Moisture Penetration Research Articles

Biodegradable nanocellulose hydrogels from agricultural waste: Impact of defibrillation on mechanical and antimicrobial properties

Food spoilage, which often leads to food waste, occurs throughout the entire food supply chain, from the upstream to downstream stages of food production. Biobased hydrogels made from cellulose nanofiber (CNF) have emerged as potential materials for extending food shelf-life. Despite this potential, the impact of defibrillation time during the production of CNF on the properties of CNF-based hydrogels (CNF-H) has not been thoroughly investigated. In this study, the defibrillation time of CNF was varied at 50–90 min to examine its effect on both the CNF itself and the resulting hydrogel properties. The findings revealed that longer mechanical defibrillation times significantly reduced the size of the CNF, leading to a denser CNF-H structure. At extended defibrillation times, the diameter of the CNF decreased from 25 to 20 nm, which strengthened the inter- and intramolecular forces between CNF fibers, resulting in a more crystallinity (from 66.64% to 77.51%) and compact hydrogel network. This denser structure reduced water absorption capacity, thereby limiting moisture penetration and decreasing biodegradability. Additionally, the antimicrobial activity of CNF-H, tested after soaking in ethanol, showed enhanced effectiveness against both gram-positive and gram-negative bacteria with increased defibrillation time, all without exhibiting cytotoxic effects.

Evaluation of static bending caused damage of glass-fiber composite structure using terahertz inspection

Abstract Composite materials find increasing applications in modern industry and transport. However, they may lose desirable mechanical properties due to external mechanical excitations, ultraviolet radiation, moisture penetration, or other factors. Therefore, an effective way to assess the condition of materials is necessary. In this article, a nondestructive evaluation of glass fiber-reinforced composite subjected to five-stage static bending is presented. For this reason, pulsed excitation terahertz imaging was utilized, and a data processing/exploration scheme was proposed. The proposed, novel approach consists of an efficient data registration algorithm based on surface approximation (for surface roughness and unevenness elimination) and a parametrization scheme applied for the signals gained from the time response of the glass fiber-reinforced polymer layer. Obtained parameters enable the global description of the evaluated material state and prediction of failure effectively, even in the early stages of destruction.

Functionalized porphyrin as a carrier bridge and a passivator for perovskite solar cells

Interfacial modification becomes one of the most emerging strategies in the state-of-the-art perovskite solar cells (PSCs). Here, two porphyrin derivatives (p-MeOTPP, m-DMeOTPP) with different methoxy groups are employed as the modifiers between perovskite and the hole transporting layer (HTL). The interaction at both of perovskite/modifier and modifier/HTL interfaces, and the hole-transfer ability of the modifier molecule are comprehensively studied, which are jointly responsible for the significant improvement in the optoelectronic properties of the device. More importantly, discussion on a molecular level reveals the distinct roles of modifiers with highly similar structures. A highest power conversion efficiency (PCE) of 24.56% is achieved for m-DMeOTPP modified PSCs, which is attributed to a synergy of efficient passivation effect at perovskite/modifier interface, sufficient built-in potential at modifier/HTL interface and minimal reorganization energy of hole hopping process. p-MeOTPP has a stronger passivation ability, but causes unfavorable interfacial dipole at modifier/HTL interface and a large energy barrier when hole’s hopping, only resulting in a smaller enhancement. Additionally, both modifers improve the device stability by strongly suppress the immigration of iodine species and moisture penetration. This work presents a synergy mechanism for interfacial engineering to pursue PSCs with high efficiency and stability, and provides practical guidelines at a molecular level to design a modifier not only as an efficient passivator but also as a high-speed carrier bridge.

Аналіз підходів щодо оцінювання просочування опадів у ґрунт узбіччя автомобільних доріг

Introduction. The article investigates the impact of atmospheric precipitation on road structures, specifically focusing on water infiltration into the roadside soil along highways, which is a critical aspect of road infrastructure maintenance. Ensuring the reliable operation of the roadway is becoming increasingly important due to rising traffic loads and climate changes that result in increased precipitation. Continuous moisture penetration into the road embankment can lead to road degradation, creating risks for safe traffic movement and necessitating frequent repairs. It is essential to develop and implement effective methods for assessing moisture infiltration into the soil, which will help ensure the longevity and cost-efficiency of road operation. Problem Statement. With climate change and increasing intensity of precipitation, the issue of assessing its impact on road structures becomes more relevant. Moisture accumulation in the road embankment can disrupt the stability of the soil foundation, reducing the load-bearing capacity of the road surface. Research aimed at analyzing rainfall infiltration and its effect on road structures will allow the implementation of effective solutions to maintain the operational condition of roads.

