Overview
ISO 10147:2011 is an international standard specifying a reliable method for estimating the degree of crosslinking in crosslinked polyethylene (PE-X) pipes and fittings. This estimation is achieved through the determination of gel content by solvent extraction. Crosslinking enhances the thermal, mechanical, and chemical resistance properties of polyethylene, making PE-X materials highly suitable for various fluid transport applications. Accurate measurement of crosslink density is critical for quality control and ensuring performance compliance with product and system standards.
Key Topics
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Scope
ISO 10147:2011 provides a standardized test method to assess the degree of crosslinking in PE-X pipes and fittings by measuring the insoluble gel fraction after solvent treatment.
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Principle of the Test
A test piece is weighed before and after immersion in xylene solvent. The insoluble fraction (gel content) is calculated as a percentage of the original mass to express the degree of crosslinking.
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Test Solvent
The standard uses xylene (≥98% purity) mixed with 1% antioxidant to prevent degradation during the boiling extraction phase. Proper safety measures must be followed due to xylene's harmful and flammable nature.
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Required Apparatus
- Reflux condenser
- Round-bottomed flask (≥500 ml)
- Heating mantle capable of boiling xylene
- Wire mesh cage for holding test specimens
- Lathe or microtome for sample preparation
- Vacuum or forced-ventilation oven for drying
- Precision balance with 1 mg accuracy
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Sample Preparation
Slices or shavings of about 0.2 mm thickness are machined from the full wall thickness of pipes or fittings, ensuring representative cross-sectional sampling.
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Testing Procedure
Samples are immersed in boiling xylene for 8 hours under reflux conditions, followed by drying and weighing to determine gel content.
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Result Calculation
Degree of crosslinking (G) is calculated as the percentage of insoluble gel content based on weight changes, accounting for fillers where present. Results are reported per specimen and averaged across samples.
Applications
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Quality Control in PE-X Manufacturing
Ensuring consistent crosslinking levels is essential to meet mechanical and thermal performance requirements in pipes and fittings used for heating, plumbing, and industrial fluid systems.
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Material Development
Enables manufacturers and researchers to evaluate the effectiveness of crosslinking processes and optimize formulations for enhanced durability and chemical resistance.
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Compliance Verification
Serves as a benchmark test referenced by product and system standards to confirm material suitability in safety-critical applications such as hot and cold water distribution.
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Failure Analysis and Troubleshooting
Helps identify substandard or improperly crosslinked PE-X products contributing to premature pipe or fitting failures.
Related Standards
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ISO 15875 (Plastic Piping Systems for Hot and Cold Water Installations)
Defines performance requirements for PE-X piping systems where gel content testing is referenced for material qualification.
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ISO 17475 (Plastics Piping Systems – Determination of Crosslinking Degree)
Covers complementary or alternative methods for crosslink density assessment.
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ASTM F2623
Provides guidelines for gel content determination in crosslinked polyethylene, often used alongside or as an alternative to ISO 10147.
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ISO/IEC Directives, Part 2
Governs the development and formulation of international standards such as ISO 10147.
Keywords: ISO 10147:2011, crosslinked polyethylene, PE-X pipes, gel content, degree of crosslinking, solvent extraction, xylene, pipe fitting standards, polymer crosslinking test, PE-X quality control, plastic piping standards, crosslink density measurement.
Open preview (PDF)Pipes and fittings made of crosslinked polyethylene (PE-X) — Estimation of the degree of crosslinking by determination of the gel content