Bio-based Fillers Research Articles

Enhancement of mechanical properties of hybrid polymer composites using palmyra palm and coconut sheath fibers: The role of tamarind shell powder

This study investigates the enhancement of mechanical characteristics of hybrid polymer composites reinforced with palmyra palm leaflet (PPL) and coconut sheath leaf (CSL) fibers by integrating tamarind shell powder as a filler material. The composites were fabricated with varying ratios of PPL and CSL fibers, and their tensile strength, flexural strength, interlaminar shear strength (ILSS), impact strength, hardness, and water absorption were evaluated. The composite with 20% PPL and 10% CSL exhibited superior mechanical performance, achieving the highest tensile strength of 42 MPa, flexural strength of 94 MPa, ILSS of 7.52 MPa, and impact strength of 5.98 J. Hardness values peaked at 84 SD for the same composition. Moreover, the integration of tamarind shell powder significantly improved the mechanical properties compared to composites without filler, which showed lower values across all parameters. Water absorption tests revealed an increase in water uptake with filler incorporation, though within acceptable limits for practical applications. Scanning electron microscopy supported these results by revealing enhanced fiber-matrix bonding and better dispersion of the filler, resulting in fewer voids and defects. This research highlights the potential of bio-based fillers in optimizing the mechanical performance of hybrid composites for sustainable engineering applications.

Experimental Investigation of Low-Cost Bamboo Composite (LCBC) Slender Structural Columns in Compression

This paper experimentally investigates the behavior of innovative sustainable Low-Cost Bamboo Composite (LCBC) structural columns under compressive loading. The LCBC columns are manufactured from bamboo culms in combination with bio-based resins to form composite structural columns. Different LCBC cross-sectional configurations are investigated in this study, including the Russian doll (RD), Big Russian doll (BRD), Hawser (HAW), and Scrimber (SCR). Two bio-based resins, including one bio-epoxies and one furan-based resin, in addition to a soft bio-based filler and a synthetic epoxy resin, are applied. The bamboo species used as the cast-in-place giant bamboo for all configurations include Moso, Guadua, and Tali. Slender LCBC columns showed maximum stress equal to 60 MPa at failure. The study found that the samples with bio-epoxy resin (BE2) exhibited enhanced material stiffness when compared to synthetic epoxy (EPX) and furan-based resin (PF1), while PF1 specimens demonstrated increased ductility. Among the specimens with Moso bamboo and BE2 resin, those with SCR and HAW configurations achieved the highest compressive strengths.

Micronized Shell-Bioaggregates as Mechanical Reinforcement in Organic Coatings.

Shells are primarily composed of calcite and aragonite, making the inclusion of micronized shells as bio-based fillers in organic coatings a potential means to enhance the mechanical properties of the layers. A water-based coating was reinforced with 5 wt.% Acanthocardia tuberculata powder, 5 wt.% Mytilus galloprovincialis powder, and 5 wt.% of an LDPE/ceramic/nanoceramic composite. An improvement in abrasion resistance was achieved using micronized seashells, as demonstrated by the Taber test (evaluating both weight loss and thickness reduction). Additionally, Buchholz hardness improved with powders derived from Mytilus galloprovincialis. No significant differences were observed among the samples in terms of color and gloss after 200 h of UV-B exposure. However, the delamination length from the scratch after 168 h of exposure in a salt spray chamber indicated that the addition of particles to the polymeric matrix resulted in premature degradation, likely due to the formation of preferential paths for water penetration from the scratch. This hypothesis was supported by electrochemical impedance spectroscopy measurements, which revealed a decrease in total impedance at 0.01 Hz shortly after immersion in a 3.5% NaCl solution. In conclusion, the particle size and shape of the micronized shells improved abrasion resistance without altering color and gloss but led to a decrease in the coating's isolation properties.