Direct Measurement of the Diffusion Coefficient of Adhesives from Moisture Distribution in Adhesive Layers Using Near-Infrared Spectroscopy.

In this study, we used near-infrared spectroscopy to measure the moisture penetration in epoxy adhesives and investigated the difference in the diffusion coefficients between the bulk and the adhesive layer. Moisture diffusion was evaluated under 100% RH and water immersion conditions. First, the effects of the curing agents and additives on moisture diffusion in the bulk were gravimetrically evaluated using epoxy-coated quartz glass plates. Different diffusion behaviors were observed depending on the curing agent used. The presence of additives resulted in higher diffusion coefficients, whereas the overall moisture content was low. Next, the moisture distribution in the adhesive layer was visualized using a specimen sandwiched between the quartz glass plates, and the diffusion coefficient of the adhesive layer was calculated. The diffusion coefficient in the adhesive layer was larger than that in the bulk. For adhesives cured with hydrophobic diamine, the diffusion coefficient within the adhesive layer increased by approximately 1.5 times compared with that in the bulk, regardless of the exposure environment. The adhesive, composed of a resin, Dicyandiamide, and additives, showed a 2-fold increase in the diffusion coefficient under high-humidity exposure conditions but no significant change under the water immersion condition. Therefore, these results suggest that, for an accurate analysis of moisture distribution, it is important to measure the diffusion coefficient of the adhesive layer directly rather than using the diffusion coefficient of the material itself.

Development of Water Repellent Polish for the Pointing and Finishing on NBRRI Earth Block Walls

Assessment of the challenges facing the adoption and promotion of NBRRI CSEBs reviewed the issues of instability or erosion of the brick wall surfaces, a case study reveals that it is a common problem to all walls made of this block within different zones of the country. The quest to proffer sustainable solution to these challenges necessitated this research work. The study aimed at producing a locally sourced water repellent polish for painting and finishing on NBRRI earth block walls. A substance (slurry) that can resist moisture penetration into adobe walls through the surfaces. The materials used were sourced from the rainforest zone of the country, investigated and tried with different mix ration depending on the Oxide composition in phases. The first phase featured the following materials and equipment; limestone, crab soil, periwinkle shell, Termite mould, natural clay, Hydrated lime (Ca (OH)2, Soluble Rubber (Top Bond) and Distilled water for mixing. Equipment includes; Weighing balance of 0.1g accuracy, sieve no 2020 (75pm) stirring rod, brushes and spray. In this phase soluble rubber was tried differently with the materials in various oxide composition applied on the existing CSEB walling unit, from observation some performed well while others performed moderately. The second and the third phase of the trial employed limestone and hydrated lime (Ca (OH)2 as the main stabilizer to activate reaction between the combination of any of the samples that contained high silica and a certain percentage of aluminium oxide (Al2CO3) x H2O(c) to produce an effective result as the Ca (H2O(s)) react in the presence of air to give Ca2SiO3(s) a solid that is stable in water, and applied on CSEB wall surfaces for observation across wet and dry Season.

Size Effects in Climatic Aging of Epoxy Basalt Fiber Reinforcement Bar.

The purpose of this study was to obtain information on the influence of the size factor on the climatic aging of circular fiber plastics produced by pultrusion. The kinetics of moisture transfer was obtained in humidification and drying modes at 60 °C in samples of epoxy basalt fiber reinforcement bars: after 28 months of exposure in the extremely cold climate of Yakutsk and 30 months of exposure in the moderately warm climate of Gelendzhik. It was shown that the 2D Langmuir model adequately describes the kinetics. The diffusion coefficients in the reinforcement direction for bars with diameters of 6, 8, 10, 16 and 20 mm turned out to be significantly higher than in the radial direction. To clarify the aging mechanism of the bars and the tensile, compressive and bending strength, the coefficient of linear thermal expansion and the glass transition temperature of the epoxy matrix of the bars with a diameter of 6, 8 and 10 mm after 51 months of exposure in Yakutsk and 54 months of exposure in Gelendzhik were measured. It was shown that after climatic exposure, the deformability of the bars decreased with increasing diameter of the bar; the glass transition temperature increased more significantly in the bar with a smaller diameter. In 6 mm diameter bars, the compressive and bending strength limits decreased by 10-25 % due to the plasticizing effect of moisture. With the same depth of moisture penetration into the volume of the samples, its effect on the strength of thin bars was significant, and for thick bars, it was insignificant. An increase in the glass transition temperature by 6 °C, associated with the additional curing of the polymer matrix, occurred in the surface layer of the epoxy basalt fiber reinforcement bars and was revealed in bars with a smaller diameter.

