Overview
ISO 1875:1982 specifies a laboratory method for the determination of the percentage of matter extractable by diethyl ether from plasticized cellulose acetate. The method applies to samples in any form (moulding material, sheet, manufactured articles). The procedure converts the plasticized sample to a cast film, extracts soluble matter in a Soxhlet apparatus using diethyl ether, removes the solvent by heating under vacuum and determines the mass of the residual extract. Note: the extract consists principally of the plasticizer.
Key Topics
- Scope and applicability: method applicable to plasticized cellulose acetate in any physical form.
- Reagents and solvents: use analytical-grade solvents. For film preparation a 90:10 (v/v) mixture of dichloromethane and methanol is specified for dissolution. Diethyl ether used for extraction must be free of peroxides.
- Sample preparation: typically 10 ±0.2 g of sample is dissolved in 100 ±2 ml of the dichloromethane/methanol mixture and cast to produce a film of about 0.1 mm thickness on a glass plate (~200 mm × 400 mm, 4 mm thick). After solvent evaporation the film is cut into strips for extraction.
- Extraction apparatus and conditions: a Soxhlet extractor with a 250 ml flask and suitable cartridge is used. Around 2 g of prepared film is placed in the cartridge and extracted with approximately 200 ml diethyl ether. Extraction is carried out for 3 hours on a water bath.
- Drying and weighing: remove most ether by aspiration, then dry the extract-containing flask in a vacuum oven at 50 ±2 °C for 2 hours, cool in a desiccator and weigh to 0.001 g. The cartridge is dried 30 minutes at 50 ±2 °C under vacuum, then 3 hours at 105 ±2 °C, cooled and weighed.
- Modes A and B: the standard defines alternative preparatory modes (freshly prepared sample versus pre-dried sample); results are reported accordingly.
- Reporting and calculation: extractable matter is reported as mass percent. The final reported value is the arithmetic mean of two determinations. The test record should include standard reference, full product identification, percentage extractables, and mode used.
Applications
- Quality control: routine assessment of plasticizer content and extractables in raw materials and finished articles.
- Material safety and compliance: verification of leachable components relevant to product safety, regulatory compliance and formulation stability.
- Development and acceptance testing: comparative testing during formulation trials or batch acceptance where extractable content is a critical parameter.
Related Standards
- Complementary ISO methods on plastics testing, laboratory glassware and solvent purity should be consulted for equipment and reagent specifications.
- Cross-reference other ISO tests for comprehensive characterization of plasticized cellulose acetate when broader mechanical or chemical property data are required.
Keywords: ISO 1875:1982, plasticized cellulose acetate, diethyl ether extractables, Soxhlet extraction, quality control, material testing.
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