Acid-Resistant Plastics for Industrial Applications
Acid-resistant plastics offer critical solutions for applications, preventing material degradation, ensuring safety, and maintaining product integrity in challenging operating environments. Various plastic materials provide characteristics to resist chemical attack, to support applications across industries, extending product lifespans, and enabling key processes that include:
- Chemical and petrochemical processing
- Metal treatment processes
- Laboratory and safety equipment
- Manufacturing across various industries
- Industrial and municipal water treatment
Which Plastic Materials Provide the Best Acid Resistance for Applications?
When choosing a material for applications that expose components or assemblies to acidic environments, it is essential to select one that offers properties that resist degradation and ensure long-term performance. Plastic materials such as PTFE, PVDF, PEEK, and others are known for their acid resistance, providing suitable material solutions for applications where chemicals, acids, bases, or solvents are present.
PTFE
Also known as Teflon®, PTFE is a high-performance fluoropolymer that offers exceptional acid resistance. This material is chemically inert, making it nearly immune to attack from most acids, bases, and organic solvents. PTFE is insoluble in all solvents, except molten alkali metals and specific fluorinated or perfluorinated compounds and features a high degree of crystallinity to enhance its barrier properties against chemicals. Additionally, it offers exceptional thermal stability, maintaining its properties over a temperature range from -200°C to 260°C.
PVDF
With strong carbon-fluorine bonds, PVDF is resistant to a variety of strong inorganic acids. PVDF features low permeability to most gases and liquids, preventing chemical ingress in addition to its ability to withstand a wide range of corrosive substances and oxidizing agents. It also offers UV and weather resistance, along with thermal stability, to maintain performance in extreme outdoor conditions and withstand continuous service at temperatures up to 150°C without deforming. However, this material can degrade when exposed to concentrated alkalis, amines, or polar solvents at high temperatures.
PEEK
Polyetheretherketone, or PEEK, delivers acid resistance and performs well in environments or operations that use dilute inorganic and organic acids. It can handle percentages of hydrochloric acid, sulfuric acid, and nitric acid at ambient conditions without dissolving, swelling, or degrading, as well as resisting acetic and lactic acid. PEEK combines chemical stability with exceptional mechanical properties and thermal stability for chemical pipelines, valve linings, and more. While PEEK offers suitable acid resistance, it can be degraded by concentrated oxidizing acids, especially at high temperatures.
HDPE
High-density polyethylene, also known as HDPE, is a strong, versatile plastic with a non-polar, stable molecular structure that provides excellent resistance to acids, chemicals, and various bases. This material has a high-density construction, contributing to overall chemical resistance and low moisture absorption. Essentially impermeable and unreactive to chemicals, water, and solvents, HDPE is a highly reliable material for containment and piping. It is important to note that HDPE’s resistance can decrease at higher concentrations and temperatures, under stress, or in the presence of strong oxidizing agents.
ECTFE
Known by the brand name Halar®, ECTFE, or ethylene chlorotrifluoroethylene, is a fluoropolymer material offering superior chemical resistance, supported by high-temperature stability and good mechanical strength. ECTFE is resistant to a range of corrosive chemicals, including strong acids, chlorine, and caustics, providing a high-performance material for chemical processing, oil and gas, semiconductors, and the food and beverage industries. This material also demonstrates flame resistance and electrical properties and is available in FDA- and USDA-graded options for comprehensive solutions across various applications.
