Article

Wood Adhesives Based on Natural Resources: A Critical Review Part I. Protein-Based Adhesives

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Abstract

This series of critical reviews on Wood Adhesives Based on Natural Resources (in total four parts) describes the experience and actual status of wood adhesives based on natural resources and gives an outlook into the future of these materials. Desite boundless results and papers in the development, purely naturally based wood adhesives are in industrial use only in negligible amounts; therefore this review series also reports on combinations of naturally based adhesives with synthetic components, such as modifiers or crosslinkers. Part I of this series concentrates on general topics and questions related to wood adhesives based on natural resources, such as systematic overview on the various types of naturally based wood adhesives, including cases where the adhesive is not applied separately but is used in situ , originating from the various components of the wood material. As a first product group, proteins from plants and animal sources and their use as wood adhesives will be described in this Part I.

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... Although protein adhesives (soy, casein, blood, collagen, etc.) have been replaced by the invention and extensive development of synthetic adhesives from fossil fuels, concerns about formaldehyde emissions from urea-formaldehyde, the largest-volume wood adhesive, have renewed interest in bio-based adhesives [1][2][3]. While most of the research has been on soybean-based adhesives, other oilseeds (canola, cottonseed, etc.) have been studied [4][5][6]. ...
... Unfortunately these natural materials, except for egg whites [7], do not provide high-strength wood bonds under wet test conditions without further modification. In recent years, many ways to improve the bond strength of soy-based adhesives have been published [1,5], including adding chaotropic agents (urea, guanidine hydrochloride, dicyandiamide, etc.), changing the amount and type of salts (Hofmeister series), adding surfactants (including sodium dodecyl sulfate and sodium dodecyl benzene sulfonate), modifying the proteins (dopamine, cysteamine, CaCO 3 , MgO and POCl 3 ), breaking apart protein agglomerates (sodium metabisulfite, acid, base hydrolysis, or enzymatic cleavage), grafting reactive side chains (epoxies, 2-octen-1-ylsuccinic anhydride, 3-aminopropyltriethoxysilane, 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride, maleic anhydride, etc.), or crosslinking the proteins/carbohydrates (formaldehyde, glyoxal, polyamidoamine-epichlorohydrin (PAE) resin, etc.) [1,8]. According to the literature, most of these modifications provide better wood-bond strengths than the unmodified soy adhesives. ...
... Unfortunately these natural materials, except for egg whites [7], do not provide high-strength wood bonds under wet test conditions without further modification. In recent years, many ways to improve the bond strength of soy-based adhesives have been published [1,5], including adding chaotropic agents (urea, guanidine hydrochloride, dicyandiamide, etc.), changing the amount and type of salts (Hofmeister series), adding surfactants (including sodium dodecyl sulfate and sodium dodecyl benzene sulfonate), modifying the proteins (dopamine, cysteamine, CaCO 3 , MgO and POCl 3 ), breaking apart protein agglomerates (sodium metabisulfite, acid, base hydrolysis, or enzymatic cleavage), grafting reactive side chains (epoxies, 2-octen-1-ylsuccinic anhydride, 3-aminopropyltriethoxysilane, 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride, maleic anhydride, etc.), or crosslinking the proteins/carbohydrates (formaldehyde, glyoxal, polyamidoamine-epichlorohydrin (PAE) resin, etc.) [1,8]. According to the literature, most of these modifications provide better wood-bond strengths than the unmodified soy adhesives. ...
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The surprising lack of literature on using the very common wood adhesive polymeric methylenediphenyl diisocyanate (pMDI) with protein adhesives may be because of perceived poor improvement of protein wet strength. Reacting pMDI with the flour (soy or canola) before adding water unexpectedly improves wood bonding compared to adding the pMDI to an aqueous protein slurry. Mixing the liquid pMDI with the oilseed flour produces a free-flowing powder with up to 50% of pMDI to flour by weight. The mixture slowly reacts since the isocyanate band in the infrared spectra remains for several days but diminishes with time. Adding pMDI increases the dry and wet strength of wood bonds using Automated Bonding Evaluation System (ABES) testing and levels off at about 50%. Similarly, adding the polyamidoamine-epichlorohydrin (PAE) cross-linker to the oilseed flour increases dry and wet bond strength, but the effect levels off at about 20% of PAE. However, the combination of these two cross-linkers added to the flours results in greater dry and wet shear strength than either one alone. In addition to tests using ABES (ASTM D 7998), the increase in strengths is also observed-but with a diminished effect-in bonding plywood using the interior plywood strength test ASTM D 906.
