Post-curing agent is an effective method to improve the water resistance of nanocellulose food packaging film coating. The post-curing agent can chemically react with nanocellulose or other components in the coating to form a crosslinked structure, thereby enhancing the water resistance and stability of the membrane. Here are some common strategies and suggestions: 1. The role of using post-curing agent: Formation of cross-linking networks: The post-curing agent can form chemical cross-links between nanocellulose molecules, build a more stable three-dimensional network structure, and reduce moisture pairs. Invasion of membrane. Improve the stability of the coating: The crosslinked structure can enhance the swelling and moisture resistance of the coating, preventing the nanocellulose from dispersing or dissolving after contacting water. Improved mechanical properties: Post-curing not only improves water resistance, but also increases the hardness and wear resistance of the coating. 2. Commonly used post-curing agent types: multifunctional crosslinking agents: such as epoxy compounds, isocyanates or multifunctional crosslinking agents containing hydroxyl and amino groups. These compounds can be combined with nanofibers.

When selecting sulfonated modified CNC or carboxylated modified CNC as the coating material for OPP food packaging film, the following key factors need to be considered: dispersibility, enhanced performance, functional requirements and safety. The following is an analysis of the application of these two modified CNCs in OPP film coating: Advantages of sulfonated modified CNCs: Good dispersion: The dispersion of sulfonated modified CNCs in water and polar organic solvents is better. This helps to prepare a uniform coating. Antistatic properties: The sulfonic acid groups of sulfonated CNCs impart good antistatic properties, which is helpful in preventing the OPP film surface area from electrostatic and adsorbing dust. Suitable for conductive applications: If the packaging film needs to have conductive or antistatic functions, sulfonated CNC may be more suitable. Film transparency: The coatings prepared by sulfonated modified CNC are usually more transparent, which is conducive to maintaining the visual effect of the packaging film. Advantages of carboxylated modified CNC: Improved mechanical properties: carboxylated CNC can be more

In the coating of OPP food packaging film, the following types of nanocellulose can be used: Nanocellulose (CNF): Cellulose nanofibers are extracted from natural cellulose, with good mechanical strength and biocompatibility , can improve the strength and barrier properties of the film. Nanocellulose hydrogel: This form of nanocellulose can be used as a coating, providing good flexibility and moisture retention ability, suitable for fresh-preserving packaging. Modified nanocellulose: Chemically or physically modified nanocellulose can impart additional properties to the membrane, such as antibacterial, ultraviolet or anti-fog functions. Nanocellulose composite materials: Combining nanocellulose with other materials (such as polymers, metal oxides, etc.) can enhance the barrier properties and mechanical properties of the film. Using nanocellulose as coating material can not only improve the functionality of food packaging film, but also increase its biodegradability, meeting the needs of sustainable development.

The physical properties and structural differences in microcrystalline cellulose (MCC) and nanocellulose (NC) lead to their different ease of preparation into powders. Microcrystalline cellulose (MCC): Microcrystalline cellulose is a polymer composed of the crystalline region portion of cellulose, with a short fiber length and a lower specific surface area. This structure makes microcrystalline cellulose have high stability and can be easily ground into a fine powder. Since the particles of microcrystalline cellulose are coarse and do not easily adhere to each other or form agglomerates, powders can be made by conventional drying and crushing methods. Nanocellulose (NC): Nanocellulose consists of smaller fibrous nanostructures, generally between 1-100 nanometers in diameter and can reach several microns in length. Its specific surface area is very large, resulting in a significant increase in surface energy. This high surface energy makes nanocellulose particles very easy to adhere to each other or form aggregates. Nanocellulose has a high level of

There are some research and practical cases of the application of nanocellulose as an additive in oil well drilling fluids. Its main function is to improve the rheological performance of drilling fluids, reduce filtration loss, enhance well wall stability and improve drilling efficiency. The specific amount of addition and use effect will vary depending on the drilling conditions, type of drilling fluid (such as water-based or oil-based drilling fluid) and the modification type of nanocellulose. Here are some common use cases and added information: 1. Improve the rheological properties of drilling fluids Nanocellulose can increase the viscosity and thixotropy of drilling fluids, making it easier to carry drilling chips and improve shear thinning of drilling fluids characteristic. The addition amount is usually between 0.1% and 1.5% (mass fraction)**, and the rheological parameters of the drilling fluid are adjusted as needed. Case: Studies have shown that when using unmodified cellulose nanofibers (CNF) as additives for water-based drilling fluids, adding 0.5%** can significantly increase the viscosity of the drilling fluids.

