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Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

In this work, the use of a recycled mix stemming from the treatment of multilayer aseptic packaging used in the food and beverage industry is proposed as the matrix for short fibre composites reinforced with flax fibres, to generate value-added materials in contrast to the more common end-of-life scenario including energy recovery. This is expected to be a preferred choice in the waste hierarchy at the European level. A commercially available material (EcoAllene) obtained from multilayer packaging recycling was compounded with short flax fibres up to 30 wt.% by twin screw extrusion, with a view to enhancing its poor mechanical profile and broadening its applications. Composites were in depth analyzed by thermogravimetric analysis and differential scanning calorimetry, which highlighted the complex nature of this recycled product, a limited nucleation ability of flax fibres and a lower thermal stability due to the premature degradation of natural hemicellulose and cellulose, though featuring in any case onset degradation temperatures higher than 300 °C. Composites' mechanical properties were assessed in tension, bending and impact conditions, with remarkable improvements over the neat matrix in terms of stiffness and strength. In particular, at 30 wt.% fibre content and with 5 wt.% of maleated coupling agent, an increase in tensile and flexural strength values by 92% and 138% was achieved, respectively, without compromising the impact strength. The effectiveness of flax fibres confirmed by dynamo-mechanical analysis is beneficial to the exploitation of these composites in automotive interiors and outdoor decking applications. [ABSTRACT FROM AUTHOR] more...

The effect of four lignocellulosic waste fillers on the thermal and mechanical properties of biocomposites was investigated. Powdered licorice root, palm leaf, holm oak and willow fillers were melt compounded with polypropylene at two different weight contents, i.e., 10 and 30, and then injection molded. A commercially available maleated coupling agent was used to improve the filler/matrix interfacial adhesion at 5 wt.%. Composites were subjected to chemical (FTIR-ATR), thermal (TGA, DSC, DMA) and mechanical (tensile, bending and Charpy impact) analyses coupled with a morphological investigation by scanning electron microscopy. Although similarities among the different formulations were noted, holm oak fillers provided the best combination of thermal and mechanical performance. In particular, at 30 wt.% content with coupling agent, this composite formulation displayed remarkable increases in tensile strength and modulus, flexural strength and modulus, of 28% and 110%, 58% and 111%, compared to neat PP, respectively. The results imply that all these lignocellulosic waste fillers can be used successfully as raw materials for biocomposites, with properties comparable to those featured by other natural fillers. [ABSTRACT FROM AUTHOR] more...

The low-density polyethylene (LDPE)/aluminium mix obtained after the recovery of cellulose from multilayer aseptic packaging used in the food and beverage industry is generally destined for energy recovery. In this work we propose it as a matrix for value-added composite materials. A commercially available material (EcoAllene) obtained from multilayer packaging recycling was reinforced with short natural basalt fibres up to 30 wt.% by twin screw extrusion, aiming at improving the mechanical profile of such material and widening its applications. Thermal characterizations by thermogravimetric analysis and differential scanning calorimetry showed that the material is indeed a complex mixture of LDPE, HDPE, PP, and aluminium. Basalt fibres did not modify the melting and crystallization profile as well as the global degradation behaviour. Composites were then subjected to tensile, bending, Charpy impact tests and the fracture surfaces were investigated by scanning electron microscopy. Results highlighted a beneficial effect of basalt fibres to stiffness and strength in both loading conditions, with improvements by 107% and 162% for tensile and bending strength, respectively, which were linked also to a 45% enhancement of impact strength. This increased mechanical performance is promising for their use in automotive interiors and outdoor decking applications. [ABSTRACT FROM AUTHOR] more...

