Introduction to Chemical Resistance Testing of Plastics
Plastic materials are used extensively across automotive, medical, chemical processing, packaging, electrical, consumer, and industrial applications. Their structural performance, however, can be significantly affected when they come into contact with aggressive reagents during manufacturing, storage, transportation, cleaning, or service. Conducting routine chemical resistance testing of plastics is essential to evaluate polymer compatibility, prevent environmental stress cracking, and verify long-term material integrity before real-world deployment.
Exposure to acids, alkalis, solvents, fuels, oils, detergents, and other chemical agents can cause changes in the physical appearance, dimensions, mass, hardness, flexibility, and mechanical properties of plastic materials. In some applications, chemical exposure may also contribute to cracking, swelling, embrittlement, or loss of structural integrity.
Chemical resistance testing provides a controlled method for evaluating how plastics and plastic components respond to specified chemical environments. Testing according to recognized standards generates comparative performance data that can support material selection, product development, quality control, risk assessment, and compliance activities.
Two widely referenced standards in this area are ASTM D543 and ISO 175, which provide procedures for evaluating the effects of chemical reagents and liquid chemicals on plastics.
What Is Chemical Resistance Testing of Plastics?
Chemical resistance testing evaluates the behavior of a plastic material or finished component after exposure to specified chemicals under controlled laboratory conditions.
Depending on the applicable standard and test requirement, specimens may be exposed to selected chemicals for a defined period and under specified conditions such as concentration and temperature. Changes before and after exposure are then evaluated.
Typical observations and measurements include:
- Change in mass or weight
- Dimensional change
- Surface appearance
- Cracking, crazing, blistering, or discoloration
- Hardness and flexibility
- Tensile strength and elongation
- Impact resistance
- Environmental stress cracking
- Other application-specific mechanical or physical properties
ASTM D543 provides procedures for evaluating the resistance of plastics to chemical reagents, while ISO 175 provides an international framework for determining the effects of liquid chemicals on plastics.
The selection of chemicals and exposure conditions should be based on the intended application and the actual environment in which the product is expected to operate.
Why Is Chemical Resistance Testing Important for Polymer Selection?
A plastic material may appear stable during brief contact with a chemical but may experience significant degradation after prolonged or repeated exposure. Laboratory testing helps identify such potential changes before a material or component is introduced into service.
Chemical resistance testing can support:
Material Selection
Testing helps manufacturers compare candidate materials and identify plastics suitable for specific chemical environments.
Product Development
Chemical exposure data can be used during product development to evaluate material choices, component designs, coatings, seals, and other polymer-based solutions.
Quality Control
Testing can provide comparative data for verifying consistency between materials, suppliers, formulations, or production batches.
Product Reliability
Understanding how a material responds to chemical exposure helps identify potential failure mechanisms such as swelling, cracking, embrittlement, or loss of mechanical strength.
Regulatory and Customer Requirements
Where applicable, standardized testing can provide documented technical evidence for customer specifications, regulatory submissions, qualification programs, and product certification activities.
Risk Assessment
Chemical resistance data can help engineers and manufacturers evaluate whether a material is appropriate for its intended chemical exposure conditions.
What Happens When Plastics Are Exposed to Aggressive Chemicals?
The response of a plastic to a chemical depends on several factors, including:
- Polymer type and formulation
- Chemical identity
- Chemical concentration
- Exposure temperature
- Exposure duration
- Mechanical stress
- Surface condition
- Component geometry
- Frequency of exposure
Depending on these conditions, chemical exposure may result in absorption, swelling, shrinkage, softening, embrittlement, discoloration, surface attack, cracking, or changes in mechanical properties.
For this reason, test conditions should be carefully selected to represent the intended application or the applicable product specification.
Key Parameters Evaluated During Chemical Resistance Testing
A chemical resistance evaluation may include several physical and mechanical parameters.
- Weight Change
- Dimensional Stability
- Appearance
Visual examination can identify:
- Cracking
- Crazing
- Blistering
- Discoloration
- Surface deposits
- Loss of gloss
- Other visible degradation
- Mechanical Property Retention.
- Environmental Stress Crack Resistance
- Hardness and Flexibility
Types of Plastics and Polymer Products Commonly Evaluated
Chemical resistance testing can be relevant to a wide range of polymeric materials and finished products.
Thermoplastics
Common materials include:
- Polypropylene (PP)
- Polyethylene (PE)
- Polycarbonate (PC)
- Acrylonitrile Butadiene Styrene (ABS)
- Polyamide (PA/Nylon)
- PETG
- Polyoxymethylene (POM)
- Polyvinyl Chloride (PVC)
- Polysulfone (PSU)
Relevant International Standards for Plastic Chemical Resistance (ASTM D543, ISO 175)
Several standards may be relevant depending on the material, application, and performance characteristic being evaluated.
ASTM D543
ASTM D543 addresses the resistance of plastics to chemical reagents and includes evaluation of changes such as weight, dimensions, appearance, and mechanical properties.
ISO 175
ISO 175 provides procedures for determining the effects of liquid chemicals on plastics, including exposure and evaluation of changes in properties.
ASTM D1693
ASTM D1693 is associated with environmental stress-cracking resistance of polyethylene under specified conditions.
ISO 22088
The ISO 22088 series addresses environmental stress cracking and related evaluation of plastics.
Other product- or application-specific requirements may also apply. For example, food-contact and medical applications can involve additional regulatory or performance requirements beyond general chemical resistance testing.
Important: The applicable standard, chemical, concentration, exposure duration, temperature, specimen configuration, and acceptance criteria should be defined before testing.
Conclusion: Ensuring Polymer Reliability in Chemical Environments
Chemical resistance testing of plastics is an essential process when selecting polymers for demanding applications involving exposure to fuels, oils, solvents, acids, or industrial cleaning agents. Comprehensive laboratory evaluation of physical, mechanical, and optical properties helps manufacturers prevent catastrophic field failures, ensure regulatory compliance, and deliver long-lasting products.
To discover how our material evaluation capabilities support your broader manufacturing needs, explore our complete chemical testing services or Contact METS Laboratories today to consult with our polymer testing specialists.
Standards such as ASTM D543 and ISO 175 provide structured methods for evaluating the response of plastics under defined chemical exposure conditions. The resulting data can support material selection, product development, quality control, qualification, and risk assessment.
However, meaningful chemical resistance evaluation depends on selecting representative chemicals and appropriate exposure conditions and interpreting results against the relevant product or application requirements.
METS Laboratories provides chemical resistance testing support for plastic and polymer materials based on applicable standards and customer-specific requirements. Contact our technical team to discuss your material, chemical exposure conditions, applicable standard, and testing requirements.
Frequently Asked Questions (FAQs)
What is chemical resistance testing of plastics?
What is ASTM D543?
What is ISO 175?
Does chemical resistance testing predict the complete service life of a plastic?
Which plastics can be tested?
How long does chemical resistance testing take?
Can finished plastic components be tested?
How should the test chemicals be selected?
Manufacturers and Exporters Recommend Us
Dedicated professionals committed to providing you with accurate and reliable testing services. Get METS Lab services today from the best lab experts & get the accurate reports from our laboratory.
