Self-Assembly of Graphene Oxide at Poly(3-hydroxybutyrate) Microparticles Toward High-performance Intercalated Nanocomposites

As one of the most important natural biopolymers, poly(3-hydroxybutyrate)(PHB) has been identified by an ecofriendly lifecycle from bacterial synthesis to practical processing and recycling, holding great promise in applications for biomedical and packaging materials. However, due to the intrinsic characters including poor self- nucleation capability and excessively large spherulites, the application of PHB is dwarfed by low impact resistance, poor ductility and high creep compliance. Herein, a combination of aqueous processing and confined structuring was proposed to prepare graphene oxide(GO)-intercalated PHB nanocomposites. In specific, GO nanosheets were exfo- liated and dispersed in water, which would encapsulate the submicron PHB microspheres to form the PHB@GO self-assemblies, followed by confined structuring under a high pressure above the melting temperature of PHB. Albeit at an ultralow loading of 0.1%(mass fraction), the intercalated GO nanosheets showed high capability to enhanced the isothermal and non-isothermal crystallization kinetics of PHB, resulting in highly dense spherulites with a relatively uniform size. An unexcepted brittle-ductile transition was developed in the intercalated nanocomposites, leading to remarkable increase in tensile strength and elongation at break. This was accompanied by significant rise of thermomechanical properties and creep resistance, especially at high temperatures. The flexibility in the choice of functional nanofillers permits broad applications in the fabrication of high-performance PHB-based composites. © 2022, Editorial Department of Chem. J. Chinese Universities. All right reserved.