The influence of sunflower nanocellulose on the quality indicators of moisture-resistant packaging cardboard

Improving the production technology of products with improved quality indicators and with less impact on the environment remains an urgent scientific and practical problem of paper industry enterprises. This refers to the technology for the production of paper-bases for wallpaper using environmentally safe chemical additives, in particular nanocellulose (NC), which was obtained by acid hydrolysis from reed cellulose. The production of cellulose was carried out in two stages - extraction from reed stalks with a solution of alkali and an organosolvent method of cooking in a solution of peracetic acid. The obtained organosolvent cellulose contained the remains of lignin and mineral substances, which allows it to be used for the preparation of NC. As a result of the hydrolysis of organosolvent cellulose, a time-stable NC suspension was extracted, the properties of which were investigated by scanning electron microscopy (morphological changes in the structure of reed cellulose-containing materials), atomic force microscopy (determination of topographic characteristics of NC), analysis of electronic absorption spectra (transparency of NC films). It was established that reed NC films had nanoparticles with a cross-sectional size of 5-25 nm, density up to 1.52 g/cm3, transparency up to 81.6 %, tensile strength up to 65 MPa. For the production of castings of paper-bases for wallpaper samples, sulfated pine bleached cellulose and polyester synthetic fiber were used, to the fibrous mass of which were added the following chemical additives: alkyl ketene dimer, reed NC, binder, and optical brightener. It has been shown that the use of nanocellulose at a rate of 0.35 % to 1.0 % of the paper mass leads to a significant improvement in the physical and mechanical quality indicators of the paper base for wallpaper. It was established that the replacement of 50 % of the synthetic chemical auxiliary substance alkyl ketene dimer with nanocellulose or additional application of nanocellulose at a rate of 0.5 g/m2 on the surface of the casting with 0.7 % alkyl ketene dimer allows to obtain paper that meets the requirements of the standard. The obtained results indicate the prospects of using reed nanocellulose for the production of other mass types of paper and cardboard.

Engineering surface roughness of nanocellulose film via spraying to produce smooth substrates

Nano cellulose was successfully isolated from sugarcane bagasse through sulphuric acid hydrolysis of sugarcane bagasse cellulose. Physically, Nano cellulose was transparent and broken white. The crystallinity index of sugarcane bagasse nano cellulose was 80.72%. The particle size of sugarcane bagasse nano cellulose was 225 nm. Delignification process in isolation was successfully showed by releasing peaks in 1239.3 and 1507.7. It show C-O-C vibration of aryl group in lignin and C=C aromatic ring in lignin respectively. Sugarcane bagasse cellulose shows peaks at 1720.2 that represent COOH and hemicellulose carboxylic groups, while the others were not found. The crystallinity index of Nano cellulose was 42.65%. Nano cellulose film prepared in several concentrations (3%, 6%, and 9%). Nano cellulose film also prepared with adding HPMC 2%. Nano cellulose film prepared in 9% concentration was too strict and broken easily. The tensile strength and elongation of Nano cellulose film that prepared in 3% + HPMC 2% and 6% + HPMC 2% were 3.177 Mpa, 10.93% and 3.315 Mpa dan 3.7% respectively.

Nanocrystalline cellulose (NCC) was used as a modifier for waterborne polyurethane (WPU) to investigate the water and ethanol resistance of WPU-NCC composites. The NCC surface was modified with γ-glycidoxypropyltrimethoxysilane (GPTMS) and γ-ammnonimpropylmethyldimethoxysilane (APMDS) to improve its compatibility with waterborne polyurethane (WPU), as indicated by the contact angle (CA). The characteristic properties of WPU modified by NCC and a control group were compared by a Fourier-transform infrared spectroscope (FTIR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The CA between the modified NCC and WPU was decreased by 31.2% (with 8.0% APMDS (v/v)), and the NCC modified by GPTMS resulted in a 33.8% decrease of the CA. Compared to the original WPU, the crystal structure and crystallinity of the modified WPU showed a slight alteration. The SEM micrographs showed that the NCC particles modified by GPTMS were dispersed more uniformly. The FT-IR results showed that the addition of modified NCC led to the reduction of the characteristic absorption peak of the hydroxyl group. The water resistance of WPU with 1.5% NCC modified by GPTMS was increased by 47.2%, and the ethanol resistance decreased by 67.0%, while the modification from APMDS led to a 38.1% increase in water resistance and a 56.9% decrease in ethanol resistance.

