Synthetic Adhesives Research Articles

Dynamic covalent bonds enabled recyclable chitosan oligosaccharide-based wood adhesive with high adhesion and anti-mildew performances

Biomass wood adhesives have emerged as a promising alternative to traditional synthetic resins due to their ability to address issues related to formaldehyde pollution and reliance on petrochemical resources. However, these adhesives are generally not recyclable and require high curing temperatures. Herein, a novel eco-friendly, strong, and recyclable chitosan oligosaccharide (CS)-based wood adhesive named CS-PB was developed using CS, lignin-derived 3,4-dihydroxybenzaldehyde, and 1,4-phenylenediboronic acid. The cohesive strength and recyclability of the adhesive were significantly enhanced by the dynamic borate ester and imine networks formed through catalyst-free covalent cross-linking. The adhesive exhibited a maximum bonding strength of 5.60 MPa, surpassing many synthetic and biomass adhesives. Moreover, the recycled adhesive retained 88 % of its original strength. Even under extreme conditions such as 100 °C, −196 °C the CS-PB adhesive can still maintain high bonding strength. Notably, the CS-PB adhesive demonstrated low-temperature curing properties, achieving a high bonding strength of 5.21 MPa when cured at 90 °C, since imine bonds can be formed under mild conditions. Furthermore, the adhesive displayed excellent mildew resistance attributed to the synergistic effects of amino, boronic acid, and benzene rings. The proposed straightforward design strategy provides valuable insights for constructing high-strength and recyclable biomass adhesives.

Effect of Resin Content on the Properties of Roofing Tile for Building Materials

The production process of roofing tile materials uses among other materials thermosetting adhesive resins normally urea formaldehyde (UF), phenol formaldehyde (PF), di-isocyanate (PMDI) at various content mixtures, 3wt%, 5wt%, 7wt%, 9w% and 11wt% with a usual thickness of 6 mm. The fibers, adhesives, and other materials are then placed into a steel mold with the standard dimensions of 400 mm x 400 mm, to be then hydraulically pressed at high pressure and the required temperature. Overall, PMDI synthetic adhesives have better physical and mechanical properties than PF synthetic adhesives, however the thermal properties of UF and PF synthetic adhesives are better than PMDI. The physical properties testing were density, humidity content, absorption of water, thickness inflated and water permeability. The mechanical properties such as modulus of rupture (MOR) and modulus of elasticity (MOE), impact strength and tensile strength are all measured according to JIS A 5908-2003, ASTM D 256-2006a,TIS 535-2556 and ASTM D1037-12.The testing for the thermal conductivity, thermal resistivity and solar reflectance were done according to ASTM C177-2010 and ASTM E 891-87. The type of resin content and adhesive used had a significant impact on the physical, mechanical and thermal properties of the roofing tile materials of showed in the results of the analysis of variance (p >0.05). The produced roofing tile has an improved thermal conductivity and heat insulation which can be a substitute for hazardous asbestos based roofing materials.

Electrospun Polymeric Fiber Systems Inoculated with Cyanoacrylate Tissue Adhesive: A Novel Hemostatic Alternative during Open Surgery.

Natural-based and synthetic tissue adhesives have attracted extensive attention in the last two decades for their ability to stabilize uncontrolled bleeding instances. However; these materials present several drawbacks during use that scientists have tried to minimize in order to optimize their usage. This study comprises the development of a novel wound dressing, combining the excellent properties of polylactic acid (PLA) non-woven textile, as substrate, obtained through electrospinning, and a cyanoacrylate-based (CA) tissue adhesive, for rapid hemostatic action. Thus, the fabrication of electrospun PLA membranes at three different PLA concentrations, the design and manufacturing of the support system and the production of surgical patches were carried out. SEM and FT-IR methods were employed for analyzing the morphology as well as the indicative markers for the shelf life evolution of the obtained patches. PLA fibers with well-defined structures and a mean diameter varying between 4.6 and 7.24 μm were obtained with the increase of the concentration of the PLA solutions. In vivo tests on a rat model as well as peeling tests for good patch adhesion on liver fragments harvested from the test animals, with a limit for the strength of the liver tissue of 1.5 N, were carried out. The devices exhibited excellent adhesion to the parenchymal tissue and a long enough shelf life to be used with success in surgical procedures, also facilitating prompt hemostatic action.

