Biodegradable Binder Research Articles

Innovative Hemp Shive-Based Bio-Composites: Part I: Modification of Potato Starch Binder by Sodium Meta-Silicate and Glycerol

The growing demand for sustainable building materials has boosted research on plant-based composite materials, including hemp shives bound with biodegradable binders. This study investigates the enhancement of potato-starch-based binders with sodium metasilicate and glycerol to produce eco-friendly bio-composites incorporating hemp shives. Potato starch, while renewable, often results in suboptimal mechanical properties and durability in its unmodified form. The addition of sodium metasilicate is known to improve the mechanical strength and thermal stability of starch-based materials, while glycerol acts as a plasticizer, potentially enhancing flexibility and workability. Bio-composites were produced with varying concentrations of sodium metasilicate (0–107% by mass of starch) and glycerol (0–133% by mass of starch), and their properties were evaluated through thermal analysis, density measurements, water absorption tests, compressive strength assessments, and thermal conductivity evaluations. The results demonstrate that sodium metasilicate significantly increases the bulk density, water resistance, and compressive strength of the bio-composites, with enhancements up to 19.3% in density and up to 2.3 times in compressive strength. Glycerol further improves flexibility and workability, though excessive amounts can reduce compressive strength. The combination of sodium metasilicate and glycerol provides optimal performance, achieving the best results with an 80% sodium metasilicate and 33% glycerol mixture by weight of starch. These modified bio-composites offer promising alternatives t2 o conventional building materials with improved mechanical properties and environmental benefits, making them suitable for sustainable construction applications.

Eco-friendly screen printing of silver nanowires for flexible and stretchable electronics.

Screen printing is a promising route towards high throughput printed electronics. Currently, the preparation of nanomaterial based conductive inks involves complex formulations with often toxic surfactants in the ink's composition, making them unsuitable as an eco-friendly printing technology. This work reports the development of a silver nanowire (AgNW) ink with a relatively low conductive particle loading of 7 wt%. The AgNW ink involves simple formulation and comprises a biodegradable binder and a green solvent with no toxic surfactants in the ink formulation, making it an eco-friendly printing process. The formulated ink is suitable for printing on a diverse range of substrates such as polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyimide (PI) tape, glass, and textiles. By tailoring the rheological behaviour of the ink and developing a one-step post-printing process, a minimum feature size of 50 μm and conductivity as high as 6.70 × 106 S m-1 was achieved. Use of a lower annealing temperature of 150 °C makes the process suitable for plastic substrates. A flexible textile heater and a wearable hydration sensor were fabricated using the reported AgNW ink to demonstrate its potential for wearable electronic applications.

Thermal insulation panels for buildings using recycled cardboard: Experimental characterization and optimum selection

Buildings contribute a major part to the energy use in the world. Thermal insulation of buildings is a passive strategy to achieve energy efficiency by reducing heating and cooling loads. Using recycled materials ensures efficient use of available resources by reducing material consumption. This study reports fabrication of thermal insulation panels using recycled cardboard aggregates and different biodegradable binders (corn starch, lime, clay) in varying percentage weight fractions and experimental characterization of their physical, thermal, mechanical and microstructural properties. Cardboard aggregates have been homogenized with binders and additives to fabricate nine panels. All the panels have reported good thermal conductivity values due to their porous nature, and sufficient compressive and flexural strength for use as thermal insulation in buildings. Strong adhesion between cardboard aggregates and cornstarch binder has been observed in SEM (Scanning Electron Microscope) analysis. This study also addresses selection of the optimum insulation material from various fabricated panels by considering the complex constraints that exist between physical, thermal and mechanical properties. Results of the study prove that the fabricated panels can be used for thermal insulation in buildings and can be further investigated for commercial use.

Poly(hydroxybutyrate-co-hydroxyvalerate) as a biodegradable binder in a negative electrode material for lithium-ion batteries

In this work, graphite-based negative electrode for lithium-ion battery consisting a novel and biodegradable binder poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is compared with standard graphite electrode with polyvinylidene fluoride (PVDF) as a binder. The rate and cycling performance of lithium ion insertion/extraction of electrodes with PHBV in a half-cell configuration are evaluated. Moreover, on the basis of the electrochemical tests it is concluded that the electrode with PHBV binder is characterized by similar specific capacity and diffusion coefficient of lithium ions as conventional graphite electrode with PVDF binder.

