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The growing demand for sustainable materials has driven the exploration of natural fibers as eco-friendly alternatives to synthetic reinforcements for composites. This study investigates the potential of Posidonia oceanica, an abundant marine biomass, which is often driven to be stacked on the backshore and used so far for energy recovery and low-value applications, as a filler and possible reinforcement in cementitious and polymer composites. Most applications of Posidonia are concentrated in the Mediterranean area and focused on the construction industry. However, its introduction in polymer composites, especially as a source of cellulose or in combination with the use of bio-based matrices, can also be proposed. With this aim, the physical and chemical properties of Posidonia oceanica fibers need to be characterized, and their compatibility with various matrices needs to be evaluated. Experimental results demonstrate that Posidonia oceanica fibers, especially when treated with alkali and silane, or combining both treatments, can exhibit mechanical properties quite comparable to other natural fibers, namely to those obtained from grass species. As with any other type of waste, yet with more interest for its wide accumulation over the coastal line, the use of Posidonia oceanica in composites may contribute to reducing the environmental footprint of these materials, aligning with circular economy principles. This review highlights the dual benefits of utilizing marine biomass by advancing material sustainability while not being detrimental to coastal waste management. [ABSTRACT FROM AUTHOR]

Highlights This study presents a novel equation that obtains the intrinsic flexural modulus of a natural fiber from its microfibril angle (MFA) and its crystalline cellulose content, once having estimated both parameters from X‐ray diffraction (XRD). The percentage of crystalline cellulose was estimated as the content of cellulose times the crystallinity index. Moreover, the MFA of abaca strands was obtained through an equation relating MFA with the strain at break of the strands and by XRD azimuthal integration, obtaining similar results. Fully bio‐based composites, consisting of biopolyethylene reinforced with of abaca strands at 20 to 50 wt% contents, were tested to assess the impact of the natural fibers on the flexural modulus of the composites. The intrinsic flexural modulus was also evaluated by using three micromechanics models (Hirsh equation, Halpin and Tsai equation, and its modification by Nielsen). The values obtained from the application of the new equation, the micromechanics methods, and the literature showed satisfactory agreement. Evaluation of the flexural modulus of abaca strand reinforced bio‐polyethylene composites. Use of micromechanics models to obtain the intrinsic modulus of abaca strands. Formula that correlates the intrinsic flexural modulus of abaca to its crystalline cellulose content and microfibril angle. [ABSTRACT FROM AUTHOR]

Applying coatings of paraffins and other synthetic waxes is a common approach to impart hydrophobic properties to fibres and thus control their surface characteristics. Replacing these fossil-based products with alternatives derived from renewable resources can contribute to humankind's transition to a sustainable bioeconomy. This study presents the coating of hemp fibres with waxes extracted from pine bark as an exemplar application. Two bio-based emulsifiers were used to prepare wax emulsions suitable for a dry blending process. The coatings on the fibres were characterised, quantified, and visualised using a combination of spectroscopic and microscopic techniques. Confocal fluorescence microscopy was an excellent tool to investigate the spatial distribution of the pine bark waxes on the fibre surfaces. While successful deposition was demonstrated for all tested formulations, coating homogeneity varied for different emulsifiers. Compounding the hemp fibres with a bio-based polyester resulted in the substantial improvement of the mechanical behaviour. However, the presence of a wax coating on the fibres did not lead to a significant change in mechanical properties compared to the controls with uncoated fibres. Optimising the composite chemistry or adjusting the processing conditions might improve the compatibility of the hemp fibres with the matrix material, resulting in enhanced mechanical performance. [ABSTRACT FROM AUTHOR]

