Bio-based Composite Materials Research Articles

Bio-based composite phase change material utilizing wood fiber and coconut oil for thermal management in building envelopes

Bio-based materials are attracting substantial attention for their eco-friendly attributes within the construction field, where they facilitate energy saving and emissions reduction. However, the performance of it, such as thermal properties, needs to be improved. Fully utilizing bio-based materials, we developed a novel composite phase change material (PCM), A-WF/CO/h-BN, with high thermal storage properties designed for application in building envelopes. It incorporates coconut oil (CO) as the PCM featuring an optimal phase change temperature. Hexagonal boron nitride (h-BN) was chosen to enhance the thermal conductivity. Acetylated wood fiber (A-WF) was employed as the supporting material. The prepared A-WF/CO/h-BN sample exhibits excellent and rapid heat storage and exothermic capabilities. In the experiment of thermal performance evaluation, the cold end of the A-WF/CO/h-BN sample is cooler than that of the A-WF when both hot ends are heated. Results indicate that the proposed A-WF/CO/h-BN sample can effectively delay the heat transfer and inhibit the temperature rise and fall. For these superior properties, when the A-WF/CO/h-BN sample is applied in building envelopes, it can minimize the heat transfer from the envelope to the interior and inhibit indoor temperature fluctuation. Thus, it can reduce building energy consumption and carbon emissions while achieving indoor thermal comfort.

Insights into effect of lignocellulosic biomass framework types on bio-based shape stable composite phase change materials

The utilization of biomass waste as framework materials to inhibit the leakage of phase change material (PCMs) has gained widespread attention. In this work, three new kinds of shape stable composite phase change materials (sscPCMs) were prepared which combined with stearic acid (SA) and peanut shell powders (PSP), poplar wood powders (PWP), and corn straw powders (CSP), respectively. The influence of lignocellulosic biomass types on the thermal energy storage performance of sscPCMs was studied by comparing three types of sscPCMs. The research results indicated that SA/CSP exhibited superior properties in terms of load capacity and thermal energy storage performance. According to leakage experiments the load capacity of SA/PSP, SA/PWP and SA/CSP was 31.67 %, 44.69 %, and 50.09 %, respectively. The phase change latent heat of SA/PSP, SA/PWP, and SA/CSP was 55.78, 84.27 and 98.47 J/g, respectively. In addition, the relationship between biomass component content and load rates was studied. The results showed that there was a positive correlation between the loading rates of SA and the ratio of holocellulose (cellulose + hemicellulose) to lignin. The results provided a promising approach for the selection of lignocellulosic biomass framework materials.

Potential of Plantain Pseudostems (Musa AAB Simmonds) for Developing Biobased Composite Materials.

A plantain pseudostem was harvested and processed on the same day. The process began with manually separating the sheaths (80.85%) and the core (19.14%). The sheaths were subjected to a mechanical shredding process using paddles, extracting 2.20% of lignocellulosic fibers and 2.12% of sap, compared to the fresh weight of the sheaths. The fibers were washed, dried, combed, and spun in their native state and subjected to a steam explosion treatment, while the sap was subjected to filtration and evaporation. In the case of the core, it was subjected to manual cutting, drying, grinding, and sieving to separate 12.81% of the starch and 6.39% of the short lignocellulosic fibers, compared to the fresh weight of the core. The surface modification method using steam explosion succeeded in removing a low proportion of hemicellulose and lignin in the fibers coming from the shims, according to what was shown by Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC), achieving increased σmax and ε from the tensile test and greater thermal stability compared to its native state. The sap presented hygroscopic behavior by FT-IR and the highest thermal stability from TGA, while the starch from the core presented the lowest hygroscopic character and thermal stability. Although the pseudostem supplied two types of fibers, lower lignin content was identified in those from the core. Finally, the yarns were elaborated by using the fibers of the sheaths in their native and steam-exploded states, identifying differences in the processing and their respective physical and mechanical properties.

Valorization of Winery By-Products as Bio-Fillers for Biopolymer-Based Composites.

