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PMP and Sodium Hydroxide (Caustic Soda): Chemical Resistance

Polymethylpentene (TPX)

Rating

Concentration20 °C50 °CRemark
1 %AA
30 %A–
45 %A–
50 %AA
60 %A–
concentrated––

Material comparison at 20 °C

Sodium Hydroxide (Caustic Soda): Material comparison at 20 °CPMP: A (highlighted); EPDM: A; HDPE: A; LDPE: A; Nylon (PA): A; PP: A.EPDM: AHDPE: ALDPE: ANylon (PA): APMP: APMPPP: APolystyrene: APolysulfone: APTFE: ASS 304: ASS 316: ANBR: BViton (FPM): CAcetal (POM): CAluminium: DPolycarbonate: DPETG: DPVDF: DECTFE/ETFE: –FEP: –PVC Rigid: –PVC Flexible: –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

PMP shows excellent resistance to Sodium Hydroxide (Caustic Soda) across all 5 tested concentrations (1 %, 30 %, 45 %, 50 %, 60 %) at 20 °C, making it a reliable choice for storage, transfer, and handling applications involving this chemical at any of the tested strengths. 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

Sodium Hydroxide (Caustic Soda) is commonly encountered in water treatment and pulp and paper. PMP (Polymethylpentene (TPX)) is a thermoplastic typically used for tanks, piping, containers and liners. Because Sodium Hydroxide (Caustic Soda) is classified as corrosive, the choice of containment material is especially critical to prevent leaks, equipment damage, and safety hazards.

Practical recommendation

PMP can be used with confidence for Sodium Hydroxide (Caustic Soda) containment and handling. The A rating indicates that the material shows no significant change in weight, dimensions, or mechanical properties after prolonged contact under test conditions. This holds true at both 20 °C and 50 °C, giving a good safety margin for typical process environments.

Did you know?

Polymethylpentene (TPX) was first developed in the 1960s 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 60 %, 20 °C.

Thermoplastics
HDPE A, PP A, LDPE A, Nylon (PA) A, Polystyrene A, Polysulfone A
Fluoropolymers
PTFE A
Elastomers
EPDM A, NBR B
Metals
SS 316 A, SS 304 A

About PMP

Polymethylpentene (TPX) is a transparent polyolefin used for labware. It resists many acids and alkalis, while aromatic and chlorinated solvents and strong oxidisers attack 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.