Search

The development of eco-friendly polymer composites with multifunctional properties aligns with the goals of the circular economy agenda, which aims to minimize waste and promote the sustainable use of resources by closing the loop of product life cycles. Eco-friendly polymer composites play a crucial role in achieving these objectives. The present work focuses on the preparation of fully biobased blends obtained by melt mixing a bio-polyester, poly(butylene succinate- co -adipate) (PBSA), with orange peels up to 20 wt%, to yield active polymer composites. Orange peels, employed here as natural filler, are largely available from food wastes, they are rich in phenolic compounds and possess antioxidant activity as shown by the experimental tests carried out. The thermal stability of the formulated composites is almost unchanged by the filler addition, showing only a slight decrease of the crystallization temperatures and crystalline fraction within the composites. The mechanical properties of the compounds evidence an increase in the elastic modulus together with a decrease in the tensile strength, while the elongation at break remains almost constant. The incorporation of the natural filler enabled the integration of antioxidant and antibacterial properties, which were absent in the original pristine polymer. • PBSA containing up to 20 wt% of orange peels have good antioxidant and antibacterial properties. • Biocomposites formulated with orange peels are found to retain good mechanical properties in terms of elongation at break. • The thermoplastic material produced can be used in the packaging industry or in the organic or integrated farming sector application. [ABSTRACT FROM AUTHOR]

Novel bio-based and biodegradable electrospun membranes, containing bactericidal ricinoleic acid (RA) units either by copolymerization with butylene succinate (BS) units or by blending PRA and PBS homopolymers, are characterized in their chemical, thermal, mechanical and surface properties. In the blends E. coli and S. aureus mortality rate increases with PRA amount, while the copolymer shows lower bactericidal activity compared to the blend with similar composition. XPS demonstrates that in the blends an enrichment of RA units at the fiber surface occurs during electrospinning due to phase separation, while in the copolymer RA units are homogeneously dispersed along fiber cross-section. [ABSTRACT FROM AUTHOR]

Poly(ricinoleic acid) (PRA), coming from the self-polycondensation of ricinoleic acid (RA), which derives from castor oil, is a very interesting polymer because of its intrinsic antimicrobial activity. However, its mechanical properties are insufficient for whatever application, thus copolymerization is required. In this work, two polyesters based on 1,3 propanediol (PD), such as poly(propylene terephthalate) (PPT) and poly(propylene isophthalate) (PPI), were chosen to prepare random copolyesters containing ricinoleate units. Different content of RA have been tested, such as 10 and 25 mol% respect to the comonomer (terephthalic or isophthalic dimethylester), to evaluate the lowest composition able to confer antibacterial activity. The materials were tested against Staphylococcus aureus and Escherichia coli , and 25 mol% of RA unit resulted to impart antimicrobial activity. Furthermore, thermal properties (DSC and TGA) as well as the elastomeric response of films were investigated. The copolymer PPI/PRA containing 10 mol% of RA presents very high elongation at break, around 1300%. Therefore, by tuning the RA amount it is possible to obtain outstanding elastomeric or antibacterial materials, suitable for textiles and/or film engineering applications. • Ricinoleic acid from biomass is suitable to be used in polycondensation reactions. • Copolymers properties can be tuned as a function of ricinoleic acid content. • Copolymers richest in ricinoleic acid have significant antibacterial activity. • The copolymer of PPI containing 10 mol% of ricinoleic acid unit presents very high elongation at break. • Copolymers with ricinoleic acid could be suitable for textile fibers and/or film engineering thermoplastic applications. [ABSTRACT FROM AUTHOR]

Polybutylene succinate (PBS) were processed in melt extrusion by dispersion of organo-modified layered double hydroxide (LDH). Depending on the organic anion interleaved into LDH fillers (L-tyrosine (TYR), L-tryptophan (TRP), L-ascorbate (ASA) and 3-(4-hydroxyphenyl)propionate (HPP)), it was possible to control and tune the properties of the resulting PBS composites. Each LDH filler is found to act differently toward PBS, thus modifying its viscoelastic properties (as expressed by a chain extending effect), its rate of hydrolysis and photo-degradation or its antibacterial activity. The highest chain extending effect was observed in the case of LDH with L-tryptophan, the worst – with L-ascorbate anion. However, L-ascorbate anions interleaved into LDH present 100% activity in antibacterial properties. A better compromise may be achieved when PBS is mixed with different LDHs such as those combining HPP and ASA, making possible to target efficiently multi-properties such as small rate of hydrolysis, photo-stability, biocide activity as well as chain extension, thus turning to a multifunctional (bio)nanocomposites with new possible applications. Finally, a possible scale-up is demonstrated on thin films. Unlabelled Image • Organo-modified LDH as filler for bio-based polyester. • LDH hybrid filler endowing polymer with multi-functionality. • Chain extension and stability against UV, hydrolysis and bacteria. • Enhanced processability and durability of the polymer composite. • Scale-up and applicability addressed. [ABSTRACT FROM AUTHOR]

Olive mill wastewater (OMW) is the aqueous waste derived from the production of virgin olive oil. OMW typically contains a wide range of phenol-type molecules, which are natural antioxidants and/or antibacterials. In order to exploit the bioactive molecules and simultaneously decrease the environmental impact of such a food waste stream, OMW has been intercalated into the host structure of ZnAl layered double hydroxide (LDH) and employed as an integrative filler for the preparation of poly(butylene succinate) (PBS) composites by in situ polymerization. From the view point of the polymer continuous phase as well as from the side of the hybrid filler, an investigation was performed in terms of molecular and morphological characteristics by gel permeation chromatography (GPC) and X-ray diffraction (XRD); also, the thermal and mechanical properties were evaluated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic thermomechanical analysis (DMTA). Antibacterial properties have been assessed against a Gram-positive and a Gram-negative bacterium, Staphylococcus aureus and Escherichia coli, respectively, as representatives of potential agents of foodborne illnesses. [ABSTRACT FROM AUTHOR]