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

Abstract

The thermal, mechanical and viscoelastic properties of biocomposites of poly(lactic acid) (PLA) with 20 wt.% of potato pulp powder were investigated. The potato pulp powder utilized is a byproduct from the production and extraction of starch. The results showed that the potato pulp powder does not act as reinforcement, but as filler for PLA, due to an unfavorable aspect ratio and the irregular shape of the particles. In order to improve the mechanical response of the PLA/potato pulp powder biocomposites, surface treatment of the potato pulp particles with bio-based and petroleum-based waxes was investigated. This treatment was found to improve the properties of the biocomposites, enhancing the adhesion between the PLA based polymeric matrix and the potato pulp fibers. The best result is obtained with a petroleum-based wax, but also the bio-based waxes lead to good mechanical properties of the biocomposite. Thus, the addition to PLA of potato pulp powder, treated with waxes, appears a method able to (i) utilize and valorize an abundant agro-food biomass such as potato pulp, according to the principles of circular economy, (ii) favor the production of articles with properties valuable for practical applications, and (iii) reduce the cost of the final products, considering the relatively high cost of PLA.

A Study on Exfoliation of Expanded Graphite Stacks in Candelilla Wax

“…This shift of the melting peak towards lower temperatures indicated the formation of smaller and less stable crystals. This result can be explained, analogous to what was reported above, by the crystallization-promoting effect caused by EG, which behaves as a heterogeneous nucleation center during the crystallization process, as observed in the literature for a different EG–paraffin mixtures [8]. As shown in Figure 5b, the reduced crystallinity in the EG–CW samples could be ascribed to a possible confinement of the chain segments (intercalation), which hindered the segmental rearrangement during crystallization and restricted the formation of perfect crystals in the polymer matrix.…”

“…The availability and low cost of CW and its biodegradable nature has attracted growing interest from researchers towards the development of biocomposites that, thanks to their sustainability, energy efficiency, reduced waste generation, and low greenhouse gas emissions, are emerging powerfully in the current industrial economy [8,9,10,11]. Kowalczyk et al [12] used CW to produce edible films and coatings, while Navarro-Guajardo et al [4] proposed CW as a slow-release matrix for fertilizers encapsulated by a modified spray chilling process.…”

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

“…For example, in biocomposites of PLA and potato pulp, the filler was not acting as a reinforcement due to the unfavorable aspect ratio of the potato pulp particles, which are short in length and irregularly shaped, and due to poor matrix–filler adhesion properties. Potato pulp coating with about 1 wt% of waxes improved the mechanical properties of the biocomposites and allowed for better matrix–filler adhesion; in particular, bio-based waxes based on bees or carnauba waxes resulted in bio-based compatibility between natural fibers and biopolyesters [ 162 ].…”

Evaluation of Mussel Shells Powder as Reinforcement for PLA-Based Biocomposites

“…The use of bio-polyesters and natural fillers, either organic or inorganic, for the production of biocomposites is nowadays already a reality in many sectors, ranging from agriculture and packaging to building construction components and other high value applications, in agreement with a bioeconomy approach [ 3 , 4 ].…”