Cellulose acetate is a versatile material derived from cellulose. It is used in various applications like textiles, films, and eyewear due to its excellent durability, transparency, and biodegradability.
| IUPAC Name | Cellulose acetate |
| Molecular Formula | (C6H7O2(OH)3/2)n |
| CAS Number | 9004-35-7 |
| Synonyms | Acetate cellulose, Acetylcellulose, Acetocell, Cellitose |
| InChI | InChI=1S/C6H7O2.C4H6O2/c1-4(7)8-6-3-2-5(6)9;1-3(2)4/h2-3,6H,1H3;1-2H3 |
Cellulose Acetate Properties
Cellulose Acetate Formula
The formula of cellulose acetate is (C6H7O2(OH)3/2)n. It is derived from cellulose by replacing some hydroxyl groups with O(CO)CH3 groups. This formula represents the repeating unit structure of cellulose acetate polymer.
Cellulose Acetate Molar Mass
The molar mass of acetylcellulose can vary depending on the degree of polymerization. On average, it ranges from several thousand to over a hundred thousand grams per mole. The molar mass affects the physical properties and behavior of acetylcellulose.
Cellulose Acetate Boiling Point
Acetylcellulose has a relatively high boiling point, typically ranging from 260 to 350 degrees Celsius. This temperature range is necessary for processing and shaping acetylcellulose materials, such as in the production of fibers, films, and other industrial applications.
Cellulose Acetate Melting Point
Acetylcellulose has a moderate melting point, typically around 200 to 260 degrees Celsius. This temperature range allows for easy melting and shaping of acetylcellulose materials during manufacturing processes.
Cellulose Acetate Density g/mL
The density of acetylcellulose varies depending on its specific formulation and degree of polymerization. Generally, the density ranges from 1.27 to 1.34 grams per milliliter. This density contributes to the lightweight nature of acetylcellulose products.
Cellulose Acetate Molecular Weight
The molecular weight of acetylcellulose depends on its degree of polymerization. It typically ranges from several thousand to over a hundred thousand grams per mole. The molecular weight influences various properties of acetylcellulose, including its mechanical strength and solubility.
Cellulose Acetate Structure
The structure of acetylcellulose consists of glucose units linked together through glycosidic bonds. O(CO)CH3 groups are attached to some of the hydroxyl groups, resulting in a partially substituted cellulose chain. This structure gives acetylcellulose its unique properties.
Cellulose Acetate Solubility
Acetylcellulose is soluble in a wide range of solvents, including acetone, ethyl acetate, and chloroform. This solubility allows for easy processing and fabrication of acetylcellulose materials into various forms such as films, fibers, and coatings.
| Appearance | White solid |
| Specific Gravity | 1.27 – 1.34 g/mL |
| Color | Colorless to pale yellow |
| Odor | Odorless |
| Molar Mass | Several thousand – over 100,000 g/mol |
| Density | 1.27 – 1.34 g/mL |
| Melting Point | 200 – 260°C |
| Boiling Point | 260 – 350°C |
| Flash Point | > 150°C |
| Water Solubility | Insoluble |
| Solubility | Soluble in acetone, ethyl acetate, chloroform |
| Vapour Pressure | Negligible |
| Vapour Density | Not available |
| pKa | Not available |
| pH | Not applicable |
Cellulose Acetate Safety and Hazards
Acetylcellulose is generally considered safe for common uses, with low toxicity and minimal health risks. However, it is important to handle it responsibly. Direct contact with acetylcellulose fibers or films may cause mild skin and eye irritation in some individuals. During processing or manufacturing, it is advisable to maintain good ventilation to prevent inhalation of fine particles or vapors. Combustible acetylcellulose materials can ignite if exposed to open flames or high heat, producing irritating and potentially toxic fumes. Proper storage, handling, and disposal procedures should be followed to minimize any potential hazards and ensure safety in working environments.
| Hazard Symbols | None |
| Safety Description | Acetylcellulose is generally considered safe when handled properly. Avoid direct contact with eyes and skin. Maintain good ventilation during processing. Store in a cool, dry place away from open flames. Follow proper handling, storage, and disposal procedures. |
| UN IDs | Not applicable |
| HS Code | 3912.39.00 |
| Hazard Class | Not classified as hazardous |
| Packing Group | Not applicable |
| Toxicity | Low toxicity |
Cellulose Acetate Synthesis Methods
Various methods can synthesize acetylcellulose. One common method involves esterifying cellulose with acetic anhydride or acetic acid in the presence of a catalyst. In this process, hydroxyl groups of cellulose react with acetyl groups from acetic anhydride, substituting hydroxyl groups with -O(CO)CH3 groups. Controlled conditions of temperature and time achieve the desired degree of substitution.
