From Natural Cellulose to Nanocrystals: Structural Characteristics, Application Directions, and Industrialization Challenges of CNC

Cellulose is found in paper, cotton, wood, hemp fibers, straw, and many plant tissues. For a long time, people have been familiar with the macroscopic uses of cellulose: papermaking, textiles, packaging, wood processing, and daily consumer products. It is widely available, inexpensive, renewable, and appears to be a very common natural polymer material.

However, the performance of a material depends not only on its chemical composition, but also on its scale and structure. The same cellulose, when present as wood pulp, cotton fiber, or paper, mainly serves as a structural support material. When it is processed down to the nanoscale while retaining highly ordered crystalline regions, it may exhibit high crystallinity, high specific surface area, abundant surface hydroxyl groups, colloidal dispersibility under suitable aqueous conditions, surface modification capability, and self-assembly behavior.

Cellulose nanocrystals, abbreviated as CNC, are precisely this type of nanomaterial derived from natural cellulose. The value of CNC lies in its ability to transform cellulose from ordinary plant fibers into functional nanoparticles with high rigidity, small size, tunable surfaces, and the ability to participate in composite formation and assembly.

1. What Is CNC?

1.1 Basic Definition of CNC

Cellulose nanocrystals, abbreviated as CNC, are nanoscale crystalline particles isolated from natural cellulose. CNC typically appears as short rods, rods, or needle-like particles, with relatively high crystallinity and high rigidity. Its dimensions are affected by the raw material source, pretreatment method, hydrolysis conditions, and post-treatment process. Therefore, the length, diameter, and aspect ratio of CNC may vary significantly among different studies.

From a structural perspective, natural cellulose fibers are not completely uniform. Cellulose molecular chains contain both ordered crystalline regions and relatively disordered amorphous regions. The preparation principle of CNC is to remove or weaken the amorphous regions as much as possible while preserving the more stable and ordered crystalline regions. Therefore, CNC can be understood as nanoscale crystalline fragments isolated from cellulose fibers.

1.2 What Raw Materials Can CNC Be Derived From?

CNC can be derived from a wide range of sources. Common raw materials include wood pulp, cotton linters, microcrystalline cellulose, hemp fibers, bamboo fibers, sugarcane bagasse, rice straw, corn stover, and other agricultural by-products. Differences in cellulose content, lignin content, hemicellulose content, and fiber structure among raw materials can affect the morphology, yield, crystallinity, and surface properties of the resulting CNC.

Raw Material Type	Representative Sources	Characteristics
Lignocellulosic raw materials	Wood pulp, paper pulp	Stable sources, suitable for scale-up studies
High-purity cellulose raw materials	Cotton linters, microcrystalline cellulose	Fewer impurities and better experimental reproducibility
Agricultural and forestry by-products	Straw, sugarcane bagasse, rice husks, hemp fibers	Beneficial for high-value utilization of waste biomass

1.3 Preparation Principle of CNC

A common method for preparing CNC is acid hydrolysis, especially sulfuric acid hydrolysis. Sulfuric acid can preferentially hydrolyze the amorphous regions of cellulose, allowing the more stable crystalline regions to remain. At the same time, sulfuric acid hydrolysis introduces a certain amount of sulfate half-ester groups onto the CNC surface. These negatively charged groups help CNC form relatively stable colloidal dispersions in water, but they may also reduce its thermal stability.

In addition to sulfuric acid hydrolysis, CNC can also be prepared through hydrochloric acid hydrolysis, phosphoric acid hydrolysis, organic acid hydrolysis, persulfate oxidation, enzymatic methods, ionic liquid treatment, and deep eutectic solvent treatment.

2,2,6,6-Tetramethylpiperidine-1-oxyl, abbreviated as TEMPO, mediated oxidation is a commonly used cellulose surface oxidation method. It can selectively oxidize some primary hydroxyl groups on the cellulose surface into carboxyl or carboxylate groups, thereby helping improve aqueous dispersibility and providing reactive sites for subsequent coupling and functional modification. Unlike sulfuric acid hydrolysis, which mainly obtains CNC by removing amorphous regions and retaining crystalline regions, TEMPO oxidation focuses more on regulating the surface chemistry of cellulose nanomaterials. Under appropriate conditions, TEMPO oxidation can also be combined with acid hydrolysis, ultrasonication, or high-pressure homogenization to prepare carboxylated CNC or other carboxylated nanocellulose materials.

1.4 What Are the Differences Among CNC, CNF, and BNC?

Nanocellulose is a class of materials. Common types include cellulose nanocrystals, abbreviated as CNC; cellulose nanofibrils, abbreviated as CNF; and bacterial nanocellulose, abbreviated as BNC.