Grape seeds (GS), wine lees (WL), and grape pomace (GP) are common winery by-products, used as bio-fillers in this research with two distinct biopolymer matrices-poly(butylene adipate-co-terephthalate) (PBAT) and polybutylene succinate (PBS)-to create fully bio-based composite materials. Each composite included at least 30 v% bio-filler, with a sample reaching 40 v%, as we sought to determine a composition that could be economically and environmentally effective as a substitute for a pure biopolymer matrix. The compounding process employed a twin-screw extruder followed by an injection molding procedure to fabricate the specimens. An acetylation treatment assessed the specimen's efficacy in enhancing matrix-bio-filler affinity, particularly for WL and GS. The fabricated bio-composites underwent an accurate characterization, revealing no alteration in thermal properties after compounding with bio-fillers. Moreover, hygroscopic measurements indicated increased water-affinity in bio-composites compared to neat biopolymer, most significantly with GP, which exhibited a 7-fold increase. Both tensile and dynamic mechanical tests demonstrated that bio-fillers not only preserved, but significantly enhanced, the stiffness of the neat biopolymer across all samples. In this regard, the most promising results were achieved with the PBAT and acetylated GS sample, showing a 162% relative increase in Young's modulus, and the PBS and WL sample, which exhibited the highest absolute values of Young's modulus and storage modulus, even at high temperatures. These findings underscore the scientific importance of exploring the interaction between bio-fillers derived from winery by-products and three different biopolymer matrices, showcasing their potential for sustainable material development, and advancing polymer science and bio-sourced material processing. From a practical standpoint, the study highlighted the tangible benefits of using by-product bio-fillers, including cost savings, waste reduction, and environmental advantages, thus paving the way for greener and more economically viable material production practices.

Preparation of a long-term mildew resistant and strong soy protein adhesive via constructing multiple crosslinking networks

Developing strong soy protein-based adhesive (SPA) to replace harmful formaldehyde-based resins in the wood-based panel industry is a hot research. However, the lack of long-term antibacterial and antifungal properties of SPA significantly impacts its durable bonding performance and limits application. The commonly used anti-mold agents often decrease the protein compatibility and strength. Inspired by the robust and resilient dissipative matrix found in slug mucus, a green and sustainable adhesive with long-term antibacterial, antifungal properties, and excellent bonding performance was prepared using classic self-assembly and building toughened crosslinked networks. Specifically, caffeic acid and L-arginine were grafted onto tubuchitosan via acylation to prepare a chitosan with strong cationic graft modification (CCL), which combined with self-made triglycidylamine as a crosslinking agent to synergically strengthen the adhesive network. The SPA demonstrated excellent antibacterial properties against Staphylococcus aureus (20 mm) and Escherichia coli (19 mm). The prepared plywood and liquid/cured adhesive showed effective antifungal periods of 30, 80, and 120 days, respectively. Moreover, the incorporation of CCL significantly enhanced the dry and wet shear strengths of the prepared plywood to 2.73 MPa and 1.86 MPa, respectively. And a dry shear strength of 2.10 MPa and a wet shear strength of 1.53 MPa maintained even after a 30-day antifungal observation period, which still meet the interior use plywood requirement (≥0.7 MPa). The corresponding plywood after placing 30 days (1.46 MPa) is obviously higher than E0 level (0.05 mg/m3, GB18580-2017, Climate chamber method) of melamine-urea–formaldehyde resin (0 MPa after ten days). This study provides a straightforward and effective strategy for developing high performance and durable bio-based composite material, including adhesive, film, hydrogel.

Towards dynamic in situ observation of flax fibres under varying water contents through environmental SEM and X-ray tomography

Flax fibre represents one of the most promising natural components for the development of new innovative high-performance biobased composite materials. Their properties are closely related to the lumen, the central cavity of the fibre, which was only studied, to date, under unrealistic environments as in dry conditions. The objective of the current study is to characterise, at a micrometre-scale, the surface and volume modifications induced by exposure of fibres to humid atmospheres. Different dynamic characterization strategies have shown a significant opening of the hydrated lumen "channel". Values of this opening rate are discussed in the light of potential biases linked to the investigation technique (SEM versus X-ray tomography), and to the adopted acquisition approach (in situ versus ex situ). By eSEM, after a 5 min. exposure to the water-saturated environment for instance, the lumen opening value was measured at 36 ± 2% for ex-situ hydration of the bundles with a subsequent delamination of the fibre, while it was only 15 ± 2% when hydration was progressively conducted into the SEM chamber. By microtomography, the lumen swelling for the single fibre was estimated to be within the same order of magnitude, about 7%, after hydration and measurements performed under realistic atmospheric pressure.

Environmental Durability of Bio-Based and Synthetic Thermoplastic Composites in Large-Format Additive Manufacturing.

