Related Information

Before measuring POM samples with the VM-E01, you may also want to know:

Common Questions About POM and Plastics

WKT-A9 Karl Fischer Trace Moisture Analyzer Coulometric

Reference Value Determination

The POM reference moisture value was determined with the VicoMeter WKT-A9 Karl Fischer moisture analyzer and WKT-V2 Karl Fischer oven; released moisture is carried by dry nitrogen into the electrolytic cell.

Recommended Settings for Plastics Industry Samples

If you have no reference method for plastics samples on the VM-E01, VicoMeter recommends these settings from experimental experience:

• Heating mode: Standard

• Shutoff mode: Automatic (1 mg/140 s)

• Sample size: 30 g

• Resolution: High (0.1 mg/0.0001 g)

• Warm-up: standby, 100°C; at standby temperature, preheat the empty pan for 1 minute, then tare.

Selecting the Drying Temperature

Figure 1: Same Sample Heated at Different Temperatures

(Click image to enlarge)

Choose a drying temperature matching the Karl Fischer reference value. Melting or marked color change means the temperature is too high. Some samples inevitably discolor when heated (polyamide unavoidably turns brown).

Figure 1 compares samples after two heating runs. Left: correct temperature — no melting or discoloration. Right: the sample browned, so the temperature was too high.

Plastic Sample Handling

Measure samples promptly. Otherwise, fill the container completely (use a smaller one if needed) and seal it to minimize air and prevent moisture uptake during storage.

Operating Steps for POM (Polyoxymethylene) Samples

Place the VM-E01 in a suitable spot, warm up 30 min, level it (bubble centered), and perform weighing and temperature calibration. Then measure POM samples (installation, environment, warm-up, calibration: seePreparation Before Formal Measurement with a Halogen Moisture Analyzeras discussed in that article; click the link to learn more.).

Tare Sample Pan

1. Place the empty pan on the center holder, preheat 1 min at 130°C standby, press tare to zero.

Add Sample

2. Quickly spread about 30 g of POM sample evenly on the pan; wait for a stable reading.

One-Touch Start

3. Press start; the POM moisture result appears within minutes.

Test Data

VM-E01 Halogen Moisture Analyzer（0.1mg/0.0001g）

VM-E01 Settings Reference

• Heating mode: Standard

• Heating Temperature: 130°C

• Shutoff mode: Automatic (1 mg/140 s)

• Sample size: 30 g

• Resolution: High (0.1 mg/0.0001 g)

• Warm-up: standby, 100°C; at standby temperature, preheat the empty pan for 1 minute, then tare.

Sample Information

• Sample Description: POM, beige, high strength, good corrosion resistance, thermal stability, oxidation resistance, low hygroscopicity.

• Typical Maximum Allowable Moisture Content [%]: 0.2

• Hygroscopicity (23°C/50% rH) [%]: 0.2

Moisture Chart for POM Samples Before and After Drying

Chart Notes

Moisture Data for POM Samples Before and After Drying

Sample-Specific Test Notes

Maximum allowable moisture for pellet processing must always follow supplier specifications. Values here are typical only and may not suit your material or process.

These drying parameters were obtained on common plastics and do not cover all grades or colors; optimizing them may be needed for best results on a specific material.

Dr. Wei's Classroom

Polyoxymethylene (POM), also known as acetal resin, polyoxymethylene, or polyacetal, is a thermoplastic crystalline polymer hailed as "super steel" or "steel-like plastic."

POM is a high-performance engineering plastic, known abroad as a "steel substitute" or "super steel." With metal-like hardness, strength, and rigidity, excellent self-lubrication over wide temperature and humidity ranges, good fatigue resistance, elasticity, and good chemical resistance, POM is replacing zinc, brass, aluminum, and steel parts at lower cost than many other engineering plastics. It is widely used in electronics and electrical, machinery, instrumentation, consumer goods, automotive, building materials, and agriculture, with strong growth in medical technology and sports equipment.

Widely used for sliding and rotating parts — gears, levers, pulleys, sprockets, and especially bearings; hot water valves, precision metering valves, conveyor links and rollers, flow meters, automotive interior/exterior handles, cranks and window mechanisms, oil pump seats and impellers, gas switch valves, electronic switch parts, fasteners, terminals, mirror covers, fan parts, heating plates, instrument knobs; audio/video tape bearings; pipes and agricultural irrigation systems, valves, nozzles, faucets, bathtub parts; switch keypads, buttons, tape reels; temperature control timers; power and garden tool parts; surfboard, sailboat, and sled parts; watch micro-gears, sports equipment frames, backpack buckles, fasteners, lighters, zippers, clasps; pacemakers, artificial heart valves, spinal implants, and prosthetics.

Used in chemical and pharmaceutical synthesis, including synthesis using anhydrous formaldehyde as a raw material.