Bioinspired ‘phenol-amine’ cross-linking and mineral reinforcement enable strong, tough, and formaldehyde-free tannic acid-based adhesives

Conventional tannin-based adhesives have limitations such as formaldehyde emission, inadequate strength and toughness, which restrict their practical applications. Herein, motivated by the natural mechanisms of ‘phenol-amine’ cross-linking and biomineralization, a strong, tough and formaldehyde-free tannic acid-based adhesive was prepared by using all-biomass feedstock. The adhesive was prepared by integrating tannic acid-Zn nanoparticles (TA-Zn NPs), hyperbranched polyamide-grafted dialdehyde chitosan (HPCS), and triglycidylamine (TGA), which formed the fundamental cross-linking network of the prepared adhesive through a Schiff base reaction. The dry and wet bonding strength of the adhesive achieved 1.91 MPa and 1.54 MPa, respectively. The presence of sacrificial bonds such as N…Zn complexation and hydrogen bonding in the adhesive significantly enhance its toughness with a debonding work of 0.595 J. Benefiting from the exceptional antimicrobial properties of TA, chitosan, and Zn2+, the prepared adhesive demonstrated excellent mechanical properties even after being stored in a humid environment for 2 days, with wet and dry bond strength of 1.42 MPa and 1.10 MPa, respectively. Moreover, this adhesive exhibited remarkable resistance to mildew for a duration of 30 days and emitted lower volatile organic compounds compared to other synthetic and biomass adhesives. This innovative bionic strategy holds great potential in enhancing the toughness and functionality of adhesives and composites.

Optimizing a canola-gelatine-urea bio-adhesive: effects of crosslinker and incubation time on the bonding performance

The importance of creating eco-friendly and health-conscious materials has become paramount in striving to attain long-term development goals. For the past decades, constant efforts have been made to tackle the issue of formaldehyde release from wood-based panels which, to date, are still mainly produced from unsustainable synthetic adhesives. In the pursuit of sustainable and environmentally responsible adhesive solutions for the wood industry, sodium bisulfate, sodium bisulfite, and sodium nitrite were used under different heat treatment conditions as crosslinkers for canola protein-based bio-adhesive formulations. The developed adhesive formulations showed outstanding mechanical properties, with a viscosity below 4000 mPa/s despite the relatively high solid content, as well as excellent bonding performances. The one-layer particleboards bonded with the canola-based adhesive demonstrated outstanding mechanical properties, with the internal bonding and the bending strength values surpassing 0.60 N/mm2 and 10 N/mm2, respectively. Notably, the sodium nitrite-crosslinked variants exhibited significantly superior performance compared to the UF-bonded control boards. Longer incubation times generally improve bonding strength, with sodium nitrite showing the most pronounced effects. The results of this research showcase not only the possibility of developing a plant protein-based wood adhesive with high solid content, but also the potential superiority of canola protein-based wood adhesives when compared to conventional, synthetic counterparts. These findings offer valuable insights for optimizing bio-based adhesives in wood composite manufacturing, highlighting sodium nitrite as a promising crosslinker for enhancing the adhesive’s performance.

Pressure-sensitive acrylic adhesives (PSAs): how it began and the present state of art

Pressure-sensitive adhesives, especially acrylate-based pressure-sensitive adhesives, are the main group of polymers used to produce a wide range of pressure-sensitive adhesives. Self-adhesive adhesives based on well-known natural resins and polymers have been known for a long time. The development of synthetic adhesives, especially those based on acrylate, began after World War II. BASF has made great contributions in this field. Therefore, because polyacrylates are relatively cheap, they are resistant to aging and the damaging effects of oxygen and UV radiation. Polyacrylate-based adhesives are known as solvent-based, water-dispersion, and solvent-free adhesives.

The potential therapeutic value of terpenes

Terpenes form part of a huge and diverse class of naturally occurring and volatile secondary metabolites produced by many plants, fruits, animals, insects, and other organisms. They are the largest group of naturally occurring metabolites, with over 55,000 types of terpenes produced by plants alone, primarily as essential oils. In humans, they contain significant biological properties such as antifungal, antiviral, antimicrobial, anti-inflammatory, antiparasitic, antihyperglycemic, anti-cancer, and analgesic agents. In plants, terpenes also play significant roles in defensive mechanisms against herbivores and invasive plants, disease resistance, chemical signaling and communication between plants, protection against photo-oxidation, plant-environment mediation, thermo-protection, and the attraction of pollinators. In addition, terpenes are responsible for a plant’s scent, taste, flavor, and pigmentation, leading to their commercial use as fragrances and food dyes. Terpenes are also used in the production of synthetic polymers, natural rubbers (polyisoprene), organic solvents, varnishes, inks, adhesives, cleaning products, biofuels, pesticides, and food and drink products. For these reasons, terpenes have significant value in modern medicine, pharmacy, nutraceuticals, cosmetics, and other industries.

