The rising demand for sustainable alternatives to conventional formaldehyde-containing binders has accelerated the development of renewable adhesives for environmentally friendly wood-inspired composites (WIC). Addressing a gap in the study of elastomeric matrices, this work introduces a novel WIC utilizing sugarcane bagasse fibers (SBF) bonded by an innovative bio-based adhesive (ADV) composed of natural rubber latex (NR) and alkali lignin. The WIC materials were fabricated via a straightforward hot-pressing process. Critically, the ADV binder was the key innovation, yielding composites with up to 60 % higher performance compared to formulations using only NR. Furthermore, varying the SBF content enabled significant modulation of the material properties, achieving a Young’s modulus of 5–35 MPa, yield strength of 0.25–1.25 MPa, and hardness of 30–90 IRHD. Abrasion resistance was also enhanced by nearly 40 %. Scanning electron microscopy revealed that lignin in the ADV improved the wettability and mechanical anchoring of the SBF within the matrix. Complementary X-ray microtomography further demonstrated a reduction in porosity in the ADV-WIC, while dynamic mechanical analysis suggested improved interfacial compatibility due to lignin incorporation in ADV. These results demonstrate a tunable, high-performance, and formaldehyde-free WIC material with strong potential for structural and coating applications as a green alternative to conventional wood-based products.

Adhesives are glue substances that serve as a binder which holds up materials together that is are able to make things adhere or stick together without deformation or failure through a process called adhesion (Baumann and Conner, 2003). Adhesives are categorized as either natural or synthetic. Natural adhesives include animal glues, casein glues, natural gums and resins, sodium silicates and vegetable glues. Vegetable glues are starch-based and are made from starches and dextrin (Kennedy, 2013). Starch has several advantages as a raw material in the production of adhesives, including: renewability, biodegradability, abundance, relatively cheap and affordability (Agboola, et al., 2010) and can also be used to produce diverse products as food, paper, textiles, beverages, confectionery, pharmaceuticals, and building materials (FAO, 2010).

Natural colorants, with their sustainable origins, offer a promising alternative for various applications. Advanced studies have unveiled the remarkable properties, resilience, and durability of these ancient dyes, which our ancestors developed through sustainable material processing. This serves as a testament to the potential of sustainable solutions in our field. As part of our research, we prepared three medieval temperas using gum arabic, parchment glue, and casein glue. These tempera were explicitly designed to protect the purples obtained from Chrozophora tinctoria extracts. A comprehensive multi-analytical approach guides our research on natural colorants. Central to this approach is the use of molecular fluorescence by microspectrofluorimetry, a key tool in our study. By analyzing the emission and excitation spectra in the visible range, we can identify specific formulations. This method is further supported by fingerprinting techniques, including Fourier Transform Infrared Spectroscopy (FTIR) and High-Performance Liquid Chromatography with Diode Array Detection (HPLC-DAD). These are further complemented by Fiber Optics Reflectance Spectroscopy (FORS) and colorimetry. Building on our understanding of orcein purples, we have extended our research to purples derived from Chrozophora tinctoria extracts. Our findings reveal the unique properties of Chrozophora tinctoria, which can be accurately distinguished from orcein purples, highlighting the distinctiveness of each.

The effective use of natural casein-based adhesives requires the reduction of shrinkage phenomena associated with the evaporation of water, which is largely used for preparation. After the procedure optimization of a casein natural glue by aid of an alkaline solution, it was modified by the addition of two different sugars with long and short chains—chitosan and dextrose, respectively—at different weight concentration levels to absorb and retain water. The thermal decomposition and degradation kinetics of prepared sugar-based casein glues have been analyzed by performing thermogravimetric TGA characterization at different heating rates. Experimental results and the evaluation of thermal degradation activation energy by Kissinger analysis evidenced that the chitosan and dextrose could be efficient and sustainable additives to control and mitigate the degradation mechanisms of casein glues. Further, vertical flammability tests (UL 94 standards) on the sugar-modified casein materials with the highest sugar content confirmed the positive effect of chitosan and dextrose addition under flame exposure too.

