ASTM D570 Water Absorption of Plastics Test

ASTM D570 is a test method to calculate the relative Water Absorption of plastics in 24 Hours when immersed in water under equilibrium conditions. This test method for rate of water absorption has two main purposes: first, as a guide to the amount of water absorbed by a material. Second, as a control test on the uniformity of a product. Results help to evaluate the material performance in water or humid conditions come across during application.

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ASTM D570 Water Absorption of Plastics Test

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Overview
Scope, Applications, and Benefits
Test Process
Specifications
Instrumentation
Results and Deliverables

Overview

ASTM D570 evaluates the water absorption characteristics of plastics by measuring the amount of water absorbed under specified immersion conditions. It determines how exposure to water affects material properties such as weight, dimensional stability, and mechanical performance over time. This test is essential for understanding moisture sensitivity and long-term durability of plastic materials.

The method is widely used to assess how plastics behave in humid or submerged environments, where moisture uptake can lead to swelling, reduced strength, or degradation. By providing quantitative absorption data, ASTM D570 helps manufacturers select suitable materials, optimize formulations, and ensure consistent performance in applications exposed to moisture or water.

Scope, Applications, and Benefits

Scope

ASTM D570 covers the determination of water absorption of plastics under controlled immersion conditions. It focuses on measuring weight change and evaluating the effect of moisture on material properties.

Applicable to various plastic materials
Measures water absorption percentage
Uses immersion in water for defined durations
Evaluates dimensional and weight changes
Supports material selection and quality control

Applications

Plastic material selection for humid environments
Electrical insulation performance evaluation
Automotive and outdoor component testing
Packaging material analysis
Construction and piping applications
Consumer product durability assessment
Research and development studies

Benefits

Determines moisture resistance of plastics
Supports long-term durability assessment
Helps prevent material degradation
Improves product reliability
Enables material comparison
Ensures consistent quality

Test Process

Specimen Preparation

Specimens are dried at a specified temperature, cooled in a desiccator, and weighed before immersion.

Immersion Conditioning

Samples are placed in water, typically at 23°C for 24 hours or until equilibrium is reached.

Post-Immersion Handling

Specimens are removed, surface-dried with a lint-free cloth, and weighed immediately.

Absorption Measurement

Water absorption is calculated based on the percentage weight gain; results also help evaluate product uniformity.

Technical Specifications

Parameter	Details
Specimen Type	Molded plastic disks (50.8 mm diameter × 3.2 mm thickness) preferred
Sheet Thickness	Typically, 0.13 mm sheets for cut specimens
Sample Preparation	Injection molded or cut from sheets, plates, rods, or tubes
Conditioning Temperature	Usually 23°C
Exposure Duration	Typically, 24 hours or until moisture equilibrium
Test Output	Water Absorption %, Moisture Influence on Mechanical & Electrical Properties

Instrumentation Used for Testing

Analytical balance
Drying oven
Water bath or immersion tank
Desiccator
Measuring tools (calipers, micrometer)
Timer
Sample handling tools

Results and Deliverables

Water absorption percentage
Initial and final weight data
Dimensional change observations
Material performance assessment
Compliance evaluation
Detailed test report

Why Choose Infinita Lab for ASTM D570?

With Infinita Lab (www.infinitalab.com), you are guaranteed a Nationwide Network of Accredited Laboratories spread across the USA, the best Consultants from around the world, Convenient Sample Pick-Up and Delivery, and Fast Turnaround Time.

Our team understands the stakes and subtleties of every test. Whether you’re validating a new Product, de-risking a prototype, or navigating complex compliance requirements, our specialists guide the process with rigor and clarity.

Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you. Request a Quote

Frequently Asked Questions

Water absorption determines the amount of water absorbed under specified conditions. Factors affecting water absorption include the type of plastic, additives used, temperature, and length of exposure.

ASTM D570 is important because it quantifies water absorption, which directly affects dimensional stability, mechanical strength, and electrical properties. Understanding moisture uptake helps manufacturers ensure material reliability in environments exposed to humidity, water immersion, or outdoor conditions.

ASTM D570 measures the percentage increase in weight due to water uptake, indicating how much moisture a plastic can absorb and how it may affect performance under wet or humid conditions.

ASTM D570 results are influenced by material composition, sample thickness, immersion time, temperature, and conditioning, all of which must be controlled for accurate and repeatable measurements.

ASTM D570 uses defined immersion durations to evaluate both short-term and long-term water absorption behavior, providing insight into how materials perform over time.

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