Basic concept of cellulose ether

Cellulose ether refers to cellulose derivatives in which the hydroxyl groups on cellulose are partially or completely replaced by ether groups. The addition of cellulose ether can improve the performance of dry mixed mortar products and is an important additive in dry mixed mortar products.

Physical and chemical properties

Classification of cellulose ethers

① According to the different chemical structures of ether substituents, cellulose ethers can be classified into anionic, cationic, and nonionic ethers.

② Non ionic ethers are divided into water-soluble ethers and oil soluble ethers, and are mainly used in mortar products.

③ Monosubstituted ether refers to cellulose ether molecular chains with only one type of substituent, while mixed ether refers to cellulose ether molecular chains with two or more different substituents.

④ Ionic cellulose ethers are unstable in the presence of calcium ions. Due to their suspension stability and water retention properties, non-ionic water-soluble cellulose ethers are used in the building materials industry.

⑤ Cellulose ethers used in the building materials industry include methyl cellulose ether (MC), propyl methyl cellulose ether (HPMC), ethyl methyl cellulose ether (HEMC), ethyl cellulose ether (HEC), and ethyl ethyl cellulose ether (EHEC). In dry mix mortar products, HPMC and HEMC have been applied due to their own characteristics.

Specification

The synthesis mechanism of cellulose ether

Cellulose ether undergoes etherification under alkaline conditions. Firstly, cellulose reacts with alkaline solution to form swollen alkali cellulose, which then undergoes etherification reaction with etherification reagent. Mixed ethers can be prepared by adding different etherification reagents simultaneously or in segments.

The etherification reaction is as follows (Cell-O for cellulose):

In Reaction Formula 1: R-X is an inorganic acid ester, X is a halogen, and CL, R-C1, such as CH3 Cl, are used in industry. The reaction consumes an equivalent amount of base.

Reaction formula 2 involves the addition of an epoxide catalyzed by a base to the hydroxyl group of cellulose, without consuming any base (such as CH3); H2H5, etc.). This reaction can be carried out continuously.

(3) Production process

The production process of cellulose ether mainly consists of four parts: preparation of raw materials, alkalization, etherification neutralization, and post-treatment, as shown in the figure. The production process and control of process parameters of cellulose ether are the guarantee of the quality of cellulose ether products.

Packaging and Storage

Molecular Structure of Cellulose and Cellulose Ether

Methyl hydroxyethyl cellulose ether dissolved in water (as shown in the figure)

Molecular structure diagram of methyl hydroxyethyl cellulose ether