Utilization of nanotalc modified adhesives in plywood panels

As an alternative for the partial replacement of synthetic adhesives are the modifications that occur still during their synthesis, to improve and adhere new properties. Among the possible materials used in nanoscale, talc is a mineral material of natural origin and a promising raw material due to its low cost, lightness, natural hydrophobicity. Due to the scarcity of studies with the insertion of nanotalc in adhesives, this study aimed to produce plywood panels bonded with phenol-formaldehyde adhesive nanomodified with talc to evaluate its physical-mechanical resistance when compared to conventional synthetic adhesives. To carry out this study, three Pinus oocarpa trees with 28 years of age were used. Different concentrations of talc were used in the formulation with the phenol-formaldehyde adhesive, being the treatments 0; 0,05; 1; 1,5 and 2 % of talc (mass/mass) in relation to the adhesive, with three panels per treatment, totaling 15 panels. The pressing time was 8 minutes with temperature of 160 ºC and pressure of 1 MPa. The physical-chemical characteristics of the lignocellulosic material and of the plywood panels were determined. The quality of the adhesive produced was demonstrated by its resistance to water absorption with the insertion of up to 2 % talc to the adhesive, reducing it considerably. From 1 % talc inserted, the plywood panels had their mechanical characteristics superior to those glued with pure phenol-formaldehyde adhesive. However, as the study is innovative in nature, further research should focus on the application and quality evaluation of other talc nanomodified adhesives on different types of wood panels.

Comparative Analysis of the Quality and Electrical Energy of Wood Waste Briquettes with Natural (Starch) and Synthetic Adhesives (Synthetic Rubber Adhesive)

On average, small and medium-scale wood processing industries produced at least 2 to 4 cubic meters of wood a day, this production produced 0.25 to 2 m3 of wood waste a day. In fact, this waste can be used as a renewable energy source by processing it into briquettes. This research will produce wood waste briquettes using the pyrolysis method from two types of adhesive, namely starch and synthetic rubber adhesive with a composition ratio of 3:1. Apart from that, the resulting briquettes were tested using a bomb calorimeter to obtain the calorific value, water content, ash content, and volatile matter content, and then compared with the SNI 01-6235-2000 standard. The resulting briquettes were then calculated using mathematical calculations for the potential electrical energy they could generate. From laboratory tests, the calorific value, water content, ash content, and volatile matter content of natural adhesive briquettes were obtained at 5194.44 cal/g, 11.3%, 1.36%, and 40.8%, while synthetic adhesive briquettes respectively had values of 6369.46 cal/g, 4.33%, 2.74%, and 25.54%. From these results, synthetic adhesive briquettes had better calorific value, water content, and volatile matter content compared to natural adhesive briquettes. Apart from that, synthetic adhesive briquettes also had greater energy potential with an energy potential of 7,407 kWh/kg compared to briquettes with natural adhesives which only had a value of 6,041 kWh/kg. Thus it can be concluded that synthetic adhesive briquettes are better quality compared to natural adhesive briquettes because they can generate greater energy, and meet 3 of the 4 test parameters based on SNI while natural adhesive briquettes only meet 2 of the same 4 test parameters

Special Prey, Special Glue: NMR Spectroscopy on Aggregate Glue Components of Moth-Specialist Spiders, Cyrtarachninae.

Orb-weaver spiders produce upwards of seven different types of silk, each with unique material properties. We focus on the adhesive within orb-weaving spider webs, aggregate glue silk. These droplets are composed of three main components: water, glycoproteins, and a wide range of low molecular mass compounds (LMMCs). These LMMCs are known to play a crucial role in maintaining the material properties of the glycoproteins, aid in water absorption from the environment, and increase surface adhesion. Orb-weavers within the Cyrtarachninae subfamily are moth specialists and have evolved glue droplets with novel material properties. This study investigated the biochemical composition and diversity of the LMMCs present in the aggregate glue of eight moth-specialist species and compared them with five generalist orb-weavers using nuclear magnetic resonance (NMR) spectroscopy. We hypothesized that the novel drying ability of moth-specialist glue was accompanied by novel LMMCs and lower overall percentages by silk weight of LMMCs. We measured no difference in LMMC weight by the type of prey specialization, but observed novel compositions in the glue of all eight moth-catching species. Further, we quantified the presence of a previously reported but unidentified compound that appears in the glue of all moth specialists. These silks can provide insight into the functions of bioadhesives and inform our own synthetic adhesives.