Plastic-free chitosan and cellulose binder providing dry and wet strength to paper and nonwoven

Chemically-bonded nonwoven is commonly used in single-use products, and are often composed of cellulose fibers with a fossil-based binder. To reduce the amount of plastic littering, we investigated a biobased and biodegradable binder consisting of polyelectrolyte complexes based on chitosan, carboxymethyl cellulose and citric acid. The binder significantly improved the mechanical properties of two different types of cellulosic fiber systems in both dry and wet states. The quality of the water used in the binder had a significant impact on the mechanical properties, especially in the dry state, indicating a beneficial effect by the presence of cations. It was shown that covalent bonds were formed during the low temperature drying, and that the amount of bonds increased with a high temperature curing. Electron microscopy and tensile data indicated that the binder acted as a joint between the fiber/fiber parts. The presented results enable a sustainable solution for the current plastic-based nonwoven industry.

Application of Poly-L-Lysine for Tailoring Graphene Oxide Mediated Contact Formation between Lithium Titanium Oxide LTO Surfaces for Batteries.

When producing stable electrodes, polymeric binders are highly functional materials that are effective in dispersing lithium-based oxides such as Li4Ti5O12 (LTO) and carbon-based materials and establishing the conductivity of the multiphase composites. Nowadays, binders such as polyvinylidene fluoride (PVDF) are used, requiring dedicated recycling strategies due to their low biodegradability and use of toxic solvents to dissolve it. Better structuring of the carbon layers and a low amount of binder could reduce the number of inactive materials in the electrode. In this study, we use computational and experimental methods to explore the use of the poly amino acid poly-L-lysine (PLL) as a novel biodegradable binder that is placed directly between nanostructured LTO and reduced graphene oxide. Density functional theory (DFT) calculations allowed us to determine that the (111) surface is the most stable LTO surface exposed to lysine. We performed Kubo–Greenwood electrical conductivity (KGEC) calculations to determine the electrical conductivity values for the hybrid LTO–lysine–rGO system. We found that the presence of the lysine-based binder at the interface increased the conductivity of the interface by four-fold relative to LTO–rGO in a lysine monolayer configuration, while two-stack lysine molecules resulted in 0.3-fold (in the plane orientation) and 0.26-fold (out of plane orientation) increases. These outcomes suggest that monolayers of lysine would specifically favor the conductivity. Experimentally, the assembly of graphene oxide on poly-L-lysine-TiO2 with sputter-deposited titania as a smooth and hydrophilic model substrate was investigated using a layer-by-layer (LBL) approach to realize the required composite morphology. Characterization techniques such as X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), scanning electron microscopy (SEM) were used to characterize the formed layers. Our experimental results show that thin layers of rGO were assembled on the TiO2 using PLL. Furthermore, the PLL adsorbates decrease the work function difference between the rGO- and the non-rGO-coated surface and increased the specific discharge capacity of the LTO–rGO composite material. Further experimental studies are necessary to determine the influence of the PLL for aspects such as the solid electrolyte interface, dendrite formation, and crack formation.

Mechanical and Biocompatibility Properties of Sintered Titanium Powder for Mimetic 3D-Printed Bone Scaffolds.