... Milk, egg, and meat proteins are animal proteins that are important as food sources for humans. On the other hand, waste and by-products from the processing of meat, poultry and fish, such as blood, skin, feathers, scales, skins and spine fish still contain protein that can be utilized [185]. As pointed out by Cheng et al. [186], animal proteins are mainly consumed as high-value meats, hence the limited animal protein-based adhesives are typically exploited as wasted or by-products of the meat industry as raw materials. ...
... Amino acid composition influences protein hydrophobicity and charge. At the same time, amino acid configuration affects the surface properties of protein, which in turn may affect protein solubility and thermal stability [185]. The differences between animal and plant protein structures are that plant proteins contain more b-sheet structures and relatively low a-helixes [189,190], and plant proteins consist of more fibers than animal proteins [191]. ...
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Over the last 50 years, the use of wood adhesives in the manufacturing of wood-based panel goods has increased the efficiency of wood resources. Wood adhesives are becoming more popular as the need for wood-based panels grows. By 2028, the global market for wood adhesives is expected to reach 21.8 billion dollars. Even though urea-formaldehyde (UF), phenol-formaldehyde (PF), melamine-formaldehyde (MF), phenol-resorcinol-formaldehyde (PRF), and resorcinol-formaldehyde (RF) resins are excellent in terms of bonding performance, workability, quality, and economy, they consist of harmful or toxic chemical agents derived from fossil resources, which make their application severely limited. This review aims to go through the most significant ‘green’ wood adhesives for manufacturing high-performance wood-based panels, such as lignin, tannin, protein, natural rubber, emulsion polymer isocyanate (EPI), 1C PUR polyurethane (for glue-laminated wood and cross-laminated timber), PMDI (for particleboards, medium-density and low-density fiberboards), carboxylic acid, and vegetable oil. The physical and mechanical characteristics of bio-based wood adhesives, as well as the development of sustainable, greener, and high-performance bio-based wood adhesives, are discussed in this work. Original research papers and review articles are among the most important sources since they provide complete information on the most recent developments in sustainable, eco-friendly, and high-performance bio-based wood adhesives.
... [11][12][13] Water resistance can be improved by adding active substances, which can crosslink protein functional groups. [4,14,15] Glyoxal is one of the most reactive crosslinkers. [4,[16][17][18] It can react with functional protein groups such as lysine and arginine. ...
... For this purpose, polyethyleneimine (PEI) can be used. [20] This water-soluble polymer has been used for improving paper wet strength by crosslinking cellulose [14] and for wood adhesives based on hyper-branched polyethyleneimine, urea, and glyoxal. [21] The most extensively studied plant protein is soy protein due to its successful application in wood adhesives in North America. ...
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Corn gluten protein, potato protein, and pea protein isolate were used as natural raw materials for preparing bio-based environmentally friendly adhesives. Glyoxal and polyethyleneimine (PEI) were used as crosslinking agents. Dry and wet bonding performances of the adhered wood samples were tested for different protein-based adhesives, i.e., protein alkaline-modified adhesives, protein–glyoxal adhesives, and protein–glyoxal–PEI adhesives. The results indicate that crosslinking by glyoxal and polyethyleneimine effectively improves the bonding performance of pea, corn, and potato protein-based adhesives after water storage.
... Poor water resistance is one of the main disadvantages of protein-based adhesives. A lot of research has been conducted to improve the wet strength of protein-based adhesives by adding active substances that crosslink protein functional groups [5,11,12]. Compared to formaldehyde, glyoxal is less toxic and less volatile [13]. Glyoxal is a bi-functional aldehyde, which is studied as a crosslinking agent for other bio-based adhesives, such as tannin [14,15] or lignin-based [16] ones. ...
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Proteins obtained as side-products from starch production (potato and corn proteins) were investigated for wood adhesives application. To improve the wet strength of protein-based adhesives, glyoxal was added as a crosslinking agent. The effect of glyoxal on the wet strength of protein-based adhesives was investigated at different pH, protein: glyoxal ratios and solid content. The alkaline pretreatment of proteins was carried out by two different methods which reduced the molecular weight of proteins to different extents. The effect of molecular weight reduction on the wet strength of protein-glyoxal adhesives was also observed. It was found that pH level affects wet strength more significantly compared to solid content and protein-to-crosslinker ratio. Potato and corn proteins crosslinked with glyoxal showed maximal wet strength results in an acidic pH range
... In addition, many research groups have studied bio-insulating materials based on natural fibers and bio-adhesive agents from tannins [26], soybean protein [27], starch [28], and lignin [29]. Manfred et al. [30] and Antov et al. [31] reviewed bio-based adhesives for wood composites. They reported that bio-based adhesives of lignin, starch, and tannins can potentially be used to produce eco-friendly wood composite materials. ...
