Thermal, Mechanical, and Rheological Properties of Biocomposites Made of Poly(lactic acid) and Potato Pulp Powder

Abstract

The thermal, mechanical, and rheological properties of biocomposites of poly(lactic acid) (PLA) with potato pulp powder were investigated in order to (1) quantify how the addition of this filler modifies the structure of the polymeric material and (2) to obtain information on the possible miscibility and compatibility between PLA and the potato pulp. The potato pulp powder utilized is a residue of the processing for the production and extraction of starch. The study was conducted by analyzing the effect of the potato pulp concentration on the thermal, mechanical, and rheological properties of the biocomposites. The results showed that the potato pulp powder does not act as reinforcement but as filler for the PLA polymeric matrix. A progressive decrease in elastic modulus, tensile strength, and elongation at break was observed with increasing the potato pulp percentage. This moderate loss of mechanical properties, however, still meets the technical requirements indicated for the production of rigid packaging items. The incorporation of potato pulp powder to PLA offers the possibility to reduce the cost of the final products and promotes a circular economy approach for the valorization of agro-food waste biomass.

Thermal, Mechanical, Viscoelastic and Morphological Properties of Poly(lactic acid) based Biocomposites with Potato Pulp Powder Treated with Waxes

“…As a general rule, the elastic modulus of a composite increases with increasing the fiber content, if the rigidity of the filler is higher than that of the polymeric matrix and if the length of the filler is sufficiently high [47,48]. Thus, the behavior displayed by the PLA based biocomposites with PPP has to be ascribed to the low aspect ratio of the potato pulp particles and their irregular shape [21]. Poor adhesion between the potato pulp powder and the polymeric matrix is attested by the lower tensile strength exhibited by the biocomposite.…”

“…Several types of natural fibers have been used to produce PLA based biocomposites [16,17,18,19,20], for which the effects of the processing conditions and/or surface chemical modification of the fibers on the mechanical, thermal and viscoelastic properties have been investigated. Recently also potato pulp powder has been utilized to produce biocomposites with PLA [21].…”

“…In the present study, biocomposites made of PLA and 20 wt.% of potato pulp powder (PPP) have been produced by melt mixing, processed by injection extrusion and characterized in terms of thermal, mechanical and viscoelastic properties. A previous article on the effect of increasing percentage of PPP (5, 10 and 20 wt.%) added to PLA, demonstrated that PPP can be mixed with PLA and easily processed up to 20 wt.% [21], with the addition of a non-toxic plasticizer, acetyl-tri-n-butyl citrate (ATBC) [22] and calcium carbonate (CaCO 3 ), which acts as inert filler to facilitate the removal injection molded specimen from the mold. In an attempt to improve the adhesion between PLA and PPP, in the present study potato pulp fibers coating with bio-based and petroleum-based waxes was investigated.…”

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.…”

Foaming of PLA Composites by Supercritical Fluid-Assisted Processes: A Review

“…This property, which is closely related to the intrinsic rheological behavior of PLA and processing conditions, is critical during the growth phase of the cells to limit coalescence and obtain uniform cell morphology [10]. In the previously listed works, different strategies were tested in order to improve the PLA foamability: (i) introducing a chain extender to create a branched structure [97][98][99], (ii) modifying the L/D ratio of the PLA molecules [100,101], or (iii) varying the PLA molecular weight [97,[100][101][102]. These macromolecular approaches proved to be efficient in improving PLA foamability thanks to enhanced crystallization rate and melt strength [13].…”