PRELIMINARY STUDY ON MICROBIAL DEGRADATION OF FLEXIBLE POLYURETHANE FOAMS - PHYSICO-MECHANICAL AND WEIGHT CHANGES DURING FUNGAL DETERIORATION

摘要

The ability of the fungus, Aspergillus niger, to utilize palm-based flexible polyurethane foam as food was determined via the petri-dish test. A commercial polyurethane foam was used as the control. A dense fungal growth was detected by visual examination of foams inoculated on minimal nutrient agar (MNA) but not on the mineral salts agar (MSA). The weight changes for all samples were analysed after four weeks. Both the palm-based and commercial flexible polyurethane foams incubated on MNA suffered significant weight losses while slight increases were recorded by the samples incubated on MSA. Under a SEM, dense fungal growth was observed covering the samples incubated on MNA but none on the samples incubated on MSA. Instead, the presence of spores on the latter indicated that the fungus had not germinated sufficiently to degrade the polyurethanes. The compression strength for all the samples increased with time. The increase in hardness was more in the palm-based polyurethanes than in the commercial ones. This study showed that palm-based flexible foam can be degraded by Aspergillus niger in the presence of sufficient nutrients.