Article
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Oil palm wood is the primary biomass waste produced from plantations, comprising up to 70% of the volume of trunks. It has been used in non-structural materials, such as plywood, lumber, and particleboard. However, one aspect has not been disclosed, namely, its use in thermal insulation materials. In this study, we investigated the thermal conductivity and the mechanical and physical properties of bio-insulation materials based on oil palm wood. The effects of hybridization and particle size on the properties of the panels were also evaluated. Oil palm wood and ramie were applied as reinforcements, and tapioca starch was applied as a bio-binder. Panels were prepared using a hot press at a temperature of 150 °C and constant pressure of 9.8 MPa. Thermal conductivity, bending strength, water absorption, dimensional stability, and thermogravimetric tests were performed to evaluate the properties of the panels. The results show that hybridization and particle size significantly affected the properties of the panels. The density and thermal conductivity of the panels were in the ranges of 0.66–0.79 g/cm3 and 0.067–0.154 W/mK, respectively. The least thermal conductivity, i.e., 0.067 W/mK, was obtained for the hybrid panels with coarse particles at density 0.66 g/cm3. The lowest water absorption (54.75%) and thickness swelling (18.18%) were found in the hybrid panels with fine particles. The observed mechanical properties were a bending strength of 11.49–18.15 MPa and a modulus of elasticity of 1864–3093 MPa. Thermogravimetric analysis showed that hybrid panels had better thermal stability than pure panels. Overall, the hybrid panels manufactured with a coarse particle size exhibited better thermal resistance and mechanical properties than did other panels. Our results show that oil palm wood wastes are a promising candidate for thermal insulation materials.
... Further developments to reach economic alternatives and to design processes fitting to wood industry requirements are needed. This is currently a hot topic in academic research, and the reader will find exhaustive information in recent reviews [43][44][45][46]. ...
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Wood is considered the most important renewable resource for a future sustainable bioeconomy. It is traditionally used in the building sector, where it has gained importance in recent years as a sustainable alternative to steel and concrete. Additionally, it is the basis for the development of novel bio-based functional materials. However, wood's sustainability as a green resource is often diminished by unsustainable processing and modification techniques. They mostly rely on fossil-based precursors and yield inseparable hybrids and composites that cannot be reused or recycled. In this article, we discuss the state of the art of environmental sustainability in wood science and technology. We give an overview of established and upcoming approaches for the sustainable production of wood-based materials. This comprises wood protection and adhesion for the building sector, as well as the production of sustainable wood-based functional materials. Moreover, we elaborate on the end of lifetime perspective of wood products. The concept of wood cascading is presented as a possibility for a more efficient use of the resource to increase its beneficial impact on climate change mitigation. We advocate for a holistic approach in wood science and technology that not only focuses on the material's development and production but also considers recycling and end of lifetime perspectives of the products. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 1)’.
... A wider industrial usage of tannins suffers from the limited availability of raw materials and high transportation costs. Only South Africa is the only actual producer of mimosa tannins on industrial scale [121]. Tannins react with formaldehyde the main crosslinker, and form hardened and crosslinked structures, similar to synthetic phenolic resins. ...
Chapter
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In recent years industries are attempting to decrease their dependency on petroleum-based fuels and products due to increased environmental issues. The tremendous increase in production and use of plastics in every sector of life has led to huge plastic waste disposal problems and also an environmental threat. In order to prevail over the present scenario, the viable and cost-effective approaches are to prepare eco-friendly bio-composites based on non-wood forest products (NWFP), a part of forest wealth of the globe, especially natural fibres, agricultural wastes and extractives. Natural fibres and extractives have many advantages viz. low density, low cost, considerable toughness properties, nontoxicity, sustainability and biodegradability. NWFP based composites may be utilized to produce non-structural parts for diverse applications in various industries as high-performance materials with interesting properties for specific applications viz. furniture, thermal, acoustic insulations and automotive industries etc. In the present chapter, opportunities of extractives, cellulosic and lignocellulosic fibres from non-wood forest products in Bio-composites will be discussed.