Exploiting Turmeric’s Coloring Capability to Develop a Functional Pigment for Wood Paints: Sustainable Coloring Process of Polyamide 11 Powders and Their Strengthening Performance

Currently, the wood coatings industry is focusing on creating unique, vibrant finishes using new functional pigments. Simultaneously, there is a growing adoption of eco-friendly bio-based materials, reflecting trends in other sectors and supporting the circular economy. Thus, the aim of this study is to unveil a straightforward, cost-effective, and notably sustainable process for exploiting the coloring potential of turmeric powder and coloring polyamide 11-based fillers, employed as multifunctional pigments for wood coatings. Through the incorporation of this additive into a wood paint, the study demonstrates its dual effect of enhancing the aesthetics of the final composite layer while leveraging the beneficial protective properties inherent to polyamide 11. The impact of these additives on sample aesthetics is assessed through optical observations, as well as measurements of color, gloss, and surface roughness. The strengthening contribution of the functional pigment is evaluated using the Taber abrasion resistance test, static friction coefficient measurements, and Buchholz surface hardness test. Finally, the aesthetic consistency of the bio-based filler and the coloring efficiency of the sustainable process are tested by subjecting the samples to aggressive conditions, including the UV-B chamber exposure test, cold liquids resistance tests, and water uptake test. Ultimately, the study illustrates how this functional bio-based pigment not only provides sufficient protection but also meets current eco-requirements, thereby contributing to the sustainability of the wood coatings industry.

Introducing a Novel Application of Bio-Based Fillers Based on Rice Bran Wax Infused with Green Tea: Transitioning from a Cosmetic Additive to a Multifunctional Pigment for Wood Paints

Introducing a Novel Application of Bio-Based Fillers Based on Rice Bran Wax Infused with Green Tea: Transitioning from a Cosmetic Additive to a Multifunctional Pigment for Wood Paints

Synergy of Hybrid Fillers for Emerging Composite and Nanocomposite Materials-A Review.

Nanocomposites with polymer matrix provide tremendous opportunities to investigate new functions beyond those of traditional materials. The global community is gradually tending toward the use of composite and nanocomposite materials. This review is aimed at reporting the recent developments and understanding revolving around hybridizing fillers for composite materials. The influence of various analyses, characterizations, and mechanical properties of the hybrid filler are considered. The introduction of hybrid fillers to polymer matrices enhances the macro and micro properties of the composites and nanocomposites resulting from the synergistic interactions between the hybrid fillers and the polymers. In this review, the synergistic impact of using hybrid fillers in the production of developing composite and nanocomposite materials is highlighted. The use of hybrid fillers offers a viable way to improve the mechanical, thermal, and electrical properties of these sophisticated materials. This study explains the many tactics and methodologies used to install hybrid fillers into composite and nanocomposite matrices by conducting a thorough analysis of recent research. Furthermore, the synergistic interactions of several types of fillers, including organic-inorganic, nano-micro, and bio-based fillers, are fully investigated. The performance benefits obtained from the synergistic combination of various fillers are examined, as well as their prospective applications in a variety of disciplines. Furthermore, the difficulties and opportunities related to the use of hybrid fillers are critically reviewed, presenting perspectives on future research paths in this rapidly expanding area of materials science.

Synthesis of Hybrid Composites from Bio-Based Fillers: Chicken Feather, Groundnut Shell, Sawdust

Experimental research has investigated the mechanical characteristics and water absorption performance of polyethylene-based composites reinforced with sawdust, chicken feathers and groundnut shells. Composite samples have been produced with preset volumetric ratios (20%, 30%, 40%, and 50%) at 160°C and 25 kN pressure. A compression molding machine was used to produce specimens of composite materials. The findings indicate that the composites exhibit promising mechanical properties, making them potentially suitable for various applications. However, the waste polyethylene sheet was tested for comparison. It displayed a tensile strength of 7.56 MPa, impact strength with an average energy absorption of 0.093 J, and hardness strength with an average energy value of 92.72 J. The water absorbency data showed minimal water absorption for composite samples, indicating their resistance to water penetration. Similarly, the thickness swelling data revealed no significant change in thickness after immersion, demonstrating dimensional stability in the presence of moisture. This article presents the details of these experiments conducted systematically.

