Enzymatic degradation of starch thermoplastic blends using samples of different thickness.
The material studied was a thermoplastic blend of corn starch with a poly(ethylene-vinyl alcohol) copolymer, SEVA-C. The influence of both the material's exposed surface and enzyme concentration on degradation kinetics was studied. As alpha-amylase is present in the blood plasma, experiments were performed, varying the material thickness and the alpha-amylase between 50 and 100 units/l, at 37 degrees C, lasting up to 90 days. Four different batches using SEVA-C and starch samples of different thickness were performed. The positive correlation between degradation rate and the exposed material surface was confirmed, since thin films with larger exposed surfaces were degraded faster than thick square plates having the same total mass. The degradation extent depends on the total amount of amorphous starch present in the formulation rather than on the amount of enzyme used and the minimum thickness to ensure maximum degradation was estimated to be close to 0.25 mm.
Escola Superior de Tecnologia e Gestão, IPVC, Avenida Atlântico, 4900-348 Viana do Castelo, Portugal. alberta@estg.ipvc.pt
M Alberta
MA
Araújo
António M
AM
Cunha
Manuel
M
Mota
D020341:Absorbable Implants; D001672:Biocompatible Materials / Q000737:chemistry*; D004789:Enzyme Activation; D008422:Materials Testing; D008970:Molecular Weight; D010969:Plastics / Q000737:chemistry*; D013213:Starch / Q000737:chemistry*; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry*
D001672:Biocompatible Materials; D010969:Plastics; D013213:Starch; D000516:alpha-Amylases