Reinforcement of the mechanical properties in nitrile rubber by adding graphene oxide/silicon dioxide hybrid nanoparticles

A Comprehensive Review of Nanoparticles: From Classification to Application and Toxicity

Nanoparticles are structures that possess unique properties with high surface area-to-volume ratio. Their small size, up to 100 nm, and potential for surface modifications have enabled their use in a wide range of applications. Various factors influence the properties and applications of NPs, including the synthesis method and physical attributes such as size and shape. Additionally, the materials used in the synthesis of NPs are primary determinants of their application. Based on the chosen material, NPs are generally classified into three categories: organic, inorganic, and carbon-based. These categories include a variety of materials, such as proteins, polymers, metal ions, lipids and derivatives, magnetic minerals, and so on. Each material possesses unique attributes that influence the activity and application of the NPs. Consequently, certain NPs are typically used in particular areas because they possess higher efficiency along with tenable toxicity. Therefore, the classification and the base material in the NP synthesis hold significant importance in both NP research and application. In this paper, we discuss these classifications, exemplify most of the major materials, and categorize them according to their preferred area of application. This review provides an overall review of the materials, including their application, and toxicity.

Graphene-Based Hybrid Fillers for Rubber Composites

Graphene and its derivatives have been confirmed to be among the best fillers for rubber due to their excellent properties, such as high mechanical strength, improved interface interaction, and strain-induced crystallization capabilities. Graphene rubber materials can be widely used in tires, shoes, high-barrier conductive seals, electromagnetic shielding seals, shock absorbers, etc. In order to reduce the graphene loading and endow more desirable functions to rubber materials, graphene-based hybrid fillers are extensively employed, which can effectively enhance the performance of rubber composites. This review briefly summarizes the recent research on rubber composites with graphene-based hybrid fillers consisting of carbon black, silica, carbon nanotubes, metal oxide, and one-dimensional nanowires. The preparation methods, performance improvements, and applications of different graphene-based hybrid fillers/rubber composites have been investigated. This study also focuses on methods that can ensure the effectiveness of graphene hybrid fillers in reinforcing rubber composites. Furthermore, the enhanced mechanism of graphene- and graphene derivative-based hybrid fillers in rubber composites is investigated to provide a foundation for future studies.

Development of poly(hydroxybutyrate) film incorporated with nano silica and clove essential oil intended for active packaging of brown bread

The objective of current study was to develop Poly(hydroxybutyrate) (PHB) based active packaging film with long lasting antimicrobial potential in food-packaging applications. For developing such films, PHB was incorporated with poly(ethylene glycol) (PEG) as a plasticizer, nano-silica (n-Si) as strengthening material and clove essential oil (CEO) as an antimicrobial agent. These solvent-casted films with varying concentration of n-Si (0.5, 1, 1.5, 2 %) and 30 % CEO of total polymer matrix weight i.e., PHB/PEG (90/10) were prepared and studied on the basis of morphological, mechanical, thermal, degradation and antimicrobial behaviours. The presence of CEO and n-Si was confirmed by Fourier transform infrared spectroscopy (FTIR). Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) were used to investigate homogeneous dispersal of n-Si in polymer matrix. PHB/PEG/CEO/Si 1.0 film was selected as optimized one after mechanical testing and therefore further carried for antimicrobial testing. This selected film extended the shelf-life of brown bread up to 10 days comparable to bread wrapped in polyethylene. This revealed that PHB/PEG/CEO/Si 1.0 exhibited superior antibacterial activity against the food borne microbes i.e., Escherichia coli, Staphylococcus aureus and Aspergillus niger. Our findings indicate that this film improved the shelf-life of packaged bread and has promising features for active food packaging.

Effects of Silicon Dioxide/Graphene Oxide Hybrid Modification on Curing Kinetics of Epoxy Resin

In this study, SiO₂-grafted graphene oxide (GO-SiO₂) was prepared using the oxygen-containing group on the GO surface as the active site of the reaction. The chemical structure, morphology, and particle size of GO and GO-SiO₂ were carefully investigated by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, thermogravimetry, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy, and the results proved that the grafting modification was successful. Furthermore, epoxy (EP)/GO composites were prepared, and the effects of unmodified GO and GO-SiO₂ on the curing kinetics of EP were comparatively studied by differential scanning calorimetry (DSC). The results showed that, compared with neat EP and EP/GO, GO-SiO₂ significantly reduces the curing temperature of the composites, indicating that GO-SiO₂ has a more significant catalytic effect on the curing process of EP. The calculation results of the Kissinger method showed that the curing activation energy of EP/GO-SiO₂ is obviously lower than that of EP/GO and neat EP. Results of the Ozawa method showed that the introduction of GO-SiO₂ reduces the curing activation energy during the whole curing process, and in the middle and late stages of curing (α = 0.5-1) can significantly reduce the curing activation energy. The related mechanism has been proposed.