Type	Chinese Name	Main Source and Preparation	Typical Structure	Main Characteristics
CNC	Cellulose nanocrystals	Mostly obtained from natural cellulose through hydrolysis or oxidation-assisted isolation	Short rod-like or needle-like particles with high crystallinity	High rigidity, modifiable surface, and easy formation of colloidal dispersions
CNF	Cellulose nanofibrils	Mostly obtained through mechanical fibrillation, often after oxidative pretreatment	Long fibrous structure, easily entangled into networks	Strong film-forming, thickening, and network-building capabilities
BNC	Bacterial nanocellulose	Produced by microbial fermentation	High-purity three-dimensional nanofiber network	High water content and high purity; suitable for hydrogel and biomedical membrane research

2. Why Is CNC Special?

The uniqueness of CNC comes from its structure. High crystallinity provides rigidity, the nanoscale dimension brings high specific surface area, surface hydroxyl groups provide room for modification, and CNC can enter various aqueous systems when surface charge and dispersion conditions are suitable. Its self-assembly capability also enables it to form ordered micro- and nanostructures.

Structural Feature of CNC	Corresponding Material Function
High crystallinity	Reinforcement, improved modulus, and dimensional stability
Nanoscale dimension	Increased specific surface area and enhanced interfacial interactions
Abundant surface hydroxyl groups	Convenient for modification, grafting, and composite formation
Tunable surface charge	Beneficial for colloidal dispersion and emulsion stabilization
Chiral self-assembly capability	Enables structural color and optically responsive materials

2.1 Reinforcement Ability Brought by High Crystallinity

CNC has relatively high crystallinity and rigidity, making it suitable as a nano-reinforcing component in composite materials. When CNC is uniformly dispersed in polymers, films, hydrogels, or coatings, and forms good interfacial interactions with the matrix, it can help improve tensile strength, modulus, dimensional stability, or creep resistance.

However, reinforcement does not simply improve with increasing CNC loading. If CNC aggregates, it may become a stress concentration point, making the material brittle or reducing performance. Therefore, the reinforcing ability of CNC should be evaluated together with the following factors: ① dispersion state; ② interfacial bonding; ③ orientation degree; ④ loading amount.

2.2 Barrier Ability Brought by Nanoparticle Arrangement

In films or coatings, CNC can make the diffusion pathways of oxygen and some small molecules more tortuous. The more complex the diffusion path, the longer it usually takes for small molecules to pass through the material. Therefore, CNC is often used to improve the barrier performance of packaging films, paper-based coatings, and biodegradable films.

In barrier materials, CNC more readily demonstrates advantages in oxygen barrier performance. It can form a dense and tortuous diffusion pathway within the film layer, reducing oxygen transmission. However, because CNC surfaces are rich in hydroxyl groups and readily absorb water, water vapor barrier performance and stability under high humidity remain application challenges. Under high-humidity conditions, water uptake and changes in the hydrogen-bonding network may also weaken oxygen barrier performance. In practical applications, hydrophobic modification, crosslinking, multilayer structures, or composite coating designs are often needed for improvement.

The barrier effect of CNC is highly dependent on its dispersion and arrangement state:

① Uniform dispersion, dense packing, and good interfacial bonding help improve barrier performance;

② Aggregation, pores, and phase separation may weaken the barrier effect.

2.3 Rheological Regulation Brought by Colloidal Dispersion

CNC can affect the viscosity, shear-thinning behavior, thixotropic recovery, and gelation tendency of aqueous systems or some composite systems. Its rheological behavior is related to multiple factors:

① CNC concentration;

② Particle size;

③ Aspect ratio;

④ Surface charge;

⑤ Ionic strength;

⑥ Dispersion state.

This feature allows CNC to act not only as a solid filler, but also as a rheology modifier in coatings, inks, slurries, emulsions, and 3D printing inks. For processing applications, rheological properties are often more closely related to practical performance than a single mechanical index.

2.4 Modification Capability Brought by Surface Hydroxyl Groups

CNC surfaces contain abundant hydroxyl groups. Depending on the preparation process, CNC may also carry sulfate ester groups, carboxyl groups, aldehyde groups, or other functional groups. These surface groups allow CNC to undergo esterification, etherification, oxidation, silanization, graft polymerization, metal nanoparticle loading, and biomolecular coupling. The main purposes of surface modification include three aspects:

① Improving CNC dispersion in non-aqueous systems or hydrophobic polymers;

② Enhancing interfacial bonding between CNC and the matrix material;

③ Endowing CNC with functions such as antibacterial activity, adsorption, conductivity, catalysis, fluorescence, or responsiveness.

2.5 Optical Properties Brought by Chiral Self-Assembly

Under suitable concentration, surface charge, and dispersion conditions, cellulose nanocrystal dispersions can self-assemble to form a chiral nematic liquid crystal phase, also known as a cholesteric phase.

This structure has a helical arrangement. During drying, if the ordered arrangement can be preserved, CNC can form solid films with structural color. The color does not come from dyes or pigments, but from the selective reflection of specific wavelengths of light by ordered micro- and nanostructures.

This property has attracted attention for CNC in optical films, anti-counterfeiting labels, humidity-responsive materials, and optical sensing materials. For example, when environmental humidity, ionic strength, or the internal structure of the film changes, the reflected color of a CNC film may change accordingly, enabling its use in research on visually responsive materials.