This research investigates the durability of large-format 3D-printed thermoplastic composite material systems under environmental exposure conditions of moisture and freeze-thaw. Durability was evaluated for two bio-based composite material systems, namely wood-fiber-reinforced semi-crystalline polylactic acid (WF/PLA) and wood-fiber-reinforced amorphous polylactic acid (WF/aPLA), and one conventionally used synthetic material system, namely short-carbon-fiber-reinforced acrylonitrile butadiene styrene (CF/ABS). The moisture absorption, coefficient of moisture expansion, and reduction of relevant mechanical properties-flexural strength and flexural modulus-after accelerated exposure were experimentally characterized. The results showed that the large-format 3D-printed parts made from bio-based thermoplastic polymer composites, compared to conventional polymer composites, were more susceptible to moisture and freeze-thaw exposure, with higher moisture absorption and greater reductions in mechanical properties.

Bioinspired pullulan-starch nanoplatelets nanocomposite films with enhanced mechanical properties

Inspired by the leaf-vein network structure, the pullulan-starch nanoplatelets (SNPs) bioinspired films with enhanced strength and toughness were successfully fabricated through a water evaporation-induced self-assembly technique. SNPs (SNP200 and SNP600) of two sizes were separated by differential centrifugation. Interactions between SNPs and pullulan during drying resulted in the vein-like network structure in both nanocomposite films when the appropriate amounts of SNP200 or SNP600 were added to pullulan, respectively. The TS and toughness values of pullulan with 1 % w/w SNP200 films reached up to 51.05 MPa and 69.65 MJ·m−3, which were 86 % and 223 % higher than those of the neat pullulan films, respectively. Moreover, the TS and toughness values of pullulan-SNP200 were significantly higher than those of pullulan-SNP600 films, when SNP content exceeded the 1 % w/w level. By applying a graph theory, the network structures were found to correlate with the mechanical properties of the pullulan-SNPs bioinspired films. The new strategy for designing starch nanoplatelets-based edible films that combine mechanical strength and toughness holds promises for the development of novel biobased composite materials for food packaging application.

A novel bio-based composite phase change material with excellent photo-thermal conversion capability for solar energy harvesting and energy storage

Organic solid-liquid phase change materials (PCMs) have been widely studied in the field of photo-thermal conversion and thermal energy storage. However, problems such as easy leakage and low efficiency of photo-thermal conversion limit their applications. To solve these problems, this study developed a shape-stable composite phase change material (CPCM) using sponge tissue of discarded corn stem (STCS), polyethylene glycol (PEG), pyrrole (Py), and multi-walled carbon nanotube (MWCNT). PPy and MWCNT enable the CPCM to have excellent photo-thermal conversion capability and thermal conductivity. With 0.2 % MWCNT content, the CPCM achieved a thermal conductivity of 0.4609 W/m·K and a photo-thermal conversion efficiency exceeding 95.3 %. It also demonstrated high enthalpy and relative enthalpy efficiency (152.2 J/g, 96.01 %). Moreover, the CPCM exhibited remarkable shape and thermal stability, with no pyrolysis below 340 °C and nearly unchanged enthalpy after 100 cycles. Meanwhile, this CPCM also showed excellent ability in promoting seawater desalination. This work provides a new idea for recycling of agricultural waste and storage of solar energy as well as desalination of seawater.

Anisotropic compressive properties and behavior of a bio-based composite material

In this work, the composite materials made of straw fibers from the cereal crop as bio-aggregates and lime as a binder have been developed. The compressive properties and behavior of composite specimens have been examined for various test speeds and directions. The highest density and compressive strengths are 391 kg/m3 and 0.170 MPa, respectively, in which the compressive strength is obtained in the parallel direction tested composite specimen. The highest Young’s modulus in global values is found to be 2.25 MPa for specimen test at parallel direction and 10 mm/min of speed rate of loading test. In the speed rates of 100 mm/min, stress values are faster and bigger than the specimens conducted at 10 mm/min of speed rates at the same strain level. The different behavior of specimens is obviously seen in the parallel and pouring testing specimens. The composites had been debonding on fibers-binders, buckling in fibers, and then they had been in densification. However, the debonding and buckling process are not clearly visible in the pouring directions specimen tested. Before densification, it had regularly compacting process.

