Bio-based Binder Research Articles

StarchCrete: A starch-based biocomposite concrete for lightweight building material applications

StarchCrete is a novel composite material that utilizes starch as a biobased binder, replacing traditional inorganic binders. The composite was prepared using varying hemp shives ratios (from 0−1) at constant sand: corn starch: water ratio (5:1:1). The mixture was manually compacted into a mold and heated under microwave radiation. The effect of different starches on a composite’s compressive strength was investigated. The result reveals that high-viscosity starch leads to strong compressive strength. Increasing the hemp shives ratio significantly reduced thermal conductivity (from 0.52 to 0.15 W/(m·K)) and thermal diffusivity (from 0.85 to 0.35 mm2/s). With its strong compressive strength (2.8 MPa), low density (887 kg/m3), and low thermal conductivity (0.18 W/(m·K)), the hemp shives ratio of 0.5 was deemed appropriate. Furthermore, coating the material with paraffin wax improved its water resistance, extending its durability from 7 to 16 days, making it suitable for industrial applications.

3D Printing with Bamboo: An Early-Stage Exploration towards Its Use in the Built Environment

Along with the circular bioeconomy principles, alternative ways of utilizing biomass waste streams are considered viable approaches to reaching sustainability goals. Accordingly, a growing body of literature is exploring new materials utilizing biomass in 3D-printing applications. This article presents early-stage research that initially investigates the usability of bamboo fibers and dust with bio-based binders in 3D printing towards its use in the design and production of the built environments. The research delves into solutions through a material tinkering approach to develop a bio-based composite material that can be used in fused deposition modeling (FDM). It includes mechanical strength analyses of printed specimens to understand the effects of different infill designs on the structural performance of objects printed using bamboo-based composite. Then, it demonstrates a design-to-production workflow that integrates a mechanically informed infill pattern within a self-supporting wall design that can be produced by 3D printing with bamboo. The workflow is presented with a partial demonstrator produced through robotic 3D printing. The article concludes with discussions and recommendations for further research.

Alternative strategies for the recombinant synthesis, DOPA modification and analysis of mussel foot proteins – A case study for Mefp-3 from Mytilus edulis

Mussel foot proteins (Mfps) possess unique binding properties to various surfaces due to the presence of L-3,4-dihydroxyphenylalanine (DOPA). Mytilus edulis foot protein-3 (Mefp-3) is one of several proteins in the byssal adhesive plaque. Its localization at the plaque-substrate interface approved that Mefp-3 plays a key role in adhesion. Therefore, the protein is suitable for the development of innovative bio-based binders. However, recombinant Mfp-3s are mainly purified from inclusion bodies under denaturing conditions. Here, we describe a robust and reproducible protocol for obtaining soluble and tag-free Mefp-3 using the SUMO-fusion technology. Additionally, a microbial tyrosinase from Verrucomicrobium spinosum was used for the in vitro hydroxylation of peptide-bound tyrosines in Mefp-3 for the first time. The highly hydroxylated Mefp-3, confirmed by MALDI-TOF-MS, exhibited excellent adhesive properties comparable to a commercial glue. These results demonstrate a concerted and simplified high yield production process for recombinant soluble and tag-free Mfp3-based proteins with on demand DOPA modification.

Utilizing discarded face masks to fabricate sustainable high-performance panels for enhanced building thermal and acoustic comfort

