Crystallization behavior, mechanical properties, and enzymatic degradation of biosourced poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/graphene nanocomposites

Abstract

Herein, through a solution and coagulation method, biodegradable poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)]/graphene nanocomposites were prepared. The nonisothermal melt crystallization peak temperature values and overall isothermal melt crystallization rates in the nanocomposites are greater than in neat P(3HB-co-4HB), indicating a nucleating effect of graphene; however, the crystallization mechanism of P(3HB-co-4HB) remains unchanged in the nanocomposites, regardless of graphene level and crystallization temperature. The nonisothermal and melt crystallization processes of the nanocomposites are found to vary with the graphene loading, exhibiting a maximum at 1 mass% graphene loading. The incorporation of graphene obviously increases spherulites nucleation density values of the nanocomposites and does not modify the crystal structure of P(3HB-co-4HB) in the nanocomposites. The storage modulus has been apparently improved in the nanocomposites compared to neat P(3HB-co-4HB). Moreover, the enzymatic hydrolytic degradation rates have been enhanced obviously in the P(3HB-co-4HB)/graphene nanocomposites than in neat P(3HB-co-4HB).