Evaluation of poly(lactic acid) and ECOVIO based biocomposites loaded with antimicrobial sodium phosphate microparticles

Herein, biobased composite materials based on poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) as matrices, sodium hexametaphosphate microparticles (E452i, food additive microparticles, 1 and 5 wt%) as antimicrobial filler and acetyl tributyl citrate (ATBC, 15 wt%) as plasticizer, were developed for potential food packaging applications. Two set of composite films were obtained by melt-extrusion and compression molding, i) based on PLA matrix and ii) based on Ecovio® matrix (PLA/PBAT blend). Thermal characterization by thermogravimetric analysis and differential scanning calorimetry demonstrated that the incorporation of E452i particles improved thermal stability and crystallinity, while the mechanical test showed an increase in the Young's modulus. E452i particles also provide antimicrobial properties to the films against food-borne bacteria Listeria innocua and Staphylococcus aureus, with bacterial reduction percentages higher than 50 % in films with 5 wt% of particles. The films also preserved their disintegradability as demonstrated by an exhaustive characterization of the films under industrial composting conditions. Therefore, the results obtained in this work reveal the potential of these biocomposites as appropriated materials for antibacterial and compostable food packaging films.

Design and fabrication of bio-based functional composite materials with antibacterial, antioxidant, and improved mechanical properties based on poly (butylene adipate-co-terephthalate) (PBAT) for food packaging

The PBAT/epoxy chain extender (ADR-4468) film, with its competitive pricing, excellent biodegradability, and outstanding mechanical properties, stands out. Through experimental design, quercetin (QR) with antibacterial and antioxidant properties was effectively grafted onto the epoxy chain extender (ADR-4468), resulting in the successful synthesis of the functional modifier A-QR. PBAT composite films containing different weight percentages (0.2, 0.4, 0.6, 0.8, and 1% w/w) of A-QR were prepared using extrusion blow molding technology. QR and ADR are chemically bonded together, forming a strong and tightly knit composite. The composites exhibit excellent composite effects and outperform single-component blends, reducing A-QR migration, improving mechanical properties, and enhancing the barrier properties of the composite film. Structural, mechanical, and water barrier properties, antibacterial and antioxidant properties, as well as freshness preservation effects of the film, were analyzed. A-QR and PBAT formed a cross-linked network structure through chain extension reactions. Tensile strength increased from 19.7 MPa to 37.9 MPa, representing a 92.4% improvement. Antioxidant activity reached up to 65%. It exhibited excellent antibacterial activity against Staphylococcus aureus and Escherichia coli. The maximum total migration was only 0.7 mg/dm2, significantly below the specified overall migration limit (OML). PBAT/A-QR films successfully extended the shelf life of bananas, strawberries, apples, and oyster mushrooms due to their excellent antioxidant, antibacterial, and water barrier properties.

MXene-decorated bio-based porous carbon composite phase change material for superior solar-thermal energy storage and thermal management of electronic components

Energy storage technology based on phase change materials (PCM) can effectively solve the problem of poor energy utilization. However, PCM suffer from problems such as low thermal conductivity and easy leakage, which seriously hinder their application in fields such as thermal energy storage. To solve the above issues, this research prepared a series of novel composite PCM by immersing polyethylene glycol (PEG) into MXene-wrapped wood-based porous carbon support materials through a simple vacuum impregnation method. Specially, the balsa wood-derived porous carbon has excellent skeletal structure and hydrophilicity under 1000 °C carbonization temperature and delignification treatment. Further, the effect of MXene content on the properties of the composite PCM was systematically investigated. It was shown that the composite PCM (PDM-20) made within 20 mg/mL MXene dispersion had the best overall performance, with a significant increase in thermal conductivity up to 0.69 W m−1 K−1, the enthalpy efficiency and relative enthalpy efficiency values of 96.8 %/103.0 %, respectively, while the photo-thermal conversion efficiency reaching 90.1 %, which was much higher than that of the unmodified composite PCM. In addition, PDM-20 provided a remarkable delayed effect on the heating and cooling of electronic components. Therefore, PDM-20 prepared in this study has broad application prospects in heat storage, solar thermal absorption and heat management of electronic devices. Meanwhile, it also offers a new idea for the development and fabrication of green and environmentally friendly composite PCM.

Thermal Conductivity and Microstructure of Novel Flaxseed-Gum-Filled Epoxy Resin Biocomposite: Analytical Models and X-ray Computed Tomography.