This study aims to design, fabricate, and optimize fibrous panels made of discarded polypropylene face masks (FMs) for application in sound absorption and thermal insulation. The discarded FMs were shredded and transformed into a fibrous mass using a Garnet machine. The resulting fibers, after being mixed with a bio-based binder, were molded based on an experimental design using response surface methodology in conjunction with the central composite experiment design (RSM-CCD) with five different thicknesses, densities, and blending ratios of spunbond to meltblown fabrics. The average of the sound absorption coefficients for the twelve one‐third‐octave bands from 200 to 2500 Hz (SAA) and effective thermal conductivity (Keff) of the panels were measured as the dependent parameters. These values were calculated within the ranges of 0.28–0.53 and 0.031–0.056 W/(mK), respectively. Additionally, the interactive effects of input variables on SAA and Keff of the manufactured panels were discussed. The quadratic and two-factor interaction models were proposed for optimizing the values of SAA and Keff, respectively. The optimal conditions were determined to achieve the maximum SAA and minimum Keff in a thickness of 26.7 mm, density of 135 kg/m3, and blending percentage of 32.4 %. Under these conditions, the measured values of SAA and Keff were 0.534 and 0.0279 W/mK, respectively. Finally, three fibrous panels were manufactured under optimal conditions, and their acoustic and thermal properties were measured. It was observed that excellent agreement exists between the model results and the experimental data with a 95% confidence level. The bending properties of the optimally designed panels were also investigated and the panels exhibited an impressive flexural strength of 2.1 MPa. Additionally, the fire performance of the panels was examined and all panels showed self-extinguishing properties. These findings suggest that panels made of discarded FMs hold promise as an eco-friendly and sustainable construction material for manufacturing acoustic and thermal insulation panels. Moreover, the frequency-dependent absorption coefficients of the panels were predicted using the Johnson-Champoux-Allard model.

Particle Boards from Forest Residues and Bio-Based Adhesive

Wood chipboard, common in interior spaces for applications ranging from furniture to decorative panelling, often falls short due to the presence of toxic adhesives, posing risks to both human health and the environment. This research delves into the potential transformation of wood chipboard into a 100% bio-based product. Previous research has shown the possibility of the partial replacement of petrochemical-based adhesives with bio-based adhesives. Hence, previous results do not reach the policy ambitions of the Green Deal of making the Green Transition to a bio-based economy. For chipboard production, logging residues from Latvian State Forests were systematically gathered within two months post-logging, comprising primarily Picea abies and Pinus sylvestris biomass, including branches, needles, bark, and various particles. A custom chipper and Vibrotehnik PM-120 hammer mill were employed for particle size separation into three fractions via sieving: <2.8 mm, 2.8–8 mm, and 8.0–10.0 mm, and combined with binders and hot-pressed into board samples. As a result, particle boards containing 100% bio-based carbon were achieved, demonstrating the possibility of excluding petroleum adhesives from chipboard production, paving the way for new research exploring bio-based binders and conifer bark.

Rapid UV-curable preparation of durable soybean oil-based superhydrophobic anti-icing surfaces with excellent photothermal deicing property

Photothermal superhydrophobic coatings are promising for anti-icing/deicing. However, preparing such coatings from environmentally friendly and sustainable strategies is challenging. Herein, a bio-based and durable photothermal superhydrophobic coating is prepared via layer-by-layer strategy. Bio-based methacrylic acid epoxidized soybean oil oligomers are synthesized as an alternative to petroleum-based binders. Meanwhile, efficient photothermal conversion of hydrophobic particles are enabled by oxidative self-polymerization of dopamine to decorate hydrophobic silica particles grafted with hydrophobic long-chain alkanes and photo-curable methacrylic acid moieties. Ultimately, the superhydrophobic coating is achieved by spraying photothermal hydrophobic particles onto an oxygen-inhibited layer of pre-cured bio-based binder followed by thorough photocuring treatment. The coating exhibits powerful water repellency (WCA of 158.2 ± 1.6°, SA of 4.6 ± 0.8°), good robustness, chemical and UV irradiation resistance. Moreover, under NIR laser irradiation (808 nm, 1 W/cm2), the coating features excellent photothermal conversion efficiency (ΔT of 41.0 °C at 30 s) and stable photothermal conversion performance. And in frigid conditions (-15 °C, ∼73 ± 5 % RH), the coating delivers rapid defrosting (few seconds) and deicing (20 μL water droplet melts in 42 s) performance under NIR irradiation of 1 W/cm2. Therefore, the as-prepared coating provides valuable insight into global anti-icing/deicing action.

