The introduction of nanoparticles (NPs) and nanostructured materials (NSMs) in papermaking originally emerged from the perspective of improving processing operations and reducing material ...consumption. However, a very broad range of nanomaterials (NMs) can be incorporated into the paper structure and allows creating paper products with novel properties. This review is of interdisciplinary nature, addressing the emerging area of nanotechnology in papermaking focusing on resources, chemical synthesis and processing, colloidal properties, and deposition methods. An overview of different NMs used in papermaking together with their intrinsic properties and a link to possible applications is presented from a chemical point of view. After a brief introduction on NMs classification and papermaking, their role as additives or pigments in the paper structure is described. The different compositions and morphologies of NMs and NSMs are included, based on wood components, inorganic, organic, carbon-based, and composite NPs. In a first approach, nanopaper substrates are made from fibrillary NPs, including cellulose-based or carbon-based NMs. In a second approach, the NPs can be added to a regular wood pulp as nanofillers or used in coating compositions as nanopigments. The most important processing steps for NMs in papermaking are illustrated including the internal filling of fiber lumen, LbL deposition or fiber wall modification, with important advances in the field on the in situ deposition of NPs on the paper fibers. Usually, the manufacture of products with advanced functionality is associated with complex processes and hazardous materials. A key to success is in understanding how the NMs, cellulose matrix, functional additives, and processes all interact to provide the intended paper functionality while reducing materials waste and keeping the processes simple and energy efficient.
A huge variety of plants are harvested worldwide and their different constituents can be converted into a broad range of bionanomaterials. In parallel, much research effort in materials science and ...engineering is focused on the formation of nanoparticles and nanostructured materials originating from agricultural residues. Cellulose (40-50%), hemicellulose (20-40%), and lignin (20-30%) represent major plant ingredients and many techniques have been described that separate the main plant components for the synthesis of nanocelluloses, nano-hemicelluloses, and nanolignins with divergent and controllable properties. The minor components, such as essential oils, could also be used to produce non-toxic metal and metal oxide nanoparticles with high bioavailability, biocompatibility, and/or bioactivity. This review describes the chemical structure, the physical and chemical properties of plant cell constituents, different techniques for the synthesis of nanocelluloses, nanohemicelluloses, and nanolignins from various lignocellulose sources and agricultural residues, and the extraction of volatile oils from plants as well as their use in metal and metal oxide nanoparticle production and emulsion preparation. Furthermore, details about the formation of activated carbon nanomaterials by thermal treatment of lignocellulose materials, a few examples of mineral extraction from agriculture waste for nanoparticle fabrication, and the emerging applications of plant-based nanomaterials in different fields, such as biotechnology and medicine, environment protection, environmental remediation, or energy production and storage, are also included. This review also briefly discusses the recent developments and challenges of obtaining nanomaterials from plant residues, and the issues surrounding toxicity and regulation.
Nanomaterials (NMs) have gained prominence in technological advancements due to their tunable physical, chemical and biological properties with enhanced performance over their bulk counterparts. NMs ...are categorized depending on their size, composition, shape, and origin. The ability to predict the unique properties of NMs increases the value of each classification. Due to increased growth of production of NMs and their industrial applications, issues relating to toxicity are inevitable. The aim of this review is to compare synthetic (engineered) and naturally occurring nanoparticles (NPs) and nanostructured materials (NSMs) to identify their nanoscale properties and to define the specific knowledge gaps related to the risk assessment of NPs and NSMs in the environment. The review presents an overview of the history and classifications of NMs and gives an overview of the various sources of NPs and NSMs, from natural to synthetic, and their toxic effects towards mammalian cells and tissue. Additionally, the types of toxic reactions associated with NPs and NSMs and the regulations implemented by different countries to reduce the associated risks are also discussed.