Lignosulfonate/silica hybrid nanoparticles as a novel biobased filler in polybenzoxazine matrix

AbstractLignin is an abundant and sustainable resource that exhibits numerous attractive functional properties as a reinforcing agent for benzoxazine‐based composites, due to its stiffness, thermal stability, and high carbon content. However, the low quality of lignin particles dispersions associated with the weak particles‐matrix interactions reduces the reinforcement capability. In this work, hybrid lignin/silica (NaLS/SiO2) nanoparticles were obtained from sodium lignosulfonate (NaLS) and tetraethylorthosilicate (TEOS) under basic conditions. The particles were characterized by transmission electron microscopy (TEM) confirming their spherical morphology and narrow nanometric‐size distributions. The hybrid particles were incorporated into conventional benzoxazine (BA‐a) and a difuran biobased benzoxazine (SA‐dfda) to prepare nanocomposites with different mass compositions (3, 5, and 10 wt%). Morphological, mechanical, dynamo‐mechanical, and thermal properties of the obtained composites were assessed. All the materials exhibited a homogenous filler dispersion that contributed to improve the reinforcement properties. Hybrid nanoparticles proved to be an interesting alternative as a filler in the benzoxazine matrix to prepare high‐performance thermosetting composites.

Recent Advances in Bio-Based Wood Protective Systems: A Comprehensive Review

This review emphasizes the recent ongoing shift in the wood coating industry towards bio-based resources and circular economy principles, promoting eco-friendly alternatives. In addressing wood’s vulnerabilities, this study investigates the use of natural compounds and biopolymers to enhance wood coatings. These materials contribute to protective matrices that safeguard wood surfaces against diverse challenges. Essential oils, vegetable oils, and bio-based polymers are explored for their potential in crafting eco-friendly and durable coating matrices. Furthermore, this review covers efforts to counter weathering and biological decay through the application of various natural compounds and extracts. It evaluates the effectiveness of different bio-based alternatives to traditional chemical preservatives and highlights promising candidates. This review also delves into the incorporation of sustainable pigments and dyes into wood coatings to enhance both protective and aesthetic qualities. Innovative pigments are able to provide visually appealing solutions in line with sustainability principles. As the wood coating industry embraces bio-based resources and the circular economy, researchers are actively developing protective solutions that encompass the coating matrix, preservatives, bio-based fillers, and natural-pigment dyes. This review showcases the continuous efforts of academia and industry to enhance wood coatings’ effectiveness, durability, and sustainability, while maintaining their aesthetic appeal.

Structural features of biobased composite foams revealed by X-ray tomography.

Polymer foams can have heterogeneous and complex internal structures, especially when material blends or particles have been integrated to create composites. It becomes even more challenging to probe and understand foam structure/properties when using non-uniform particles, such as biobased fillers. Optical or SEM imaging can only provide limited information as these are two-dimensional (2D) surface techniques. In this study, 3D X-ray tomography was applied to comprehensively analyze the structural features of biobased polyurethane foams containing porous rice hull fillers. The in-depth characterization at a wide range of length scale enabled us to quantify and obtain statistics of the unique trends in foam pore size and pore orientation corresponding to rice hull particle fraction and particle size. Rice hull particles were found to induce smaller cell formation. In addition, these biobased particles influenced cell expansion and caused cells to have less consistent orientation. Furthermore, after foam samples were subjected to cyclic compressive loading, X-ray tomography showed fractures in large (>100 μm) particles. This helps reveal the premature failing mechanism of composite foams with highly porous and coarse particles. The study elucidates novel microstructural evolution and deformation mechanisms using 3D X-ray tomography. The results offer new insights on internal structures for biobased composites and foams that are not previously possible through the conventional characterization tools.

Rice husk fibers and their extracted silica as promising bio-based fillers for EPDM/NBR rubber blend vulcanizates

Bio-based natural wastes could be considered eco-friendly alternatives to conventional fillers for enhancing the properties and reducing the cost of final rubber products. Thus, in the present research, EPDM/NBR rubber blend composites filled with kaolin and mixed with rice husk fibers (RHFs) were prepared. Homogeneity of the EPDM/NBR blends was improved by the incorporation of maleic anhydride (MAH) as a compatibilizing agent (1 phr), as evidenced by scanning electron microscopy (SEM). Of all EPDM/NBR blend ratios investigated, the 25/75 blend revealed good mechanical properties, thermal stability, and the least weight swell at equilibrium (Q%) in motor oil and brake fluid. EPDM/NBR/kaolin (25/75/30) blend vulcanizates containing RHFs at various loadings demonstrated a significant improvement in swelling resistance, primarily in motor oil and brake fluid, accompanied by a slight reduction in the mechanical properties at high RHFs content. That was complemented by the enhancement of thermal stability of the rubber blends, as demonstrated by TGA analysis. Among the filler types investigated (RHFs, silica ash (SA), rice husk silica (RHS), and kaolin), RHFs exhibited the best swelling resistance of the composite vulcanizates in motor oil and brake fluid. In addition, RHS could be used successfully as a supporting filler for carbon black-reinforced EPDM/NBR composite vulcanizates because it enhanced their thermal stability and swelling resistance in the motor oil.Graphical