Cellulosic biomass hydrolysis yields a nanoscale substance known as nanocrystalline cellulose (NCC). Gel, liquid, or powder is adaptable to a variety of uses. Nanocrystalline cellulose has unique renewability, biodegradability, and mechanical and physicochemical qualities, and abundance boosts the material’s mechanical strength by many orders of magnitude when introduced into the material matrix (polymer, ceramic, or metal). Nanocrystalline cellulose is not related with any serious environmental issues because it is a natural substance. The progress of this biomaterial as a green and renewable biomaterial for the fabrication of lightweight and biodegradable composite materials gives further impetus. The current aim of nanocrystalline cellulose research is to optimise nanocrystalline cellulose characteristics for dispersion in hydrophilic and hydrophilic media. To assess the nanocrystalline cellulose reinforcing, antibacterial, stability, hydrophilicity, and biodegradability, imaging methods and protocols in complicated matrices will need to be developed. This review includes a discussion on nanocrystalline cellulose biocomposites.

Biodegradable packaging film from watermelon rind pectin and pineapple peel nanocellulose: Preparation, characterization, and food application.

An energy efficient production of high moisture barrier nanocellulose/carboxymethyl cellulose films via spray-deposition technique

An urgent scientific and practical task for electrical engineering enterprises is to improve the specific characteristics of component transformers and capacitors that use electrical insulating paper. Electrical insulating paper is characterized by a wide list of special quality indicators, the necessary values ​​of which are achieved due to the use of cellulose with special properties and various chemical auxiliary substances. There are known attempts to use nanocellulose (NC) from wood to reduce the consumption of harmful synthetic chemical auxiliaries, but there are practically no research results on the impact of consumption of NC from non-wood plant materials. Therefore, in the work, a comparative study of the effect of NC from hemp fibers and coniferous wood on the target indicators of the quality of electrical insulating paper was carried out. For this, cellulose, suitable for extracting NC from hemp fibers, was obtained by an environmentally safe organosolv method. NC is obtained as a result of acid hydrolysis of organosolv hemp and sulfate unbleached coniferous cellulose, which is traditionally used in the production of electrical insulating paper. Laboratory samples of electrical insulating paper were made with a weight of 65±3 g/m2 from sulfated unbleached coniferous cellulose with the addition from 1% to 5% NC by weight of paper. The research results confirmed the hypothesis that the addition of NC paper pulp from various plant raw materials leads to an increase in the mechanical and electrical strength of the paper. It has been established that the effect of NC from hemp fibers on the quality indicators of electrical insulation paper is not inferior to the effect on them of NC from coniferous wood, and in some cases even a better result is observed. It was established that the introduction of NC into the composition of paper practically does not reduce its degree of polymerization, which is of great importance for maintaining high reliability and a long duration of work of paper insulation. The obtained results have scientific and practical significance for other types of insulating papers: capacitor, cable, telephone, impregnation, transformer, etc.

Fabrication of hydrophobic self-assembled monolayers (SAM) on the surface of ultra-strength nanocellulose films

Spraying of nanocellulose (NC) on a solid surface to prepare films is an alternative technique to vacuum filtration, which requires a long drainage time and produces films which can sometimes be difficult to separate from the filter. This letter reports a rapid preparation technique for nano-cellulose films using a bench scale system spray coating nanocellulose suspension onto stainless steel plates. After spraying NC suspension onto a smooth steel plate travelling on a constant velocity conveyor, the films can be dried directly on the plates using standard laboratory procedures, saving processing time and effort. By adjusting the suspension consistency, we were able to reproducibly make films with a basis weight ranging from 52.8 ± 7.4 to 193.1 ± 3.4 g/m2 when spraying on to a plate moving at a velocity of 0.32 cm/s. The operator preparation time for the nanocellulose film was 1 min, independent of the sample basis weight, which compares to production times reported in the literature of 10 min using filtration techniques. The films made by spray coating showed higher thickness, but comparable uniformity, to those made by vacuum filtration. Optical profilometry measurements showed that over a 1 cm × 1 cm inspection area that the surface roughness (RMS) of the NC film is only 389 nm on the spray coated side in contact with the steel plates, compared to 2087 nm on the outside surface. Thus, the reduction in preparation time for producing the nanocellulose film recommends this spray coating technique as a rapid and flexible method to produce NC films at the laboratory scale.