Cellulose nanofibrils as a bio-based binder for wood fiber composite insulation panels with enhanced thermo-mechanical properties for structural wall sheathing applications

A low-density wood fiber insulation panel (WIP) composite was developed with 100 % petrochemical-free, bio-based binder with high mechanical strength, water resistance and thermal insulation properties. This study investigated the manufacturing process of composite WIPs made with mechanical pulp fibers with cellulose nanofibrils (CNFs), lignin-containing CNFs (LCNFs), hybridized CNFs-LCNFs, and CNFs-starch as a binder on different scales and evaluated the effects of binder type and content on the panels’ physical, mechanical, and thermal properties. All panels had excellent thermal resistivity values, which increased with the decrease in density. The WIPs made with LCNFs as binder had lower mechanical properties, but it was possible to replace 20 % CNFs with LCNFs to obtain the same performance as neat CNFs as the binder. Untreated panels had poor water resistance but the water absorption properties were significantly improved with the addition wax. The WIPs made with 5 % and 7.5 % binder content and 2 % wax addition could fulfill the criteria of regular and structural wall sheathing applications, respectively. Overall, the results confirm the potential of CNFs and LCNFs to be used as 100 % bio-based adhesives to produce eco-friendly composite WIPs with excellent thermo-mechanical properties to be used for regular and structural wall sheathing applications.

Characterization of hybrid charcoal briquettes from date palm and pistachio residues and bio-based binders

As a solid biofuel, briquette is a renewable energy technology that has attracted enormous attention in the sustainable energy sector and can replace fossil fuels to reduce greenhouse gas emissions. This research developed hybrid charcoal briquettes using biochar of date palm and pistachio residues. Starch, molasses, and bitumen were used as binders to produce the hybrid briquettes with different contents. The briquettes were compacted at pressure levels of 100 bar using a hydraulic press. Compressed density, relaxed density, compaction ratio, impact resistance index (IRI), shatter index, and compressive strength were determined using standard procedures. The results showed that the relaxed density of the hybrid briquettes ranged from 0.63 to 1.03 g/cm3, and their compressive strength ranged from 0.46 to 22.17 N/mm. The briquettes made of the starch binder at a content of 20% exhibited superior properties. The higher the binder content, the better the quality of the briquettes for storage and transportation.

Nanoarchitectonics of 3D-networked bio-based binders for silicon anodes in lithium-ion batteries based on dynamic hydrogen bonding

A bio-based binder was developed to improve the electrochemical performance of silicon-anode lithium-ion batteries.

Regioselective palladium-catalysed aerobic oxidation of dextran and its use as a bio-based binder in paperboard coatings.

The coatings industry is aiming to replace petrochemical-based binders in products such as paints and lacquers with bio-based alternatives. Native polysaccharide additives are already used, especially as adhesives, and here we show the use of oxidised dextran as a bio-based binder additive. Linear dextran with a molecular weight of 6 kDa was aerobically oxidised in water at the C3-position of its glucose units, catalysed by [(neocuproine)PdOAc]2(OTf)2. The resulting keto-dextran with different oxidation degrees was studied using adipic dihydrazide as a crosslinker in combination with the commercial petrochemical-based binder Joncryl®. Coating experiments show that part of the Joncryl® can be replaced by keto-dextran while maintaining the desired performance.