2.6 Renewable Origin and Safety Evaluation

CNC is derived from natural cellulose, which has characteristics such as broad availability, renewability, low density, and biodegradation potential. Therefore, CNC is often studied for green composites, food packaging, biomedical materials, and environmentally friendly functional materials.

However, “natural origin” does not mean absolute safety in all application scenarios. The safety of CNC needs to be comprehensively evaluated based on material properties and use conditions, including particle size and morphology, surface modification, impurities or residual reagents, dosage, exposure route, and specific application scenario. In particular, for food-contact applications, biomedical use, inhalation exposure, and consumer products, further attention should be paid to migration behavior, cytocompatibility, immune response, in vivo metabolism, environmental release, and regulatory requirements.

3. What Can CNC Do?

Role of CNC in Materials	Main Properties Utilized	Typical Applications
Nano-reinforcing component	High crystallinity and high rigidity	Composites, hydrogels, films
Barrier component	Dense arrangement and extended diffusion pathways	Food packaging, paper-based coatings
Rheology modifier	Colloidal dispersion and shear-thinning behavior	Coatings, inks, 3D printing inks
Pickering emulsion stabilizer	Interfacial adsorption and particle barrier	Food, cosmetics, drug delivery
Functional carrier	High specific surface area and surface hydroxyl groups	Drug loading, antibacterial materials, sensing
Structural regulation component	Film formation, gel formation, pore formation	Environmental remediation, energy materials

3.1 As a Nano-Reinforcing Component: For Composite Materials

CNC can be incorporated into systems such as polylactic acid, abbreviated as PLA; polyvinyl alcohol, abbreviated as PVA; starch; chitosan; natural rubber; hydrogels; epoxy resins; and acrylic resins to improve material rigidity, strength, or dimensional stability. This application mainly utilizes the high crystallinity and high rigidity of CNC.

For hydrophilic matrices such as PVA, starch, chitosan, and hydrogels, CNC can more readily form composite structures through hydrogen bonding. For hydrophobic or low-polarity matrices such as polypropylene, polyethylene, some PLA materials, and some thermosetting resins, surface modification or compatibilizers are usually needed to improve dispersion and interfacial bonding.

3.2 As a Barrier Component: For Packaging Films and Paper-Based Coatings

In packaging materials, CNC can be used in biodegradable films, food packaging coatings, paper-based barrier layers, and pharmaceutical packaging materials. Its role is to extend the diffusion pathway of oxygen and some small molecules through the dense arrangement of nanoparticles, thereby improving barrier performance.

When CNC is compounded with materials such as PVA, starch, PLA, and chitosan, it may improve both mechanical properties and oxygen barrier performance. However, because CNC is hydrophilic, the water vapor barrier and dimensional stability of the material may decrease under high-humidity conditions. Therefore, packaging applications often require hydrophobic modification, crosslinking treatment, multilayer structures, or composite coating designs.

3.3 As a Particle Stabilizer: For Pickering Emulsions

A Pickering emulsion refers to an emulsion in which the oil-water interface is stabilized by solid particles. Cellulose nanocrystals, abbreviated as CNC, have nanoscale dimensions, modifiable surfaces, and certain interfacial adsorption capability. They can adsorb at the oil-water interface and form a particle barrier, thereby helping maintain emulsion stability.

Unmodified CNC is relatively hydrophilic, and its interfacial stabilization ability may be limited. In practical applications, surface regulation or synergy with other biomacromolecules is often needed to improve emulsion stability.

3.4 As a Functional Carrier: For Biomedical Materials Research

CNC has rich surface functional groups and a relatively high specific surface area. It can load drugs, proteins, enzymes, antibacterial agents, metal nanoparticles, or fluorescent molecules. CNC has been studied for drug delivery, hydrogels, wound dressings, tissue engineering scaffolds, antibacterial materials, and biosensing materials.

In the biomedical field, the main advantages of CNC include three aspects:

① Abundant surface hydroxyl groups, facilitating chemical modification;

② Relatively high specific surface area, beneficial for loading active substances;

③ Compatibility with polysaccharides, proteins, synthetic polymers, and inorganic nanomaterials for composite formation.

When CNC is introduced into medical materials, purity, residual chemicals, sterilization methods, endotoxins, cytocompatibility, immune response, and in vivo metabolism need to be systematically evaluated. Most biomedical applications of CNC are still at the stage of materials research, in vitro evaluation, or animal experiments, and should not be directly regarded as clinically usable materials.

3.5 As an Adsorption Scaffold and Structural Regulation Component: For Environmental and Energy Materials

In environmental remediation, CNC can be used in adsorbents, aerogels, porous materials, and composite membranes. After carboxylation, amination, thiolation, magnetic compositing, or metal oxide loading, CNC can be used to adsorb heavy metal ions, dyes, and some organic pollutants.

In energy materials, CNC usually does not directly serve as the main conductive active material. Instead, it acts as a structural regulation component, carbonization precursor, separator reinforcement component, or gel electrolyte scaffold. Its main contributions are regulating pore structure, improving flexibility, enhancing interfacial stability, and increasing the sustainability profile of the material.

