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Aminated poly(ethylene terephthalate) (PET) surfaces were characterized for their use as substrates for the attachment of biologically active molecules. Amines of different chain lengths, tetraethylenepentamine, triethylenetetraamine (TTETA), and diethylenetriamine (DETA), were investigated. X-ray photoelectron spectroscopy was used to show that each amine introduced a comparable amount of nitrogen (5 atom %) to the PET surface. Contact-angle and titration analyses indicated that the amination reaction was not restricted to the surface, with evidence of diffusion into the polymer by TTETA and DETA. As a result, degradation of the PET substrate, evidenced by mass loss, was observed to occur. Annealing of the PET films before amination at a temperature of 2008C reduced the extent of degradation without producing a decrease in the nitrogen content produced.

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The tensile and tear properties of a biodegradable polymer, Biomax, have been studied in order to assess this material in film applications. While the tensile strength of Biomax was comparable to low density polyethylene, the tear strength was found to be six times lower. A study of the load-displacement curves revealed a regular variation in the load throughout the test, which was attributed to the presence of lower and higher strength regions in the polymer.The higher strength regions were characterised by the presence of polymer chains oriented parallel to the tear surface, while the lower strength regions were defined by an absence of molecular orientation and the presence of voids.