Thermomechanically Processed, Polyelectrolyte-Complexed Polysaccharide Composites with Enhanced Hydrolytic Stability and Mechanical Properties

Author / Creator

MATERIALS FOR HUMANITY (MH 21) (2021)

Conferences

MATERIALS FOR HUMANITY (MH 21) SYM C - Plastic Substitution II (2021)

Available as

Online

Summary

Biopolymers such as chitosan, cellulose and alginate from biomass have demonstrated huge potential in many important and rapidly growing applications, it is always challenging to create advanced bi...

Biopolymers such as chitosan, cellulose and alginate from biomass have demonstrated huge potential in many important and rapidly growing applications, it is always challenging to create advanced biopolymer materials cost-effectively. Herein, we present our progress in preparing a series of biopolymer composite materials with unexpected properties using a facile "dry", thermomechanical method. Chitosan/CMC composite films created in this way showed much better hydrolytic stability, compared to chitosan-only films. This is so despite inclusion of the CMC in the chitosan matrix even increasing the surface hydrophilicity. We propose that our processing method led to the polyelectrolyte complexation between chitosan and CMC generating physical crosslinking points in the materials. These crosslinks stabilised the films in water although hydration disrupted hydrogen bonding between polysaccharide chains leading to dramatically decreased tensile strength and increased elongation at break. Besides, we found chitosan/silk peptide (SP) polyelectrolyte-complexed materials prepared in the same way had extraordinary mechanical properties. Moreover, we prepared chitosan/alginate composites using the same processing protocol and demonstrate that inclusion of graphene oxide could enhance polysaccharide plasticisation, leading to enhanced mechanical properties and surface hydrophobicity. The method of materials hybridisation without chemical reactions demonstrated in this work could provide an insight into the development of cost-effective biopolymer materials with competitive properties as plastic replacements in certain applications, where biodegradability, biosafety, and biocompatibility are indeed required (e.g. functional food packaging and antimicrobial wound healing).

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