The difference between PES filter membrane and nylon microporous membrane

Polyethersulfone (PES) and nylon (NYLON) are both commonly used filter membrane materials. PES is a synthetic polymer composed of repeating units of ethylene, sulfur and oxygen. It is made of porous structure PES material, usually a film or Hollow fiber membrane form. Nylon, also known as polyamide, is a synthetic polymer composed of repeating units of amide groups. Nylon microporous filter membranes are made from a dense network of interconnected nylon fibers or a thin film of nylon material; each material has its own unique properties and suitable applications. Let’s briefly analyze their differences from several aspects:

1. Chemical compatibility:

PES membranes have excellent resistance to a wide range of chemicals and can withstand a pH range of 1 to 14, making them suitable for filtration of aqueous solvents and some organic solvents, and have good resistance to acids and alkalis.

Nylon membrane is also resistant to a variety of solvents, but its compatibility is not as good as PES. It can usually withstand a pH range of about 3 to 12-13. For example, it is not recommended to use nylon membrane with strong acids, strong bases or certain halogenated solvents, otherwise it will Degradation or deformation occurs.

2. Hydrophilicity:

PES membranes are naturally hydrophilic, meaning they have an affinity for water and can be easily wetted without the need for surfactants or wetting agents.

Nylon membranes are also hydrophilic; however, some types of nylon may need to be pre-moistened with alcohol before they can be used with aqueous solutions. For example, when using PA66 materials, they will show hydrophobic tendencies due to the manufacturing process or specific treatments. In this case, pre-wetting before use with a solvent such as alcohol (usually ethanol or isopropyl alcohol) will help overcome the initial surface tension and allow the membrane to wet more effectively when the aqueous solution is introduced before it can be combined with Used together with aqueous solutions, it is an important step in vacuum filtration.

3. Protein binding:

PES generally has lower protein binding capacity than nylon, making it a better choice for handling sensitive biological samples (minimizing protein loss). Protein binding capacity also varies based on process and application conditions, and is typically less than 20 µg. /cm² of protein.

Nylon microporous filter membranes generally have higher protein binding properties than PES membranes and are not the first choice if you want to reduce protein binding. The protein binding capacity varies greatly depending on various factors, such as those used in nylon filters. The binding capacity of membrane materials can reach 150-200 µg/cm² or even higher.

4. Thermal stability:

Both materials exhibit good thermal stability; however, PES generally has a higher temperature resistance than nylon, and its withstand temperature can reach 135-150°C, which makes it suitable for autoclaving, etc. Sterilization process; the temperature tolerance of the nylon membrane is 100-121°C.

5. Mechanical strength:

Both materials offer good mechanical strength, but due to their structural differences, they may behave differently under stress conditions (such as pressure differentials during filtration).

6.Application:

Although both can be used in a wide range of applications due to their multifunctional properties, PES membranes are generally used in the pharmaceutical/biotechnology industry, especially when low protein binding is required (such as sterile filtration/protein purification, etc.); Nylon membranes are mostly used in general laboratory work/environmental sample analysis/chemical filtration industries.