Polystyrene Volatile substances

Table 14-la Survey of volatile substances in polystyrene materials (Hempel and Riidt, 1988). 

Sugita, T Ishiwate H., Kawamura. Y., Baba, T., Umchara, T., Morita, S., Yamada, T. 1996. Headspace Gas Chromatographic Analysis of Residual Volatile Substances in Polystyrene Food Containers. J. Food Hygienic Society of Japan. 36(2) 263—268. 

This method allows for the simultaneous detection of highly volatile (e.g. dioxane), volatile (e.g. polyaromatic hydrocarbons) and non-volatile (e.g. polystyrene) substances. The sensitivity of the method depends of course on the detector(s) used. In the gas chromatography-mass spectrometry mode most compounds could be readily detected in the low part-per-million range. 

Expanded polystyrene (EPS) articles are made using high impact polystyrene formulations with incorporation of a blowing agent (this is usually a volatile solvent such as pentane). Often, EPS containers will have a crystal polystyrene skin applied to the food contact surface to act as a barrier between food and container. Applications of EPS include thermoformed packaging for eggs, meat, fish and fast food trays. Substances typically used in the manufacture of polystyrene are given in Table 10.3. 

Dichloromethane [75-09-2] (methylene chloride) is a colorless, highly volatile, neutral liquid with a characteristic odor. It is insoluble in water but miscible with organic solvents. It has a very good solvency for many organic substances, such as fats, oils, waxes, and resins. Bitumen, rubber, chlorinated rubber, polystyrene, postchlorinated poly(vinyl chloride), vinyl chloride copolymers, polyacrylates, and cellulose esters are also soluble. The solubility spectrum can be expanded by adding other solvents. A mixture of methanol or ethanol and dichloromethane is a good solvent for cellulose ethers and acetyl cellulose. Cellulose nitrate is, however, insoluble. 

Methylal [109-87-5] (formaldehyde dimethyl acetal, dimethoxymethane) is a pleasantly smelling, extremely volatile solvent. It dissolves polystyrene, polyfvinyl acetate), vinyl chloride copolymers, acrylates, methacrylates, and synthetic and natural resins. It is used in paints and lacquers, adhesives, and aerosols. Important extracting agent for natural substances, essences, and oils. It serves as a reaction medium in the chemical industry and as an intermediate for chemical syntheses. 

---