4. Emerging Applications of CNC

Traditional research on CNC has mostly focused on reinforcing fillers, films, and coatings. In recent years, with advances in surface modification, self-assembly, and composite technologies, CNC has attracted increasing attention in responsive materials, ordered optical structures, flexible devices, 3D printing, and functional delivery systems.

Emerging Application Direction	Main Role of CNC	Typical Application Scenarios	Key Considerations
Smart sensing materials	Provides modifiable surfaces, hydrophilic hydrogen-bonding networks, and stable nanostructures; after being combined with conductive or responsive materials, CNC can participate in signal response	Humidity sensing, strain sensing, pressure sensing, gas detection, metal ion detection, pH response, biomolecule detection	CNC itself is usually not a highly conductive material. Electrical sensing often relies on conductive polymers, carbon materials, metal nanoparticles, MXene, or ion gels as composite components
Structural color and anti-counterfeiting materials	Forms ordered helical structures through chiral nematic self-assembly and selectively reflects specific wavelengths of light	Structural color films, anti-counterfeiting labels, humidity-responsive indicators, optical sensing films, visually responsive coatings	The stability of structural color depends on CNC concentration, ionic strength, drying rate, surface modification, and environmental humidity; large-area uniform fabrication remains challenging
Flexible electronic materials	Enhances mechanical stability of composites, improves water retention, flexibility, and interfacial bonding; provides dispersion and support structures for conductive components	Flexible sensors, electronic skin, conductive hydrogels, wearable devices	The main role of CNC is not to provide high conductivity directly, but to help build stable flexible composite structures; signal stability after cyclic stretching, bending, and compression should be considered
3D-printed hydrogels	Regulates ink viscosity, shear-thinning behavior, and post-printing shape retention; reinforces hydrogel structures	Tissue engineering scaffolds, flexible devices, customized porous materials, functional hydrogel inks	Excessive CNC content may cause nozzle clogging, system aggregation, or embrittlement of printed structures; matrix polymer, crosslinking method, and printing parameters need to be optimized together
Energy storage devices	Serves as a structural regulation component, separator reinforcement component, gel electrolyte scaffold, or carbon material precursor	Supercapacitors, battery separators, gel electrolytes, flexible electrodes, porous carbon materials	CNC usually does not serve as the main electrochemically active material; its value mainly lies in pore structure regulation, flexibility improvement, interfacial stability, and renewable origin
Agricultural and food delivery systems	Stabilizes emulsions, constructs microcapsules, regulates active substance release, and improves composite film structures	Flavor encapsulation, antioxidant delivery, lipophilic nutrient delivery, pesticide controlled release, slow-release fertilizers, food packaging materials	Food and agricultural applications require focused evaluation of residual chemicals, migration behavior, digestive stability, environmental release risks, and regulatory requirements

5. Why Has CNC Not Yet Been Widely Adopted in Most End-Use Materials?

Research on cellulose nanocrystals, abbreviated as CNC, is highly active, and CNC already has a certain industrial foundation. However, moving from laboratory performance validation to broad application in most end-use materials still faces multiple limitations. These issues involve not only material performance, but also preparation processes, processing compatibility, storage and transportation, quality standards, and safety evaluation.

Main Issue	Impact	Possible Approach
Relatively high preparation cost and difficulty in process scale-up	Restricts the promotion of CNC in bulk material fields such as packaging, coatings, and plastic composites	Increase yield, optimize continuous preparation processes, and reduce energy consumption, water consumption, and post-treatment costs
Environmental and equipment pressure associated with strong acid hydrolysis	Sulfuric acid, hydrochloric acid, and other acid hydrolysis routes may bring wastewater treatment, acid recovery, equipment corrosion, and safety management issues	Improve acid recovery and wastewater treatment; develop milder preparation routes such as organic acid methods, enzymatic methods, oxidation methods, and deep eutectic solvent methods
Difficulty in redispersion after drying	CNC is prone to particle aggregation during drying, affecting storage, transportation, weighing, and powder-based applications	Use freeze-drying, spray drying, protective agents, solvent exchange, surface grafting, or high-solid-content stable dispersion systems
Insufficient compatibility with hydrophobic matrices	CNC surfaces are hydrophilic. Direct compounding with hydrophobic matrices such as PLA, polyethylene, polypropylene, and epoxy resin can easily lead to aggregation and weak interfacial bonding	Use surface esterification, silanization, graft modification, compatibilizers, emulsion compounding, or in situ polymerization to improve interfacial compatibility
Insufficient stability under high-humidity conditions	CNC contains abundant hydroxyl groups and readily absorbs water, which may weaken water vapor barrier performance, dimensional stability, and wet-state mechanical properties	Improve wet-state stability through hydrophobic modification, crosslinking treatment, multilayer structures, composite coatings, or compounding with hydrophobic polymers
Thermal stability limits some processing scenarios	Some CNC, especially sulfuric-acid-hydrolyzed CNC, may have reduced thermal stability due to surface sulfate ester groups, affecting extrusion, injection molding, hot pressing, and melt blending	Evaluate initial decomposition temperature, thermogravimetric curves, sulfur content, and processing residence time; choose preparation or modification routes with higher thermal stability
Insufficient characterization and standardization	Differences in source, size, crystallinity, surface charge, and drying method can lead to performance variations, affecting study comparison, result reproducibility, and industrial quality control	Standardize reporting of raw material source, preparation conditions, size distribution, aspect ratio, crystallinity, surface charge, functional groups, and redispersion method
Safety and regulatory evaluation still need improvement	Food-contact applications, medical materials, inhalation exposure, and consumer products require stricter data support	Conduct toxicology studies, migration behavior studies, inhalation exposure assessment, in vivo metabolism studies, environmental release assessment, and life cycle assessment