In the last few decades, the vast potential of nanomaterials for biomedical and healthcare applications has been extensively investigated. Several case studies demonstrated that nanomaterials can ...offer solutions to the current challenges of raw materials in the biomedical and healthcare fields. This review describes the different nanoparticles and nanostructured material synthesis approaches and presents some emerging biomedical, healthcare, and agro-food applications. This review focuses on various nanomaterial types (e.g., spherical, nanorods, nanotubes, nanosheets, nanofibers, core-shell, and mesoporous) that can be synthesized from different raw materials and their emerging applications in bioimaging, biosensing, drug delivery, tissue engineering, antimicrobial, and agro-foods. Depending on their morphology (e.g., size, aspect ratio, geometry, porosity), nanomaterials can be used as formulation modifiers, moisturizers, nanofillers, additives, membranes, and films. As toxicological assessment depends on sizes and morphologies, stringent regulation is needed from the testing of efficient nanomaterials dosages. The challenges and perspectives for an industrial breakthrough of nanomaterials are related to the optimization of production and processing conditions.
Carbon nanomaterials (CNMs) have received tremendous interest in the area of nanotechnology due to their unique properties and flexible dimensional structure. CNMs have excellent electrical, thermal, ...and optical properties that make them promising materials for drug delivery, bioimaging, biosensing, and tissue engineering applications. Currently, there are many types of CNMs, such as quantum dots, nanotubes, nanosheets, and nanoribbons; and there are many others in development that promise exciting applications in the future. The surface functionalization of CNMs modifies their chemical and physical properties, which enhances their drug loading/release capacity, their ability to target drug delivery to specific sites, and their dispersibility and suitability in biological systems. Thus, CNMs have been effectively used in different biomedical systems. This review explores the unique physical, chemical, and biological properties that allow CNMs to improve on the state of the art materials currently used in different biomedical applications. The discussion also embraces the emerging biomedical applications of CNMs, including targeted drug delivery, medical implants, tissue engineering, wound healing, biosensing, bioimaging, vaccination, and photodynamic therapy.
High-performance hybrid polymer blends can be prepared by blending different types of polymers to improve their properties. However, most polymer blends exhibit phase separation after blending. In ...this study, polymethylmethacrylate/polyethylene glycol (PMMA/PEG) polymer blends (70/30 and 30/70 w/w) were prepared by solution casting with and without ZnO nanoparticles (NPs) loading. The effect of loading ZnO nanoparticles on blend morphology, UV blocking, glass transition, melting, and crystallization were investigated. Without loading ZnO NP, the PMMA/PEG blends showed phase separation, especially the PEG-rich blend. Loading PMMA/PEG blend with ZnO NPs increased the miscibility of the blend and most of the ZnO NPs dispersed in the PEG phase. The interaction of the ZnO NPs with the blend polymers slightly decreased the intensity of infrared absorption of the functional groups. The UV-blocking properties of the blends increased by 15% and 20%, and the band gap energy values were 4.1 eV and 3.8 eV for the blends loaded with ZnO NPs with a PMMA/PEG ratio of 70/30 and 30/70, respectively. In addition, the glass transition temperature (T
) increased by 14 °C, the crystallinity rate increased by 15%, the melting (T
) and crystallization(T
) temperatures increased by 2 °C and 14 °C, respectively, and the thermal stability increased by 25 °C compared to the PMMA/PEG blends without ZnO NP loading.
Modification of calcium carbonate particles with surfactant significantly improves the properties of the calcium carbonate coating on paper. In this study, unmodified and CTAB ...(hexadecyltetramethylammonium bromide)- and oleate-modified calcium carbonate nanoparticles were prepared using the wet carbonation technique for paper coating. CTAB (cationic surfactant) and sodium oleate (anionic surfactant) were used to modify the size, morphology, and surface properties of the precipitated nanoparticles. The obtained particles were characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, zeta potential measurements, thermal gravimetric analysis (TGA), and transmission electron microscopy (TEM). Coating colors were formulated from the prepared unmodified and modified calcium carbonates and examined by creating a thin coating layer on reference paper. The effect of calcium carbonate particle size and surface modification on paper properties, such as coating thickness, coating weight, surface roughness, air permeability, brightness, whiteness, opacity, and hydrophobicity, were investigated and compared with commercial ground (GCC) calcium carbonate-coated papers. The results show that the obtained calcium carbonate nanoparticles are in the calcite phase. The morphology of the prepared calcium carbonate nanoparticles is rhombohedral, and the average particle diameter is less than 100 nm. Compared to commercial GCC, the use of unmodified and CTAB- and oleate-modified calcium carbonate nanoparticles in paper coating improves the properties of paper. The highest measured paper properties were observed for paper coated with oleate-modifed nanoparticles, where an increase in smoothness (decrease in paper roughness) (+23%), brightness (+1.3%), whiteness (+2.8%), and opacity (+2.3%) and a decrease in air permeability (−26%) was obtained with 25% less coat weight. The water contact angle at a drop age time of 10 min was about 112° for the paper coated with oleate-modified nanoparticles and 42° for paper coated with CTAB-modified nanoparticles compared to 104° for GCC-coated paper.
