Bond Durability Research Articles

THIN OVERLAYS OF STEEL FIBER REINFORCED CONCRETE AND CONTINUOUSLY REINFORCED CONCRETE STATE OF THE ART IN BELGIUM

In Belgium, resurfacing of existing roads with cement concrete has been a common practice for over a decade, with approximately 500 km of roads overlaid with continuously reinforced concrete pavement (CRCP). This interest expanded to include thin resurfacings (<15 cm) of steel fibrous reinforced concrete (SFRC) and thin continuously reinforced concrete (TCRCP) due to the advantages offered by steel fibrous reinforced concrete in terms of lower fiber content and better incorporation possibilities. Experimental sections constructed since 1982, covering nearly 25 km of roads, have explored the use of SFRC and TCRCP overlays on both old concrete and bituminous pavements. The study reveals promising outcomes for thin overlays in SFRC, particularly when applied over bituminous underlayers, showcasing remarkable and durable bond strength. The best results were achieved with new leveling courses with an overall open structure. On old concrete pavements, achieving an adequate bond is crucial for success, necessitating intensive roughening of the existing surface. Grout application showed minimal improvement in bond strength. TCRCP overlays, particularly those with a thickness of 14 cm, demonstrated satisfactory performance with no significant issues. Utilizing welded-wire fabric for reinforcement can offer cost savings and facilitate construction under traffic conditions. This research, conducted with financial assistance from the IRSIA organization and supervised by a Working Party chaired by Prof. dr. ir. F. Van Cauwelaert, aims to establish practical guidelines for thin resurfacing and explores the relationship between empirical experience and thickness design computations. The study underscores the potential of thin concrete resurfacings in the rehabilitation of the Belgian road network, emphasizing careful consideration of bond strength and overlay thickness for successful implementation. (Abstract generated by AI tool ChatGPT 4)

Effect of Accelerated Aging on the Microtensile Bond Strength of a Two-Step Adhesive Containing a Universal Adhesive Primer, an in vitro study

Background Despite the advantages of one-step universal adhesives, concerns about their bond durability exist. By introducing a two-step adhesive using universal bonding technology, the study aimed to evaluate the effect of accelerated aging on the microtensile bond strength (µTBS) of this adhesive when applied to dentin. Materials and Methods In this in vitro study, 16 extracted sound human third molar teeth were selected. Specimens were prepared by cutting the occlusal enamel perpendicular to the longitudinal axis and categorized into four groups of 18 each: G2-Bond Universal (GC Corp, Tokyo, Japan) in etch-and-rinse mode (GU-ER), G2-Bond Universal in self-etch mode (GU-SE), G-Premio Bond in etch-and-rinse mode (GP-ER), and G-Premio Bond (GC Corp, Tokyo, Japan) in self-etch mode (GP-SE). The resin composite was bonded to the dental surfaces based on the manufacturer’s instructions and light-cured for 10 seconds using an LED curing unit (Demetron A2, Kerr, Scafati, Italy, 1200 mW/cm2). The bonded specimens were then sectioned into 1 mm2 sticks and divided into two subgroups (n=36). One subgroup (9 specimens from each adhesive) underwent thermal cycling, while the other was immersed in 10% sodium hypochlorite for three hours to simulate accelerated aging. The µTBS was measured, and failure modes were determined. Data were analysed using two-way ANOVA, the Sidak test, and the Independent Samples T-Test Results The highest mean μTBS was associated with GU-SE (29.63 ± 8.59 MPa), while the lowest was observed with GP-ER (18.65 ± 9.33 MPa). The µTBS values decreased following aging (p < 0.001). The values for GU-SE and GU-ER were significantly higher than those for GP-ER (p < 0.001 and p = 0.005, respectively). GU-SE and GU-ER showed a slight, statistically insignificant decrease in bond strength with aging (p = 0.133 and p = 0.060, respectively). However, GP-SE and GP-ER showed significant reductions in bond strength after aging (p = 0.004 and p = 0.001, respectively). The interaction between accelerated aging and study groups was not significant (p = 0.311), indicating a uniform effect of aging in all groups. Failure modes were similar in groups (p > 0.05), with adhesive failure being the most common type. G-Premio had more adhesive failures than G2-Bond, though this difference was not statistically significant. Conclusion Two-step universal adhesive performed better than one-step system during aging. In etch-and-rinse mode, the two-step adhesive significantly improved bond strength, while in self-etch, both adhesives showed similar performance.

The impact of primers for wood bonding on beech wood’s Young’s modulus

When producing load-bearing timber products with one-component polyurethane adhesives and certain wood species, e.g., beech or larch, primers can be used to obtain stronger and more durable bonds. The active chemicals of three existing primer systems, hydroxymethylated resorcinol formaldehyde (HMR), polysorbate 20 (PS20), and poly(ethylene glycol) (PEG), were used to impregnate beech wood. Young’s modulus (E) in the radial direction was determined in tensile mode. A modified E can influence the deformation and stress distribution at the wood-glue interface. Compared to the untreated wood, the average E was reduced by 7% for the water-treated reference and the HMR treatment. With the PS20 treatment, the average E was reduced by 16%, compared to the untreated wood, and by 45% with the PEG treatment.