Studies on Tamarind Seed Kernel-Based Bio Composites for Fire Performance and Degradability to Enhance Shelf Life, Under the Influence of Additives

Natural fibre reinforced composites have received a lot of interest in recent years as prospective building components for low-cost applications. Natural fibers offer good opportunity as composite reinforcement, as they are strong, light, cheap and renewable. Numerous experiments have been conducted to emphasize the use of bio-based materials for various applications. Considering environmental aspects, the current research is concentrated on bio-based binder and reinforcement. The objective here is to conduct various experiments for fire behaviour to justify its insulation property, fungal behaviour for degradability, moisture absorption and mechanical properties in order to tabulate results and to quantify the variations. Justify optimal composition and parameter responsible for variation by DOE-Taguchi technique. Experimental results presented reduction in burning rate with increase in Tamarind Seed Kernel Gum (TSG), attaining lowest of 8.29 mm/min at 60% Paper Cellulose (PC) and 40% TSG falling within the class of UL94HB for horizontal testing, 26.92 mm/min for vertical testing. The PC in combination with TSG influenced development of ‘Mucore’ category fungus resulting in rapid degradation, this is addressed by additives namely ‘Boric Acid’ and ‘Turmeric Powder’. Poor performance observed in terms of moisture behaviour hampering the sustainability of composites.

Comparative Life Cycle Assessment of SLS and mFFF Additive Manufacturing Techniques for the Production of a Metal Specimen.

This work is part of a research project aimed at developing a bio-based binder, composed mainly of polylactic acid (PLA), to produce Ti6Al4V feedstock suitable for use in MAM (Metal Additive Manufacturing) via mFFF (metal Fused Filament Fabrication), in order to manufacture a titanium alloy specimen. While in Bragaglia et al. the mechanical characteristics of this sample were analyzed, the aim used of this study is to compare the mentioned mFFF process with one of the most used MAM processes in aerospace applications, known as Selective Laser Sintering (SLS), based on the Life Cycle Assessment (LCA) method. Despite the excellent properties of the products manufactured via SLS, this 3D printing technology involves high upfront capital costs while mFFF is a cheaper process. Moreover, the mFFF process has the advantage of potentially being exported for production in microgravity or weightless environments for in-space use. Nevertheless, most scientific literature shows comparisons of the Fused Filament Fabrication (FFF) printing stage with other AM technologies, and there are no comparative LCA "Candle to Gate" studies with mFFF processes to manufacture the same metal sample. Therefore, both MAM processes are analyzed with the LCA "Candle to Gate" method, from the extraction of raw materials to the production of the finished titanium alloy sample. The main results demonstrate a higher impact (+50%) process for mFFF and higher electrical energy consumption (7.31 kWh) compared to SLS (0.32 kWh). After power consumption, the use of titanium becomes the main contributor of Global Warming Potential (GWP) and Abiotic Depletion Potential (ADP) for both processes. Finally, an alternative scenario is evaluated in which the electrical energy is exclusively generated through photovoltaics. In this case, the results show how the mFFF process develops a more sustainable outcome than SLS.

Environmental Life Cycle Assessment of a Novel Hemp-Based Building Material.

The global construction sector contributes a significant share of total greenhouse gas (GHG) emissions. In Australia, infrastructure activity alone generates 18% of the GHG emissions. The use of low-embodied carbon building materials is crucial to decarbonise the construction sector and fulfil national and international climate goals. Industrial hemp (Cannabis sativa L.) is a promising feedstock for low-carbon construction materials because of its carbon sequestration capacity, fast-growing cycles, and technical functionality comparable to traditional materials. This study utilised the life cycle assessment (LCA) guideline ISO 14040:2006 to estimate the carbon footprint (CF) of hemp-based building materials in Western Australia capturing region-specific variations in terms of inputs, soil, productivity, and energy mix. The functional unit was 1 m2 of a hemp-based board, and the system boundary was cradle-to-gate, i.e., pre-farm, on-farm, and post-farm activities. The CF of 1 m2 of hemp-based board was estimated to be -2.302 kg CO2 eq. Electricity from the public grid for bio-based binder production during the post-farm stage was the main contributor to total CO2 eq emissions (26%), followed by urea production (14%) during the pre-farm stage. Overall, the use of electricity from the public grid during the post-farm stage accounted for 45% of total emissions. Sensitivity analysis showed that the CF of hemp-based boards was highly sensitive to the source of energy; i.e., total replacement of the public grid by solar power decreased the CF by 164% (-2.30 to -6.07 kg CO2 eq). The results suggested that hemp-based boards exhibit lower embodied GHG emissions compared to traditional materials, such as gypsum plasterboards.