The effect of Cumin Black (Nigella Sativa L.) as bio-based filler on chemical, rheological and mechanical properties of epdm composites

One of the significant problems of our time and future is environmental pollution. There are many factors that cause environmental pollution and the main concerns are waste material. Since production, consumption and service activities have increased with rapid industrialization and increasing population. Waste assessment is a process that includes minimization, separate collection at source, intermediate storage, pre-treatment, the establishment of waste transfer centers, recovery and disposal when necessary, which are qualified as outputs as a result of activities such as production, application and consumption. The purpose of waste assessment is to ensure the process of wastes generated by human action without harming the environment and human health. In this context, re-evaluation of agricultural and aquaculture products that turn into waste after being used as a product is important both in terms of economic and environmental pollution. Herein, the use of cumin black pulp, which is waste at the end of black seed oil production, as a bio-based filler material in ethylene-propylene diene rubber (EPDM) was examined. Accordingly, the effects of cumin black pulp added to the EPDM matrix at different content on the rheological, mechanical and crosslinking degree of EPDM were determined. With the use of 10 phr cumin black pulp, the mechanical and rheological properties of EPDM and the degree of crosslinking increased. The tensile strength and elongation at break of the EPDM/CB composites increased up to 11 MPa and 480% with the addition of 10 phr CB, respectively. In addition, it was revealed that the vulcanization parameters were also enhanced. Consequently, it has been concluded as a result of the analysis that the waste cumin black pulp can be used as a filling material in the EPDM matrix. Thus, it has been seen that a product in the state of waste can be recovered and become an economic value.

Cationic UV-curing of isosorbide-based epoxy coating reinforced with macadamia nut shell powder

The scientific community is deeply investigating bio-based derivatives to reduce the consumption of fossil-based material and lessen the environmental impact. The development of bio-based plastic is one of the main challenges that needs to be overcome to achieve the goal of sustainability and green economy. In this view, we exploit the use of a bio-based monomer, isosorbide, for the production of bio-based resins which can be used in coating applications. The isosorbide was functionalized in a two-step reaction to introduce epoxy groups that subsequently were activated via UV radiation to trigger cross-linking to obtain dry films. The curing process was followed by means of real time analyses such as FT-IR, photo-DSC and photorheology. The bio-based resin showed the feasibility to be used in UV-cationic curing reaching conversion above 85 %. Furthermore, a bio-based filler from macadamia nutshell was selected as an additive to the formulation with the aim of increasing the surface hardness of the final coating. A significant increase in hardness was observed for coatings containing 30 wt% of macadamia nut shell powder (MAC). In this case, the hardness reached 72 Shore D, whereas the pristine bio-based epoxy resin achieved only 19 Shore D. Thermo-mechanical analysis of the final properties was carried out by means of DMTA, DSC and tensile test. Interestingly, the addition of MAC resulted in a noticeable increase of the Tg, from 24 °C for the pristine resin to 39 °C for the coating with 20 wt% of filler. Lastly, a morphology assessment was performed to investigate the size and shape of the filler and the interaction between the polymer matrix and the filler.