The growing awareness of the environment and sustainable development has prompted the search for solutions involving the development of bio-based composite materials for insulating applications, offering an alternative to traditional synthetic materials such as glass- and carbon-reinforced composites. In this study, we investigate the thermal and microstructural properties of new biocomposite insulating materials derived from flaxseed-gum-filled epoxy, with and without the inclusion of reinforced flax fibers. A theoretical approach is proposed to estimate the thermal conductivity, while the composite's microstructure is characterized using X-ray Computed Tomography and image analysis. The local thermal conductivity of the flax fibers and the flaxseed gum matrix is identified by using effective thermal conductivity measurements and analytical models. This study provides valuable insight into the thermal behavior of these biocomposites with varying compositions of flaxseed gum and epoxy resin. The results obtained could not only contribute to a better understanding the thermal properties of these materials but are also of significant interest for advanced numerical modeling applications.

Ultrastrong lightweight nanocellulose-based composite aerogels with robust superhydrophobicity and durable thermal insulation under extremely environment

Ultra-lightweight porous aerogels based on nanocellulose (NC) have promising applications in various fields such as building insulation, sewage treatment, energy storage, and aerospace. One of the key advantages of these aerogels is their exceptionally low thermal conductivity. Nevertheless, the thermal insulation of NC aerogel (NCA) can deteriorate with changes in temperature and humidity conditions, making it crucial to develop a bulk aerogel that can maintain exceptional thermal insulating properties in harsh environmental conditions. A sustainable and user-friendly approach to synthesizing cellulose/poly(vinyl alcohol) aerogel (CellPA) materials has been developed, which are lightweight, possess good insulating properties, and demonstrate robust superhydrophobicity even in harsh environmental conditions. The CellPA are both exceptionally lightweight and robust, boasting outstanding resistance to combustion while also displaying a thermal conductivity of 36.1 mW m−1 K−1, suggesting they hold great promise for insulation applications. Furthermore, CellPA also exhibits robust superhydrophobicity even under harsh conditions, confirming the homogenous superhydrophobic modification of the biodegradable PVA through chemical methods. The manufacturing of bio-based composite materials with enhanced mechanical and thermal insulation features has gained immense popularity in a broad spectrum of contemporary engineering applications. These composite materials are particularly valuable as a robust, energy-efficient, lightweight, waterproof and flameproof for construction materials.

A novel carbon reducing natural composite phase change material for effective energy storage

The development of fatty acid made from natural composite materials Lac, Rosin, Flowers of silk cotton, Red ochre, Cinnabar, Beeswax, and Butter as a novel bio-based Natural Composite Phase Change Material (NCPCM) is the subject of the present study. This bio-based material was produced for the first time using natural, readily available, inexpensive, and eco-friendly with a peak phase transition temperature of 75 °C and 194 J/g as the latent heat capacity of fusion. Three distinct compositions, 2 %, 3 % and 5 % of NCPCM to the weight of the binder, were produced by the direct incorporation method into the natural hydraulic lime matrix. The newly developed NCPCM-incorporated lime mortar specimens were characterized based on their physical, mechanical, and thermal properties, and their results were compared with reference lime mortar (RLM). The compressive strength of NCPCM2 and NCPCM3 at 28 days increased by 22.64 % and 47.42 %, respectively. The produced NCPCM retains good thermal stability in its temperature operating range. The XRD findings showed that adding Lac and Rosin containing carboxylic acid esters of fatty acids increased the calcium carbonate formation. The produced FTIR validated the produced material's chemical stability, and SEM images demonstrated that the developed matrix's morphology successfully retains the added bio-additives. From an environmental perspective, the prepared NCPCM in lime mortar can reduce CO2 emissions by 296 kg·CO2/kg and 286 kg·CO2/kg. Furthermore, adding the produced NCPCM as bio-additives to lime mortar can explore the creation of sustainable mortar, which leads to environmental and economic benefits.