The industrialization challenge of CNC lies in achieving a balance among cost, processability, stability, safety, and quality consistency. For practical applications, CNC needs to move beyond performance enhancement in the laboratory toward material systems that are reproducible, processable, storable, scalable, and verifiable.

6. Key Points in CNC Research and Experimental Design

6.1 Clarify the Main Role of CNC in the System

Before experimental design, the main role of cellulose nanocrystals, abbreviated as CNC, in the material system should be clarified. Common objectives include reinforcement, barrier enhancement, rheological regulation, emulsion stabilization, drug loading, self-assembly, adsorption, or structural support. Clarifying the functional role of CNC makes it possible to reasonably determine the loading amount, modification method, dispersion method, and key characterization priorities.

6.2 Determine the Dispersion Medium for CNC

CNC is usually relatively easy to disperse in water, but it tends to aggregate in organic solvents, hydrophobic resins, and molten plastics. Therefore, before the experiment, it is necessary to determine whether the system is aqueous, alcoholic, organic-solvent-based, emulsion-based, resin-based, or melt-polymer-based. If the target system is relatively hydrophobic, surface modification, solvent exchange, compatibilizers, emulsion compounding, or in situ polymerization should be considered first, rather than directly adding an aqueous CNC dispersion into a hydrophobic matrix.

6.3 Evaluate Whether Drying Treatment Is Needed

Using an aqueous CNC dispersion directly in experiments can reduce powder aggregation issues. However, CNC often needs to be dried for storage, transportation, weighing, or compounding in non-aqueous systems. In such cases, the effect of the drying method on redispersibility should be carefully evaluated.

During drying, CNC is prone to aggregation due to hydrogen bonding between particles. After redispersion, it may not necessarily recover its original nanoscale dispersion state. Control groups such as “CNC before drying” and “dried and redispersed CNC” can be set up to determine whether performance changes are related to drying-induced aggregation.

6.4 Determine Whether Surface Modification Is Needed

Not all CNC systems require surface modification. For aqueous hydrogels, hydrophilic films, or waterborne coatings, unmodified CNC may already meet the requirements for dispersion and composite formation. For hydrophobic plastics, high-temperature processing, oil-phase emulsions, conductive composites, or specific sensing systems, surface modification is usually more important.

Common purposes of modification include increasing hydrophobicity, introducing carboxyl or amino groups, grafting polymer chains, enhancing interfacial bonding, loading metal nanoparticles, or introducing responsive groups. After modification, the modification effect should be verified using methods such as Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, elemental analysis, Zeta potential measurement, or thermogravimetric analysis.

6.5 Select Characterization Methods According to the Research Question

Different research questions should be matched with corresponding testing methods.

Research Question	Recommended Characterization Methods
CNC morphology, length, and diameter	Transmission electron microscopy, atomic force microscopy; image analysis can be used to obtain length, diameter, and aspect ratio distributions
Dispersion stability and aggregation tendency	Zeta potential, dynamic light scattering, sedimentation observation, microscopic observation; dynamic light scattering is mainly used to evaluate particle aggregation and changes in particle size distribution in dispersion
Crystalline structure	X-ray diffraction
Surface functional groups	Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, elemental analysis
Thermal stability and processing adaptability	Thermogravimetric analysis, differential scanning calorimetry
Mechanical reinforcement effect	Tensile testing, compression testing, bending testing, dynamic mechanical analysis
Barrier performance	Oxygen transmission rate, water vapor transmission rate, water absorption
Printing or coating adaptability	Steady-state rheology, dynamic rheology, thixotropic recovery testing

Appropriate methods should be used to answer specific questions. For example, research on barrier films should focus on oxygen transmission rate, water vapor transmission rate, and wet-state stability. Research on reinforced composites should pay attention to mechanical properties, fracture surface morphology, and interfacial bonding.

6.6 Set Up Necessary Control Groups

A common issue in CNC experiments is insufficient control groups, which makes it difficult to determine the true source of performance changes. The following controls are recommended according to the research objective.

