Enzymatic degradation of poly (ε-caprolactone) and cellulose acetate blends by lipase and α-amylase

Films of poly(ε-caprolactone) (PCL) and cellulose acetate (CA) containing different proportions of PCL/CA (100/0, 80/20, 60/40, 40/60, 20/80 and 0/100, w/w) were prepared by casting, and their degradation by two enzymes (lipase and α-amylase) was monitored by mass loss and light microscopy for 240 days. Significant degradation was seen only in samples digested with lipase. Lipase selectively degraded PCL, with the rate of degradation being inversely proportional to the CA content. Light microscopy indicated some changes in morphology in the samples after digestion with lipase, and a relationship between these changes and the degree of mass retention-the larger the percentage of PCL in blends, the greater the loss of mass. However, there was no difference in the morphology among the samples incubated with α-amylase. The results suggested that lipase acts selectively on PCL, with little effect on CA.