Overview
EN ISO 22088-1:2006 (ISO 22088-1:2006) provides general guidance for selecting test methods to determine environmental stress cracking (ESC) resistance of thermoplastic materials. Published by CEN/ISO, this part describes the scope, principles and factors that affect ESC testing and points to specific test methods given in Parts 2–6. It is intended primarily as guidance for choosing an appropriate ESC test rather than as a prescriptive single test procedure.
Key topics and requirements
- Scope and purpose
- Guidance for selecting ESC test methods for thermoplastics; tests are essentially ranking tests, not direct design predictors.
- Principles of ESC
- Explains mechanisms (crazing, void growth, crack initiation) and parameters influencing ESC: specimen state, stress/strain, temperature, chemical environment, test duration and failure criteria.
- Test method overviews
- Part 2: Constant tensile load methods (methods A, B, C - including determination of rupture time or stress).
- Part 3: Bent strip (fixed flexural strain) method.
- Part 4: Ball or pin impression method.
- Part 5: Constant tensile deformation method.
- Part 6: Slow strain rate method.
- Specimen preparation and conditioning
- Emphasises consistent specimen dimensions, orientation, thermal history and preparation (references ISO 293, ISO 294-1, ISO 2818).
- Test conditions
- Guidance on test temperature, test medium (liquid, gas, paste, solid), and conditioning to ensure comparable results.
- ESC index and metrics
- Defines ESC indices (ratios comparing performance in a test medium vs reference medium, usually air) and other indicative properties used to rank susceptibility.
- Applicability and limitations
- Notes sensitivity to stress relaxation and that short-term laboratory tests may not directly predict complex in-service behaviour.
Applications and users
- Who uses it
- Materials scientists, polymer engineers, QA/QC laboratories, product designers, and R&D teams in plastics manufacturing and end-use industries (e.g., packaging, automotive, consumer goods, medical devices).
- Practical uses
- Material ranking and screening for ESC resistance, quality control of production batches, evaluating effects of moulding or processing conditions, and selecting suitable thermoplastics for environments involving chemicals or mechanical stress.
Related standards
- ISO 22088 series (Parts 2–6) - specific test methods
- ISO 293, ISO 294-1, ISO 2818 - specimen preparation and moulding
- Relevant material- and industry-specific test standards as required for application-specific assessment
Keywords: environmental stress cracking, ESC testing, thermoplastics, EN ISO 22088-1:2006, ESC index, plastics testing, constant tensile load, bent strip, pin impression, slow strain rate.