Control Group	Purpose
Blank matrix	Determine whether CNC causes performance changes
Unmodified CNC	Determine the baseline effect of unmodified CNC
Modified CNC	Determine the performance contribution of surface modification
Different CNC loading levels	Identify an appropriate loading range and avoid excessive aggregation
Different dispersion methods	Compare the effects of ultrasonication, stirring, solvent exchange, and other treatments
CNC before and after drying	Determine the influence of drying and redispersion on performance

If the research object is a composite material, fracture surface morphology and interfacial bonding analysis should also be included. If the research object is a sensing material, cyclic stability, response repeatability, and anti-interference capability should be evaluated. If the research object is a biomedical material, cytocompatibility and safety-related experiments should be included.

7. Representative Product Categories and Application Tables Related to Cellulose Nanocrystals

Note: The following products are provided as research-oriented selection references for cellulose nanocrystal (CNC)-related studies. They cover raw materials, pretreatment reagents, preparation reagents, surface modification reagents, and matrix materials for composite material research. The “applications” listed in the tables mainly refer to experimental design or material research directions.

Table 1. Cellulose Raw Materials, Microcrystalline Cellulose, and Nanocellulose Products

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Cellulose nanocrystal product	9004-34-6	C1520462	Cellulose	Nanocrystals, L: ~200 nm, OD: ~10 nm	Direct research material for cellulose nanocrystals; used in reinforcement, barrier, self-assembly, sensing, and hydrogel composite research
Cellulose raw material	9004-34-6	M489093	Microcrystalline cellulose	ChP, JP, European Pharmacopoeia (Ph. Eur.), E 460(i), FCC, NF	Common cellulose source; can be used for preparing cellulose nanocrystals by acid hydrolysis and as a raw-material control
Cellulose raw material	9004-34-6	M489705	Microcrystalline cellulose	JP, European Pharmacopoeia (Ph. Eur.), E 460(i), FCC, NF	Representative microcrystalline cellulose raw material for preparing cellulose nanocrystals; used for batch stability and hydrolysis condition screening
Cellulose raw material	9004-34-6	C434462	Cellulose	Microcrystalline powder	Microcrystalline cellulose powder raw material; used for acid hydrolysis, oxidation treatment, and particle-size effect studies
Cellulose raw material	9004-34-6	C434461	Cellulose	Microcrystalline, powder, 20 μm	Fine-particle-size microcrystalline cellulose; used to investigate the influence of raw-material particle size on hydrolysis efficiency and nanocrystal dimensions
Cellulose raw material	9004-34-6	P494075	Powdered cellulose	JP, European Pharmacopoeia (Ph. Eur.), E 460(ii), FCC, NF	Powdered cellulose raw material; used for cellulose pretreatment, acid hydrolysis, and benchmark samples in composite materials
Cellulose raw material	9004-34-6	C1492476	Cellulose powder	Particle size: 65 μm	Cellulose powder with defined particle size; used for comparing raw-material particle size, hydrolysis rate, and dispersion behavior
Cellulose raw material	9004-34-6	C104844	Cellulose powder	Particle size: 250 μm	Coarse-particle-size cellulose powder; used for raw-material pretreatment, evaluation of pre-hydrolysis grinding effects, and particle-size gradient controls
Cellulose raw material	9004-34-6	C104843	Cellulose powder	≤25 μm	Fine-particle-size cellulose powder; used to increase reaction contact area and compare differences in hydrolysis products
Cellulose raw material	9004-34-6	C104841	Cellulose powder	Particle size: 90 μm	Medium-particle-size cellulose powder; used for preparation process screening and raw-material particle-size controls
Cellulose raw material	9004-34-6	C104842	Cellulose powder	Particle size: 50 μm	Fine powdered cellulose raw material; used for acid hydrolysis, oxidative modification, and powder dispersion experiments
Colloidal cellulose product	9004-34-6	C434460	Cellulose	Colloidal, microcrystalline, contains 10.0–20.0% sodium carboxymethylcellulose as stabilizer	Colloidal microcrystalline cellulose system; used as a control for dispersion stability, rheological regulation, and aqueous composite systems
Pharmaceutical-grade cellulose product	9004-34-6	GMP1491563	Tableting aid K (cellulose powder)	PharmPure™, JP, BP, European Pharmacopoeia (Ph. Eur.), NF	Pharmaceutical-grade cellulose powder; used for powder forming, tablet excipients, and cellulose-source controls
Pharmaceutical-grade cellulose product	9004-34-6	M489686	Microcrystalline cellulose	JP, European Pharmacopoeia (Ph. Eur.), NF, spheres	Spherical microcrystalline cellulose; used for pellet cores, formed granules, and cellulose particle structure controls
Pharmaceutical-grade cellulose product	_	M1373792	Microcrystalline cellulose pellet cores	_	Microcrystalline cellulose pellet cores; used for formulation carriers, particle forming, and research on cellulose-based carrier materials
Co-processed cellulose product	9004-34-6	S489679	Silicified microcrystalline cellulose	JP, European Pharmacopoeia (Ph. Eur.), colloidal anhydrous, E 460(i) and silica, E 551, NF	Silicified microcrystalline cellulose; used to study the influence of silica on powder flowability, formability, and composite structure
Co-processed cellulose product	_	M498254	Microcrystalline cellulose and sodium carboxymethylcellulose	European Pharmacopoeia (Ph. Eur.), E 460(i), E 466, NF	Composite product of microcrystalline cellulose and sodium carboxymethylcellulose; used for research on aqueous dispersion, colloidal stability, and rheological properties
Co-processed cellulose product	_	P1373788	Co-processed microcrystalline cellulose and sodium carboxymethylcellulose	_	Co-processed cellulose product; used to compare the influence of sodium carboxymethylcellulose on dispersion stability and forming performance
Co-processed cellulose product	_	P1373784	Co-processed microcrystalline cellulose and colloidal silicon dioxide	_	Co-processed product of microcrystalline cellulose and colloidal silicon dioxide; used for research on powder flowability, compression forming, and composite carriers