The growing demand for sustainable materials has driven the exploration of natural fibers as eco-friendly alternatives to synthetic reinforcements for composites. This study investigates the potential of Posidonia oceanica, an abundant marine biomass, which is often driven to be stacked on the backshore and used so far for energy recovery and low-value applications, as a filler and possible reinforcement in cementitious and polymer composites. Most applications of Posidonia are concentrated in the Mediterranean area and focused on the construction industry. However, its introduction in polymer composites, especially as a source of cellulose or in combination with the use of bio-based matrices, can also be proposed. With this aim, the physical and chemical properties of Posidonia oceanica fibers need to be characterized, and their compatibility with various matrices needs to be evaluated. Experimental results demonstrate that Posidonia oceanica fibers, especially when treated with alkali and silane, or combining both treatments, can exhibit mechanical properties quite comparable to other natural fibers, namely to those obtained from grass species. As with any other type of waste, yet with more interest for its wide accumulation over the coastal line, the use of Posidonia oceanica in composites may contribute to reducing the environmental footprint of these materials, aligning with circular economy principles. This review highlights the dual benefits of utilizing marine biomass by advancing material sustainability while not being detrimental to coastal waste management.

Research in bio-based composites is rapidly rising in terms of fundamental experiments and industry applications. Natural fibres are one of the common bio-based materials used in composites. Natural fibres have many advantages, including low cost, biodegradable, good thermal conductivity, and may also be used as an alternative to synthetic polymer composites. However, the hydrophilic characteristic of natural fibres can lead to poor interfacial adhesion between natural fibres reinforced and matrix phases, which can affect the properties of bio-based composites. To overcome this problem, the surface modification of natural fibres is required to improve the hydrophobic properties of the composite. A few studies revealed that silane improved the hydrophobicity, tensile strength and thermal stability of bio-based composites. The highest water contact angle of the treated bio-based composite was reported at 135°. Meanwhile, the tensile strength of silane-treated bio-based composite can increase up to 40%. The onset decomposition temperature of silanes treated with bio-based composite is 20 ° C higher compared to untreated bio-based composite. This article provides an insightful review of the surface treatment of bio-based composites via silane treatment on mechanical properties, thermal properties, water absorption, and water contact angle. [ABSTRACT FROM AUTHOR]

This paper deals with the design, production and monitoring of a bio-composite footbridge with a span of 14 m across the river Dommel in the city of Eindhoven, the Netherlands. The specific bio-composite material that was used for this research is a Natural Fibre Reinforced Bio-Polymer (NFRBP). The goal of the research is to prove that NFRBP can be applied as a load-bearing structure in an outdoor environment. For this purpose, a multidisciplinary team of academic researchers from two universities and from the Centre of Expertise Biobased Economy, together with a manufacturer from the NFRBP industry, have developed a feasible design that could be produced in a short period of time and within a limited budget. The footbridge was designed, built and installed within less than one year. In the two years after the installation of the footbridge, the structural behaviour of the bridge was monitored by means of optical fibre glass strands, integrated within the structure, with the purpose of measuring deformations and change in elasticity that occur over time. [ABSTRACT FROM AUTHOR]

Natural fiber composites (NFC) were fabricated using a matrix consisting of an aqueous slurry of Osage orange (Maclura pomifera (Raf.) Schneid. family Moraceae) seed meal (OOSM) (50, 75 or 100 g L− 1) reinforced with non-woven hemp mats (450, 650, 800, 1000, 1200, or 1350 g m− 2 surface densities). OOSM behaves as a thermoset adhesive/resin similar to soy flours. Non-woven mats of 7.6 cm W × 17.8 cm L of various surface densities were soaked in aqueous slurries for 30 min under vacuum and then directly hot pressed at 185 °C and 4.3 MPa for 4:30 min. NFCs matrix:reinforcement percentages varied depending on the surface density of the hemp mat employed. NFCs were evaluated for their mechanical, physical and dimensional stability properties. The OOSM slurry matrix was found to be as effective as matrices generated from soy flour or soy protein isolate slurries. The influence of various temperatures for processing was also evaluated. [ABSTRACT FROM AUTHOR]

The process of determining the proper polymer matrix type, using a wide range of criteria, to form a natural fiber–reinforced polymer composite is still not established enough. This work introduces, for the first time, a model to select the proper polymer matrix type for natural fibers to enhance the sustainability of the automotive industry. The model was developed to rank different polymers and to determine their relative merits considering 20 different criteria simultaneously, including different physical, mechanical, chemical, environmental, and technical criteria. This work can support establishing a road map for proper selection of polymers in different engineering applications as well as increasing the reliability of the polymer selection process. [ABSTRACT FROM AUTHOR]