Article
The impact of jet cooking on shear strength of soy‐and‐water adhesives was investigated to understand the higher shear strength of commercial soy protein isolates compared to soy flours. Soy flour‐based wood adhesives are appealing because of their bio‐based content, low formaldehyde emission, and low cost, but their commercial application is limited by low wet cohesive strength. Previous researchers proposed that the process of jet cooking (steam injection with high turbulence followed by rapid cooling) was responsible for the high (~3 MPa) wet shear strength of adhesives made with commercially produced soy protein isolate, using the ASTM D 7998 test. In this work, we show that jet cooking did dramatically increase the wet strength of laboratory‐produced, native‐state soy protein isolate from 0.6 to 3 MPa, a strength similar to many commercial isolates. Jet cooking was far less effective at developing wet strength of soy flours, but greatly increased the viscosity of virtually all our soy materials. We hypothesize that the benefits of jet cooking are primarily a result of nonequilibrium protein aggregation states because subsequent wet autoclaving of jet cooked soy proteins dramatically decreased wet strength. The dramatic differences in adhesive properties between commercial soy protein isolates and soy flours suggests that the common practice of using results obtained with commercial isolates to predict the performance of soy flour adhesives is inappropriate.
Article
The interest in non‐formaldehyde adhesives has reinvigorated studies using proteins from plant and animal sources, with an emphasis on plant‐based sources, especially the oilseed plants such as soybean. Although animal‐based sources have received much less attention, and ovalbumin from egg whites has not been studied at all, it provides a surprising low viscosity and high wet strength as a wood adhesive. Of the animal and plant proteins used in the past, egg protein has been used for centuries as a binder in tempera, for book illumination, and for gilding, but not as a water‐resistant wood adhesive. The isolated ovalbumin is the best, but dried egg whites and whole egg have good adhesive strength. The parameters for ovalbumin wood bonding are examined with thin veneers using ASTM D 7998 and plywood tests using D 906. Sodium metabisulfite, sodium periodate, urea, and polyamidoamine‐epichlorohydrin (PAE) improve the wet bond strength, but the surfactants CTAB and SDS at low concentrations do not. Although the high protein content of the ovalbumin is important for good strength, the low viscosity of the protein adhesive provides further insight into protein–protein interactions. Ovalbumin dissolved in water has a surprising low viscosity at a high concentration and is a high wet strength wood adhesive, because it is high in protein. The wet strength was determined with ovalbumin‐bonded plywood using a standard test and compared to soy protein which can have high wet strength if it is modified.
Article
Research on adhesives made from recycled and renewable biomass materials is an important direction in wood material industry. The eco-friendly plywood adhesive named as SADP adhesive, according to its composition (Sucrose and Ammonium Dihydrogen Phosphate), developed in our research group previously has good bonding performance but bleed-through veneer. In previous studies, we found that plant proteins, such as defatted soybean flour (DSF) and dephenolized cottonseed protein (DCP) material could improve this phenomenon. However, although DCP considerably promoted the bonding performance of the SADP adhesive, DSF did not. Therefore, this study will determine the optimal preparation and hot pressing conditions of the developed adhesive, and investigate the curing mechanism. First, the evaluation of the effects of the plant protein type, mass ratio, hot pressing temperature and time on the bonding performance of these adhesives revealed that plywood prepared by hot pressing at 170°C for 7 min using DCP/SADP-1/3 ratio as adhesive had the highest wet shear strength (1.17 MPa). Additionally, the comparative analysis of the two plant proteins showed that the DCP has a higher crude protein content, more tryptophan and arginine, which might be the reason for its better bonding performance with SADP solution. Second, in the analysis of curing behavior, the result of TG-DSC analysis corresponded to the insoluble mass proportion measurement, indicating that the optimal curing temperature of DCP/SADP-1/3 adhesive was about 170°C. In addition, ATR FT-IR analysis indicated that the curing mechanism was complex, involving caramelization and Maillard reaction to form a dense crosslinking structure, with dimethylene ether bridge as the main linkage. Finally, a comparison of various scanning electron microscopy (SEM) chromatograms revealed that, with the increase of the amount of DCP added, the cured adhesive became less porous and had smoother surface, which further confirmed that DCP and SADP solution formed a novel network crosslinked structure after curing process. Furthermore, compared with the wet shear strength of SADP adhesive (0.88 MPa), the plywood prepared using the novel DCP/SADP-1/3 adhesive (1.17MPa) was increased by 33%.
