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Hydrophobic Cellulose-Based Sorbents for Oil/Water Separation
The need for sustainable, biodegradable materials to address environmental challenges, such as oil-water separation, is growing. Cellulose-based absorbents offer an eco-friendly alternative to synthetic materials. However, their hydrophobicity must be enhanced for efficient application. In this study, cellulose-based sorbents derived from Kraft and half-bleached chemo-thermomechanical pulp (BCTMP) were hydrophobized using silanization and alkyl ketene dimer (AKD) techniques. Hydrophobic properties were successfully imparted using methyltrimethoxysilane (MTMOS), n-octyltriethoxysilane (NTES), and N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (AATMS), with water contact angles ranging from 120° to 140°. The water sorption capacity was significantly reduced to below 1 g/g, whereas the oil sorption capacity remained high (19–28 g/g). The most substantial reduction in water vapor absorption (3–6%) was observed for the MTMOS- and AATMS-silanized samples. These results demonstrate the potential of hydrophobized cellulose-based sorbents as sustainable alternatives for oil-water separation, contributing to environmentally friendly water treatment solutions.
Challenges and Prospects of Applying Nanocellulose for the Conservation of Wooden Cultural Heritage—A Review
Nanocellulose is a nanostructured form of cellulose, which retains valuable properties of cellulose such as renewability, biodegradability, biocompatibility, nontoxicity, and sustainability and, due to its nano-sizes, acquires several useful features, such as low density, high aspect ratio and stiffness, a high specific surface area, easy processing and functionalisation, and good thermal stability. All these make it a highly versatile green nanomaterial for multiple applications, including the conservation of cultural heritage. This review provides the basic characteristics of all nanocellulose forms and their properties and presents the results of recent research on nanocellulose formulations applied for conserving historical artefacts made of wood and paper, discussing their effectiveness, advantages, and disadvantages. Pure nanocellulose proves particularly useful for conserving historical paper since it can form a durable, stable coating that consolidates the surface of a degraded object. However, it is not as effective for wood consolidation treatment due to its poor penetration into the wood structure. The research shows that this disadvantage can be overcome by various chemical modifications of the nanocellulose surface; owing to its specific chemistry, nanocellulose can be easily functionalised and, thus, enriched with the properties required for an effective wood consolidant. Moreover, combining nanocellulose with other agents can also improve its properties, adding new functionalities to the developed supramolecular systems that would address multiple needs of degraded artefacts. Since the broad use of nanocellulose in conservation practice depends on its properties, price, and availability, the development of new, effective, green, and industrial-scale production methods ensuring the manufacture of nanocellulose particles with standardised properties is necessary. Nanocellulose is an interesting and very promising solution for the conservation of cultural heritage artefacts made of paper and wood; however, further thorough interdisciplinary research is still necessary to devise new green methods of its production as well as develop new effective and sustainable nanocellulose-based conservation agents, which would replace synthetic, non-sustainable consolidants and enable proper conservation of historical objects of our cultural heritage.
Nanocellulose-Based Films for Surface Protection of Wooden Artefacts
This research investigated the selected properties of nanocellulose films intended to serve as protective patches on fissured surfaces of wooden artefacts. The effects of their plasticisation with glycerol and functionalisation with selected silanes ((3-Glycidyloxypropyl)trimethoxysilane, and Methyltrimethoxysilane) were also determined. The obtained pure cellulose nanopapers (CNPs) had a homogeneous and compact structure but were very brittle, stiff, and wavy. Functionalisation with silanes made their structure more packed and reduced their equilibrium moisture content by 87–96%, depending on the type and concentration of the silane. Silane functionalisation also slightly improved nanopapers’ resistance to moulds. Plasticisation with glycerol provided CNPs with higher flexibility and resistance to fracture and made them flatter and smoother, reducing the wettability of their surfaces but increasing their hygroscopicity (EMC values increased 1.7–3.5 times for pure CNPs and 5–33 times for functionalised CNPs) and vulnerability to mould infestation. All prepared nanopapers can be easily glued to the wood surface and colour-matched using a nitro wood stain, oil paint or waterborne acrylic paint. The research showed that cellulose nanopapers modified with silanes and plasticised with glycerol seem to be a promising solution for protecting the cracked surface of wooden artefacts against further degradation due to external conditions.
