Comparison of the biodegradation of poly(ε-caprolactone), cellulose acetate and their blends by the Sturm test and selected cultured fungi

In this work, we compared the biodegradation of poly(ε-caprolactone) (PCL), cellulose acetate (CA) and their blends using an aerobic biodegradation technique known as the Sturm test, and by their carbon dioxide (CO2) production and susceptibility to attack by a mixture of fungal strains in solid and liquid media in which samples of each blend were the only source of carbon. The extent of biodegradation was assessed by the loss of mass. The polymers were also characterized by thermal analysis using differential scanning calorimetry (DSC). The 40PCL/60CA blend showed faster biodegradation than the other blends because of its higher CO2 production in aerobic medium (Sturm test). PCL was more susceptible to attack by a mixture of fungi on solid medium than was CA but showed a lower loss of mass (8.4%) than the latter polymer; the 60PCL/40CA blend showed the greatest loss of mass during the period of evaluation. In contrast, in liquid medium, PCL showed a greater loss of mass. Blends of PCL with CA reduced the melting temperature (Tm) of PCL and increased the Tm of CA, indicating immiscibilty of the polymers. The blends were also less crystalline, which favoured their biodegradation.