properties of ethylene propylene diene monomer rubber matrix (EPDM). Maleic anhydride (MA) was used at a different ratios (5, 10, and 15 wt% according to the MNF). The EPDM/MA–MNF composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The results confirm the adhesion between MA–MNF and EPDM rubber matrix in presence of radiation. EPDM/MA–MNF composites have achieved higher mechanical properties than EPDM rubber matrix and EPDM/MNF composites. EPDM composites containing MNF that treated with 15% MA and gamma irradiated at 80 kGy have the highest tensile strength, tensile modulus at 100% strain, crosslink density and thermal stability over all other composites.