Abstract Objectives This research assesses the effect of the different micromechanical surface preparations and chemically adhesive surface modification strategies applied to resin-matrix ceramics (Shofu Block HC) repaired using resin composites. Materials and Methods Eighty resin-matrix ceramics were conducted and designed into eight groups of 10 specimens and surface treated with (1) micromechanical preparation with sandblast (SB) or hydrofluoric acid (HF), and (2) chemically adhesive techniques with HC primer (HC) and/or silane (Si) and/or conventional adhesive (AD) or universal adhesive (UA) designing are as follows: group 1, SB + HC; group 2, SB + HC + AD; group 3, SB + HC + Si + AD; group 4, SB + HC + UA; group 5, HF + HC; group 6, HF + HC + AD; group 7, HF + HC + Si + AD; and group 8, HF + HC + UA. An ultradent model was put on the specimen center, then filled resin composite. Mechanical testing instrument was used to determine the samples' microshear bond strength (MSBS). To inspect failure modes, a stereomicroscope was used for observing the debonded surfaces. Statistical Analysis To assess the data, a one-way analysis of variance was employed, and the significant level (p < 0.05) was established with Tukey's test. Results Group 3 (29.29 ± 2.58 MPa) and group 4 (28.34 ± 1.26 MPa) demonstrated the two maximum MSBS values. The minimum MSBS (10.02 ± 3.31 MPa) was discovered by group 5. Nevertheless, group 2's MSBS values (22.78 ± 2.44 MPa) differed significantly from the values for groups 3 and 4. All the fractured samples in groups 1, 5, 6, 7, and 8 had an adhesive failure pattern. Furthermore, group 3 presented the greatest mixed failures (40%). Conclusion The SB is the most effective protocol for producing micromechanical retention. The application of HC primer and Si agent prior to the adhesive agent is the best chemical adhesive strategy for sandblasted resin-matrix ceramic surfaces. Additionally, the application of HC primer before the use of UA containing acid-resistant Si is the best alternative chemical adhesive strategy for improving the MSBS.

Investigation of mechanical properties of nano hexagonal boron nitride integrated epoxy adhesives in bonded GFRP and CFRP composite joints

To modify an adhesive system with halloysite clay nanotubes (HNTs) containing arginine and calcium carbonate and to evaluate their cytocompatibility, viscosity and efficacy in reducing dentin permeability. HNTs containing arginine and calcium carbonate were incorporated into the primer and adhesive of a three-step adhesive system (SBMP), and their viscosity was measured. Discs (n= 4/group) were prepared: SBMP (control), HNT-PR (modified primer), HNT-ADH (modified adhesive) and HNT-PR + ADH (modified primer and adhesive) were evaluated regarding cell death and viability. Dentin discs were prepared and randomly assigned into the following treatments (n= 10): NC (no treatment), SBMP, HNT-PR, HNT-ADH, HNT-PR + ADH and COL (Colgate® Sensitive Pro-relief™ prophylaxis paste). After, they were submitted to an erosive-abrasive cycling. Dentin permeability (hydraulic conductance) was evaluated at baseline, 24 h after treatment and after cycling. Both the modified primer and adhesive showed significantly higher viscosity than their controls. Group HNT-PR resulted in significantly higher cytotoxicity when compared to SBMP and HNT-PR + ADH groups. Group HNT-ADH resulted in the highest cell viability compared to all other groups. All groups showed significantly lower dentin permeability when compared to the NC group. Post-cycling, SBMP and HNT-ADH groups showed significantly lower permeability when compared to COL group. The addition of encapsulated arginine and calcium carbonate did not affect the cytocompatibility of the materials nor their ability to reduce dentin permeability.