Industrial byproducts as adhesive allies: Unraveling the role of proteins and isocyanates in polyurethane wood bonding

Wooden structures are becoming increasingly popular in the construction world. However, these structures often rely on synthetic adhesives, raising concerns about the environmental risks associated with their chemical composition. In response to these concerns, this study aims to explore sustainable alternatives, particularly focusing on polyurethane adhesives that incorporate proteins from industrial byproducts. The investigation involved three protein sources: soybean meal, shrimp shells, and skim milk, modified under mild alkaline conditions to obtain protein concentrates. These concentrates were then incorporated into the adhesives at varying protein contents: 5%, 10%, and 15%. Additionally, two isocyanate systems were examined, one being petrochemical-based and the other a partially bio-based blend. Chemical, thermal, optical, and mechanical characterizations were conducted to evaluate the adhesive performance. This study demonstrates that the adhesives’ thermal properties remain unaffected by both the protein content and the isocyanate system. However, these factors influence the adhesive penetration into the wood substrate. Ultimately, the results suggest that higher protein content offers superior retention of mechanical strength in adhesives compared to the petrochemical reference when subjected to humid conditions. Overall, this research demonstrates the potential of proteins from industrial byproducts as sustainable adhesive allies, providing valuable insights into their interactions with different isocyanates.

Древесно-композитные плиты с низким коэффициентом линейного теплового расширения

A number of industries require materials with a low coefficient of linear thermal expansion (CLTE), in particular, in the production of satellite spherical antennas. The latter are formed from composites containing carbon fibers and synthetic resins. The composition is cured by heating up to 180 °C. This leads to a thermal expansion of the mold and a change in the geometric characteristics of the product. Therefore, specific requirements are imposed on the materials for making molds. The high cost of special materials used for molds determines the need to search for other materials with a low CLTE. Wood is a possible solution to this problem. Its CLTE along the fibers is less than that of the vast majority of materials, and is approximately 3 ‧ 10-6 K–1, which is comparable to special materials. However, the expansion of wood across the fibers is much higher than the longitudinal one, which excludes the use of solid wood. Anisotropy can be reduced by creating a composite in which the fibers are uniformly oriented in all structural directions, bringing the value of wood expansion across the fibers closer to the value of expansion along the fibers. The traditional approach to producing wood composites, based on the use of synthetic adhesives, fails to achieve a noticeable reduction in thermal expansion due to the high CLTE of adhesives The use of boards made of hydrodynamically activated wood particles without binders is promising. Three series of experiments have been carried out: with varying the density of the boards, preliminary thermal modification of the original wood and the use of alkali during hydrodynamic processing. The thermal expansion study has been carried out using the NETZSCH DIL-402 C induction dilatometer in dynamic mode with a heating rate of 2 K/min. It has been established that thermal expansion increases with increasing density.The average CLTE at a density of 950 kg/m3 is 12 ‧10–6 K–1 and at a density of 1,100 kg/m3 it is 17‧10–6 K–1. At a comparable density, the thermal expansion of boards without binders is significantly lower than that of fiberboards (MDF). Preliminary thermal modification of wood does not significantly affect the CLTE of the boards. The use of alkali in the hydrodynamic treatment also has no effect.

Production of Chemically Modified Bio-Based Wood Adhesive from Camote and Cassava Peels.

Adhesives are significant for manufacturing competent, light, and sturdy goods in various industries. Adhesives are an important part of the modern manufacturing landscape because of their versatility, cost-effectiveness, and ability to enhance product performance. Formaldehyde and polymeric diphenylmethane diisocyanate (PMDI) are conventional adhesives utilized in wood applications and have been classified as carcinogenic, toxic, and unsustainable. Given the adverse environmental and health effects associated with synthetic adhesives, there is a growing research interest aimed at developing environmentally friendly bio-based wood adhesives derived from renewable resources. This study aimed to extract starch from camote and cassava peels and focuses on the oxidization of starch derived from camote and cassava peels using sodium hypochlorite to create bio-based adhesives. The mean yield of starch extracted from camote and cassava peels was 13.19 ± 0.48% and 18.92 ± 0.15%, respectively, while the mean weight of the oxidized starches was 34.80 g and 45.34 g for camote and cassava, respectively. Various starch ratios sourced from camote and cassava peels were examined in the production of bio-based adhesives. The results indicate that the 40:60 camote to cassava ratio yielded the highest solid content, while the 80:20 ratio resulted in the best viscosity. Furthermore, the 40:60 ratio produced the most favorable particle board in terms of mechanical properties, density, thickness, swelling, and water absorption. Consequently, the starch extracted from camote and cassava peels holds promise as a potential source for bio-based adhesives following appropriate chemical modification.