Importance of Window Installation in Residential Building Envelopes Having Continuous External Insulation in Order to Realize Energy Efficiency

Residential buildings are one of the prime candidates in the United States for reducing energy consumption. Continuous exterior insulation (CEI) is being used increasingly often in residential buildings to improve energy efficiency. Windows constitute 15–40% of a building envelope and are the weakest component in energy performance. The installation of windows in walls with CEI has not been well evaluated. We identified four cases of installing windows in walls with CEI of 25–76 mm (1–3 in.) thickness and analyzed the energy loss between the window and wall interface (flanking loss), structural issues, air leakage, and moisture penetration. Thermal analysis showed that the insulation value (RSI) of the 305 mm (12 in.) perimeter wall surrounding a window decreased by 7.6–34.5% in the four cases when compared with the RSI of the wall without the window. A window installation method is proposed to address the issues likely to occur with installation methods currently being used in the field. An out-of-the-box installation system was also designed to achieve a better thermal performance, cost effectiveness, and structural performance in high-performance residential buildings.

Influence of mountain orientation on precipitation isotopes in the westerly belt of Eurasia

Mountains have a significant impact on the transport path of water vapour and local meteorological variations. Therefore, understanding the influence mechanism of mountains on stable isotopes of precipitation is essential. In this study, we analyzed the precipitation stable isotope data within the Westerlies in the Eurasian continent. The results indicate the following: (1) East-west-oriented mountain ranges and plains play a “channelling role” in facilitating the inland penetration of westerly moisture, with this effect being more pronounced in the northern part of the Alps. Conversely, north-south-oriented mountain ranges and plateaus act as a “barrier” to westerly moisture. (2) Mountains influence stable isotopes of precipitation primarily by altering the water vapour movement paths and regulating local meteorological factors. (3) The “altitude effect” is the most common mechanism through which mountains affect local meteorological elements reflected in stable isotopes of precipitation. Furthermore, we anticipate that with global climate warming, the interaction and feedback between mountains and climate will become even more complex. This aspect deserves consideration in future research.

Self-Healing Stretchable Li-Ion Battery Based on a High-Voltage Hydrogel Electrolyte

Safe and deformable soft batteries are desirable for future wearable electronic devices. However, current Li-ion batteries on the commercial market are rigidly packaged and hermetically sealed to prevent moisture penetration and the leakage of toxic and flammable organic electrolytes. Since the modulus of elasticity and gas permeability of materials are inextricably linked, stretchable batteries often experience significant performance degradation over time in the ambient due to inevitable moisture penetration. Furthermore, the polymer-based flexible packaging materials can be easily damaged resulting in electrolyte leakage that poses significant safety concerns. Here we report a non-toxic, aqueous hydrogel electrolyte instead of its organic counterpart that is demonstrated to 1) enable highly safe operations due to its non-toxic and non-flammable nature; 2) alleviate the moisture penetration problem from the outside environment; (3) have a high-voltage working window of ~2.97V; and (4) allow the construction of stretchable batteries by using elastic polymer packaging materials instead of rigid hermetic seals. The prototype batteries have shown good stretchability (50% strain) and flexibility (radius of curvature < 2mm) to enable conformal attachments to a wide range of geometric surfaces. The prototype battery also shows outstanding cyclic stability, retaining ~90% of the original capacity after 100 cycles for over 2 months in the ambient environment without using any rigid hermetic sealing package. Finally, a prototype battery with a self-healing elastomer package remains functional after being punctured by a needle 5 times at different locations in the package. Furthermore, it can recover >90% of its capacity after being cut through by a razor blade and subsequently healed at 70 for 10 minutes. Such safe and highly stretchable batteries would be useful for several wearable electronic applications such as blood glucose monitoring, hearing rate monitoring, temperature monitoring, wireless charging, smart clothing, etc. Figure 1

Experimental investigation on Nano-Al2O3 and hydroxypropyl methyl cellulose (HPMC) modified cement-based coatings for corrosion resistance