A new concept of bio-based prestress technology with experimental Proof-of-Concept on Bamboo-Timber composite beams

This paper presents a pioneering experimental proof-of-concept study to validate a novel concept of prestress technology that used only pure bio-based composite materials while achieved consistent prestressed stress distribution within the structure member, and provided in-situ flexibility, improved structural performance, and maximised the rate of utilisation of each material. Industrial level of facilities were used during this development. The prestress is achieved by pressurised/forced lamination of multiple components with different materials and geometrical properties. The prestressing process is activated during the pressure release stage during which the components are interacting with each other, creating different stress statuses that would favour the weaker and adverse the stronger components to maximise the strength exploitation of different materials. Using laminated bamboo and timber as an example pair, twenty-two glulam, non-prestressed and prestressed laminated bamboo-timber composite beams were manufactured, tested, and analysed to provide an in-depth understanding of the structural behaviours of these novel structural members. Failure modes, yielding, ultimate and serviceability limit loads, and corresponding deflections, as well as the histories of strain development at key positions of the specimens were examined. The experimental study confirmed the feasibility, effectiveness and industrial scalability of the proposed technology. The novel concept provides a new approach for developing the prestress technology for bio-based materials, and this experimental study laid the foundation for its future analytical development and numerical studies.

Search for Qualified Soil for the Production of Low-Energy Biobased Composite Materials

The development of earth-based bio-sourced materials requires a thorough analysis of the study soil. For the present study, we took five (05) soil samples from a tunnel-digged quarry in the layer between 0.5 m and 5 m : white clay (MSB-BL), red clay (MSB-RG), weak clay or sandy clay (MSB-FB), strong clay (MSB-FR) and mixture (MSB-ME). To verify the quality of these five (05) soils samples, their intrinsic properties were determined at the National Building and Public Works Laboratory (LNBTP). These included grain size, clay content, specific weight, loss on ignition and moisture content. These analyses revealed that MSG-RG and MSG-BL clays have fine fractions of 64.28% and 47.85% respectively; clay fractions of 27.51% and 20.61% respectively; and methylene blue values in the range (6;8). Their plasticity indices are in the range (20;40). These two (02) clays thus meet the requirements in terms of granularity, and their relatively high clay fraction will favor their adhesion with admixtures such as plant fibers. What's more, the particle size distribution of these clays is within the ideal CRAterre range for soils used in the manufacture of BTC or adobes, so they are all eligible.

3D-Printed Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)-Cellulose-Based Scaffolds for Biomedical Applications.

While biomaterials have become indispensable for a wide range of tissue repair strategies, second removal procedures oftentimes needed in the case of non-bio-based and non-bioresorbable scaffolds are associated with significant drawbacks not only for the patient, including the risk of infection, impaired healing, or tissue damage, but also for the healthcare system in terms of cost and resources. New biopolymers are increasingly being investigated in the field of tissue regeneration, but their widespread use is still hampered by limitations regarding mechanical, biological, and functional performance when compared to traditional materials. Therefore, a common strategy to tune and broaden the final properties of biopolymers is through the effect of different reinforcing agents. This research work focused on the fabrication and characterization of a bio-based and bioresorbable composite material obtained by compounding a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) matrix with acetylated cellulose nanocrystals (CNCs). The developed biocomposite was further processed to obtain three-dimensional scaffolds by additive manufacturing (AM). The 3D printability of the PHBH-CNC biocomposites was demonstrated by realizing different scaffold geometries, and the results of in vitro cell viability studies provided a clear indication of the cytocompatibility of the biocomposites. Moreover, the CNC content proved to be an important parameter in tuning the different functional properties of the scaffolds. It was demonstrated that the water affinity, surface roughness, and in vitro degradability rate of biocomposites increase with increasing CNC content. Therefore, this tailoring effect of CNC can expand the potential field of use of the PHBH biopolymer, making it an attractive candidate for a variety of tissue engineering applications.

Poisson’s ratio influence on structural dynamic properties of 3D printed bio-based sandwich with an anti-trichiral core

The main interest of this study is to analyze the effect of Poisson’s ratio (negative for auxetic materials) on the dynamic behavior of anti-trichiral structures: an experimental and numerical study is proposed. Using three-dimensional printing technology, anti-trichiral structures (cores and sandwiches) with different geometric parameters were produced with a bio-based composite material. The material used was polylactic acid (PLA) with flax fibers. The structure geometry (anti-trichiral) is the main factor that has an influence in determining its auxetic behavior. In this study, we show the effect of the elementary cell size of the anti-trichiral structure on the auxetic behavior and its impact on the static and dynamic properties of the materials. Initially, experimental tensile tests were used to establish the static characteristics of all specimens, including Poisson’s ratio values. From these results concerning Poisson’s ratios, experimental vibration tests were also carried out to determine their dynamic properties and this is to understand the field of application of these structures and to analyze their behavior in practical use. To validate experimental results, finite element studies were carried out. In this study of the dynamic properties, we observe close agreement convergence between the results of the experimental tests and the numerical analysis.