Rapid, Tough, and Trigger-Detachable Hydrogel Adhesion Enabled by Formation of Nanoparticles In Situ.

Integrating hydrogel with other materials is always challenging due to the low mass content of hydrogels and the abundance of water at the interfaces. Adhesion through nanoparticles offers characteristics such as ease of use, reversibility, and universality, but still grapples with challenges like weak bonding. Here, a simple yet powerful strategy using the formation of nanoparticles in situ is reported, establishing strong interfacial adhesion between various hydrogels and substrates including elastomers, plastics, and biological tissue, even under wet conditions. The strong interfacial bonding can be formed in a short time (60 s), and gradually strengthened to 902 J m-2 adhesion energy within an hour. The interfacial layer's construction involves chain entanglement and other non-covalent interactions like coordination and hydrogen bonding. Unlike the permanent bonding seen in most synthetic adhesives, these nanoparticle adhesives can be efficiently triggered for removal by acidic solutions. The simplicity of the precursor diffusion and precipitation process in creating the interfacial layer ensures broad applicability to different substrates and nanoparticle adhesives without compromising robustness. The tough adhesion provided by nanoparticles allows the hydrogel-elastomer hybrid to function as a triboelectric nanogenerator (TENG), facilitating reliable electrical signal generation and output performance due to the robust interface.

Upcycling of protein concentrates from industrial byproducts into polyurethane wood adhesives

Wood structures generally rely on synthetic adhesives for their strength and versatility. However, environmental concerns linked to the chemical composition of these adhesives have stimulated the search for more environmentally friendly adhesives. Researchers have explored replacing petroleum-based constituents with natural raw materials such as lignins, tannins, and proteins. Of these alternatives, proteins, being biological macromolecules, are recognized for their capacity to enhance adhesion to wood substrates. This study considered the development of protein-based adhesives derived from diverse sources, including soybean meal, microbrewery spent grains, shrimp shells, and skim milk powder. These raw materials were subjected to mild alkaline conditions to yield protein concentrates. The resulting adhesives were formulated at various protein content levels: 5%, 10%, 15%, and 20%. The study’s findings showed that the incorporation of proteins into the polyurethane adhesive system not only can preserve but also augment adhesive performance. This enhancement encompasses deeper penetration into wood substrates and an overall improvement in mechanical strength. These results underscore the promise of proteins as a sustainable alternative to petroleum-based polyols in adhesive formulations.

The possibility of application of bonded joints on different facade systems

Bonded joints in the construction industry have a rich history dating back to ancient civilisations, where they were mainly used to join materials such as wood or stone. In particular, natural materials such as bitumen or natural resins were used for this purpose. In the present modern era, with the development of adhesive technologies and synthetic adhesives, they have become an essential part of construction industry practice. Within facade cladding, bonded joints are becoming key to achieving high thermal insulation performance and overall building energy efficiency. The correct design of the building envelope is increasingly relevant in the context of the geopolitical situation starting with the global pandemic COVID-19 and the two conflicts between Russia and Ukraine and between Israel and Palestine that resulted in energy crises [1]. The paper summarizes the potential applications of adhesive bonded joints on facades, the types of adhesives used at different joints and their ability to provide strong and durable joints when exposed to different climatic conditions during summer and winter months.