A composite comprising Ti and NaCl powders was sintered similar to a three-dimensional (3D)-printed patient-customized artificial bone scaffold. Additionally, a proper microstructure of the mimetic scaffold and the optimum processing parameters for its development were analyzed. The mechanical properties of the metal-based porous-structured framework used as an artificial bone scaffold were an optimum replacement for the human bone. Thus, it was confirmed that patient-customized scaffolds could be manufactured via 3D printing. The 3D-printed mimetic specimens were fabricated by a powder-sintering method using Ti for the metal parts, NaCl as the pore former, and polylactic acid as the biodegradable binder. Scanning electron microscopy (SEM) images showed that pores were formed homogeneously, while X-ray computed tomography confirmed that open pores were generated. The porosity and pore size distribution were measured using a mercury porosimeter, while the flexural strength and flexural elastic modulus were calculated using the three-point bending test. Based on these measurements, a pore-former content of 15 vol % optimized the density and flexural strength to 2.52 g cm–2 and 283 MPa, respectively, similar to those of the actual iliac bone. According to the 3D-printing production method, a selective laser-sintering process was applied for the fabrication of the mimetic specimen, and it was determined that the microstructure and properties similar to those of previous metal specimens could be achieved in the as-prepared specimen. Additionally, a decellularized extracellular matrix (dECM) was used to coat the surfaces and interiors of the specimens for evaluating their biocompatibilities. SEM image analysis indicated that the adipose-derived stem cells grew evenly inside the pores of the coated specimens, as compared with the bulky Ti specimens without the dECM coating. The doubling time at 65% was measured at 72, 75, and 83 h for specimens with pore-former contents of 5, 10, and 15 vol %, respectively. The doubling time without the pore former was 116 h. As compared with the specimens without the pore former (73 h), 15% of the dECM-coated specimens showed a doubling time of 64%, measured at 47 h.

Development of novel persulfate tablets for passive trichloroethylene (TCE)-contaminated groundwater remediation

In this study, a biodegradable binder, hydroxypropyl methyl cellulose (HPMC), was used for the first time to mix with persulfate powder for developing novel persulfate-releasing tablets to remediate trichloroethylene (TCE)-contaminated groundwater. To obtain feasible parameters for the preparation of persulfate tablets, different pressures, HPMC/tablet mass ratios, and persulfate dosages were evaluated. The results showed that the persulfate tablet released 2868 mg-persulfate/day for 12 days under the optimal manufacturing parameters of HPMC/tablet mass ratio of 0.5 and pressure of 4.90 × 108 N/m2. Persulfate diffusion and gel layer erosion were dominant mechanisms for controlling the persulfate released in water. The persulfate release time and rate can be controlled by adjusting the persulfate dosage at the optimal HPMC/tablet ratio. In the column experiment, TCE with an initial concentration of 70 mg/L reached 55% removal efficiency by the tablet, which showed that the developed tablet was capable of degrading highly concentrated TCE. The results of electron spin resonance (ESR) spectroscopy showed that both SO4−· and ·OH were responsible for the oxidation of TCE. During 150 days of incubation, the biodegrading efficiency of HPMC by microbes in soil and activated sludge was 67% and 80%, respectively, under aerobic conditions, while 58% of HPMC was removed by soil bacteria under anaerobic conditions. The results showed that persulfate tablets could be used as a passive groundwater remediation system. There is no waste generated after persulfate is completely released during groundwater remediation. The developed persulfate tablets are environmentally friendly and meet the green remediation aspect.

Excellent Wideband Acoustic Absorption of a Multifunctional Composite Fibrous Panel with a Dual-Pore Network from Milled Corrugated Box Wastes

A multifunctional composite fibrous sound-absorption panel was acquired via sustainable fabrication from milling corrugated cardboard box wastes to unleash its fibrous property, creating a high-porosity material. Here, a multifunctional composite fibrous panel from the milled fibers of corrugated cardboard boxes reinforced by cross-linked polyvinyl alcohol as a biodegradable binder is generated. It is designed to have a dual-pore structure with a low density of 0.04 g/cm3, which can withstand a load of 5000 times its weight and is effective for the dissipation of sound at a wide range of frequencies. The prepared material demonstrates an excellent average absorption coefficient of 0.83 at wideband frequency, which is about 280–6300 Hz. The outstanding sound absorption performance of the material is primarily ascribed to its dual-pore architecture, the anisotropic pores interconnected by the random pores formed from the collection of cardboard box fibers within the architecture of the porous material, its thickness, and the concentration of corrugated box fibers. Furthermore, the prepared material manifests a unique porous morphological structure, favorable thermal properties, excellent mechanical stability and sustainability, and superhydrophobic properties. The successful fabrication of this riveting material endowed a promising result that may be applicable for various types of applications.