Table 2. Reagents for Cellulose Pretreatment, Bleaching, Hydrolysis, and Oxidative Preparation

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Cellulose pretreatment reagent	1310-73-2	S431793	Sodium hydroxide	Anhydrous grade, ≥98%, pellets	Used for alkali treatment of plant fibers, hemicellulose removal, cellulose purification, and raw-material activation
Cellulose pretreatment reagent	7722-84-1	H112519	Hydrogen peroxide solution (explosive precursor)	ACS, 30 wt. % in H₂O, contains stabilizer	Used for cellulose bleaching, oxidation-assisted treatment, and decolorization of cellulose raw materials
Cellulose pretreatment reagent	7758-19-2	S104904	Sodium chlorite	≥80%	Used for lignin removal, cellulose bleaching, and preparation of high-purity cellulose raw materials
CNC hydrolysis preparation reagent	7664-93-9	S399872	Sulfuric acid (controlled precursor chemical)	ACS, 95–98%	Classical acid hydrolysis reagent; used to prepare cellulose nanocrystals with sulfate ester groups on the surface
CNC hydrolysis preparation reagent	7647-01-0	H399545	Hydrochloric acid (controlled precursor chemical)	ACS, ≥37%	Acid hydrolysis reagent; used to prepare cellulose nanocrystals with low surface sulfate ester content
CNC organic acid hydrolysis reagent	144-62-7	O107179	Oxalic acid, anhydrous	Anhydrous grade, ≥99%	Organic acid hydrolysis reagent; used for green preparation of cellulose nanocrystals and research on carboxyl-related systems
CNC organic acid hydrolysis reagent	77-92-9	C108869	Citric acid, anhydrous	AR, ≥99.5% (T)	Organic acid treatment and crosslinking modification reagent; used for cellulose nanocrystal preparation, esterification, and green crosslinking research
CNC oxidative modification reagent	2564-83-2	T478495	TEMPO	Sublimed grade, ≥99%	Selective oxidation catalyst for cellulose; used to introduce carboxyl groups and improve water dispersibility
CNC oxidative modification reagent	7647-15-6	S433755	Sodium bromide	Anhydrous grade, ACS, ≥99%	Used together with TEMPO and sodium hypochlorite to form an oxidation system for cellulose surface carboxylation
CNC oxidative modification reagent	7681-52-9	S101636	Sodium hypochlorite solution	AR, 6–14% active chlorine basis	Oxidant in the TEMPO oxidation system; used for introducing carboxyl groups onto cellulose surfaces and assisting fiber disintegration
CNC oxidative modification reagent	7790-28-5	S755649	Sodium periodate	UltraBio™, ≥99.5% (RT)	Used for oxidation of vicinal diols in cellulose to prepare dialdehyde cellulose and reactive cellulose nanocrystals
CNC oxidative modification reagent	7727-54-0	A112448	Ammonium persulfate (APS)	AR, ≥98%	Oxidative hydrolysis and radical initiator reagent; used for cellulose nanocrystal preparation and graft polymerization

Table 3. Surface Esterification, Silanization, and Bioconjugation Reagents

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
CNC surface esterification reagent	108-24-7	A1506320	Acetic anhydride (controlled precursor chemical)	European Pharmacopoeia (Ph. Eur.), puriss. p.a., ISO, ACS, ≥99% (GC)	Used for acetylation modification of cellulose nanocrystals to improve hydrophobicity and polymer compatibility
CNC surface esterification reagent	108-30-5	S104823	Succinic anhydride	≥99%	Used for cellulose nanocrystal esterification and carboxyl group introduction, facilitating subsequent coupling and adsorption function design
CNC surface esterification reagent	108-31-6	M116389	Maleic anhydride	AR, ≥99% (GC)	Used to introduce carboxyl groups and unsaturated structures, improving the reactivity and interfacial bonding of cellulose nanocrystals
CNC silanization reagent	919-30-2	A107147	3-Aminopropyltriethoxysilane (APTS)	≥99%	Aminosilane coupling agent; used for cellulose nanocrystal amination, inorganic filler compositing, and interfacial reinforcement
CNC silanization reagent	2530-83-8	G107576	3-Glycidyloxypropyltrimethoxysilane	≥97%	Epoxy silane coupling agent; used for compositing cellulose nanocrystals with epoxy resins, coatings, and inorganic components
CNC hydrophobic silanization reagent	3069-42-9	T106562	Octadecyltrimethoxysilane (ODTMS)	≥90%	Long-chain silanization reagent; used for hydrophobic modification of cellulose nanocrystals and regulation of oil-water interfaces
CNC surface coating reagent	62-31-7	D103111	Dopamine hydrochloride	Moligand™, ≥98%	Used to construct polydopamine coatings, enhancing cellulose nanocrystal surface reactivity and multi-component composite capability
Bioconjugation reagent	25952-53-8	E106172	1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride	≥98%	Carboxyl-activating reagent; used for coupling carboxylated cellulose nanocrystals with amino-containing molecules
Bioconjugation auxiliary reagent	6066-82-6	H109330	N-Hydroxysuccinimide (NHS)	≥98%	Used together with carbodiimide hydrochloride to improve the coupling efficiency of carboxylated cellulose nanocrystals