Pull-off dynamics of mushroom-shaped adhesive structures

Dynamic adhesion characteristics of synthetic adhesives have attracted massive attention recently. Specific to the mushroom-shaped adhesive structures with outperformed adhesion properties, a clear understanding of the pull-off dynamics, especially the role of retraction velocity, has not been addressed yet. In this paper, based on a custom-built adhesion test apparatus allowing in-situ high-speed measurement of the interface failure, we conducted detachment tests on hundreds-micrometer-scale mushroom-shaped adhesive structures with different cap thicknesses at a retraction velocity range spanning 4 orders of magnitude. It is found that the crack propagation mode for a thin or thick cap remains the same at different retraction velocities, whereas for an intermediate cap the transition from the edge-crack mode to the center-crack mode is observable. Notably, for center-crack mode, the crack area at pull-off remains relatively constant at different velocities. The variation of the pull-off forces with velocity exhibits a scaling law at high velocity regardless of the propagation mode. Dynamic detachment models are developed by considering the rate-dependent work of adhesion to demonstrate the critical-crack-dimension invariance at different velocities and the scaling law of pull-off force with the velocity with the same scaling exponent for center- and edge-crack mode. The theoretical scaling agrees well with experiments. Furthermore, finite element analysis of the viscoelastic detachment demonstrates the stress redistribution against retraction velocities. A prominent feature is the increasing length of the cohesive zone at pull-off with the increasing velocity, indicating a potential trend of a transition to a long-range adhesive interaction. At a sufficiently large velocity, the stress spike at the crack tip disappears and a theoretical strength is almost obtained at the region beneath the stalk.

Eco-friendly adhesives for wood-based composite production

In the process of creating composites, especially if we talk about wood-based composites, great attention should be paid on a variety of factors which affect the final composite properties.One of the essential elements is proper adhesive selection. Most common used are synthetic formaldehyde adhesives. We are aware how dangerous emission of free formaldehyde can be; we tend to minimize its usage. Using adhesives which are safe for the environment and humans as well, we tend to find safer composites which are ecologically acceptable and recognized as a better option.The paper briefly describes the adhesives used so far and their dangers, and selects several types of adhesives with basic characteristics that can meet the requirements for the production of ecologically acceptable composite panels, with an emphasis on wood-based composites. Certain tests and achievements in the development of these adhesives are also presented.

Rapid Reassembly, Biomass-Derived Adhesive Based on Soybean Oil and Diels-Alder Bonds.

Synthetic adhesives play a crucial role in holding together solid materials through interfacial interactions. Thermoplastic and thermosetting adhesives are important types of synthetic adhesives, with thermoplastic adhesives being reassemblable and thermosetting adhesives exhibiting high adhesive strength and creep resistance. However, there is a need to combine the advantages of both types and develop high bonding strength, reassemblable adhesives. Here, epoxidized soybean oil (ESO) was used to prepare adhesive networks and Diels-Alder bonds were incorporated to enhance reassembly ability. The ESO was functionalized with furyl groups and cross-linked via the reaction between furyl and imide groups to involve the Diels-Alder bonds. The resulting adhesive exhibited good solvent resistance and mechanical properties, which could be regulated by adjusting the quantity of cross-linker. The prepared adhesives also demonstrated self-healing capabilities, as the scratch on the surface gradually diminished with heating. Additionally, the adhesives showed the ability to undergo recycling without significant changes in properties. The prepared adhesives exhibited hydrophilicity and the flow characteristics during reassembly were characterized by a decrease in torque. This study provides a promising approach for the development of synthetic adhesives with reassembly ability, which has important implications for the field of bonding.

Characterization of Densified Pine Wood and a Zero-Thickness Bio-Based Adhesive for Eco-Friendly Structural Applications.

This study investigates a sustainable alternative for composites and adhesives in high-performance industries like civil and automotive. This study pioneers the development and application of a new methodology to characterize a bio-based, zero-thickness adhesive. This method facilitates precise measurements of the adhesive's strength and fracture properties under zero-thickness conditions. The research also encompasses the characterization of densified pine wood, an innovative wood product distinguished by enhanced mechanical properties, which is subsequently compared to natural pine wood. We conducted a comprehensive characterization of wood's strength properties, utilizing dogbone-shaped samples in the fiber direction, and block specimens in the transverse direction. Butt joints were employed for adhesive testing. Mode I fracture properties were determined via compact tension (CT) and double cantilever beam (DCB) tests for wood and adhesive, respectively, while mode II response was assessed through end-loaded split (ELS) tests. The densification procedure, encompassing chemical and mechanical processes, was a focal point of the study. Initially, wood was subjected to acid boiling to remove the wood matrix, followed by the application of pressure to enhance density. As a result, wood density increased by approximately 100 percent, accompanied by substantial improvements in strength and fracture energy along the fiber direction by about 120 percent. However, it is worth noting that due to the delignification nature of the densification method, properties in the transverse direction, mainly reliant on the lignin matrix, exhibited compromises. Also introduced was an innovative technique to evaluate the bio-based adhesive, applied as a zero-thickness layer. The results from this method reveal promising mechanical properties, highlighting the bio-based adhesive's potential as an eco-friendly substitute for synthetic adhesives in the wood industry.