Poly(Hydroxybutyrate-Co-Hydroxyvalerate) as a Biodegradable Binder in a Negative Electrode Material for Lithium-Ion Batteries

Poly(Hydroxybutyrate-Co-Hydroxyvalerate) as a Biodegradable Binder in a Negative Electrode Material for Lithium-Ion Batteries

In Vitro Evaluation of Dalbergia sissoo and Acacia modesta gum as Pharmaceutical Binders for Drug Delivery System

The present study aimed to compare the crude, modified and hydrolyzed gums of Dalbergia sissoo and Acacia modesta as a biodegradable binder for drug delivery system using acetaminophen as a model drug. The physiochemical properties such as pH, fluorescence analysis and swelling index were determined. The gums were hydrolyzed and modified. Acetaminophen tablets were prepared using wet granulation technique and the gum solutions were used as a binder. Hydroxypropyl methylcellulose was used as a synthetic binder. Different properties of granules and tablets were evaluated. Results showed that both gums were acidic in nature, while D. sissoo and A. modesta showed light brown and creamy color in fluorescence analysis. The swelling ratio was the highest in water followed by 0.1N HCl and least in phosphate buffer. The prepared tablets showed faster and slower dissolution profiles in the same dissolution system. The crude gums have the highest dissolution rate, and this rate was decreased in the case of modified and hydrolyzed gums samples. The crude gums showing slower release can be useful in sustained-release tablets, while the modified gums having faster release rate are helpful in conventional tablet formulation. Taken together, the selected gums could be a good model for evaluation as a binder or hydrophilic polymer in tablet formulation.

Green Fabrication of Bio-based Aerogels from Coconut Coir for Heat Insulation and Oil Removal

Each year, the global annual production of coconut fibre (CF) is around 350×103 t, while they are utilized for fine art, fertilization, and animal feed. However, there have not seen many engineering applications to utilize these materials. The coir with high cellulose content of over 40 % has potential for high-value engineering applications like fabricating cellulose-based aerogels. Recently, the cellulose aerogel from CF was formed using a sol-gel method in an NaOH/Urea solution, with an anticipated completion time of 7 d due to the time required for gelation and solvent exchange, which might take up to 4 d. This demonstrates that the present approach is subject to several time limitations. To improve this, for the first time, a novel fabrication of aerogels from the CF with chemical pre-treatment in advance has been successfully developed by using polyvinyl alcohol (PVA) and xanthan gum (XTG) as biodegradable binders. The treated CFs are dispersed homogeneously into a PVA/XTG solution, followed by freeze-drying to remove water, leaving behind a highly porous called CF aerogel. The influences of CF content on CF aerogels' physical and mechanical characteristics, as well as oil adsorption and thermal conductivity, have all been thoroughly investigated. For oil removal, the fabricated CF aerogels are surface-modified with methyltrimethoxysilane (MTMS) to enhance their hydrophobicity. This method required 2 times less time and used fewer chemicals while retaining the same oil adsorption capabilities of up to 20 g/g as previous CF aerogel and demonstrating additional good insulation of 0.040 W/(m·K). Thus, this study provides a new novel approach to synthesize an oil-absorbing and insulating CF aerogel.

Tackiness of a novel biodegradable binder for erosion control mulch

Kraft lignin, acidic (LA) and alkaline (LB) types, byproducts of pulp manufacturing were mixed with crude glycerol, a by-product of biodiesel production, and humic acid to produce a mulch tackifier for soil erosion control. Lignin was dried at 70°C for 24 h before use. The study was a full factorial with lignin levels of 20, 50, and 80% and humic acid levels of 1, 2, and 5% (w/w). The remaining portion consisted of crude glycerol. The samples were homogenized using water to facilitate the homogenization process. After homogenization, the samples were left to settle for 36 h and then separated into solid and liquid portions. Both portions were dried at 70°C for 24 h and tested for tack after wetting with water. Dried lignin, as a standalone ingredient, was also tested for tack. The values for the strength of tack were compared to those obtained from a commercial tackifier. Acidic lignin could be used with lignin content ≥50%. Acidic lignin was comparable to the commercial tackifier, whereas alkaline lignin was found to have significantly more tack but was found to be unsuitable for soil erosion use.