Peculiarities of bone tissue remodeling processes affect the use of the latest molecular and cellular methods of fracture treatment, in particular, the use of biological glue. Currently, adhesive materials are used in surgery quite widely, but it is important to soberly assess the current state of tissue fixation methods in orthopedics and traumatology. Medical adhesives are special type of polymer alloimplants. Their main purpose is a strong connection of living tissues with an optimal ratio between good adhesive properties, speed of biodestruction and minimal inflammatory reaction. The most common adhesives used in surgery are: polyurethanes, cyanoacrylates, epoxies, and adhesives based on a mixture of natural and synthetic rubbers. It is important to separately discuss the glue, which is used not only in orthopedics and traumatology, but also in neurosurgery, maxillofacial surgery, vertebrology, cardiac surgery, thoracic surgery and dentistry. It is a bone replacement material called Kryptonite. Biological glue Bio Glue is a surgical glue intended for sealing and strengthening surgical sutures and gluing tissues together. Casein glues belong to the class of alkaline glues that turn into jelly and take a solid form. Surgical glue “Cryofit” – fibrinthrombin sealant creates a positive environment for the attachment, differentiation and survival of transplanted cells, excludes the possibility of their uncontrolled migration. PRF (Platelet Rich Fibrin) is fibrin rich in platelets obtained from blood by centrifugation. Depending on the blood processing protocol, i-PRF is obtained – injectable fibrin rich in platelets. A less well-known synthetic medical glue is the ZRF system (gelatin-resorcinol-formaldehyde composition). In the works of Braunwald N.S. etc. and Tatooles C.J., Braunwald N.S. it is shown that the glue reliably connects tissues in a humid environment, has a lower histotoxic effect, and is quickly absorbed. The current state of using medical glue as the main (and not additional) method of tissue fixation has significant prospects. It is important to continue studying the properties of materials to achieve the highest results in gluing living tissues.

Since 2004, scientific research on the damaged Giant Buddha statues and Buddhist paintings in Bamiyan, Afghanistan, has been conducted at various laboratories and large-scale facilities using mass-spectrometry techniques (GC-MS, LC-MS, LC-MS/MS, nano-LC/ESI-MS/MS), ELISA, and synchrotron-based micro-analyses) in parallel to conservation intervention. Studies on samples from these cultural heritage objects have shown that each is composed of a polychromatic multilayered structure with sizing layers, ground layers, painted layers, and glaze. The carefully produced complex multilayered structures were examined using optical microscopy (visible and UV light) as well as synchrotron-based infrared microscopy, both of which revealed various organic and inorganic components in each layer. High sensitivity bulk MS and ELISA methods were used to further identify details regarding organic materials, such as fatty acids and collagens, and these results suggest different vegetable oils and animal species of glues. For example, cow milk casein and cow skin glue were identified in the Eastern Giant Buddha, suggesting that casein was used as a sizing agent and the cow skin glue as a binder for painting. The wall paintings from Cave N(a) (mid-7th century AD) were found to have horse glue used as sizing and drying oil (poppyseed/walnuts/perilla oils) as a binding media. The paintings’ complex structures and their organic and inorganic materials were fully understood using both imaging and bulk methods, and thus, these methods help to reconstruct historical wall painting techniques in full.

The article considers the effect of weak cationic polyelectrolytes on the structure- and paper-forming properties of glued fibrous suspensions and the quality of glued and coated paper and cardboard samples obtained from them. It is shown for the first time that the efficiency of using cationic polyelectrolytes increases by 2…3 times due to a change in the sequence of its introduction into glued fibrous suspensions (cellulose and waste paper) in relation to rosin emulsion and electrolyte, as well as by «correction» their dosages. It is found that the use of the developed technology allows cationic polyelectrolytes to participate not only in the process of flocculation, but also in the formation of new sizing complexes in the form of finely dispersed positively charged peptized particles. It is revealed that the replacement of the sizing process in the homocoagulation mode with a more efficient mode of heteroadagulation of peptized particles due to the use of weakly basic cationic polyelectrolytes provides an increase in hydrophobicity and strength of the glued types of paper and cardboard. The expediency of using cationic polyelectrolytes to obtain high-quality products in the developed resource-saving and ecologically safe technology of glued types of paper and cardboard is substantiated based on the established increase in the degree of retention of fibers and sizing complexes and the simultaneous decrease in the content of suspended solids in recycled water. It is determined that the coating of glued paper and cardboard samples obtained with weakly basic cationic polyelectrolytes improves the printing properties of the resulting products. Recommendations are given for replacing the traditionally used complex of natural compounds in the coating paste formulation, including oxidized starch (2,0 parts by weight), sodium carboxymethyl cellulose (0,7 parts by weight) and casein glue (2,0 parts by weight), for one synthetic binder — modified urea-formaldehyde oligomer (3,2 parts by weight).

