Methods of testing plastics. Chemical properties. Determination of formaldehyde in phenolic mouldings (colorimetric method). Determination of formaldehyde in phenolic mouldings (gravimetric method). Determination of sulphates in phenolic mouldings. Determination of chlorides in phenolic mouldings|Formaldehyde, Plastics and rubber technology, Aqueous extraction methods, Precipitation methods, Specimen preparation, Chemical analysis and testing, Plastics, Polymers, Gravimetric analysis, Phenolic resins, Determination of content, Colorimetry, Moulding (process), Extraction methods of analysis, Chlorides, Sulfates