Delivery of Arbuscular Mycorrhiza Fungus Spores via Seed Coating with Biodegradable Binders for Enhancement of the Spores Viability and Their Beneficial Properties in Maize

biodegradable polymer such as PVA is considered the most promising candidates for developing the sustainable sticker. The objective of this study was to determine the most suitable PVA + TS blends as adhesives agent for AMF spores inoculation via seed coating which can enhance the spores viability and their beneficial properties in maize. The polythene bag experiment was performed in a screen house of the Department of Plant Protection Faculty of Agriculture, University of Bengkulu Indonesia in 2015. Six adhesive blends were employed: 100% PVA + 0% TS, 75% PVA + 25% TS, 50% PVA + 50% TS, 25% PVA + 75% TS, 0% PVA + 100% TS, and no coating. The six experimental treatments were laid out in a completely randomized design with three replications. The results show that root colonization, AMF spore population, and shoot dry weight in 75% PVA + 25% TS were equal to those in 100% PVA. Root colonization, AMF spore population, shoot P content, and shoot P concentration were greater for 50% PVA + 50% TS than 100% PVA, 100% TS, and no coating. A mixture of 50% PVA + 50% TS was considered the preferred sticker. Thus, the tapioca starch can be used to substitute 25 - 50% of the PVA used without reducing AMF inoculant adhering to seed.Keywords: polymeric seed coating, seed coating formulation, arbuscular mycorrhizal fungi, sustainable coating adhesive, seed inoculation, seed inoculant

Pullulan-ionic liquid-based supercapacitor: A novel, smart combination of components for an easy-to-dispose device

Strategies that simultaneously target energy/power performance, sustainable manufacturing processes, valorization of green raw materials, and easy recycling of supercapacitors are urgently needed. Today, efforts have to be devoted not only to improve system performance but also to address the sustainability of materials and devices manufacturing and recyclability. Specifically, pullulan is herein proposed as a novel bio-degradable binder and separator for green supercapacitors. It is processed by electrospinning from aqueous solutions, therefore overcoming issues related to conventional membrane processing by organic solvents. Furthermore, combining the water-soluble, biodegradable pullulan with a hydrophobic ionic liquid electrolyte brings about a novel approach for end-of-life management of devices. The use of pullulan is demonstrated in a supercapacitor with carbon electrodes obtained from pepper-seeds waste and 1-Ethyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide as the electrolyte. The supercapacitor delivers up to 5 kW kg−1 specific power and 27.8 Wh kg−1 specific energy at 3.2 V, that well compare with conventional electrical double-layer capacitor performance with the added value of being eco-friendly and cheap.

Effect of Biodegradable Binder Properties and Operating Conditions on Growth of Urea Particles in a Fluidized Bed Granulator.

Granulation is an important step during the production of urea granules. Most of the commercial binders used for granulation are toxic and non-biodegradable. In this study, a fully biodegradable and cost-effective starch-based binder is used for urea granulation in a fluidized bed granulator. The effect of binder properties such as viscosity, surface tension, contact angle, penetration time, and liquid bridge bonding force on granulation performance is studied. In addition, the effect of fluidized bed process parameters such as fluidizing air inlet velocity, air temperature, weight of primary urea particles, binder spray rate, and binder concentration is also evaluated using response surface methodology. Based on the results, binder with higher concentration demonstrates higher viscosity and higher penetration time that potentially enhance the granulation performance. The viscous Stokes number for binder with higher concentration is lower than critical Stokes number that increases coalescence rate. Higher viscosity and lower restitution coefficient of urea particles result in elastic losses and subsequent successful coalescence. Statistical analysis indicate that air velocity, air temperature, and weight of primary urea particles have major effects on granulation performance. Higher air velocity increases probability of collision, whereby lower temperature prevents binder to be dried up prior to collision. Findings of this study can be useful for process scale-up and industrial application.