In this work, cementitious coatings doped with nano-Al2O3 (NA) and hydroxypropyl methyl cellulose (HPMC) were prepared in order to enhance corrosion resistance of steel bar. The electro-chemical behaviors and corrosion inhibition properties of coated steel bar and tensioned coated steel bars (subjected to 10 %, 30 % and 50 % yield load) were analyzed in 3.5 wt% NaCl solution for 840 h (35 days). At the end of electrochemical test, coating overall performance was evaluated by visual inspection. In addition, scanning electron microscopy (SEM), transmission electron microscopy (TEM) with energy dispersive spectroscopy (EDS) were used to examine microstructure and elemental composition of coatings. To comprehend the anti-corrosion mechanism of the coatings, X-ray diffraction (XRD) and infrared spectroscopy (FTIR) analysis to characterize products composition and chemical groups. Test results obtained by linear polarization resistance and electrochemical impedance spectroscopy indicated that both tensile and non-tensile coatings resistance show an increasing trend followed by a decrease with increasing NA content. Cementitious coatings incorporating 1 % NA and 0.12 % HPMC by weight of cement exhibited the best corrosion protection. The LPR fluctuates around 3700 Ω cm2, which is about twice as much as a single doped NA coating. Whether subjected to tensile loads or not, OCP values for all coated steel bar were below −0.273 V/SCE, indicating has a 90 % probability of being in active-corrosion. The corrosion resistance of tensioned coated bars decreased as time and increased load level. According to SEM and TEM image, HPMC forms a thin and continuous film on the substrate surface, which acts as a barrier to the penetration of moisture and corrosive agents. Coatings doped with 1 % NA and 0.12 % HPMC formed denser integrated polymer films at the microscopic. FTIR and XRD results showed that coating incorporated NA consumed the cement hydration product Ca(OH)2 to generate more nanofibers filling pores and microcracks. Coatings incorporating HPMC show better resistance to carbonization.

A crystal capping layer for formation of black-phase FAPbI3 perovskite in humid air.

Black-phase formamidinium lead iodide (α-FAPbI3) perovskites are the desired phase for photovoltaic applications, but water can trigger formation of photoinactive impurity phases such as δ-FAPbI3. We show that the classic solvent system for perovskite fabrication exacerbates this reproducibility challenge. The conventional coordinative solvent dimethyl sulfoxide (DMSO) promoted δ-FAPbI3 formation under high relative humidity (RH) conditions because of its hygroscopic nature. We introduced chlorine-containing organic molecules to form a capping layer that blocked moisture penetration while preserving DMSO-based complexes to regulate crystal growth. We report power conversion efficiencies of >24.5% for perovskite solar cells fabricated across an RH range of 20 to 60%, and 23.4% at 80% RH. The unencapsulated device retained 96% of its initial performance in air (with 40 to 60% RH) after 500-hour maximum power point operation.

Moisture penetration and distribution characterization of hard coal: a µ-CT study

Moisture content of rock/coal can change its mechanical properties and absorption capacities, which can directly affect gas diffusivity, change the stress distribution and hence cause significant impacts on the overall gas or coal extraction process. Observation of the water penetration process and water distribution in the coal matrix will be beneficial for the understanding of the fluid-solid coupling mechanism in hydraulic fracturing, aquifer cracking and coal seam infusion. However, the observation of water penetration process and the determination of water distribution mode were hard to be non-destructively achieved as coal is a non-uniform, inhomogeneous and un-transparent material. µ-CT imaging, which is based on variation of X-ray attenuation related to the density and atomic composition of the scanned objects, enables a four-dimensional (spatial-temporal) visualise of the heterogeneous and anisotropic coal samples. The primary aim of this paper is extending the application of µ-CT imaging to explore the moisture penetration and distribution within coal samples during water infusion process, which has been reported by very little literature. The working principle and procedures of CT imaging was firstly introduced. Then, the determination equation of moisture distribution based on density profile was established. The CT determined moisture content has been compared with weighting method for verification. The paper has demonstrated that µ-CT can be used for non-destructively imaging the moisture distribution within coal samples.