Processing of tropical agro-industrial waste for particleboard manufacture: Dimensional stability and mechanical performance

Agro-industrial by-product shells are an interesting ecological and economical option to reduce the use of wood in particleboard formulation. However, knowledge of the thermal stability and physical properties of these shells is required for their use in construction materials. In this work, Doum Palm (DPS) and Balanite (BS) tropical fruit shells from the sub-Saharan region of Cameroon were characterised and processed as fillers for the manufacture of polyester-bonded particleboard. Gravimetric tests showed that water absorption and porosity were minimal for BS compared to DPS. In addition, thermogravimetric analyses indicated that both shells had almost the same thermal stability. Fifteen classes of particleboard were then manufactured by hot pressing from the prepared blends with particle sizes of 500–1250 μm, 1250–2500 μm and 2500–4000 μm, with Balanite/palm Doum (B/D) hybridisation ratios of 0/70, 20/50, 35/35, 50/20 and 70/0 by volume. The dimensional stability and mechanical performance of the samples were analysed by means of water immersion tests, and bending and internal adhesion tests, respectively. Analysis of variance (ANOVA) revealed a significant increase in density in samples containing at least 20% BS regardless of particle size, resulting in a decrease in porosity and water sensitivity with an increasing B/P ratio. The performance of the samples was much better when both shells were used in equal proportions (35/35), with density (612 kg.m−3), thickness swelling (8%) and internal bond strength (1.12 MPa) in accordance with EN312. In addition, the bending strength (4.3 MPa) and stiffness (510 MPa) were in line with literature values for shell-based particleboards. These performances make DPS and BS promising biobased fillers for the manufacture of particleboards for construction purposes.

Development of BioPolyurethane Coatings from Biomass-Derived Alkylphenol Polyols-A Green Alternative.

Bio-based polyols were obtained from the thermochemical liquefaction of two biomass feedstocks, pinewood and Stipa tenacissima, with conversion rates varying between 71.9 and 79.3 wt.%, and comprehensively characterized. They exhibit phenolic and aliphatic moieties displaying hydroxyl (OH) functional groups, as confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy (NMR) analysis. The biopolyols obtained were successfully employed as a green raw material to produce bio-based polyurethane (BioPU) coatings on carbon steel substrates, using, as an isocyanate source, a commercial bio-based polyisocyanate-Desmodur® Eco N7300. The BioPU coatings were analyzed in terms of chemical structure, the extent of the reaction of the isocyanate species, thermal stability, hydrophobicity, and adhesion strength. They show moderate thermal stability at temperatures up to 100 °C, and a mild hydrophobicity, displaying contact angles between 68° and 86°. The adhesion tests reveal similar pull-off strength values (ca. 2.2 MPa) for the BioPU either prepared with pinewood and Stipa-derived biopolyols (BPUI and BPUII). Electrochemical impedance spectroscopy (EIS) measurements were carried out on the coated substrates for 60 days in 0.05 M NaCl solution. Good corrosion protection properties were achieved for the coatings, with particular emphasis on the coating prepared with the pinewood-derived polyol, which exhibited a low-frequency impedance modulus normalized for the coating thickness of 6.1 × 1010 Ω cm at the end of the 60 days test, three times higher than for coatings prepared with Stipa-derived biopolyols. The produced BioPU formulations show great potential for application as coatings, and for further modification with bio-based fillers and corrosion inhibitors.

Composite hydrogels with host–guest interaction using cellulose nanocrystal as supramolecular filler

The functional nanocomposite hydrogels are of great interest in the research field of materials science because of their improved mechanical performances and their ability to be used in a wider range of applications. Herein, the supramolecular composite hydrogels were developed and studied using a cellulose nanocrystal (CNC) as bio-based filler. The hydrogels were designed by introducing supramolecular bonding between host β-cyclodextrin (β-CD) and guest adamantane (Ad) groups at the interface between the highly dispersed CNC and the polymer matrix. For this purpose, the CNC surface was successfully modified with Ad to act not only as a reinforcing filler in the polymer network but also as a supramolecular cross-linker with the β-CD-modified polymer. Importantly, CNC exhibited the ability of preserving their good dispersibility in aqueous media, even after modification with the hydrophobic Ad group, owing to electrostatic repulsion among negative charges incorporated onto CNC surface. Furthermore, the modification of CNC with Ad contributed to the greater interfacial compatibility between the filler and the matrix. The present study therefore highlights that the toughness of a hydrogel can be improved by the incorporation of supramolecular bonding as reversible bonding at the filler/matrix interface, which sacrificially depletes the mechanical energy upon deformation of the gels.