Evaluation of Waste Cooking Oil as Sustainable Binder for Building Blocks

Increasing depletion of material resources and concern for the environment has led to the great quest for degradable and environmentally sustainable material in various industries in recent years. Application of Waste Vegetable oils as a renewable and biodegradable binder material was explored in this work. Block samples were prepared with 10% liquid binder of vegetable oil, compacted with 75 impact blows and thermally cured in a conventional oven at temperature ranges of 160-200°C. This study explores the effectiveness of waste cooking oil as a novel binder in the production of building block, called WasteVege block. Important parameters such as optimum binder content, optimum curing temperature, and optimum curing age were established. The mechanical and physical properties of the product were examined, the result shows that compressive strength in ranges of 5 - 34 MPa was achieved, initial rate of absorption (IRA), water absorption, efflorescence, and wet/dry durability of the product exhibit acceptable values within the threshold of required standards.

ПОЛИМЕРНЫЕ БИОКОМПОЗИТЫ НА ОСНОВЕ БИОРАЗЛАГАЕМЫХ СВЯЗУЮЩИХ, АРМИРОВАННЫХ НАТУРАЛЬНЫМИ ВОЛОКНАМИ (обзор)

ПОЛИМЕРНЫЕ БИОКОМПОЗИТЫ НА ОСНОВЕ БИОРАЗЛАГАЕМЫХ СВЯЗУЮЩИХ, АРМИРОВАННЫХ НАТУРАЛЬНЫМИ ВОЛОКНАМИ (обзор)

Biodegradable internal fixation plates enabled with X‐ray visibility by a radiopaque layer of β‐tricalcium phosphate and poly (lactic‐co‐glycolic acid)

Biodegradable polymer plates can be clinically used as an alternative to metal plates (e.g., titanium) for internal fixation, which, however, are not visible with X-ray imaging, often used for post-operative diagnostics. In this study, therefore, we prepared a biodegradable plate enabled with X-ray visibility by attaching a radiopaque layer on a biodegradable fixation plate in clinical use (Inion, Finland). A radiopaque layer was made of a fine powder of a radiopaque agent, β-tricalcium phosphate (TCP) and a biodegradable binder material, poly (lactic-co-glycolic acid) (PLGA), which were physically mixed without change in their chemical structure. The radiopacity increased as we increased the layer thicknesses from 0.5 mm to 1.3 mm. Regardless of layer thickness, however, the radiopacity decreased with time both in vitro and in vivo due to decreasing density of TCP in the layer by swelling and degradation of a binder material, PLGA. The in vivo study with rabbits revealed that a discernible image of the radiopaque plate could be obtained by X-ray for up to 21 days, also showing the overall biocompatibility 6 months after implantation. Therefore, we conclude that the radiopaque plate prepared in this work is a promising fixation device enabled with both X-ray visibility and biodegradability.

Biocompatibility markers for the study of interactions between osteoblasts and composite biomaterials

Biphasic calcium phosphate (BCP), a mixture of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), has attracted attention as an excellent bone graft substitute. Mixtures of ceramics with agarose, as natural biodegradable binder, have been recently performed in order to increase the flexibility of the ceramic component and to facilitate the biomaterial preparation. In previous studies we have evaluated the response of both L929 fibroblasts and Saos-2 osteoblasts to hydroxyapatite–βTCP/agarose disks observing a higher sensitivity of osteoblasts to this biomaterial. In the present study, the use of specific fluorescent probes and antibodies has allowed to evaluate different cell function parameters as biocompatibility markers for the cell/biomaterial interaction of Saos-2 osteoblasts cultured for 7 days on hydroxyapatite–βTCP/agarose disks. The cell cycle sub G 1 fraction, the exposition of phosphatidylserine on the outside surface of the plasma membrane and the analysis of plasma membrane integrity versus cell size, indicate that the interaction with the biomaterial induces a light increase of apoptosis in osteoblasts without producing cell necrosis. The high percentage of viable cells on the biomaterial and the preservation of endothelial nitric oxide synthase (eNOS) expression, eNOS activity and mitochondrial membrane potential (Δψ m), demonstrate the good biocompatibility of hydroxyapatite–βTCP/agarose disks and its potential utility for bone substitution and repair.