Another approach uses cellulose derivatives, such as cellulose triacetate or cellulose diacetate, as starting materials. These derivatives are obtained by partially or fully acetylating cellulose. Reacting these derivatives with acetic anhydride or acetic acid produces acetylcellulose.
Alternatively, direct acetylation of cellulose with acetic anhydride and a strong acid catalyst can synthesize acetylcellulose. This method eliminates the need for pre-modified cellulose derivatives.
Each synthesis method offers its own advantages and considerations in terms of reaction conditions, degree of substitution, and the properties of acetylcellulose. The choice of synthesis method depends on specific application requirements and desired properties of the acetylcellulose product.
Cellulose Acetate Uses
Acetylcellulose finds applications in various industries due to its versatile properties. Here are some common uses of acetylcellulose:
- The textile industry utilizes acetylcellulose fibers to produce fabrics with a luxurious feel, high luster, and excellent drapability.
- Acetylcellulose films find employment in the production of photographic films, as well as in packaging, laminating, and graphic arts applications.
- Manufacturers widely employ acetylcellulose in the production of eyeglass frames due to its lightweight nature, durability, and ability to mold into different shapes and colors.
- Producers use acetylcellulose in cigarette filters to effectively trap harmful particulate matter.
- Various applications such as paints, varnishes, and lacquers utilize acetylcellulose as a coating material.
- Filtration processes such as reverse osmosis and ultrafiltration employ acetylcellulose membranes for water purification and separation of substances.
- Industries such as woodworking and packaging use acetylcellulose-based adhesives for their good bonding properties.
- Medical applications, including wound dressings, drug delivery systems, and tissue engineering scaffolds, utilize acetylcellulose.
- The production of consumer goods like hairbrushes, combs, and handles for kitchen utensils incorporates acetylcellulose.
- Packaging materials, including blister packs and acetylcellulose bags, employ acetylcellulose due to its transparency and moisture resistance.
The diverse range of applications highlights the versatility and widespread use of acetylcellulose in numerous industries.
Questions:
Q: Is cellulose acetate biodegradable?
A: Yes, Acetylcellulose is biodegradable, meaning it can be broken down by natural processes over time.
Q: Is cellulose acetate polar or nonpolar?
A: Acetylcellulose is polar due to the presence of acetate groups, which impart some polarity to the molecule.
Q: Will methanol dissolve cellulose acetate?
A: Yes, methanol can dissolve acetylcellulose due to its ability to disrupt the intermolecular forces within the polymer.
Q: Can cellulose acetate stick to another negative?
A: No, acetylcellulose does not have inherent adhesive properties and typically requires additional adhesive agents to stick to other surfaces.
Q: How to prevent hydrolysis of cellulose acetate sheet?
A: To prevent hydrolysis of acetylcellulose sheet, it should be stored in a dry environment, away from moisture and high humidity conditions.
Q: How to make cellulose acetate?
A: Acetylcellulose can be made by acetylating cellulose using acetic anhydride or acetic acid in the presence of a catalyst, followed by purification and processing steps.
Q: How to make cellulose acetate jewelry?
A: Acetylcellulose jewelry can be made by cutting, shaping, and polishing acetylcellulose sheets or beads, and then assembling them into desired jewelry designs.
Q: Is cellulose acetate toxic?
A: Acetylcellulose is generally considered to have low toxicity and is safe for common uses when handled properly.
Q: What is cellulose acetate made of?
A: Acetylcellulose is made from cellulose, a natural polymer derived from plant sources, through a chemical modification process that introduces -O(CO)CH3 groups onto the cellulose structure.