Polylactic acid as biobased binder for the production of 3D printing filaments for Ti6Al4V alloy manufacturing via bound metal deposition

In this paper, a biobased binder mainly composed of polylactic acid (PLA) was developed for the production of Ti6Al4V feedstock suitable for 3D printing via material extrusion. 3D printed samples were debound via solvent and thermal treatments and successfully sintered in reducing atmosphere obtaining dense metallic components. The designed and produced bio-binder is completely eliminated during the debinding processes leading to sintered samples showing a high densification (93–94%), with a microstructure composed of primary alpha phase with segregated beta phase at grain boundaries and having average grain size of 70 μm. 3D printed sintered samples show good mechanical properties (yield strength (σy) = 662 MPa, ultimate tensilte strength (UTS) = 743 MPa, elongation at break (εmax) = 12%, hardness = 5.15 GPa) influenced by the sintering parameters and the presence of some degree of micro-porosity in the final structure.

A biobased binder of carboxymethyl cellulose, citric acid, chitosan and wheat gluten for nonwoven and paper

The amount of disposable nonwovens used today for different purposes have an impact on the plastic waste streams which is built up from several single-use products. A particular problem comes from nonwoven products with “hidden” plastic (such as cellulose mixed with synthetic fibers and/or plastic binders) where the consumers cannot see or expect plastic. We have here developed a sustainable binder based on natural components; wheat gluten (WG) and a polyelectrolyte complex (PEC) made from chitosan, carboxymethyl cellulose and citric acid which can be used with cellulosic fibers, creating a fully biobased nonwoven product. The binder formed a stable dispersion that improved the mechanical properties of a model nonwoven. With WG added, both the dry and the wet strength of the impregnated nonwoven increased. In dry-state, PEC increased the tensile index with >30 % (from 22.5 to 30 Nm/g), and with WG, with 60 % (to 36 Nm/g). The corresponding increase in the wet strength was 250 % (from 8 to 28 Nm/g) and 300 % (to 32 Nm/g). The increased strength was explained as an enrichment of covalent bonds (ester and amide bonds) established during curing at 170 °C, confirmed by DNP NMR and infrared spectroscopy.

Development of a novel infrared methodology to assess the degree of blending in cold and warm recycled asphalt mixtures incorporating a bituminous or bio-based virgin binder

2/3 of the reclaimed asphalt pavement (RAP) amount is used for recycling of European asphalt mixtures. An issue that remains unresolved is the blending between the RAP binder and the new binder. Using infrared microscopy, the binder blending is assessed in low-energy mixtures using a bituminous or bio-based binder. Infrared data were acquired and quantified using average and standard deviation indicators; their evolution is monitored over 3 months. A relationship between the average and the binder concentration is highlighted. Binders homogeneity depends on the RAP content and virgin binder. On cold mixes, infrared data evolve over time, highlighting emulsion curing.

Bio-Based Binder Development for Lithium-Ion Batteries.

The development of rechargeable lithium-ion battery (LIB) technology has facilitated the shift toward electric vehicles and grid storage solutions. This technology is currently undergoing significant development to meet industrial applications for portable electronics and provide our society with "greener" electricity. The large increase in LIB production following the growing demand from the automotive sector has led to the establishment of gigafactories worldwide, thus increasing the substantial consumption of fossil-based and non-sustainable materials, such as polyvinylidene fluoride and/or styrene-butadiene rubber as binders in cathode and anode formulations. Furthermore, the use of raw resources, such as Li, Ni, and Mn in cathode active materials and graphite and nanosilicon in anodes, necessitates further efforts to enhance battery efficiency. To foster a global sustainable transition in LIB manufacturing and reduce reliance on non-sustainable materials, the implementation of bio-based binder solutions for electrodes in LIBs is crucial. Bio-based binders such as cellulose, lignin, alginate, gums, starch, and others can address environmental concerns and can enhance LIBs' performance. This review aims to provide an overview of the current progress in the development and application of bio-based binders for LIB electrode manufacturing, highlighting their significance toward sustainable development.