The Effects of Graphene Oxide-Silica Nano-Hybrid Materials on the Rheological Properties, Mechanical Properties, and Microstructure of Cement-Based Materials

Despite their excellent performance, two-dimension nanomaterials have certain limitations in improving the performance of cement-based materials due to their poor dispersity in the alkaline environment. This paper has synthesized a new two-dimension stacked GO-SiO₂ (GOS) hybrid through the sol-gel method. Nano-SiO₂ is coated on the surface of GO with wrinkling characteristics, and the atomic ratio of C, O, and Si in GOS is 1:1.69:0.57. The paper discusses the impacts on the spreading, Marsh cone flow time, rheological properties, mechanical properties, and microstructure of cement-based materials for the GOS at different mixing quantities. Furthermore, with the same mixing quantity of 0.01%, the influences on the dispersity, flow properties, rheological parameters, and mechanical properties of GOS and graphene oxide (GO) are compared. Lastly, fuzzy matrix analysis has been adopted to analyze the comprehensive performance of cement-based materials containing GOS. The research results indicate that, compared with the reference sample, the spreading for the GOS cement mortar with 0.01% mixing quantity was reduced by 4.76%, the yield shear stress increased by 37.43%, and the equivalent plastic viscosity was elevated by 2.62%. In terms of the 28 d cement pastes, the compressive and flexural strength were boosted by 27.17% and 42.86%, respectively. According to the optical observation, GOS shows better dispersion stability in the saturated calcium hydroxide solution and simulated pore solution than GO. Compared with the cement-based materials with the same mixing quantity (0.01%), GOS has higher spreading, lower shear yield stress, and higher compressive and flexural strength than GO. Finally, according to the results of fuzzy matrix analysis, when the concentration of GOS is 0.01%, it presents a more excellent comprehensive performance with the highest score. Among the performance indicators, the most significant improvement was in the flexural properties of cement-based materials, which increased from 8.6 MPa to 12.3 MPa on the 28 d.

Graphene Nanoplatelets as a Replacement for Carbon Black in Rubber Compounds

In this work, we evaluated the processing and reinforcement characteristics of both carbon black (CB) and graphene nanoplatelets (GNPs) within a nitrile butadiene rubber (NBR) matrix. The aspect ratio of the GNPs was measured using atomic force microscopy (AFM) and related to the dispersion and agglomeration within the NBR matrix, as observed by scanning electron microscopy (SEM). The relationship between GNP aspect ratio and mechanical properties was studied by micromechanical modelling. The tensile and tear properties of NBR after compounding with GNPs were enhanced to a greater extent compared to carbon black, while curing times were smaller and scorch times longer, indicating some of the advantages of using GNPs. Overall, the inherent properties of GNPs along with their geometry led to the production of better-performing rubber compounds that can replace their CB-filled counterparts in applications where flexibility, tear strength and compliance are important. The influence of processing on dispersion, orientation and agglomeration of flakes was also highlighted with respect to the Young’s modulus of the NBR compounds.

Designing a Highly Stable Slippery Organogel on Q235 Carbon Steel for Inhibiting Microbiologically Influenced Corrosion

Microbiologically influenced corrosion (MIC) accelerates the corrosion and degradation of metal materials due to the settlement of microorganisms on the surface. However, environmentally friendly and efficient methods to fabricate antifouling and anticorrosion surfaces are still lacking. Inspired by Nepenthes, a slippery liquid-infused porous surface (SLIPS) has been proven to be an efficient way to inhibit settlement of microorganisms on the metal surface and the following MIC due to the existence of a mobile defect-free lubricant layer. However, the stability of the lubricant layer and substrate of the SLIPS prevented its long-term antifouling and anticorrosion application. Herein, a highly stable slippery organogel was fabricated by depositing a homogeneous mixture of PDMS (base and curing agent), silicone oil, triethoxyvinylsilane, and SiO₂ on Q235 and curing in an oven. Triethoxyvinylsilane was not only able to cross-link with the curing agent of PDMS through hydrosilylation but also able to interlink the organogel and Q235 through condensation between the -OH of the metal surface and hydrolyzed siloxane. As a result, the adhesion force between the organogel without triethoxyvinylsilane and the substrate (0.45 MPa) increased to 1.50 MPa for the organogel with triethoxyvinylsilane and SiO₂. Also, the tensile strength of the organogel without SiO₂ (0.97 MPa) increased to 3.88 MPa for the organogel with 2 wt % SiO₂ because of the high elastic modulus of SiO₂, which was important to improving its stability under external force. In addition, the organogel showed stable oil distribution and slippery performance after spinning at 4000 rpm for 30 s. Then, the bacterial settlement demonstrated that the organogel could effectively inhibit Pseudoalteromonas sp. settlement on the substrate under both static and dynamic conditions. Finally, an electrochemical test indicated that the MIC could be effectively mitigated by the organogel. This study provides an efficient method to fabricate a highly stable slippery surface on a metal surface for its potential application in mitigating MIC.