Hydrothermally Treated Lignin as a Sustainable Biobased Filler for Rubber Compounds

Increasing emphasis in the rubber world on the production of environmentally friendly products has created a demand for alternative reinforcing fillers. Industrial lignin side-stream of lignocellulosic biomass has gained significant interest in this respect due to its abundancy and eco-friendly nature. In the present study, a recently developed, biobased hydrothermally treated (HTT) lignin was investigated as a potential functional filler for a solution styrene butadiene and butadiene rubber blend. Commercial reinforcing fillers N330 carbon black and ULTRASIL 7000 precipitated silica were used as references. Bis(triethoxy silylpropyl)tetrasulfide silane was used as a coupling agent for in situ surface compatibilization of this hydrothermally treated lignin with the hydrophobic rubber, as is commonly done for hydrophilic silica. The influence of unmodified and silane-modified lignin on the vulcanization, morphological, static and dynamic mechanical properties was investigated and examined with the reference fillers. The overall in-rubber properties exhibited by the silane-modified hydrothermally treated lignin are superior in comparison with those of the unmodified version. In comparison with reference fillers, this modified lignin shows semireinforcing behavior. The reinforcing properties are primarily due to networking of HTT lignin particles with rubber trapped-in or formation of sponge-like HTT lignin textures in the presence of silane, as observed with atomic force microscopy. The present work describes the complex reinforcement phenomena of using a silane as coupling agent for hydrothermally treated lignin and outlines its potential as an alternative rubber reinforcing filler.

Preparation of Bio-based EPDM Rubber Composites by Utilizing Date (Phoenix dactylifera L.) Kernel as Bio-based Filler

Preparation of Bio-based EPDM Rubber Composites by Utilizing Date (Phoenix dactylifera L.) Kernel as Bio-based Filler

Technological Evaluation of Algae-Based Fillers for Polymer 3D Printing

One approach to reducing the environmental footprint of conventional polymers is to compound them with bio-based fillers. Plant-based materials have already been successfully used as polymer fillers. In this context, algae-based fillers received minor attention. Due to their unique growth efficiency and ability to capture large amounts of CO2, the use of algae-based fillers could have economic and ecologic advantages. In this work, a possible use of algae as a sustainable filler for filament materials was technologically evaluated. In practical investigations, conventional polyethylene-terephthalate-glycol (PETG) was mixed with the microalgae spirulina platensis and chlorella vulgaris and extruded to 3D printing filaments. Based on printed test specimens and material samples, the printability, mechanical, and thermal properties of the composite were determined. Filaments with a homogeneous distribution of algae particles and stable diameters up to a filler content of 30 wt.% could be produced. All filaments had good printability and adequate moisture sensitivity for higher algae contents. For 30 wt.% the tensile strength of the produced filaments decreases from 54 MPa to 24 MPa, the flexural strength decreases from 87 MPa to 69 MPa, and the material operating temperature decreases slightly from 70 °C to 66 °C. The addition of smaller amounts of algae results in minor changes regarding the overall performance. The properties of the material were comparable to those of other natural fillers such as wood, bamboo or cork. The main objective of adding bio-based materials to polymeric matrices can be achieved. Our results suggest that algae-based filaments can be produced as a more sustainable and low-cost material.

Functional Olive Pit Powders: The Role of the Bio-Based Filler in Reducing the Water Uptake Phenomena of the Waterborne Paint

In this study, olive pit powders were added to a polyurethane-acrylate paint for examining the impact of two alternative functionalization processes in increasing the filler hydrophobicity in an effort to increase the durability of the paint. In order to look into potential changes in morphology and appearance owing to the surface conversion treatments of the two bio-based additives, the coatings were examined using electron microscopy and colorimetric tests. The coating’s resilience and the hydrophobic/hydrophilic role of the fillers were evaluated by salt spray chamber exposure, contact angle measurements, paint liquid resistance, UV-B exposure, and electrochemical impedance spectroscopy measurements, which highlighted the reduction in water absorption inclination of the filler made of lignocellulose due to the silane and wax functionalization. This study demonstrated that the bio-based filler, if properly functionalized, can actually be implemented as multifunctional pigment in waterborne paints, giving specific aesthetic characteristics, but also improving the barrier performance of the polymeric matrix and increasing the durability of the composite coating.