Bionanocomposites From Poly(3-Hydroxybutyrate-co-3- hydroxyhexanoate) (PHBH) and Cellulose Nanofibres: Mechanical and Thermal Properties

Hlotse, Daphney; Mhike, Washington; Ojijo, Vincent; Shongwe, Mxolisi Brendon; John, Maya Jacob

doi:10.22034/jams.2026.260206

Bionanocomposites From Poly(3-Hydroxybutyrate-co-3- hydroxyhexanoate) (PHBH) and Cellulose Nanofibres: Mechanical and Thermal Properties

Document Type : Original Article

Authors

Daphney Hlotse ¹

Washington Mhike ¹

Vincent Ojijo ²

Mxolisi Brendon Shongwe ¹

Maya Jacob John ²^{, 3}

¹ Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria, South Africa

² Centre for Nanostructures and Advanced Materials, Council for Scientific and Industrial Research, Pretoria, South Africa

³ Department of Chemistry, Nelson Mandela University, Port Elizabeth, South Africa

10.22034/jams.2026.260206

Abstract

Poly(3-hydroxybutyrate-co-3-hydroxybutyrate) (PHBH) is a biodegradable polyester that has attracted significant attention in research thanks to its remarkable qualities, including non-toxicity, biodegradability across various environments, and biocompatibility. Cellulose nanocrystals have emerged as the most-researched bio-based reinforcement, mainly due to their high mechanical properties, biodegradability, and the fact that they can be extracted from various waste biomass resources such as sawdust and bagasse. This study aimed to examine how cellulose nanofibres (CNFs) influence the mechanical and thermal properties of PHBH bionanocomposites. The PHBH bionanocomposites, incorporating CNFs of different concentrations, were produced through casting and melt-processing. The results obtained showed that the addition of CNFs as a reinforcement to the PHBH matrix enhanced the mechanical properties. At a 1% CNF loading, an enhancement in both tensile strength and Young’s Modulus was observed. This improvement is attributed to the establishment of a hydrogen bonding network between PHBH macromolecular chains and the hydroxyl groups on CNFs. However, increasing the content of CNFs led to agglomeration during processing, which affected these mechanical properties. The resulting mechanical and thermal characteristics suggest that PHBH/CNF bionanocomposites could be effectively used as alternatives to conventional plastics in various applications.

Keywords

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)

Cellulose nanofibers

Mechanical properties

Thermal properties