13 research outputs found
Influence of Reaction Parameters on the Gelation of Silanised Linseed Oil
No full textThe subject of this work was to characterize the catalytic course of the linseed oil silylation reaction with vinyltrimethoxysilane (VTMOS), carried out under elevated pressure and temperature conditions, and an explanation of the reasons for rapid gelation of the reaction product. To explain and describe the process, analytical methods were used, i.e., 1H and 13C NMR (nuclear magnetic resonance), GC-FID (gas chromatography coupled with flame ionisation detection), and GPC (gel permeation chromatography). Reaction products were monitored after 3, 6 and 12 h. The molar mass of the VTMOS-modified oil in only 3 h was comparable with the molar mass of the product obtained by conventional polymerisation. An increase in the reaction time resulted in further transformations resulting from the hydrolysis and condensation reactions taking place. In contrast to reactivity of soybean oil, the silanisation of linseed oil occurred much faster and without the need for cross-linking catalysts. The reason for the high reactivity of linseed oil to VTMOS and rapid gelation of the resulting product was primarily the amount of double bonds present in linseed oil and their high availability, in particular the double bond in the acid linolenic acid located at the C16 carbon
Wood from Field Tests as a Model for Assessing the Suitability of Post-Consumer Wood
No full textThe 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
Starch-Silane Structure and Its Influence on the Hydrophobic Properties of Paper
No full textStarch is an inexpensive, easily accessible, and widespread natural polymer. Due to its properties and availability, this polysaccharide is an attractive precursor for sustainable products. Considering its exploitation in adhesives and coatings, the major drawback of starch is its high affinity towards water. This study aims to explain the influence of the silane-starch coating on the hydrophobic properties of paper. The analysis of the organosilicon modified starch properties showed an enhanced hydrophobic behavior, suggesting higher durability for the coatings. Molecules of silanes with short aliphatic carbon chains were easily embedded in the starch structure. Longer side chains of silanes were primarily localized on the surface of the starch structure. The best hydrophobic properties were obtained for the paper coated with the composition based on starch and methyltrimethoxysilane. This coating also improved the bursting resistance and compressive strength of the tested paper. A static contact angle higher than 115° was achieved. PDA analysis confirmed the examined material exhibited high barrier properties towards water. The results extend the knowledge of the interaction of silane compositions in the presence of starch
Catalyzed Reaction of Cellulose and Lignin with Methyltrimethoxysilane—FT-IR, 13C NMR and 29Si NMR Studies
No full textIt can be found that reaction mechanisms and interactions between wood and organosilicone compounds have not been sufficiently explored. The aim of the study was to determine bonds formed between either cellulose or lignin and methyltrimethoxysilane (MTMOS) during a catalytic silanization reaction. Silanization was performed in the presence of two catalysts of a diverse mechanism of functionalization: aluminum acetylacetonate (Al(acac)3) and acetic acid (AcOH). For this purpose, FT-IR, 13C and 29Si NMR techniques were used. Cellulose silanization efficiency without a catalyst was unlikely. Lignin undergoes a silanization reaction with alkoxysilanes much easier than cellulose. The results showed new bonds between biopolymers and the silanising agent. The new bonds were confirmed by signals at the FT-IR spectra, e.g., 770 cm−1 and 1270 cm−1 (Si–CH3), and at the NMR signal coming from the T1, T2 and T3 structures. Efficiency of reaction was confirmed by atomic absorption spectroscopy (AAS) analysis
Hydrophobic Cellulose-Based Sorbents for Oil/Water Separation
No full textThe 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
Nanocellulose-Based Films for Surface Protection of Wooden Artefacts
No full textThis 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
Influence of Chemical Pre-Treatments and Ultrasonication on the Dimensions and Appearance of Cellulose Fibers
No full textDue to the wider use of nanocellulose in various areas of economic life, better and more optimal methods of obtaining nanocellulose are constantly being sought. Therefore, an attempt was made to evaluate the hybrid cellulose treatment, based on the use of a chemical method combined with an ultrasound of medium frequency. The study employs two different starting materials (Södra Black R cellulose or microcrystalline cellulose), two types of chemical pre-treatments (acid hydrolysis or oxidation), and two sonication durations. It was found that the reduction fiber cross-sectional dimensions was the result of prolonged exposure of cellulose to the ultrasound. From Södra Black R and the microcrystalline cellulose nanometer scale, structures were obtained in the form of isolated fibers. The TEMPO reagent accelerated the degradation process of two cellulose varieties due to its oxidizing character. The resulting products had nanofibrous structures. Cellulose degradation as a result of the combined action of sonication and TEMPO activity progressed gradually. Places of fiber degradation were characterized by their longitudinal breakage and initiated the next stages of the defibering process
Challenges and Prospects of Applying Nanocellulose for the Conservation of Wooden Cultural Heritage—A Review
No full textNanocellulose 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
Enhancing Water Barriers by Protein-Based Surface Treatments for Cellulose-Based Materials
No full textThe global packaging sector has grown consistently, and the use of sustainable materials, including recycled and biodegradable products, is expected to rise. This study focuses on the potential of producing barriers for water and water in moist air (water vapor) from proteins to protect cellulosic materials. Owing to the specific requirements of packaging materials, the main subject of this research was their barrier and strength properties. The scope of this work includes selecting components and their physicochemical treatment to produce functionalized coatings on sprayed paper and pure films, as well as film-coated samples (paper laminated with film). The following tests were used to estimate the hydrophobic, hygroscopic, and strength properties: Cobb absorption, contact angle testing, dynamic vapor sorption, and dynamic mechanical analysis. In most cases, the spray-coated paper and film-coated samples absorbed less liquid water than untreated paper. Wheat gluten protein was the most effective water barrier. In all variants, the vapor sorption, desorption, and hysteresis effects (or the lack thereof) showed significant differences compared to those of cellulosic materials. All variants of the spray-coated and film-coated samples in the dynamic mechanical analysis showed an increase in the strength properties of the samples in comparison to the untreated paper. The increased humidity caused a significant loss in the mechanical properties of all variants, exceeding the strength loss of the untreated control samples
Influence of Nanocellulose Structure on Paper Reinforcement
No full textThis article describes how crystalline or fibrous nanocellulose influences the mechanical properties of paper substrate. In this context, we used commercially available cellulose nanocrystals, mechanically prepared cellulose nanofibers dispersed in water or ethanol, and carboxy cellulose nanofibers. Selective reinforcement of the paper treated with the nanocellulose samples mentioned above was observed. The change in the fibre structure was assessed using scanning electron microscopy, roentgenography, and spectroscopy techniques. In addition, the effect of nanocellulose coating on physical properties was evaluated, specifically tensile index, elongation coefficient, Elmendorf tear resistance, Bendtsen surface roughness, Bendtsen air permeability, and bending strength. It can be concluded that the observed decrease in the strength properties of the paper after applying some NC compositions is due to the loss of potential disturbances in hydrogen bonds between the nanocellulose dispersed in ethanol and the paper substrate. On the other hand, significantly increased strength was observed in the case of paper reinforced with nanocellulose functionalized with carboxyl groups