Table 4. Products Related to Composite Material Matrices, Hydrogels, and Packaging Materials

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Natural polymer composite matrix	9012-76-4	C105802	Chitosan	Medium viscosity, 200–400 mPa·s	Forms polysaccharide composite films, hydrogels, and antibacterial materials with cellulose nanocrystals
Hydrogel and packaging material matrix	9002-89-5	P119362	Mowiol® PVA-124 polyvinyl alcohol (PVA)	Viscosity: 54–66 mPa·s	Hydrophilic polymer matrix; used for cellulose nanocrystal-reinforced films, hydrogels, and barrier materials
Natural polymer composite matrix	9005-38-3	S100126	Sodium alginate	Viscosity: 200 ± 20 mPa·s	Used with cellulose nanocrystals and calcium ions to construct ionically crosslinked hydrogels, microcapsules, and printing inks
Cellulose derivative matrix	9004-32-4	C104986	Sodium carboxymethylcellulose (CMC)	Viscosity: 1000–1400 mPa·s, USP grade	Water-soluble cellulose derivative; used for cellulose nanocrystal dispersion, thickening, film formation, and hydrogel compositing
Biodegradable composite material matrix	26100-51-6	P169115	Polylactic acid	Mw ~60,000	Biodegradable polymer matrix; used for cellulose nanocrystal reinforcement, barrier packaging, and green composite material research
Hydrogel crosslinking reagent	6902-77-8	G101204	Genipin	Moligand™, ≥98%	Bio-based crosslinking agent; used in chitosan, gelatin, and other systems to form composite hydrogels with cellulose nanocrystals
Hydrogel crosslinking reagent	111-30-8	G105905	Glutaraldehyde (50%)	AR, 50% in H₂O	Aldehyde crosslinking agent; used for crosslinking composite systems based on polysaccharides, proteins, and polyvinyl alcohol
Ionic crosslinking reagent	10043-52-4	C110766	Calcium chloride, anhydrous	AR, ≥96%	Ionic crosslinking agent for alginate; used in cellulose nanocrystal composite hydrogels, microspheres, and carrier materials

Table 5. Representative Products for Emulsion Interface Regulation and Conductive Sensing

Category	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Emulsion interface regulation reagent	151-21-3	S432157	Sodium dodecyl sulfate (SDS)	Anhydrous grade, ACS, ≥99%	Surfactant control; used to compare differences between particle-stabilized emulsions and surfactant-stabilized emulsions
Conductive composite material precursor	62-53-3	A112120	Aniline	AR, ≥99.5%	Polyaniline precursor; used in research on cellulose nanocrystal conductive composites, flexible sensing, and responsive materials

Note: The products above are representative Aladdin products. More product specifications can be searched on the Aladdin website by product name, CAS number, or catalog number.

References

[1] ISO/TS 20477:2023. Nanotechnologies — Vocabulary for cellulose nanomaterial. International Organization for Standardization, 2023.

[2] Abdelhamid H. N., et al. Comprehensive review of cellulose nanocrystals: preparation, properties, modifications and applications. Bulletin of the National Research Centre, 2025.

[3] Advancements in cellulose nanocrystals: A review of functionalization, applications, and challenges. International Journal of Biological Macromolecules, 2025.

[4] Nanocellulose Composite Films in Food Packaging Materials: A Review. Polymers, 2024.

[5] Multiscale study of the chiral self-assembly of cellulose nanocrystals during the frontal ultrafiltration process. Nanoscale, 2024.

[6] Roman M. Toxicity of Cellulose Nanocrystals: A Review. Industrial Biotechnology, 2015.

[7] Sustainable Pickering Emulsions with Nanocellulose: Innovations and Challenges. Foods, 2023.

[8] Singh S., Bhardwaj S., Tiwari P., Dev K., Ghosh K., Maji P. K. Recent advances in cellulose nanocrystals-based sensors: a review. Materials Advances, 2024.

[9] Recent Advances in Cellulose Nanocrystal Production from Green Methods. Processes, 2025.

[10] Xu Y., Xu Y., Chen H., Gao M., Yue X., Ni Y. Redispersion of dried plant nanocellulose: A review. Carbohydrate Polymers, 2022.

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