Hygrothermal effect and statistical analysis of the interfacial performance of nano and microscale polymer composites

ABSTRACT Hygrothermal exposure significantly impacts polymer composite (PMC) performance, affecting various industries. This study evaluated the short-term hygrothermal effects on PMCs by examining interfacial shear strength (IFSS), water uptake, glass transition temperature (Tg), and morphology. Data-driven techniques minimized experimental time while analyzing multiple factors. Specimens were immersed in water at 25°C and 70°C for 3, 7, and 14 days. The IFSS between carbon nanotube yarns and carbon fiber with epoxy (EPON™ 862) was measured before and after exposure. Statistical analysis indicated that fiber type significantly influenced IFSS, while time had a marginal effect and temperature had no impact. The IFSS decreased by 4.14% for CF/epoxy and 14.9% for CNT/epoxy. Water uptake analysis revealed weight gains of 0.465% and 1.566% for epoxy after 14 days at 25°C and 70°C, respectively. Morphological studies showed moisture penetration between 7 and 14 days. Thermomechanical analysis (TMA) indicated that pristine epoxy expanded by 0.318% of its original height. After 14 days, the Tg of epoxy decreased by 6.4% at 25°C and 9.7% at 70°C. Dynamic mechanical analysis (DMA) on dried epoxy samples showed similar Tg but varied tan delta curves due to plasticization. Short-term hygrothermal evaluation revealed degradation in interface quality and viscoelastic properties.

Comparative Analysis of Drought Effects on the Soil Moisture Level and Penetration Resistance in Conventional and Non-Conventional Tillage Systems in Maize Production

The period of extreme weather anomalies in recent years has challenged farmers, and this has encouraged greater adaptability in farming practices. In the last decade, conventional tillage systems have been complemented by more biologically based cropping systems. The research evaluated the impact of drought on soil physical parameters in maize production by testing different conventional and non-conventional tillage systems to ensure optimal soil physical parameters. In the analysis of the prevailing weather conditions, rainfall values were divided into two parts, the pre-growing season and the growing season. We studied different climatic seasons. In 2021, the soil moisture content in the upper shallow 15 cm soil layer during the sowing period in April in the case of conventional tillage was significantly lower than in reduced tillage, conservation tillage and strip tillage. The most significant difference was measured between conventional and conservation tillage, with a difference of 11.25 v/v%. The 2022 crop year was extremely dry. In June, the highest moisture value in the soil was measured in the case of strip tillage with a value of 21.64 v/v%, which was more than 60% higher than in the case of conventional and conservation tillage. In conventional tillage, a very pronounced compacted layer was observed in the lower part of the ploughed layer. This zone reached a compaction of 6.9 MPa between 28 and 34 cm, which is agronomically harmful. No compacted soil layer was found in the experiment site under conservation tillage. In the severe drought year of 2022, only the strip-till system provided the proper water management conditions for the maize stand.

Hydrophobic Electron‐Transport Layer for Efficient Tin‐Based Perovskite Solar Cells

AbstractWith excellent biocompatibility, a narrow bandgap, and long thermal carrier lifetime, tin‐based perovskite solar cells (TPSCs) are promising within the solar technology. The fullerene derivative indene‐C60 bisadduct (ICBA) is recognized as the most efficient electron‐transport material for TPSCs, thanks to its suitable band structure. Nevertheless, the limited electron transport capability and susceptibility to moisture penetration of ICBA have hindered the progress of TPSCs. Herein, the study proposes a new hydrophobic electron‐transport layer (ETL) comprising a surface‐anchored non‐fullerene n‐type semiconducting polymer layer, poly (naphthalene diimide‐alt‐dithiophenebezothiadiazole) (PNDI‐BT), in conjunction with ICBA. PNDI‐BT exhibits high electron mobilities, a fitting band structure, robust interaction with Sn‐based perovskites, and exceptional moisture resistance, effectively addressing the shortcomings of ICBA. Consequently, this innovative hydrophobic ETL of PNDI‐BT/ICBA enhances electron transport and protects Sn‐based perovskites from moisture. As a result, the inverted TPSCs with the new hydrophobic ETL achieve an impressive efficiency of 13.90%, surpassing TPSCs with the ICBA layer (12.75%). Moreover, even after 1000 h of storage in ambient atmosphere, the encapsulated TPSC maintains a remarkable 81% of its initial efficiency. This comprehensive study seamlessly integrates the synthesis of non‐fullerene n‐type semiconducting polymer and device fabrication, providing valuable insights into designing cutting‐edge ETL structure for inverted TPSCs.