Hybrid bio-based composites from blends of petroleum and vegetable oil resins reinforced with natural fibers and nanoclay platelets can lead to synergistic property enhancements from the multi-scale constituents. Twelve material designs with average hemp fiber content of 30 wt%, varying nanoclay, up to 5 wt%, and epoxidized methyl linseedate (EML), up to 30%, in unsaturated polyester (UPE) were processed and their tensile, impact, and moisture properties were experimentally characterized. The resulting biocomposites displayed synergistic behavior with the effects of bio-resin addition being complemented by nanoclay and vice versa. Optimal performance with balanced properties (stiffness, toughness, and resistance to moisture absorption) was observed in material systems with 2.5 wt% nanoclay and up to 20% EML. Overall, hybrid biocomposites show promise in applications that require excellent stiffness-toughness balance. [ABSTRACT FROM AUTHOR]

Abstract: Proper utilization of the available natural resources and wastes became crucial for developing sustainability in industry. In this work, the feasibility of using the date palm fibers in the natural fiber reinforced polymer composites (NFC) for automotive industry was reported. Moreover, this work identifies a gap in the way of evaluating NFC relative to comprehensive desired criteria. This gap leads to disregard potential natural fiber types in industrial applications and keep it no more than an environmental waste problem. Here, criteria that affect the NFC were categorized and classified into levels. Governing criteria were suggested, collected and tabulated according to each level. To ensure the potential and competitiveness of the date palm fiber (DPF) in developing sustainability of the automotive industry, several comparisons between DPF and other fiber types commonly used in this industry were carried out. In most comparisons, DPF was the best selected fiber among all other types. DPF was the best regarding specific Young's modulus to cost ratio criterion. Technical properties and performance, environmental, economical, and societal aspects strongly contribute toward adopting DPF into the automotive sector to improve its sustainability and productivity. Furthermore, this adoption has a significant environmental influence throughout achieving an efficient sustainable waste management practice. [Copyright &y& Elsevier]

The Musaceae family has significant potential as a source of lignocellulosic fibres and starch from the plant's bunches and pseudostems. These materials, which have traditionally been considered waste, can be used to produce fully bio-based composites to replace petroleum-derived synthetic plastics in some sectors such as packaging, the automotive industry, and implants. The fibres extracted from Musaceae have mechanical, thermal, and physicochemical properties that allow them to compete with other natural fibres such as sisal, henequen, fique, and jute, among others, which are currently used in the preparation of bio-based composites. Despite the potential use of Musaceae residues, there are currently not many records related to bio-based composites' developments using starches, flours, and lignocellulosic fibres from banana and plantain pseudostems. In this sense, the present study focusses on the description of the Musaceae components and the review of experimental reports where both lignocellulosic fibre from banana pseudostem and flour and starch are used with different biodegradable and non-biodegradable matrices, specifying the types of surface modification, the processing techniques used, and the applications achieved. [ABSTRACT FROM AUTHOR]

Bio-epoxy resins based on five epoxidized vegetable oils were formulated with an aromatic disulfide crosslinker with diacid functionality, 2,2′-dithiodibenzoic acid (DTBA), to obtain recyclable epoxy thermosets. Flax fibres (FF) and PLA woven were used as bio-based reinforcements for these matrices. Different percentages of reinforcement were tested and the effect of the natural fibres on the matrix's crosslinking reaction was studied by DSC analysis. Then, the obtained materials were analyzed by Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), water absorption and Scanning Electron Microscopy (SEM). The reinforcements improved the thermal and mechanical properties of the neat resins, with tan δ values varying from 91 to 148 °C showing a good compatibility matrix-FF but a reduced one in case of matrix-PLA woven. The dynamic nature of the networks crosslinking allowed the chemical and mechanical recycling of both resins and bio-composites. Moreover, the obtained results show the possibility to recuperate the natural FF filler for the preparation of second-life generation bio-composites. Image 1 [ABSTRACT FROM AUTHOR]