This study employed response surface methodology to optimize the preparation of biocomposites based on whey protein isolate, glycerol, and nanocrystalline cellulose from pineapple crown leaf. The effects of different concentrations of nanocrystalline cellulose as a filler and glycerol as a plasticizer on the thickness, the tensile strength, and the elongation at break on the resulting biocomposite films were investigated. The central composite design was used to determine the optimum preparation conditions for biocomposite films with optimum properties. The regression of a second-order polynomial model resulted in an optimum composition consisting of 4% glycerol and 3.5% nanocrystalline cellulose concentrations, which showed a desirability of 92.7%. The prediction of the regression model was validated by characterizing the biocomposite film prepared based on the optimum composition, at which the thickness, tensile strength, and elongation at break of the biocomposite film were 0.13 mm, 7.16 MPa, and 39.10%, respectively. This optimum composition can be obtained in range concentrations of glycerol (4–8%) and nanocrystalline cellulose (3–7%). Scanning electron microscope images showed that nanocrystalline cellulose dispersed well in the pure whey protein isolate, and the films had a relatively smooth surface. In comparison, a rough and uneven surface results in more porous biocomposite films. Fourier transform infrared spectroscopy revealed that nanocrystalline cellulose and glycerol showed good compatibility with WPI film by forming hydrogen bonds. The addition of nanocrystalline cellulose as a filler also decreased the transparency, solubility, and water vapor permeability and increased the crystallinity index of the resulting biocomposite film.

The humidity sensor is an important device used in many areas of human life, such as agriculture, medicine, industry, meteorology and more. Most often, synthetic polymers are used for the manufacture of humidity sensors, which after the end of their operation are accumulated in the form of electronic waste, polluting the environment. Currently, biodegradable polymers are in great demand. Such materials include nanocellulose, which can be made from both wood and plant raw materials. It has already been proven that nanocellulose is a promising material for use in humidity-sensitive devices. However, it was not clear the effect of sensitive film’s thickness on the characteristics of humidity sensors. In this work, capacitive humidity sensors based on nanocellulose were fabricated. Nanocellulose (NC) was obtained from reeds by the TEMPO method. The moisture-sensitive layer of NC was applied by dripping. Static (sensitivity, response, hysteresis) and dynamic (response time, recovery time, short- and long-term stability) characteristics of the manufactured humidity sensors were measured in dependence on mass of NC film (from 0.3 to 3.6 mg) and test signal frequency (100 Hz and 1000 Hz). The response of the sensors was increased with the weight of moisture-sensitive NC film and reached 1412 nF at 100 Hz (783 nF at 1000 Hz) for the sample of 0.6 mg NC, and then decreased with further increase in mass. The sensitivity of the sensors varied similarly, but the maximum value was observed for the sample with a mass of 1.8 mg and was 0.161 (%RH)-1 for 100 Hz (0.165 (%RH)-1 for 1000 Hz). The shortest response time had the sample with the lowest mass of moisture-sensitive film (100 s). With a further increase in the mass of moisture-sensitive NC film, the response and recovery time increased monotonically. Also, the sample with the lowest mass of the moisture-sensitive layer shows the lowest value of hysteresis (0.1%) and also increased with the increasing mass of the moisture-sensitive layer. In the study of short-term stability, samples weighing from 0.3 to 0.6 mg showed a significantly higher level of fluctuations (10 - 20%) compared to samples with a weight of the moisture-sensitive layer of 1.8 - 3.6 mg (1 - 4%). So, you should use nanocellulose film of larger mass (1.8… 3.6 mg) in order to improve the sensitivity and short-term stability of the devices. In view of the responce and recovery time as well as repeatability of the sensor characteristics, thin nanocellulose films (0.3… 0.5 mg) should be used. The direction of further research is to improve the long-term stability of the devices, in particular by modifying the nanocellulose film with adding certain impurities.

