Cellulose Fibre Reinforced Polyhydroxyalkanoate Composites and Films with Enhanced Mechanical Properties

Abstract

Abstract The invention relates to processes for producing biodegradable biopolymer composites and films. Polyhydroxybutyrate (PHB), a biodegradable polyhydroxyalkanoate, has inherent brittleness and low strength that limit its application in packaging and biomedical fields. The invention addresses these limitations by reinforcing PHB with cotton fibres and applying a polyvinyl alcohol (PVA) coating to enhance fibre / matrix adhesion. Additionally, maleic anhydride (MA) may be grafted onto PHB to further improve interfacial bonding through hydrogen bonding with hydroxyl groups in PVA and cotton fibres. The resulting composites exhibit significantly improved mechanical properties, including up to 290% increase in tensile strength and 109% improvement in failure strain compared to pure PHB. The MA-grafted composites achieve a 9-fold increase in modulus of toughness and improved gas barrier properties. The biopolymer composites and films may be used as sustainable alternatives to fossil-fuel based plastics in packaging, biomedical, agricultural, and other applications. Abstract 20 26 20 13 20 20 F eb 2 02 6 A b s t r a c t 2 0 2 6 2 0 1 3 2 0 2 0 F e b 2 0 2 6 1 / 10 Figure 1 1 / 10 Chloroform (a) 0 Dissolve Cast to film Mix PHB BPO 60 °C melt Hot press MA - MA grafted Water P3HB 0 90 °C dissolve Soak 0 Dry PVA Cotton O O (b) BPO P3HB MA O O MA grafted O P3HB + O n O. O P4HB MA BPO O O MA grafted + O P4HB OJn O_n 20 26 20 13 20 20 F eb 2 02 6 1 / 1 0 2 0 2 6 2 0 2 6 2 0 1 3 2 0 2 0 F e b P H B M A W a t e r P 3 H B S o a k P V A O B P O P 3 H B M A O O O P 3 H B + - n O - n O P 4 H B M A B P O O o O J n O J n

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