In this study, the feasibility of giving added value to spent yerba mate residues by manufacturing thermoplastic composites, and their potential benefits, is investigated. Experimental tests performed on yerba mate residues demonstrated that such residue, after a simple extraction procedure by water/ethanol solution, showed an acceptable level of interfacial compatibility with polyolefins. Biocomposites at different yerba mate residue amount in polypropylene and high‐density polyethylene (HDPE) were produced by a two‐stage process, involving extrusion and injection molding, and their mechanical and thermal properties were evaluated through tensile, TGA, and DSC tests, respectively. The addition of yerba mate residues resulted in a significant improvement (up to 23% when 20 wt% of filler was added to HDPE) of tensile properties compared to the neat matrices. This result was obtained without showing a positive effect on their crystallization behavior, as found from DSC results. Composite materials modified with maleic anhydride as coupling agent exhibited an even greater reinforcing efficiency due to enhanced interfacial compatibility. Basing on the results of this study, yerba mate residue/thermoplastic composites appear to be a viable alternative to wood composite materials, with associated environmental benefits related to the valorization of such agro‐food waste. Highlights: Yerba mate (YM) residue was added to a polymer matrix as a reinforcement material.Yerba mate residue can be effectively recycled as a reinforcement in sustainable biocomposites.Thermal, mechanical, and morphological properties of biocomposites were characterized.Significant improvements of tensile strength and modulus were observed up to a 20 wt% content of YM.The interfacial compatibility was enhanced using maleic anhydride coupling agents (5 wt%). [ABSTRACT FROM AUTHOR] more...

A poly(urethane-acrylate) polymer (PUA) was synthesized, and a sufficiently high molecular weight starting from urethane-acrylate oligomer (UAO) was obtained. PUA was then loaded with two types of powdered ligno-cellulosic waste, namely from licorice root and palm leaf, in amounts of 1, 5 and 10%, and the obtained composites were chemically and mechanically characterized. FTIR analysis of final PUA synthesized used for the composite production confirmed the new bonds formed during the polymerization process. The degradation temperatures of the two types of waste used were in line with what observed in most common natural fibers with an onset at 270 °C for licorice waste, and at 290 °C for palm leaf one. The former was more abundant in cellulose (44% vs. 12% lignin), whilst the latter was richer in lignin (30% vs. 26% cellulose). In the composites, only a limited reduction of degradation temperature was observed for palm leaf waste addition and some dispersion issues are observed for licorice root, leading to fluctuating results. Tensile performance of the composites indicates some reduction with respect to the pure polymer in terms of tensile strength, though stabilizing between data with 5 and 10% filler. In contrast, Shore A hardness of both composites slightly increases with higher filler content, while in stiffness-driven applications licorice-based composites showed potential due to an increase up to 50% compared to neat PUA. In general terms, the fracture surfaces tend to become rougher with filler introduction, which indicates the need for optimizing interfacial adhesion. [ABSTRACT FROM AUTHOR] more...

The composites based on basalt fibres and poly(lactic acid) (PLA) show promising applications in biomedical and automotive fields, but their mechanical performance is still largely hindered by poor interfacial properties. Zinc oxide nanorods have been successfully used to tune the PLA/basalt fibre interface by growing them on commercially available basalt fabrics. The hierarchical fibres significantly enhanced the mechanical properties of PLA-based composites, especially their flexural strength and stiffness. These values are 26% and 22% higher than those of unmodified basalt/PLA composites, and 24% and 34% higher than those of glass/PLA composites used as a baseline. The increase in tensile and flexural properties hinges on the mechanical interlocking action promoted by ZnO nanorods and on the creation of a compact transcrystallinity structure. A degradation of PLA matrix was detected but it was positively counteracted by the better interfacial stress transfer. This study offers a novel approach for modifying the fibre–matrix interface of biocomposites intended for high-performance applications. [ABSTRACT FROM AUTHOR] more...

Mechanical recycling is a viable option for reducing plastic waste, especially for post-consumer waste and scraps from production processes. Biodegradable polymers have gained attention as alternatives to conventional ones, and their potential for reprocessing using standard techniques before composting needs to be explored. This study focused on a commercial biodegradable polymer blend which underwent ten extrusion cycles to assess the effects of mechanical recycling on mechanical properties, rheological behavior, and thermal stability. The results indicated that the blend's mechanical properties were largely maintained across the extrusion cycles, with only a 53 % decrease in ductility. The thermal stability slightly declined by 2.3 % in T 5% onset temperature. This can be attributed to a balance between molecular chain scission (resulting in an average molecular weight reduction of approximately 8.4 %) and crosslinking phenomenon (evidenced by an increase in complex viscosity throughout the extrusion cycles). Overall, the results suggest a suitable recycling attitude of this material. • The impact of mechanical recycling on a commercial polymer blend was studied. • The mechanical recycling was simulated using repeated extrusion/injection molding. • The mechanical, rheological and thermal properties of the blend were assessed. • The reprocessing had negligible effects on the thermal stability of the blend. • The crosslinking contributed in preserving good mechanical properties. [ABSTRACT FROM AUTHOR] more...