A Detailed Introduction of Cellulose Acetate and CA Syringe Filters

Cellulose acetate is the earliest commercial production of cellulose derivatives, and the continuous development of cellulose organic acid esters. It is a chemically modified natural high polymer obtained after the hydroxyl group in the cellulose molecule is esterified with acetate. Commercially available products can be divided into general cellulose acetate (acetyl content of 37% to 40%). Plasticizers are often added for injection molding parts such as toothbrush handles, brushes, etc. Cellulose acetate with high acetyl content (40%~42% acetyl content), white granular, powdery or cottony solid. It can be eroded by dilute lye, tough, transparent and glossy and other advantages, good melt fluidity, easy to shape and process.

The dichloromethane homogeneous method adopts refined cotton linters and acetic anhydride, and uses acetylsulfuric acid as a catalyst to carry out esterification in the presence of the solvent dichloromethane, and partial hydrolysis to obtain acetic acid with a combined acetic acid content in the range of 60%±0.5% cellulose. The traditional method is to dry the purified cotton linters, activate them with acetic acid, acetylate them with a mixture of acetic acid and acetic anhydride in the presence of a sulfuric acid catalyst, and then add dilute acetic acid to hydrolyze them to the corresponding degree of substitution, neutralize the catalyst, precipitate, and deacidify. Washed, boiled and dried to obtain the finished product.

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Partially hydrolyzed is called diacetate cellulose, and the esterification degree γ value is 220~270. Unhydrolyzed, that is, the esterification degree γ value of 300 is called triacetate cellulose. 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 holders, spectacle frames and lenses, toys, daily necessities, etc. , can also be used as seawater desalination membrane. Cellulose triacetate has a high melting point and can only be processed after being formulated into a solution.

CA syringe filters

Cellulose acetate syringe filters are manufactured from pure cellulose acetate, which makes this membrane ideal for biological and clinical analysis, sterility testing, and scintillation measurements.The protein adsorption capacity of cellulose acetate membrane is very low. It is a hydrophilic membrane, suitable for aqueous solutions and alcohol (medium). Cellulose acetate syringe filters have improved solvent resistance, especially to low molecular weight alcohols, and enhanced thermal stability. Due to its high physical strength, the CA syringe filters can withstand high temperatures of 180 degrees, so it is suitable for hot gas and disinfection by various methods, while maintaining the integrity of the membrane.

Features of CA syringe filters

1. Uniform pores and high porosity
2. High flow rate and good retention effect
3. High strength, good biological inertness, stable chemical properties
4. Thin texture, small resistance, fast filtration
5. Good thermal stability, can withstand high temperature working environment
6. Hydrophilic membrane, large water flux
7. Excellent economy, the maximum use effect can be achieved at the lowest cost
8. Different specifications available, with the dismeter ranging from 4mm to 50mm and pore size from 0.1μm to 5.0μm.

Chemical Compatibility

In HPLC analysis, the column filler has a small particle size and is easily blocked by impurity particles. So, it’s necessary to filter the solvents and samples to remove contaminants and protect the syringe filter. The CA syringe filter commonly used in ion chromatography for environmental analysis also requires that inorganic contaminants are not introduced in sample pretreatment. Syringe filters can be used for HPLC analysis and IC analysis. Please note, the CA syringe filter is unsuitable for organic solvents filtration, such as the dichloromethane, acids, chloroform, NaOH and ketones and so on.

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