Summary
- PMP is rated better with
- Mineral acids (+66 points); Organic acids (+51 points); Salts and salt solutions (+24 points); Oxidising agents and halogens (+24 points); Alkalis (+24 points)
- Acetal (POM) is rated better with
- Aromatic hydrocarbons (+90 points); Halogenated hydrocarbons (+77 points); Vegetable and animal oils, fats, essential oils (+71 points); Fuels, mineral oils and aliphatic hydrocarbons (+66 points); Ketones and aldehydes (+54 points); Esters and ethers (+52 points); Amines and nitrogen compounds (+24 points)
- Within 10 points of each other
- Alcohols and glycols; Foods and beverages
Points are the difference in the share of rows rated A or B.
The two materials
PMP
Polymethylpentene (TPX)
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.
Rated rows: 416. A 55 %, B 6 %, C 7 %, D 32 %
Acetal (POM)
Polyoxymethylene (acetal)
Acetal (POM) resists many organic solvents and fuels. Strong acids and oxidising agents degrade it.
Rated rows: 956. A 41 %, B 32 %, C 12 %, D 15 %
Share of rows rated A or B, by chemical class
How often the two ratings agree
Chemical classes were assigned by this site, not by the source. Mixtures and trade products without a clear class are not counted.
By chemical class
| Chemical class | PMP: rated A or B | Acetal (POM): rated A or B |
|---|---|---|
| Mineral acids | 71 % (35 rows) | 5 % (63 rows) |
| Organic acids | 85 % (26 rows) | 34 % (64 rows) |
| Alkalis | 100 % (17 rows) | 76 % (21 rows) |
| Salts and salt solutions | 100 % (67 rows) | 76 % (197 rows) |
| Oxidising agents and halogens | 67 % (30 rows) | 43 % (63 rows) |
| Alcohols and glycols | 96 % (28 rows) | 96 % (57 rows) |
| Phenols | – | 0 % (14 rows) |
| Ketones and aldehydes | 37 % (27 rows) | 91 % (35 rows) |
| Esters and ethers | 36 % (42 rows) | 88 % (68 rows) |
| Amines and nitrogen compounds | 50 % (10 rows) | 74 % (38 rows) |
| Aromatic hydrocarbons | 10 % (10 rows) | 100 % (14 rows) |
| Fuels, mineral oils and aliphatic hydrocarbons | 30 % (37 rows) | 96 % (73 rows) |
| Vegetable and animal oils, fats, essential oils | 29 % (14 rows) | 100 % (45 rows) |
| Halogenated hydrocarbons | 3 % (33 rows) | 80 % (70 rows) |
| Foods and beverages | 100 % (13 rows) | 100 % (46 rows) |
Where the ratings differ most
Rows where the two ratings at 20 °C are at least two grades apart: 177 in total, the first 40 shown.
| Chemical | Concentration | PMP | Acetal (POM) |
|---|---|---|---|
| Acetic Acid | 90 % | A | D |
| Acetophenone | D | A | |
| Battery Acid | 38 % | A | D |
| Benzyl Alcohol | D | A | |
| Bromobenzene | D | A | |
| Chloroacetic Acid | A | D | |
| Chlorobenzene | D | A | |
| Chlorotoluene | D | A | |
| Chromic Acid | 10 % | A | D |
| Cyclohexane | D | A | |
| Decahydronaphthalene | D | A | |
| Dibutyl Ether | technical grade | D | A |
| Diethyl Ether | technical grade | D | A |
| Diisobutyl Ketone | technical grade | D | A |
| Diisobutylene | D | A | |
| Dipropyl Ketone | D | A | |
| DL-Limonene | D | A | |
| Epichlorohydrin | 100 % | D | A |
| Ethyl Acetate | 100 % | D | A |
| Ethylene Dichloride | D | A | |
| Formic Acid | 50 % | A | D |
| Formic Acid | 98-100 % | A | D |
| Hexachlorobenzene | D | A | |
| Hexachlorobutadiene | D | A | |
| Hexene | D | A | |
| Hydrochloric Acid | 1-5 % | A | D |
| Hydrochloric Acid | 20 % | A | D |
| Hydrochloric Acid | 35 % | A | D |
| Hydrochloric Acid | concentrated | A | D |
| Hydrofluoric Acid | 4 % | A | D |
| Hydrofluoric Acid | 50 % | A | D |
| Hydrogen Peroxide | 30 % | A | D |
| Hydrogen Peroxide | 90 % | A | D |
| Ferric Chloride (Iron(III) Chloride) | saturated | A | D |
| Isobutyl Acetate | D | A | |
| Isooctane | technical grade | D | A |
| Isopropyl Ether | technical grade | D | A |
| Methyl Ethyl Ketone (MEK) | D | A | |
| Nitric Acid | 1-10 % | A | D |
| Orange Peel Oil | D | A |
Rating scale
- A very good resistance
- B good resistance
- C limited resistance
- D not resistant
- – no data
- K no general statement possible
A rating marked * is an estimate in the source, not a test result. An estimate is given as one value without a temperature.
More comparisons
Frequently Asked Questions
Is PMP or Acetal (POM) more chemical-resistant?
Of 414 chemicals rated for both materials at 20 °C, PMP and Acetal (POM) share the same rating in 156 rows (38 %). PMP is rated better in 121 rows and Acetal (POM) in 137 rows.
How do PMP and Acetal (POM) compare for chemical resistance?
Based on 414 chemicals tested for both: PMP is rated better with Mineral acids, Organic acids, Salts and salt solutions, Oxidising agents and halogens. Acetal (POM) is rated better with Aromatic hydrocarbons, Halogenated hydrocarbons, Vegetable and animal oils, fats, essential oils, Fuels, mineral oils and aliphatic hydrocarbons. They perform similarly with Alcohols and glycols, Foods and beverages.
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.