Résumé : |
Reinoculation of a range of microbial isolates showed fungal attack to be the reason for the deterioration of some boots with polyester polyurethane (PU) poromeric uppers. Bacteria were not implicated although they had grown along nylon fibers in the poromeric.
Flaking of the top coating of the PU foam layer resulted from surface growth, whereas deep cracking, a slower expression of fungal attack, was caused by growth from underneath the foam layer. Peeling of the surface coating was produced by two Fusarium spp but not by Alternaria alternate. Cracks were colorless to pinkish light grey with the two Fusarium spp and dark greenish grey with A. alternate. Similar discolorations were produced in polyether PU poromeric where fungi grew beneath the PU coating (without further deterioration) to form “blooms”.
The results of experiments were mold growth was kept separate from substrate indicated that exoenzymes were responsible for polyester PU deterioration.
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