Bio-production of fire retardant and hydrophobic packaging paperboard with enhanced tensile strength through coating with modified cellulose nanofiber
Fire Properties of Paper Sheets Made of Cellulose Fibers Treated with Various Retardants
This article presents the results of flame-retardancy tests conducted on cellulose sheets produced using a Rapid Köthen apparatus treated with retardants. The agents used were potassium carbonate (PC) K2CO3 (concentrations of 20; 33.3; and 50% wt/wt), monoammonium phosphate (MAP) NH4H2PO4 (concentrations of 35% wt/wt), diammonium phosphate (DAP) (NH4)2HPO4 (concentrations of 42.9% wt/wt), and bisguanidal phosphate (FOS) C2H10N6 (concentrations of 22.5% wt/wt). The agents were used to improve Kraft cellulose-based sheets’ flame-retardant properties and compare their performances. As part of the study, the flammability of the materials was determined by the following methods: an oxygen index (OI) test, a mass loss calorimeter (MLC) test, and a mini fire tube (MFT) test. All formulations showed an increase in flame retardancy compared to the control test. All protected samples were non-flammable for OI determinations, and DAP-protected samples showed the highest OI index. For the MLC test, DAP-protected and MAP-protected samples showed the best heat-release rate (HRR), total heat release (THR), and average heat-release rate (ARHE) (samples did not ignite for 600 s). In the MFT test, all treated samples had comparably reduced weight loss. The best parameter was achieved for MAP and DAP (15% weight loss).
Impact of Cellulose Modification by Expandable Graphite andCarbon Nanotubes on Flammability and Thermal Properties
Wood from Field Tests as a Model for Assessing the Suitability of Post-Consumer Wood
The circular economy forces societies to take actions aimed at giving post-consumer products a “second life”. As we know, wood is perfect for this. Moreover, reusing wood helps keep carbon in circulation, thus limiting its emissions into the atmosphere. It turns out that extensive research on determining the durability of wood is very useful and valuable for one more reason. Well, they can be used to create a model to determine the usefulness of wood, which has only apparently lost its utility value during many years of exposure to external factors. The research subject was samples of wood impregnated with protection agents and modified, originating from many years of field tests. The aim of the research was to correlate the results of wood durability determined after a period of exposure in open space with the results of determining the potential usefulness of such wood. On this basis, a model for determining the value of post-consumer wood was created. As a main result of post-consumer wood analysis, the high durabilities against C. puteana with mass loss below 3% were noticed for acetylated, furfurylated, and CCA-treated wood. Moreover, high color stabilities (ΔE < 10) were observed for thermowood and furfurylated wood.
Hydrophobic and hygroscopic properties of cellulose treated with silicone agents
AbstractThe effects of various cellulose treatments on the hydrophobic properties and sorption behavior with respect to liquid water uptake and water vapor sorption were examined within the study. Different hydrophobic agents based on silicon compounds were applied to improve the properties of cellulose-based sheets. The 1H,1H,2H,2H perfluorooctyltriethoxysilane treatment increased hydrophobicity significantly, while N-octyltriethoxysilane and inorganic sodium silicate solution treatments only slightly affected the properties. Silicone-cellulose interaction varied, influencing the fiber saturation and moisture content of the material. The swelling differences between untreated and treated cellulose and, consequently, the uncovering of new active sorption sites during a swelling process and the increase in the content of bound water were confirmed by the T2 relaxation times analysis. The GDW sorption model estimated maximum water content but lacked activation dynamics. The blocking phenomenon of active sorption sites together with silicone improved hydrophobicity had different mechanisms for applied agents. The 1H,1H,2H,2H perfluorooctyltriethoxysilane additionally cross-linked silane structure and restricted cellulose swelling.
Dziedzictwo kulturowe – poszukiwanie nowoczesnych środków i metod konserwacji drewna zabytkowego
The strength and fire properties of paper sheets made of phosphorylated cellulose fibers
Phosphorylated cellulose can be an intrinsic flame retardant and a promising alternative for halogenated fire inhibitors. In this study, the mixture of di-ammonium hydrogen phosphate (DAP) and urea (U), containing phosphate and nitrogen groups, was applied to attain fire inhibitor properties. Functional groups of cellulose were grafted with phosphorous by keeping the constant molar ratio of 1/1.2/4.9 between anhydroglucose units of cellulose/DAP/U in different concentrations of bleached kraft pulp. Phosphorus concentrations were determined using the ICP hrOES method, and paper sheets were made using the Rapid Köthen apparatus. The tensile strength of phosphorylated cellulose increased twice compared with unmodified cellulose when the phosphorous concentration increased to 10,000 g/kg. An increase in the tensile index comes from the higher freeness of pulp and cross-linking of the phosphorous group between cellulose fibers. Remarkable fire retardancy effects were achieved in cellulose concentrations above 5 wt%. The raised phosphorous concentration above 10,000 g/kg due to the phosphorylation process caused the formation of a char layer on a cellulose surface and the nonflammable gas emission. That effect was indirectly confirmed by reducing the combustion temperature and HRR by 50 and 45%, respectively. Due to increasing phosphorus concentration in cellulose sheets, cellulose’s fire and strength properties increased significantly.