cellulose acetate; CA
It is a chemically modified natural polymer obtained by esterification of hydroxyl group in cellulose molecule with acetic acid. Its performance depends on the degree of acetylation.
Commercial products can be divided into general cellulose acetate (acetyl content 37%~
Use of different cellulose acetate
Use of different cellulose acetate
40%)。 Plasticizer is often added for injection molded parts such as toothbrush handle and brush. Cellulose acetate with high acetyl content (acetyl content 40%~42%), white granular, powdery or cotton solid. It is stable to light and is not easy to burn. It is stable in dilute acid, gasoline, mineral oil and vegetable oil. It swells in chloroform and dissolves in acetone, methyl acetate, etc. It can be eroded by dilute alkali. It has the advantages of toughness, transparency, luster, good melting fluidity and easy molding. In the dichloromethane homogeneous method, refined cotton linter and acetic anhydride are used, acetyl sulfuric acid is used as the catalyst, esterification is carried out in the presence of solvent dichloromethane, and partial hydrolysis is carried out to obtain cellulose acetate with a combined acetic acid content of 60% ± 0.5%. The traditional method is to dry the refined cotton linter, activate it with acetic acid, acetylate it with the mixture of acetic acid and acetic anhydride in the presence of sulfuric acid catalyst, then hydrolyze it with dilute acetic acid to its degree of substitution, neutralize the catalyst, precipitate, deacidify and wash it, and fine boil and dry it to obtain the finished product. Partially hydrolyzed cellulose diacetate, esterification degree γ Values 220-270. Unhydrolyzed, i.e. degree of esterification γ The value of 300 is called cellulose triacetate. Cellulose diacetate plastic can be used as various tool handles, alphanumeric keys of computers and typewriters, telephone casings, automobile steering wheels, textile equipment parts, radio switches and insulating parts, pen poles, spectacle frames and lenses, toys, daily sundries, etc. It can also be used as seawater desalination film. Cellulose triacetate, with high melting point, can only be prepared into solution for post-processing, and can be used as film substrate, X-ray film substrate, insulating film electromagnetic, tape recording, transparent container, separator in silver zinc battery, etc.
Cellulose acetate (hereinafter abbreviated as CA, or cellulose acetate) was first prepared in 1865 as the acetate of cellulose. CA is used as the base of photographic film and is one of the components of some adhesives; Also used as synthetic fibers.
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