Silica (SiO2) nanoparticles and silica/calcium carbonate (SiO2/CaCO3) core–shell nanocomposites were prepared by sol–gel technique as fillers for papermaking application. Semi-burned rice straw ash ...(SBRSA), as waste material, was used to prepare the targeted fillers. Preparation of SiO2 nanoparticles and SiO2/CaCO3 nanocomposites was carried out using Na2SiO3 solution that was prepared from SBRSA and CaCO3 nanoparticles of 30–70nm. The targeted SiO2/CaCO3 nanocomposites were prepared with different molar ratio of SiO2:CaCO3 1:15, 1:10 and 1:5. The percentage of silica increased from 62.5% to 82.9% by thermal treatment of SBRSA at 800°C for 2h. The prepared SiO2 nanoparticles and SiO2/CaCO3 nanocomposites were characterized by using XRD, XRF, TEM, FT-IR and Zeta potential. The results indicate that a pure semi-crystalline SiO2 nanoparticle and semi-crystalline shell of SiO2 coated CaCO3 core particles were produced. The work extended also to investigate the effect of the prepared fillers on physical, mechanical and optical properties of paper.
Application of the prepared SiO2 nanoparticles and SiO2/CaCO3 nanocomposites improved the optical properties of paper (brightness, whiteness and opacity) but it slightly reduced the mechanical properties when compared to commercial precipitated CaCO3 (PCC) filler.
The results showed that the retention of SiO2 nano-particles was highly increased. The retention of the prepared nanocomposites increased along with increasing of SiO2:CaCO3 molar ratio.
Rapid urbanization proportionally increases the waste products which force humankind to find a suitable waste management system. This study aims at identifying the possibility of using toner waste ...powder (TWP) as a filler for fabricating polymer composites for enhanced electrical conductivity of polymer blends. TWP was successfully incorporated into a polymer blend of low-density polyethylene/high impact polystyrene (LDPE/HIPS) at a high loading percentage of up to 20 wt %. Elemental analysis (SEM-EDS and XRF) showed that the main constituents of TWP are carbon and iron with traces of other metals such as Ca, Cs, Ti, Mn, Si. The electrical conductivity of LDPE/HIPS is significantly enhanced by loading the TWP into the polymer blend. The addition of TWP to LDPE/HIPS blend decreases the electrical resistivity of the LDPE/HIPS/TWP composite to ~2.9 × 107 Ohm.cm at 10 wt % of TWP, which is several orders of magnitude lower than that of the neat blend with maintaining the thermal stability of the polymer composite. The prepared polymer composite is lightweight and shows electrical conductivity, thus it can have potential applications in electronic materials and automotive industries.
Nanomaterials are becoming important materials in several fields and industries thanks to their very reduced size and shape-related features. Scientists think that nanoparticles and nanostructured ...materials originated during the Big Bang process from meteorites leading to the formation of the universe and Earth. Since 1990, the term nanotechnology became very popular due to advances in imaging technologies that paved the way to specific industrial applications. Currently, nanoparticles and nanostructured materials are synthesized on a large scale and are indispensable for many industries. This fact fosters and supports research in biochemistry, biophysics, and biochemical engineering applications. Recently, nanotechnology has been combined with other sciences to fabricate new forms of nanomaterials that could be used, for instance, for diagnostic tools, drug delivery systems, energy generation/storage, environmental remediation as well as agriculture and food processing. In contrast with traditional materials, specific features can be integrated into nanoparticles, nanostructures, and nanosystems by simply modifying their scale, shape, and composition. This article first summarizes the history of nanomaterials and nanotechnology. Followed by the progress that led to improved synthesis processes to produce different nanoparticles and nanostructures characterized by specific features. The content finally presents various origins and sources of nanomaterials, synthesis strategies, their toxicity, risks, regulations, and self-aggregation.
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