Vibration characteristics of wood-based materials are essential parameters in considering the indoor environment of a building. This study investigates the effect of the physical properties of water-based adhesives on vibration characteristics of wood-based materials. Adhesive films and particle boards (PB) were prepared from acrylic emulsion adhesives (AE) with differential glass transition (Tg), and loss tangent of dynamic viscoelasticity (tanδD) and flexural vibration property (tanδF) were compared. The tanδD master curve and tanδF showed a similar tendency regarding frequency dependence. The apparent activation energy (ΔH) calculated from the shift factor of the master curve tends to be different depending on the Tg of AE and was especially high for AE with Tg = 13 °C along with blended AE. The dynamic Young’s modulus (EF) calculated from the flexural vibration tests showed higher values for AE at Tg = 13 °C, 41 °C, and 90 °C than that of urea–formaldehyde adhesive (UF).

To evaluate through a systematic review and meta-analysis the bonding performance of adhesive materials to silver diamine fluoride (SDF)-treated dentin. Studies located in PubMed, Web of Science, LILACS, and Scopus up to September 2020, which compared the bond strength of adhesives (AD) or glass-ionomer cement (GIC) to SDF-treated and untreated (control) dentin were included. Mean differences were estimated separately by material and dentin condition (sound or caries-affected), with a random-effects model, at a 5% significance level. Twenty-two studies, including 11 new studies not included in our previous systematic review, met the eligibility criteria, and 21 studies were considered in the meta-analyses. SDF dentin pretreatment did not influence the bonding of GIC (Z = 0.53; p = 0.60), independent of dentin condition. SDF treatment significantly impaired the bonding of AD (Z = 2.43; p = 0.01). A rinsing step after SDF eliminated this effect in sound dentin (Z = 1.82; p = 0.07) and increased the bond strength to caries-affected dentin (Z = 2.14; p = 0.03). SDF pretreatment does not influence the bond strength of GIC. A rinsing step after SDF application can improve the bond strength of AD to caries-affected dentin.

Вивчений вплив препарату Афлазин® (UTIRoseтм) й окремо його комбінації з левофлоксацином на адгезивні якості умовно-патогенних мікроорганізмів. Установлено, що додавання діючої речовини препарату Афлазин® (UTIRoseтм) сприяє істотному (р ≤ 0,05) зниженню показників адгезії мікроорганізмів в 1,4–5,0 раза порівняно з контролем. Додавання комбінації діючої речовини препарату Афлазин® (UTIRoseтм) й левофлоксацину сприяло ще більшому зниженню показників адгезивності для досліджуваних штамів.

Micropapillary adenocarcinoma of the lung is a type of cancer associated with a poor prognosis and is characterized by the presence of tumor cells with a ring‑like glandular structure floating within alveolar spaces. In the present study, the association between its morphological, biochemical and immunohistochemical characteristics, and malignancy was investigated using the KU‑Lu‑MPPt3 cell line established from a patient with MIP adenocarcinoma. Two subpopulations of KU‑Lu‑MPPt3 cells, namely adhesive (AD) and clumpy and suspended (CS) cells, were prepared and subjected to DNA microarray, reverse transcription‑quantitative PCR, western blot and immunostaining analyses. Protein expression patterns were compared between the cell types and their derived tissues using immunostaining. The results revealed similar protein expression patterns between the tumor cells found in the alveolar spaces and CS cells, which exhibited morphological characteristic of MIP adenocarcinoma. Based on the results of DNA microarray analysis, the present study then focused on Akt and focal adhesion kinase (FAK), which were markedly activated in the KU‑Lu‑MPPt3 CS and AD cells, respectively. Following KU‑Lu‑MPPt3 CS cell plating onto collagen‑coated culture dishes, some cells exhibited a transformation of their morphology into KU‑Lu‑MPPt3 AD‑like cells within a few days, and their Akt and FAK activities were similar to those of the AD cells. Additionally, the inhibition of Akt and FAK activities with Akt and FAK inhibitors reduced KU‑Lu‑MPPt3 CS cell adhesion and proliferation. Thus, the aforementioned results indicated that the phosphorylation of FAK and Akt may play a crucial role in the regulation of KU‑Lu‑MPPt3 CS cell adhesion and proliferation, respectively. Furthermore, the malignant potential of MIP adenocarcinoma may be attributed to these morphological and biochemical alterations in the KU‑Lu‑MPPt3 cells.