CNSL oxyacetic derivatives, new bio-based binders for paint preparation

The global coating industry produces tens of millions of metric tonnes of paints each year, and this quantity continues to grow. Most of these paints are obtained totally or partially from fossil resources, and many of them still use volatile organic compounds (VOCs) and/or other harmful chemicals. This paper describes the use of the cashew nutshell liquid (CNSL) as a raw material for synthesis of paint binders (sustainable materials). These binders are obtained in a single chemical step without tedious separation. These new bio-based materials (renewable resources) form stable films (green coatings) in a short drying time. The formulated paints are 100% aqueous, have low toxicity and ecotoxicity and require no additional drying agents or VOCs. Oxidative coupling of the alkylidene chain and addition of carboxylic acid to the carbon–carbon double bonds are implemented. The products obtained can be applied on different kinds of surfaces, such as glass slides, metal, wood or concrete, and exhibit good stability against various solvents and tropical conditions.

The use of nature’s own chemistry to produce hydrophobic binders for nonwovens, combining a polyelectrolyte complex and pea protein

Chemically bonded nonwovens are strong, paper-like materials that traditionally contains a latex binder comprising a plastic polymer and (often) cellulosic fibers. With this composition, these materials are only partly biobased, having a low biodegradability and cannot be recycled in traditional waste streams. In the strive for a fully biobased nonwoven system with a hydrophobic character, a biobased binder (polyelectrolyte complex, PEC) out of carboxymethyl cellulose and chitosan dissolved in citric acid) was here combined with pea protein (PP). By varying the fat content in the pea protein, as well as the content of the protein in the binder, it was possible to obtain different degrees of cellulosic nonwoven hydrophobicity and mechanical properties. At equal amounts of PEC and PP, the cured system showed a contact angle of ≈ 120°, which was stable in time. As compared to the binder-free nonwoven, the dry strength was doubled in the presence of defatted PP, and the stiffness and strength in the wet state was significantly higher for all combinations between PEC and PP.

Cellulose nanofibers as a green binder for symmetric carbon nanotubes-based supercapacitors

The demand for flexible lightweight supercapacitors (FSCs), mainly applied in flexible electronics, has spun by the ever-increasing energy storage market. To meet the market criteria, electrodes with high porosity and specific surface areas are ideal candidates as lightweight and flexible supercapacitors components. This work highlights the use of nanocellulose as a bio-derived binder for flexible supercapacitors. This binder contributes to the enhancement of electrochemical performance due to its 1D fibrous hierarchical structures. In turn, nanocellulose is a promising candidate for medical and implantable devices owing to its biocompatibility. Here, we report the fabrication of freestanding, flexible, porous, and conductive electrodes via a facile scalable fabrication process. The electrodes are comprised of multi-walled carbon nanotubes as the conductive material and cellulose nanofibers as the bio-based binder. Due to the combined synergistic effect of carbon nanotubes and cellulose nanofibers, the fabricated electrodes show a high porosity. The effect of cellulose type was evaluated at 16 wt.%, which showed no significant effect on the electrochemical performances at this percentage. However, we demonstrate that the cellulose dry content for a specific cellulose type affects the electrochemical performances, with optimized performances for a dry cellulose percentage between 4 and 6 wt.%. In these formulations, the ratio between nanocellulose and CNTs contributes to the formation of porous and conductive nanosheets. The samples’ porosity was assessed regarding their specific surface area (N2 Adsorption-desorption) while scanning electron microscopy (SEM) emphasized their morphology. Due to the high porosity as well as conductivity, the samples showed a good specific capacitance (∼ 9 F/g) and outstanding cycling stability with an increase in specific capacitance of about 10% after 3500 cycles at 0.13 A/g.