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Acetal (POM) and Picric Acid: Chemical Resistance

Polyoxymethylene (acetal)

Rating

Concentration20 °C50 °CRemark
1 % aqueousC*–

* estimated rating, given in the source without a temperature

Material comparison at 20 °C

Picric Acid: Material comparison at 20 °CAcetal (POM): C (highlighted); Aluminium: A; FEP: A; Viton (FPM): A; HDPE: A; LDPE: A.Aluminium: AFEP: AViton (FPM): AHDPE: ALDPE: APP: APTFE: APVC Rigid: APVDF: ASS 304: ASS 316: AEPDM: CNBR: CNylon (PA): CPolycarbonate: CAcetal (POM): CPOMPVC Flexible: DECTFE/ETFE: –PETG: –PMP: –Polystyrene: –Polysulfone: –SAN: –Silicone: –
A very good resistanceB good resistanceC limited resistanceD not resistantno data
Each bar is one material. Taller bars indicate better resistance. The highlighted bar is the current material.

Resistance overview

Acetal (POM) has limited resistance (C) to Picric Acid at 1 % aqueous at 20 °C. This indicates that the chemical has a noticeable effect on the material, which may include visible swelling, softening, or a measurable loss of tensile strength. Use is generally limited to short-term or intermittent contact where full structural integrity is not required. The rating remains stable between 20 °C and 50 °C, which means this material can also handle moderately elevated process temperatures without additional risk.

Application context

Picric Acid is commonly encountered in surface cleaning and water treatment. Acetal (POM) (Polyoxymethylene (acetal)) is a thermoplastic typically used for tanks, piping, containers and liners. The compatibility between these two is therefore an important consideration for engineers and procurement teams selecting containment, transfer, or processing equipment.

Practical recommendation

Acetal (POM) has limited resistance to Picric Acid and should only be used for short-term or intermittent contact at ambient temperature. The C rating means the material undergoes noticeable changes — swelling, loss of strength, or surface degradation — that make it unsuitable for permanent installations. For prolonged or continuous exposure, HDPE, LDPE, PP offer significantly better resistance and are rated A.

Did you know?

Polyoxymethylene (acetal) was first developed in the 1950s and remains one of the most widely used thermoplastics in chemical handling equipment.

Materials rated A or B at 20 °C

Based on the row for 1 % aqueous, 20 °C.

Thermoplastics
HDPE A, PP A, PVC Rigid A, LDPE A
Fluoropolymers
PTFE A, PVDF A, FEP A
Elastomers
Viton (FPM) A
Metals
SS 316 A, SS 304 A, Aluminium A

About Acetal (POM)

Acetal (POM) resists many organic solvents and fuels. Strong acids and oxidising agents degrade it.

Rating scale

A rating marked * is an estimate in the source, not a test result. An estimate is given as one value without a temperature.

About this data

The ratings come from the chemical resistance list published by Bürkle GmbH, which compiled them from raw-material manufacturers’ data. They describe laboratory tests on the raw material at 20 °C and 50 °C.

A finished part also sees pressure, mechanical stress, welds and mixtures that a laboratory test does not. Treat the rating as a first filter and test under your own conditions before relying on it.