Observation on the effect of modified adhesive retained posterior implant denture on the tissue around the implant.

Ashland may not stick with exit adhesives

Fibrillar dry adhesives are state-of-the-art solutions for controllable and reversible attachments, inspired by nature from animals like the gecko. They depend on short-ranged intermolecular bonds, necessitating discrete attachment terminals with low elastic modulus in order to conform to the adhered material's surface roughness. At the same time, high stiffness grants resistance against interfacial crack growth and detachment under external loading. Nature provides us with a solution to this contentious requirement in the form of bi-material composite adhesives consisting of a soft tip confined by a much stiffer backing, significantly improving the adhesive performance. However, different detachment mechanisms introduced by this design and the adhesive strength corresponding to them have not been thoroughly investigated. We study the adhesive strength of an axisymmetric bi-material with a soft tip adhered to a rigid substrate subjected to normal loading, using linear elastic fracture mechanics. Two major detachment mechanisms are noticed: Crack propagation from the perimeter of the interface and from its center. Geometry and incompressibility of the adhesive layer determine the predominant detachment mode. For a geometrically confined tip under certain conditions, the maximum adhesive strength becomes independent of the crack size due to center crack stable propagation. This maximum adhesive strength is ultimately presented in the form of a power-law equation evidencing an increase in adhesive strength for thinner tips. Finally, we found a good agreement between our results and experiments.

This thesis explores two investigations into improving the detachment strength and load distribution at the interface of dry bio-inspired fibrillar adhesives subjected to normal loading. The first is in how interfacial curvature affects the load sharing efficiency of engineering prototypes. Previous investigations unraveled the benefits of backing layer (BL) thickness in counteracting the detrimental load concentration created by interfacial misalignment. However, little attention was dedicated to the role of interfacial curvature on load distribution and the resulting adhesive strength. Based on the concavity of the curvature, the adhesive can detach more easily or develop stronger adhesion, compared to a flat-on-flat interface. This suggests the possibility to actuate curvature and better control adhesion. The curvature-induced strengthening/weakening of the adhesive was analyzed in combination to BL thickness, interfacial misalignment, and imperfections in the fibril length distribution. Detrimental load concentrations, created by BL interaction and interfacial misalignment, drastically reduce when the curvature prompts larger stretch to the central fibrils. This also mitigates load concentrations created by uneven fibril length distribution. These beneficial effects are reverted when the curvature prompts larger stretch to the peripheral fibrils. The quantitative analysis provides a design tool for stronger and more controllable adhesives. The second investigation is into an asymptotic solution to the optimal compliance distribution attributable to fibrils within the array. The optimal compliance distribution allows the adhesive to achieve equal load sharing (ELS) which is its theoretical maximum strength i.e all fibrils carry the same load and detach simultaneously. The array of fibrils is modelled as a continuum of linear elastic material that cannot laterally transmit load (analogous to a Winkler soil). Ultimately, the closed form solution for the continuum distribution of fibril compliance is obtained and compared to the data from a discrete model. The results show improving accuracy for an incremental number of fibrils and smaller center to center spacing. Surprisingly, the approximation introduced by the asymptotic models shows reduced sensitivity of the adhesive strength with respect to misalignment and improved adhesive strength for large misalignment angles.

Understanding of Crack Growth in Single- and Bi-Material Bonded Joints with “Extra-Thick” Adhesive Bond-Lines

Application of Polysilsesquioxane to Pressure-sensitive Adhesives and Adhesives