Chemical Properties
white powder
Uses
Coatings
Coatings for glass
Coatings for paper/paperboard
Consumer electronics
Electrical
Food packaging
Food-contact applications
Pressure sensitive tape
Wood sealers
Definition
ChEBI: Cellulose acetate is a glucan derivative obtained through the esterification of cellulose by acetic anhydride or acetic acid, resulting in the substitution of some of the hydroxy groups of cellulose by acetyl groups. It is used in a variety of applications including base material for photographic film, clothing, membrane filters, coatings, food packaging, and as a frame material for eyeglasses. It is a glucan derivative and an acetate ester.
Production Methods
Cellulose acetate is prepared from highly purified cellulose by
treatment with acid catalysis and acetic anhydride.
General Description
Cellulose acetate (CA) is a class of cellulose based esters which can be produced by a reaction of cellulose with acetic acid and acetic anhydride. It can be used in a variety of forms such as films, membranes, and fibers. It can be used as a biodegradable polymer in medical and automotive applications.
Agricultural Uses
Cellulose acetate is an ester in which cellulose (cotton
linters or wood pulp) is treated with a mixture of acetic
anhydride, acetic acid and concentrated sulphuric acid.
This solution, when treated with water, forms a
flocculent white mass of cellulose acetate which is used as
a fiber and in lacquers, non-breakable glass and
varnishes.
Pharmaceutical Applications
Cellulose acetate is widely used in pharmaceutical formulations
both in sustained-release applications and for taste masking.
Cellulose acetate is used as a semipermeable coating on tablets,
especially on osmotic pump-type tablets and implants. This allows
for controlled, extended release of actives. Cellulose acetate
films, in conjunction with other materials, also offer sustained
release without the necessity of drilling a hole in the coating as is
typical with osmotic pump systems. Cellulose acetate and other
cellulose esters have also been used to form drug-loaded microparticles
with controlled-release characteristics.
Cellulose acetate films are used in transdermal drug delivery
systems and also as film coatings on tablets or granules for
taste masking. For example, acetaminophen granules have been
coated with a cellulose acetate-based coating before being processed
to provide chewable tablets. Extended-release tablets can also be
formulated with cellulose acetate as a directly compressible matrix
former. The release profile can be modified by changing the ratio
of active to cellulose acetate and by incorporation of plasticizer, but
was shown to be insensitive to cellulose acetate molecular weight
and particle size distribution.
Therapeutically, cellulose acetate has been used to treat cerebral
aneurysms, and also for spinal perimedullary arteriovenous
fistulas.
Industrial uses
Cellulose acetate is an amber-colored, transparentmaterial made by the reaction of celluloseand acetic acid or acetic anhydride in the presenceof sulfuric acid.
It is thermoplastic and easily molded. Themolded parts or sheets are tough, easilymachined, and resistant to oils and many chemicals.In coatings and lacquers the material isadhesive, tough, and resilient, and does not discoloreasily. Cellulose acetate fiber for rayonscan be made in fine filaments that are strongand flexible, nonflammable, mildew proof, andeasily dyed. Standard cellulose acetate formolding is marketed in flake form.
In practical use, cellulose acetate moldingsexhibit toughness superior to most other general-purpose plastics. Flame-resistant formulationsare currently specified for small appliancehousings and for other uses requiring this property.Uses for cellulose acetate molding materialsinclude toys, buttons, knobs, and otherparts where the combination of toughness andclear transparency is a requirement.
Safety
Cellulose acetate is widely used in oral pharmaceutical products and
is generally regarded as a nontoxic and nonirritant material.
storage
Cellulose acetate is stable if stored in a well-closed container in a
cool, dry place. Cellulose acetate hydrolyzes slowly under
prolonged adverse conditions such as high temperature and
humidity, with a resultant increase in free acid content and odor
of acetic acid.
Incompatibilities
Cellulose acetate is incompatible with strongly acidic or alkaline
substances. Cellulose acetate is compatible with the following
plasticizers: diethyl phthalate, polyethylene glycol, triacetin, and
triethyl citrate.
Regulatory Status
Included in the FDA Inactive Ingredients Database (oral tablets).
Included in the Canadian List of Acceptable Non-medicinal
Ingredients.
