Overview
ISO 9782:1993 specifies an international standard for determining the apparent volatile-matter content in reinforced moulding compounds and prepregs made from plastics. This standard applies to all unidirectional and multidirectional fibre-reinforced prepregs with thermosetting resin matrices but excludes unimpregnated reinforcement fibres. The test measures the percentage of volatile matter lost from a specimen when heated in an air-ventilated oven under controlled temperature and time conditions. Understanding the apparent volatile-matter content is crucial for assessing the quality and processing behavior of reinforced plastics in manufacturing and industrial applications.
Key Topics
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Scope and Applicability
ISO 9782:1993 covers fibre-reinforced prepregs and thermosetting resin systems, including epoxy, phenolic, polyester, silicone, and polyimide resins. It does not apply to unimpregnated fibres or materials outside these parameters.
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Testing Principle
The apparent volatile-matter content is determined gravimetrically by measuring the mass loss of a test specimen after heating in an air-circulated oven at a specified temperature and duration.
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Sampling and Specimen Preparation
Specimens must have a minimum surface area of 100 cm² or a mass of at least 1 gram, and multiple samples should be taken from different locations on the material to ensure representative results.
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Test Conditions
Specimens are conditioned under normal atmosphere and heated typically between 125 °C and 160 °C depending on the resin type. The duration ranges from 15 to 60 minutes as per the resin-specific recommendations.
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Measurement and Calculation
The volatile-matter content is expressed as a mass percentage loss, calculated from the initial and final masses of the specimen, accounting for any protective sheets used during testing.
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Reporting
Test reports must include product identification, test conditions and procedures, the average volatile-matter content, any deviations from the standard method, and the date of the test.
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Limitations
The method excludes non-impregnated reinforcement fibers and may underestimate volatile content in certain resin types such as unsaturated polyester (UP). Additionally, moisture absorbed in aramid fibers should be corrected for to avoid skewed results.
Applications
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Quality Control in Composite Manufacturing
Measuring volatile-matter content helps manufacturers ensure that reinforced moulding compounds and prepregs are consistent in quality and meet processing requirements before being used in production.
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Material Specification and Compliance
This method supports material certification and compliance with industry standards by providing a standardized way to quantify volatile substances that can affect processing or final product properties.
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Process Optimization
Understanding volatile content aids in optimizing curing and moulding processes, preventing defects such as bubbling, delamination, or incomplete curing due to excessive volatile release during manufacturing.
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Research and Development
Developers of new composite materials use this testing to evaluate and compare different resin formulations and fibre reinforcement combinations under controlled volatile-matter release conditions.
Related Standards
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ISO 291:1977 – Plastics - Standard atmospheres for conditioning and testing. Often used in conjunction with ISO 9782 to establish the test atmosphere.
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ISO 4589 – Related testing for plastics flammability which may be relevant when assessing prepregs with volatile content influencing fire performance.
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ISO 11443 – Test method for prepregs determining resin content, complementing volatile matter content tests.
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ASTM D2584 – Similar method for volatile matter determination by thermogravimetric analysis in reinforced plastics.
Keywords
Plastics testing, reinforced moulding compounds, prepregs, volatile-matter content, thermosetting resins, fibre-reinforced composites, gravimetric method, ISO standards, composite quality control, volatile substances in plastics, conditioning atmosphere, resin curing.
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