Leachables, Extractables and Migration - May 2009

This month we're focusing on the topic of Leachables, Extractables and Migration

Polymers are often complex materials that consist not only of the monomer, but also additives, fillers and sometimes remnants of processing aids including solvents and catalysts. With this variety of chemicals present, it's easy to see why some of these small molecules may leach, migrate or be extracted from the polymer bulk. Therefore, when considering a material for a specific application, care must be taken to ensure that these small molecules will not cause harm to anything they may come into contact with. This is a particular consideration in the Pharmaceutical, Medical and Food-Packaging industries where polymers come into direct, sustained contact with people or consumables.

Growing levels of legislation and regulation demonstrate that this is an issue of high importance.

Abstracts

Please see below a selection of abstracts highlighted in the May Newsletter. These are records which relate to Leachables, Extractables or Migration that have been recently added to the Polymer Library.

Click on the 7-digit accession numbers to find out about ordering a copyright-cleared full text copy of the items shown.

1038494 - PHYSICOCHEMICAL PROCESSES INVOLVED IN MIGRATION OF BISPHENOL A FROM POLYCARBONATE
Migration of bisphenol A (BPA) from samples of commercial polycarbonates into different liquids was reviewed and discussed with respect to concentration of the BPA in the original resin. Migration was found to be almost independent of BPA content in the original resin, with hydrolysis being the main release mechanism of the BPA from the polycarbonate. Important factors affecting release rates were found to be pH of the aqueous solvent, temperature and ozone concentration in the solvent. Surface ageing of the polymer also had an influence. Migration into oils was found to be lower than into aqueous solvents, and migration in all cases was found to be below migration limits for food contact applications. Gas chromatography/Mass spectroscopy, X-ray photoelectron spectroscopy and gel permeation chromatography were used in the analysis of migration. 20 refs.
Journal of Applied Polymer Science, 112, No.2, 15th April 2009 p.579-593, ISSN: 0021-8995, DOI: 10.1002/app.29421
Mercea P

1038287 - TPES ARE TAILORED FOR MEDICAL USE (short article)
It is briefly reported that thermoplastic elastomers specifically for medical use have been introduced by Teknor Apex and Vita Thermoplastic Compounds. The new Medalist compounds from Teknor Apex are part of a package of high-purity TPEs backed with tools and information for designers and processors aimed to provide a single source of elastomers for medical manufacturers. The initial range of 33 compounds spans a Shore A hardness range from 5 to 87, and clear, translucent and opaque formulations are available. Grades are available for every major process in medical manufacturing, from injection moulding to blow moulding to extrusion of thin film. The new materials from Vita have been added to its existing Mediprene line. They have been developed to address demands for transparent medical TPE grades with a minimum of potential extractables and leachables. The new products, called Mediprene OF series, prevent the possibility of oil migrating or leaching out of the material.
British Plastics and Rubber, Feb.2009, p.22, ISSN: 0307-6164

1038248 - LEACHING FROM PLASTIC BOTTLES (short article)
It is briefly reported that mineral water packaged in plastic contains roughly twice the amount of oestrogen mimics compared with water sold in glass. Oestrogenic compounds have potential adverse health effects, so it is important to determine if these compounds can migrate from packaging into water and food. Researchers at Johann Wolfgang Goethe University evaluated oestrogenic activity in 20 brands of bottled water found in German stores. They found increased activity in 12 of the 20, most of which relied on PETP bottles.
Chemical and Engineering News, 87, No.12, 23rd March 2009, p.37, ISSN: 0009-2347

1037863 - ADDRESSING PHOTOINITIATOR MIGRATION IN UV-INKS
The effect of curing conditions on the extent of photoinitiator migration in a radically curable blue flexo printing ink was investigated, focusing particularly on photoinitiator structure, UV dose and curing atmosphere. The amount of migrating species was evaluated using a specially designed analytical method. UV-dose-indicating inks were used to allow on-line monitoring of the UV curing process with the aim of minimising photoinitiator migration in food packaging applications. The results obtained demonstrated that by combining the best additives and the right processing conditions, UV curing was a cost-efficient process for the production of high-quality and safe packaging. 6 refs.
Pitture e Vernici, 85, No.1, Jan.2009, p.25-30, ISSN: 0048-4245
Studer K; Villeneuve S; Brendle E; Di Matteo A

1036642 - NEW STUDY FINDS BPA MAY LINGER IN BODY
A University of Rochester Medical Center analysis of data published online January 28 suggests that the controversial chemical bisphenol A could be lingering longer in the human body than previously thought, and could be getting into the bloodstream through sources other than food. The scientists suggest that other sources for BPA in the bloodstream could include plastic pipe and dust from carbonless paper, such as cash register receipts. The American Chemistry Council's Polycarbonate/BPA Global Group called the conclusions of the study "speculative at best" and said the levels of BPA found in the study are not a health concern. Only one country, Canada, has taken action with regard to BPA. Health Canada in October said it will draft regulations to ban the import and sale of baby bottles containing BPA, even though its view is that BPA migration is too low to cause harm.
Plastics News(USA), 20, No.48, 2nd Feb.2009, p.8, ISSN: 1042-802X
Verespej M

1035946 - MIGRATION OF ANTIFOG ADDITIVES IN AGRICULTURAL FILMS OF LOW-DENSITY POLYETHYLENE AND ETHYLENE-VINYL ACETATE COPOLYMERS
Polymer films of LDPE and EVAC containing two types of antifog additives were exposed to simulated horticultural greenhouse environments. Films were filled with calcined kaolin and prepared in a twin-screw extruder. The evolution of the antifog effect was visually observed and that of the additive concentration measured using FTIR. Melting points were measured by DSC and solubilities of the additives were calculated. 11 refs.
Journal of Applied Polymer Science, 111, No.5, 5th March 2009, p.2299-2307, ISSN: 0021-8995, DOI: 10.1002/app.29280
Irusta L; Gonzalez A; Fernandez-Berridi M J; Iruin J J; Asua J M; Albizu I; Ibarzabal A; Salmeron A; Espi E; Fontecha A; Garcia Y; Real A I

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