Among the main bio-based polymer for food packaging materials, whey protein isolate (WPI) is one of the biopolymers that have excellent film-forming properties and are environmentally friendly. This study was performed to analyse the effect of various concentrations of bio-based nanocrystalline cellulose (NCC) extracted from pineapple crown leaf (PCL) on the properties of whey protein isolate (WPI) films using the solution casting technique. Six WPI films were fabricated with different loadings of NCC from 0 to 10 % w/v. The resulting films were characterised based on their mechanical, physical, chemical, and thermal properties. The results show that NCC loadings increased the thickness of the resulting films. The transparency of the films decreased at higher NCC loadings. The moisture content and moisture absorption of the films decreased with the presence of the NCC, being lower at higher NCC loadings. The water solubility of the films decreased from 92.2% for the pure WPI to 65.5% for the one containing 10 % w/v of NCC. The tensile strength of the films peaked at 7% NCC loading with the value of 5.1 MPa. Conversely, the trend of the elongation at break data was the opposite of the tensile strength. Moreover, the addition of NCC produced a slight effect of NCC in FTIR spectra of the WPI films using principal component analysis. NCC loading enhanced the thermal stability of the WPI films, as shown by an increase in the glass transition temperature at higher NCC loadings. Moreover, the morphology of the films turned rougher and more heterogeneous with small particle aggregates in the presence of the NCC. Overall, the addition of NCC enhanced the water barrier and mechanical properties of the WPI films by incorporating the PCL-based NCC as the filler.

Nanocellulose has recently gained a foothold of significance among nanomaterials due to its unique properties, including renewability and sustainability. In this study, two promising methods, steam explosion and alkali-acid hydrolysis, were evaluated for the cellulose extraction from coconut husk fiber. Between the two methods, alkali-acid hydrolysis yielded 1.8 times higher cellulose content than the other. Hence, cellulose was obtained through the alkali-acid hydrolysis method to synthesize Nano-Crystalline Cellulose (NCC). In order to maximize cellulose content in nanocellulose synthesis, acid concentration, reaction temperature, and hydrolysis time were optimized using Response Surface Methodology (RSM). The optimum reaction condition for the synthesis of NCC was 50 °C with 45 wt% acid concentration for 60 minutes due to its high cellulose content (85.6 %). Synthesized NCC was spherical in shape with a diameter below 40 nm. NCC had better crystallinity (80.05 %) with a high zeta potential of -72.2 mV. NCC was evaluated for its adsorption capacity for different dyes at varying pH levels. Among the dyes, the removal efficiency of NCC was higher for methylene blue (90.89 %) and congo red (89.96 %) at all pH levels. But adsorption of crystal violet dye by NCC was higher in alkaline pH (9) and methyl red in acidic pH (5). As a result, synthesized nano cellulose could be used in the removal of synthetic dyes from textile effluents.

Nanocellulose (NC) suspensions can form rigid volume-spanning arrested states (VASs) at very low volume fractions. The transition from a free-flowing dispersion to a VAS can be the result of either an increase in particle concentration or a reduction in interparticle repulsion. In this work, the concentration-induced transition has been studied with a special focus on the influence of the particle aspect ratio and surface charge density, and an attempt is made to classify these VASs. The results show that for these types of systems two general states can be identified: glasses and gels. These NC suspensions had threshold concentrations inversely proportional to the particle aspect ratio. This dependence indicates that the main reason for the transition is a mobility constraint that, together with the reversibility of the transition, classifies the VASs as colloidal glasses. If the interparticle repulsion is reduced, then the glasses can transform into gels. Thus, depending on the preparation route, either soft and reversible glasses or stiff and irreversible gels can be formed.