Sustainable nanocomposite films based on SiO2 and biodegradable poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) for food packaging

Sustainable nanocomposites with transparent, biodegradable, and enhanced mechanical and barrier properties were prepared by the incorporation of SiO2 into poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) films and subsequent solvent casting. The crystallinity of composites could be increased by 67% with appropriate contents of SiO2, which proved that SiO2 were effective nucleating agents for PHBH. And it was worth mentioning that the contributions of SiO2 to the crystallization and thermal stability of composites are proved effectively by Avrami relationship and Horowitz and Metzger method. More importantly, compared with PHBH, it had not only an enhancement about 40% and 60% on the tensile strength and elastic modulus, respectively, but also half the reduction of the moisture and oxygen permeability which were much higher than the values of conventional plastics. The above, in conjunction with the low migration rate measured in food substitutes, illustrated unambiguously that the nanocomposites might be suitable for potential application in food packaging.

Chitin nanowhiskers from shrimp shell waste as green filler in acrylonitrile-butadiene rubber: Processing and performance properties

In this work, chitin nanowhiskers with high crystallinity index were obtained from shrimp shells waste using acid hydrolysis method and then comprehensively characterized. Subsequently, the impact of chitin nanowhisker content on processing and performance of acrylonitrile-butadiene rubber based nanocomposites was evaluated. The results showed that the addition of chitin nanowhiskers increased tensile strength and tear strength of nanocomposites by 116 % and 54 %, which was related to suitable dispersion of chitin nanowhiskers in matrix. Reinforcing effect of chitin nanowhiskers in acrylonitrile-butadiene rubber was also confirmed by Wolff activity coefficient, glass transition temperature and equilibrium swelling measurements. Moreover, it was found that higher content chitin nanowhiskers significantly improve the thermal stability of studied nanocomposites. The incorporation of chitin nanowhiskers resulted in increase of 74 °C for onset degradation temperature. This work confirmed that shrimp shell waste can be upcycled into chitin nanowhiskers - promising green filler in NBR for high-performance elastomeric applications.

In-situ Modification of Graphene Oxide by Insoluble Sulfur and Application for Nitrile Butadiene Rubber

Insoluble sulfur (IS) is prepared at low temperature with graphene oxide (GO) as stabilizer and ammonium persulfate as initiator. The FTIR and Raman patterns show that the non-conjugate double bond of GO can couple to the long chain free radicals of IS. The TGA and EDS results show that the mass fraction of IS is 79.75 wt% in particles by refluxing method, much higher than that in particles by hydrothermal method, when the mass ratio in reactants of GO to sulfur was 3: 1. Under constant content of sulfur, the tensile stress and elongation at break of NBR/GO-S(h) and NBR/GO-S(r) composites are higher than those of NBR/Reduced GO composites with the addition of 3 phr GO-S(h), GO-S(r) and Reduced GO particles into NBR. It can provide a new technology for the preparation of IS with lower temperature, little energy consumption and less environmental pollution. It is also a new method for the modification and application of GO in rubber.

Improving Thermo-Oxidative Stability of Nitrile Rubber Composites by Functional Graphene Oxide

Graphene oxide (GO), modified with anti-aging agent p-phenylenediamine (PPD), was added into nitrile rubber (NBR) in order to improve the thermo-oxidative stability of NBR. The modification of GO and the transformation of functional groups were characterized by Fourier transform infrared spectroscopy (FTIR), Raman, and X-ray diffraction (XRD). Mechanical performances of NBR composites before and after the thermo-oxidative aging were recorded. The results of dynamic mechanical analysis (DMA) show an increased storage modulus (G’) and a decreased value of area of tan δ peak after introducing modified GO into NBR. It indicates that filler particles show positive interaction with molecular chains. The thermo-oxidative stability of composites was investigated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Then, the thermo-oxidative aging kinetic parameters were obtained by the Flynn–Wall–Ozawa (FWO) equation. The results of aging tests show that the thermo-oxidative stability of rubber matrix increases obviously after introducing GO–PPD. In addition, mechanical properties (tensile strength and elongation at break) of both before and after aged NBR/GO–PPD composites were superior to that of NBR. This work provides meaningful guidance for achieving multifunction thermo-oxidative aging resistance rubber composites.