3 Frequently Used Filter Membranes: Nylon, PES, and PP

In laboratory filtration, the choice of membrane material is critical for achieving reliable results. Different membranes offer unique chemical resistance, flow rates, and compatibility with various sample types. Among them, Nylon, PES (Polyethersulfone), and PP (Polypropylene) are three commonly used membrane materials.
Nylon, PES and PP Filter Membranes

Understanding the Differences Between Nylon, PES, and PP Filter Membranes

In laboratory filtration, the choice of membrane material is critical for achieving accurate, reliable, and reproducible results. Different filter membranes provide different chemical resistance, temperature tolerance, hydrophilicity, flow rate, and compatibility with various sample types.

Among the many membrane materials available, Nylon, PES (Polyethersulfone), and PP (Polypropylene) are three of the most frequently used membranes in laboratory, pharmaceutical, and industrial filtration.

This article introduces their material characteristics, performance advantages, and typical applications, helping laboratories and manufacturers select the most suitable membrane for their filtration needs.

Overview of Nylon, PES, and PP Filter Membranes

Filter membranes function as the core component of laboratory filtration systems. Their material composition determines:

  • Chemical compatibility
  • Temperature resistance
  • Filtration accuracy
  • Flow rate and throughput
  • Protein adsorption behavior
  • Application suitability

Nylon, PES, and PP membranes represent three highly versatile categories covering general laboratory filtration, pharmaceutical and biological filtration, and industrial deep filtration.

Nylon Filter Membrane

Versatile Hydrophilic Membrane for Aqueous and Organic Filtration

Nylon filter membrane is a naturally hydrophilic organic polymer microporous membrane with excellent chemical stability and moderate temperature resistance. It can effectively filter all aqueous solutions and most organic solvents, including alcohols, hydrocarbons, ethers, esters, and ketones.

Nylon membranes are also tolerant of many organic and inorganic compounds, including dilute acids and bases (pH 6–13). The maximum recommended working temperature is 85 °C at 1.5 bar.

HAWACH nylon filter membranes feature:

  • Pore size range: 0.1–10 μm
  • Thickness: 90–140 μm
  • PET support layer for enhanced mechanical strength
  • Excellent tear resistance
  • Extremely low extractables due to strict cleaning procedures
  • Precise pore size control for consistent filtration performance

These characteristics ensure effective filtration performance across a wide range of solvents.

Applications of Nylon Filter Membranes

Nylon membranes are widely used in three major sectors:

1. Laboratory Filtration

  • Sterile filtration of laboratory samples
  • Liquid chromatography pre-filtration and mobile phase filtration
  • Microbiological laboratory applications
  • Removal of micron-sized particles and colloids from laboratory water, organic solvents, and biological filtrates
  • Filtration of special laboratory solvents

2. Industrial Applications

  • Removal of suspended solids and large colloids in water treatment
  • Ultrapure water preparation for the microelectronics industry
  • Preparation of sterile water for food, beverage, and brewing industries
  • Removal of microorganisms, impurities, and odors

3. Pharmaceutical, Plastic, Biological, and Chemical Industries

  • Raw material purification
  • Process filtration
  • Removal of particulate impurities
  • Quality control testing

Nylon membranes are widely selected when broad chemical compatibility and reliable mechanical strength are required.

PES Filter Membrane (Polyethersulfone)

High-Performance Hydrophilic Membrane for Pharmaceutical and Biological Filtration

Polyethersulfone (PES) is synthesized through the condensation of 4,4′-disulfonyl diphenyl ether and diphenyl ether, catalyzed by anhydrous ferric chloride. PES exhibits excellent heat resistance, rigidity, and aging stability, with a long-term operating temperature of 180–200 °C.

Compared with polysulfone, PES offers higher thermal stability and mechanical strength. PES is typically an amorphous polymer, providing excellent dimensional stability.

PES membranes feature:

  • Natural hydrophilicity
  • High flux and throughput
  • Absolute filtration performance
  • Alkaline pH stability
  • Excellent chemical inertness
  • High compatibility with pharmaceutical compounds
  • Full autoclavability with integrity retention
  • Excellent shrinkage resistance, reducing membrane tearing and flow rate loss

PES membranes also exhibit very low protein adsorption, making them especially suitable for biological and pharmaceutical filtration.

Available pore sizes include: 0.1 μm, 0.22 μm, 0.45 μm, 0.65 μm, 0.8 μm, 1.2 μm, and more.

Applications of PES Filter Membranes

  • Pharmaceutical filtration and clarification
  • Food and beverage processing
  • Biological sample preparation
  • Cell culture media filtration
  • Protein and enzyme solutions
  • Sterile filtration where minimal sample loss is critical

PES membranes are widely recognized for applications requiring high flow rate, sterility assurance, thermal stability, and minimal adsorption.

PP Filter Membrane (Polypropylene)

Chemically Resistant Deep Filtration Membrane for Industrial and Analytical Use

Polypropylene (PP) is a semi-crystalline thermoplastic polymer known for its high impact resistance, strong mechanical properties, and excellent resistance to acids, bases, and many organic solvents. It is one of the most widely used polymer materials in industry.

PP filter membranes are manufactured by hot-melt bonding polypropylene microfibers, creating a deep filtration structure with high porosity and excellent contaminant-holding capacity.

HAWACH PP filter membranes feature:

  • Hydrophobic microporous structure
  • Excellent chemical compatibility with aqueous and alcoholic solutions
  • Manufactured from food-grade polypropylene
  • Additive-free production process
  • Stable physical and chemical properties
  • High porosity and large dirt-holding capacity
  • Back-flushable design
  • Resistance to high-temperature disinfection
  • Good pressure resistance

Available diameters: 13 mm, 25 mm, 47 mm, 90 mm, 142 mm, 293 mm

Available pore sizes: 0.1 μm, 0.22 μm, 0.45 μm, 0.65 μm, 0.8 μm, 1.0 μm, 3.0 μm, 5.0 μm, 10 μm

Applications of PP Filter Membranes

  • Filtration of aqueous and organic solutions
  • High-performance liquid chromatography (HPLC) sample preparation
  • Ion exchange chromatography sample filtration
  • Gas separation and air filtration
  • Photoresist and electronics manufacturing
  • Chemical process filtration

PP membranes are ideal for applications requiring strong chemical resistance, high flow, deep filtration capability, and long service life.

Conclusion

Nylon, PES, and PP membranes each offer distinct performance advantages:

  • Nylon membranes provide outstanding versatility and broad solvent compatibility.
  • PES membranes deliver high flow, thermal stability, sterility assurance, and low protein adsorption.
  • PP membranes offer superior chemical resistance, mechanical durability, and deep filtration performance.

Understanding these differences enables laboratories and manufacturers to select the most suitable membrane material for efficient, stable, and reliable filtration processes.