The application of nanocellulose in anticorrosion coatings is increasingly attracting attention, mainly because it can improve the mechanical properties of the coating, increase shielding effect, reduce the permeability of water vapor and oxygen, thereby enhancing the anticorrosion performance. Here are some information about the use cases and typical additions of nanocellulose in anticorrosive coatings: 1. Improve mechanical strength and adhesion Nanocellulose, especially cellulose nanofibers (CNF), due to their high specific surface area and High strength characteristics can effectively increase the mechanical strength and adhesion of the coating, thereby extending the service life of the coating. Case: Adding 0.5% to 2.0% (mass fraction) of cellulose nanofibers to the epoxy resin coating can significantly improve the tensile strength and wear resistance of the coating, making it more suitable for anti-corrosion scenarios. 2. Improve shielding performance, reduce the aspect ratio and dispersion of permeable nanocellulose can form a 'maze'-like structure in the coating, thereby increasing water vapor and

The basic principle of determining the molecular weight of cellulose by terminal group analysis is to quantify specific functional groups at the end of the polymer chain through chemical or physical methods, and then calculate the average molecular weight. The terminals of cellulose often contain groups such as hydroxyl groups (-OH), so molecular weight can be estimated by detecting the concentration of these terminal groups. Detailed steps: 1. Sample preparation Dissolve the cellulose sample in an appropriate solvent to ensure complete dissolution. Cellulose molecules are not easy to dissolve, and a suitable solvent system is required to choose, such as dimethylacetamide-lithium chloride system (DMAc/LiCl), or alkaline aqueous solution. 2. The commonly used methods for calibration of terminal groups in chemical reactions include esterification or acylation reaction, which modify the hydroxyl group (-OH) at the terminal of cellulose molecules. For example, acetylation reaction is used to react with the terminal hydroxyl group to form an acetate. The product generated after the reaction is then determined by titration or other quantitative analysis techniques, thereby indirectly calculating the concentration of the terminal hydroxyl group.

Gel Permeation Chromatograph (GPC), also known as size exclusion chromatography (SEC), is an analysis method based on molecular volume differential separation of polymers. It is widely used to determine the molecular weight and molecular weight of polymers. distributed. GPC is suitable for determining the molecular weight of polymer materials such as cellulose. The following are the steps and detailed principles for determining the molecular weight of cellulose using GPC. 1. Basic Principle GPC separates molecules of different sizes by using a chromatographic column with porous fillers. Since macromolecules cannot enter small pores, they will pass through the column first, while small molecules can enter pores, thus delaying their outflow. By analyzing the retention time of the molecules in the chromatographic column, the molecular weight of the molecules can be calculated. Results of GPC usually include: • Number average molecular weight (Mn): Indicates the average molecular weight of all molecules in the sample. • Weight average molecular weight (M

Nuclear magnetic resonance (NMR) spectroscopy can be used to determine the molecular weight of cellulose, but this process is more complicated because the structure of cellulose is large and complex. Here are the general steps for determining cellulose molecular weight using NMR method: 1. Sample preparation • Purify the sample: Make sure the cellulose sample is as pure as possible and remove other impurities. • Dissolved sample: Cellulose is not easily dissolved in water and therefore requires dissolving with a suitable solvent system, such as sodium dihydrogen phosphate solution (e.g., 6% sodium phosphate solution) or other solvent systems. 2. NMR Experiment • Select the appropriate NMR frequency: Use high-field NMR instruments, such as instruments with a frequency of 300 MHz or higher, to obtain a clear spectrum. • Obtain spectra: Perform a solid or solution NMR experiment, and obtain a ¹³C-NMR or ¹H-NMR spectrum of cellulose according to the experimental settings. ¹&su

The viscosity method is a simple and effective method to determine the molecular weight of polymers, and is often used to determine the relative molecular weight of polymers such as cellulose. The specific process is based on the relationship between the intrinsic viscosity of the solution and the molecular weight of the polymer. The following are the general steps and principles for determining the molecular weight of cellulose by using the viscosity method: 1. Basic Principle In the viscosity method, by measuring the viscosity of cellulose solution and combining empirical formulas (such as Mark-Houwink equation), the average cellulose can be calculated. Molecular weight. The viscosity measurement method depends on the relationship between the viscosity and molecular weight of the polymer solution, i.e.: [η]=K⋅Mva where: • [η] is the intrinsic viscosity of cellulose (unit: dL/g) and is from the solution. A dimensionless value derived from the viscosity data. • Mv is the viscosity average molecular weight of cellulose. • K and