Research Progress of Superhydrophobic Coatings in the Protection of Earthen Sites

As an important part of human cultural heritage, earthen sites are subject to damage caused by a variety of environmental factors, such as cracking, weathering, and flooding. Due to the low mechanical strength of earthen site materials, especially in humid environments, they are susceptible to hazards like moisture penetration, freeze–thaw cycles, and biological invasion. Superhydrophobic coatings show promising potential in the protection of earthen sites, with key properties that include waterproof performance, breathability, robustness, and transparency. By exploring various material systems and preparation methods, the current state of research on the protection of building materials with superhydrophobic materials has been demonstrated, highlighting advantages in the corrosion resistance, self-cleaning, frost prevention, anti-scaling, and other aspects. At the same time, it also points out the challenges faced in the practical application of earthen site protection and the prospects for future research. These include enhancing the bonding strength between the coating and soil particles, improving durability and breathability, and developing large-scale, low-cost, and efficient coating construction techniques.

The Effect of Al2O3 on the Performance of Perovskite Solar Cells

Improving the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs) remain the two most important goals of perovskite research. Herein, the effects of Al2O3 interlayer on the performance of formamidinium‐cesiums and “triple cation” PSCs by depositing a thin Al2O3 layer via atomic layer deposition on different interfaces are analyzed. It is found that it can efficiently serve as a passivation layer of perovskite absorber, as a seed layer for the compact growth of the subsequent SnO2 layer, or as a capping layer to the whole cell in the superstrate configuration to prevent moisture ingress. The optimized devices utilizing Al2O3 have on average more than 1% absolute higher PCE, with reduced penetration of moisture inside the device. Especially, the capping layer has shown the greatest benefit, extending the stability of the devices by more than two times and allowing long‐term operation without encapsulation. In the best case, a T80 time of almost 900 h under day/night‐cycling illumination is obtained. The observed trends are based on data from a large number of devices (more than 300 devices were tested in the maximum power point), which give statistical relevance to the promising results.

Photochemical optimization of fluorescent dye-doped PDMS for enhanced luminescent solar concentrator performance

Luminescent solar concentrators (LSCs) that incorporate organic dyes face challenges such as self-absorption loss and aggregation-caused quenching (ACQ) as doping concentration increases, limiting the dye loading capacity. Particularly for dyes with a small Stokes shift, losses due to self-absorption or quenching are prominent even at low concentrations, hindering the attainment of high power conversion efficiency (PCE) in LSCs. Additionally, exposure of the dye-impregnated polymer matrix to oxygen, moisture, UV light, and other factors leads to a decrease in luminescence efficiency and stability due to the photooxidation reaction of the phosphor. This study presents a facile approach for enhancement of the efficiency and environmental stability of coumarin 6 (C6) dye-doped polydimethylsiloxane (PDMS) LSC through ultraviolet ozone (UVO) treatment. Photocleavage of the C6 dimer into a C6 monomer through UVO treatment leads to a significant enhancement in luminescence. Additionally, thin SiOx layers formed on both sides of the LSC not only assist in capturing luminescent light more efficiently but also block the penetration of oxygen and moisture into the LSC, resulting improved device stability. UVO-treated LSC shows approximately 32 % improvement in PCE compared to bare LSCs and exhibits significantly better stability during the 30-day long-term performance test.

Bonding strength between spruce glulam and birch plywood at different load-to-plywood face grain angles

There is growing interest recently in reducing the usage of metals in timber structures. Birch plywood possesses satisfactory mechanical properties compared to other wood-based panels and is promising to be utilized in timber connections as a substitute for the more conventional slotted-in metal plate. There are essentially two possibilities to connect plywood plates and other timber elements by means of either mechanical connections or adhesively bonded connections. Despite the more commonly adopted mechanical connections in current timber structures, the adhesively bonded connections hold the distinct advantages of being more cost-effective, stiffer, and with a lower risk of moisture penetration in the timber elements. When employing birch plywood in timber structure applications such as trusses and frame corners, stresses from different directions need to be transmitted by the plywood gusset plate. However, it is still uncertain how the bonding strength is affected by different loading angles to the face grain. This research question, specifically concerning the bonding strength between birch plywood and spruce glulam, has been addressed in this paper. It was found that the bonding strength varies within a relatively small range when the load-to-plywood face grain angle varies from 0° to 90°, which is promising for the development of adhesively bonded joints. Failure mainly occurred in glulam at 0° and 15°; while at other angles, a mixture of cohesive failure in glulam and plywood face veneer was dominant. The weak angle-dependence of the bonding strength can be explained by further checking the shear strength of the weaker wood adherends between glulam and plywood. A strong positive correlation was observed between bonding strength and the wood shear strength.