Article
The low comprehensive properties of soy protein-based wood adhesives (SPWAs), such as weak bonding strength, poor water and mildew resistance, etc., are the main issues that severely restrict their wide application in the wood manufacturing industry. In this study, fully biobased SPWAs with excellent bonding strength, water and mildew resistance, and flame retardancy were developed via a facile cross-linking reaction between soy protein isolate (SPI), furfuryl alcohol (FA), and phytic acid (PA). Because SPI, FA, and PA were all derived from green and sustainable biomass resources, the components of this kind of SPWAs achieved 100% biomass content. Response surface methodology (RSM) was utilized to optimize the preparation of SPWAs, and the predicted values were highly consistent with the experimental results. The optimized SPWA with a pH of 4.0 and the content of FA addition of 16.7% exhibited high aged and wet shear strengths of 1.07 and 1.47 MPa, respectively, which are superior to those for other reported soy protein-based adhesives. Meanwhile, this kind of SPWAs also displayed excellent mildew resistance, thermal stability, and flame retardancy because of the dense multiple chemical/physical cross-linking network and high P/N content. Therefore, this work provides a green and effective strategy for the development of multifunctional and high-performance fully biobased soy protein wood adhesives.
Article
In this study, kraft lignin and epichlorohydrin (ECH) were used to prepare no-formaldehyde wood adhesives. The lignin was first treated by ball milling, then reacted with glyoxal to produce glyoxalated lignin under alkaline conditions, and then blended with ECH to prepare lignin-based formaldehyde-free adhesive. The influence of the content of ECH on the physicochemical properties of the adhesives was explored, and the possible synthesis mechanism of the ECH-modified glyoxalated lignin adhesives (glyoxalated kraft lignin-epoxy [GKLE]) was investigated. The results show that ECH was beneficial to improving the plywood shear strength and water resistance; the plywood prepared with GKLE-50 adhesive displays comparable water resistance as phenol–formaldehyde resins and its wet shear strength (type I) was 1.05 MPa, exceeding the Chinese National Standards GB/T 9846-2015. Scanning electron microscopy analysis showed that the increase of ECH content promoted the adhesive to penetrate the wood to form glue nails, improving the wet shear strength of the plywood. Chemical analysis indicated that glyoxalation was used to introduce hydroxyethyl groups into the ortho positions of the aromatic rings of lignin, and then the ring-opening reaction between glyoxalated lignin and ECH occurred forming ether bonds. Overall, lignin has displayed great potential in replacing formaldehyde-based adhesives for industrial applications.
Article
The present study investigate the beneficiation potential of extracted keratin protein hydrolysate from chicken feather waste biomass as bio-adhesive for the production of particleboard. Chicken feathers were hydrolyzed using hybrid alkaline hydrolysis, and the obtained keratin protein fraction was used for bio-adhesive formulation. The formulated adhesive was employed for particleboard fabrication using the American National Standards Institute (A208.1) 1-L-1 grade specification. The quality of bio-adhesive and the particleboard mechanical strength performance were evaluated with Fourier transform infrared spectroscopy (FTIR), modulus of rupture (MOR), modulus of elasticity (MOE) and density. The FTIR spectra confirmed the amine, alkyl side chains and carboxylic groups of the amino acids in the unmodified keratin-based binder. The spectra revealed the covalent bonding between the azetidinium of the citric acid-based polyamide-epichlorohydrin cross-linking and the hydroxyl groups of the keratin protein hydrolysate. The fabricated particleboard's mechanical strength performance met the specification for the 1-L-1 grade of the American National Standards Institute (A208.1). The respective values obtained for modulus of rupture and modulus of elasticity of the panels made with unmodified keratin-based adhesive were 6, 5 and 1184, 34 MPa, respectively. The cellulose nanocrystals incorporation as a filler enhanced the formulated bio-adhesive static bending and bonding strength properties. Therefore, these findings demonstrate that keratin hydrolysate protein extracts from chicken feather waste could be considered as a potential feedstock for environmentally friendly wood composites bio-binder production.
