The rates of enzymatic hydrolysis of polyesters are in general influenced by a wide variety of parameters including molar mass, segmental mobility, chemical and stereochemical structure, surface area, morphology and crystallinity. In this study, still in progress, a series of high molar mass poly(butylenesuccinate-co-butyleneadipate)s, P(BSu-co-BAd)s, and poly(butylenesuccinate-co-butylenesebacate)s, P(BSu-co-BSe)s, were synthesized by melt polycondensation from 1,4-butanediol and dimethylesters of succinic, adipic and sebacic acids. Good filmability was achieved for all the polyesters. The structure and physical properties of the polyesters were analysed by 1H-NMR, SEC, DSC, X-Ray and Viscometry. Filmed samples were assayed to enzymatic degradation by lipase from Mucor Miehei and the relative normalised weight loss rates were compared. The preliminary results point out that molar mass values show no significant influence on the biodegradation degree of the polyesters films investigated. This could suggest that the lipase used is an endo-type enzyme that is randomly able to break down ester bonds in the polymer chain. Changes in the degree of crystallinity show negligible effect on polyesters enzymatic degradation. The rate-determining factor of the enzymatic hydrolysis appears to be closely related to the polymer chain structure that strongly influences the activity of the lipase from Mucor Miehei in P(BSu-co-BSe) and in P(BSu-co-BAd) copolymers.
ROLE OF STRUCTURE AND CRYSTALLINITY OF SYNTHETIC ALIPHATIC COPOLYESTERS ON THEIR ENZYMATIC DEGRADATION
Paola Rizzarelli;
2001
Abstract
The rates of enzymatic hydrolysis of polyesters are in general influenced by a wide variety of parameters including molar mass, segmental mobility, chemical and stereochemical structure, surface area, morphology and crystallinity. In this study, still in progress, a series of high molar mass poly(butylenesuccinate-co-butyleneadipate)s, P(BSu-co-BAd)s, and poly(butylenesuccinate-co-butylenesebacate)s, P(BSu-co-BSe)s, were synthesized by melt polycondensation from 1,4-butanediol and dimethylesters of succinic, adipic and sebacic acids. Good filmability was achieved for all the polyesters. The structure and physical properties of the polyesters were analysed by 1H-NMR, SEC, DSC, X-Ray and Viscometry. Filmed samples were assayed to enzymatic degradation by lipase from Mucor Miehei and the relative normalised weight loss rates were compared. The preliminary results point out that molar mass values show no significant influence on the biodegradation degree of the polyesters films investigated. This could suggest that the lipase used is an endo-type enzyme that is randomly able to break down ester bonds in the polymer chain. Changes in the degree of crystallinity show negligible effect on polyesters enzymatic degradation. The rate-determining factor of the enzymatic hydrolysis appears to be closely related to the polymer chain structure that strongly influences the activity of the lipase from Mucor Miehei in P(BSu-co-BSe) and in P(BSu-co-BAd) copolymers.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
