Thermal and Mechanical Properties of Biocomposites Made of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Potato Pulp Powder

Abstract

The thermal and mechanical properties of biocomposites of poly(3-hydroxybutyrate-co- 3-hydroxyvalerate) (PHBV) containing 5 wt % of valerate units, with 20 wt % of potato pulp powder were investigated in order (i) to obtain information on possible miscibility/compatibility between the biopolymers and the potato pulp, and (ii) to quantify how the addition of this filler modifies the properties of the polymeric material. The potato pulp powder utilized is a residue of processing for the production and extraction of starch. The final aim of this study is the preparation of PHBV based materials with reduced cost, thanks to biomass valorization, in agreement with the circular economy policy, as result of the incorporation of agricultural organic waste. The results showed that the potato pulp powder does not act as reinforcement, but rather as filler for the PHBV polymeric matrix. A moderate loss in mechanical properties is detected (decrease in elastic modulus, tensile strength and elongation at break), which regardless still meets the technical requirements indicated for rigid packaging production. In order to improve the mechanical response of the PHBV/potato pulp powder biocomposites, surface treatment of the potato pulp powder with bio-based and petroleum-based waxes was investigated. Good enhancement of the mechanical properties was achieved with the natural carnauba and bee waxes.

Bio-Based Packaging: Materials, Modifications, Industrial Applications and Sustainability

“…The authors concluded that more research is needed to elucidate the filler–matrix interactions to produce superior composite properties [ 147 ]. Thus, research about bio-based fillers as bio-based packaging materials is needed because natural fillers considerably reduce the price of the final material since, generally, natural fillers are cheaper than bio-based polymeric matrices such as biopolyesters, in particular PLA, PBS, or PHA [ 149 , 150 ]. The addition of polysaccharidic fibers in biopolyesters, such as PLA-based blends, as reinforcing agent [ 149 ] is a well-known alternative for producing micro- or nano-biocomposites [ 151 , 152 ].…”

Integrated Efforts for the Valorization of Sweet Potato By-Products within a Circular Economy Concept: Biocomposites for Packaging Applications Close the Loop

“…Therefore, the residue was composed mainly of starch and cellulose, with a relatively low hydrophobic lignin content, meaning a generally hydrophilic character of the residue. This waste differs from the potato pulp used by Righetti and co-workers [ 34 ] in a few aspects: the starting crop and a more than doubled starch content. At the same time, the presence of lignin, pectin and protein distinguishes sweet potato residue from simple starch, making it an interesting waste, worthy of extensive investigations.…”

“…One common way to overcome these drawbacks is to mix these biopolymers with suitable additives or fillers to obtain biocomposites. Some reports in the literature attempt to enhance the physical and mechanical properties of PHBV or other biopolyesters by blending or filling techniques, using different types of natural fibres [ 21 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ] or wastes from agro-industrial processing [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ].…”

Effect of the Addition of Natural Rice Bran Oil on the Thermal, Mechanical, Morphological and Viscoelastic Properties of Poly(Lactic Acid)

“…The main aim of the present paper is to investigate how the addition of the totally eco-friendly RBO can modify the final thermal, mechanical, morphological and viscoelastic properties of PLA-based materials. This study fits into the widely investigated topic, in general and also by our group [30][31][32][33][34], on the utilization and valorization of agro-food biomass, co-products and by-products, for the production of sustainable polymeric materials, according to the principles of circular economy, in order to favor the production of articles with properties valuable for practical applications, and reduce the cost of the final products.…”