Chapter
Various naturally-based chemicals can be used directly as wood adhesives or are precursors for the synthesis of adhesive resins. Liquefaction and pyrolysis of wood yield various smaller chemicals derived from the different wood components, which then are used in the preparation of adhesives by replacing mainly phenol as raw material. The possible replacement of formaldehyde in aminoplastic and phenolic resins would solve the question of the subsequent formaldehyde emission. The multiple unsaturations of the triglycerides in vegetable oils enable polymerization for the direct synthesis of thermosets, as well as bases for polyfunctionalization and crosslinking. Natural polymers, such as poly(lactic acid)s (PLAs), natural rubber, or poly(hyhydroxyalkanoate)s (PHAs) are thermoplastics and can be used for various special applications in wood bonding, in case they can also be crosslinked. For other thermoplastic wood adhesives, such as PUR or PA, chemicals based on natural resources can at least replace a part or even all synthetic raw materials (monomers); these monomers derive from targeted decomposition of the wood material in biorefineries. Cellulose nanofibrils (CNFs) can be used as as sole adhesives or as components of adhesives. Hydrogen bonding has a key function in binder applications related to adhesion between cellulose nanoparticles and other materials. CNFs are able to establish strong bonding between wood particles/fibres through flexible and strong films by a simple drying process. Cashew nut shell liquid (CNSL) is a by-product of the cashew nut processing with cardanol (CD) as main component. CD-formaldehyde resins show improved flexibility compared to phenol-formaldehyde (PF) resins; CD can replace up to 40% of the phenol.
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A non-isocyanate-based polyurethane (NIPU) wood adhesive was produced from organosolv lignin, which is a bio-sourced raw material, available in large quantities and produced as a by-product of the paper industry. The formulation of this new lignin-based NIPU adhesive, which is presented, was chemically characterised by Matrix-Assisted Laser Desorption Ionization Time of Flight (MALDI ToF) mass spectrometry and by Fourier Transform Infra-Red (FTIR) spectrometry analyses. The oligomers formed were determined and showed that the three species involved in the NIPU adhesive preparation were formed by the co-reaction of the three reagents used: lignin, dimethyl carbonate, and hexamethylene diamine. Linear and branched structures were both identified. Mechanical properties of the adhesive were determined using the Automated Bonding Evaluation System (ABES) and internal bond (IB) strength test of the laboratory particleboard bonded with it. The adhesive has shown satisfactory mechanical properties after hot pressing at 230°C. Such a temperature is used industrially in the most modern particleboard factories, but since it is hardly feasible for more conventional wood bonding equipment, the reactivity of the NIPU adhesive was successfully increased with the addition of a small percentage of a silane coupling agent. With the addition of the silane, the proposed NIPU adhesive could also be used at a hot-pressing temperature lower than 200°C.
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Soy protein isolate (SPI) and insoluble soy flour polymeric carbohydrates have been reacted with sodium periodate for the specific oxidation of vicinal-OH groups to investigate the reactions involved in this approach to soy flour adhesives. The reactions have been shown to generate carbohydrate oligomer fractions presenting one, two or multiple aldehyde groups. With the exception of the small molecular weight heptanedial, the smaller molecular weight aldehydes generated from mono-and disaccharides by the same reaction do not appear to form from the insoluble soy flour carbohydrates, or have already reacted. The reaction of periodate with soy protein isolate has been shown to generate some aldehydes too. When the mix of SPI and soy insoluble carbohydrates is treated with periodate, the majority of the observed aldehyde carrying species appear to be higher molecular weight carbohydrate oligomer fractions.
Article
The interest in biobased wood adhesives has steadily increased in recent years. Our previous studies have shown that water-washed cottonseed meal (WCSM) could be used as low-temperature and high-solid content biobased wood adhesives for non-structural bonding as European Standard Class D1 adhesives. In this work, we optimized WCSM-based adhesive formulations with high solid contents up to 49% for bonding of small wood items at low temperatures (40 °C). Chemical denaturing reagents guanidine hydrochloride (GdmCl) and sodium dodecyl sulfate (SDS) were added to improve the bonding capability and viscosity of WCSM. Reviewing industry preferences, four formulations with 20% and 30% of WCSM as well as 9.6% and 19.1% of SDS were used to glue “real world” pencil slat sandwiches for pencil making. All the pencils made from these sandwiches bonded at 40 °C and 1 MPa for 120 min passed the Industrial Temperature Cycle test. The results indicated that WCSM could be used as a low temperature wood adhesive, possibly for the domestic furniture and small utensils niche markets. The pencil sandwich bonding represents a specific application that could benefit from the non-toxic glue and also be an example of an interior application.