A Novel Dual Cross-linking Reagent for Dentin Bonding Interface Stability.

The cross-linking reagent has been proposed as a means of modifying dentin collagen, inhibiting matrix metalloproteinase activities, and enhancing bond durability during dentin bonding procedures. This study aimed to synthesize an operation-friendly dual cross-linking reagent-3-(4-formyphenoxy)-2-hydroxypropyl methacrylate (FPA)-to assess its ability to cross-link dentin collagen and reduce enzymatic activity at the bonding interface. Cytotoxicity was evaluated by a cell counting kit-8 test and calcein AM/propidium iodide assay. Attenuated total reflection-Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and molecular docking of FPA-collagen showed that FPA can mediate covalent bonding and hydrogen bonding. The hydroxyproline release test and thermogravimetric analysis demonstrated that FPA-collagen can resist exogenous proteases and thermolysis. The gelatin zymography and in situ zymography indicated that FPA can reduce enzymatic activity at the bonding interface. The bonded samples were subjected to microtensile bond strength analysis after 24 h and thermocycling. The bonding interface quality was evaluated by the water contact angle, confocal laser scanning microscope, field emission scanning electron microscopy, and nanoleakage assessment. This study demonstrated the effectiveness and significant clinical potential of the dual cross-linking reagent FPA in that it increases the longevity of resin-dentin bonds and reduces dentin matrix metalloproteinase activities at the bonding interface.

Effect of different surface treatments on PEEK-enamel bonds: Bonding durability and mechanism

Polyetheretherketone (PEEK) has been used in clinical dentistry because of its excellent physical and biological properties. However, achieving an effective and durable bond with enamel is challenging because of its chemical inertness and low surface energy, and data on the effects of different surface treatments on the durability of PEEK-enamel bonds are scarce. The purpose of this in vitro study was to investigate airborne-particle abrasion, sulfuric acid etching, and the combined use of these treatments on the bonding durability of PEEK-enamel bonds and to gain a deeper understanding of their bonding mechanism. Sixty specimens were divided into 6 groups based on different surface treatments: untreated, sulfonation for 30 seconds, sulfonation for 60 seconds, airborne-particle abrasion, airborne-particle abrasion and sulfonation for 30 seconds, and sulfonation for 30 seconds and airborne-particle abrasion. Comprehensive evaluations were carried out on the surface morphology and physicochemical properties of the pretreated PEEK. After screening out the preferred surface treatment strategy of PEEK, the durability of PEEK-enamel bonds after thermal cycling (10 000 cycles at 5 to 55°C) and the bonding mechanism were investigated by bond strength testing, cross-sectional topography, molecular dynamics,and Fourier transform infrared spectroscopy. Data were analyzed by 1-way analysis of variance, Weibull analysis, and the Fisher exact test (α=.05). The shear bond strength of the 98% sulfuric acid etching group for either 30 seconds or 60 seconds was significantly higher than that of the other groups (P<.05). Intermolecular hydrogen bonding was found between PEEK and the methyl methacrylate- (MMA-) containing adhesive resin. Cross-sectional topography showed that the adhesive resin infiltrated into the pores of the sulfonated PEEK, thereby forming micromechanical locking at the bonded interface. The bond strength between the enamel and PEEK treated with 98% sulfuric acid for 60 seconds was found to be more reliable than that observed in the group treated with 98% sulfuric acid for 30 seconds after aging (P<.05). PEEK pretreated by 98% sulfuric acid etching for 60 seconds presented the best physicochemical properties. This was better than combined etching and airborne-particle abrasion or airborne-particle abrasion alone and showed durable PEEK-enamel bonds with the application of an MMA-containing adhesive.

A Simple Surface Treatment for Improving the Adhesive Bonding Properties and Durability of an AlMg3 Alloy.

The structural adhesive bonding of aluminum is widely used in the aircraft and automotive industries. The surface preparation of aluminum prior to adhesive bonding plays a significant role in improving the bonding strength. Surface cleanliness, surface roughness, and surface chemistry can be controlled, primarily, by proper surface treatment methods. In this study, the effect of varying the chemical treatment period on the adhesive bonding characteristics was investigated. An epoxy adhesive was used to join the treated surfaces, and the bond strengths were evaluated via single lap-shear (SLS) tests in pristine, as well as degraded, conditions. The surface morphology, chemistry, and corrosion properties of the surfaces with chemical treatments were characterized using various surface analytical tools, such as scanning electron microscopy, an energy dispersive spectrometer (SEM/EDX), and an electrochemical workstation. Excellent adhesion characteristics, with the complete cohesive failure of the adhesive, were encountered on the surfaces of the H2O2-treated samples. The H2O2-treated samples exhibited the highest initial bond strength, reaching 22.5 ± 0.5 MPa, and showed a decrease of only 10% (to 18.1 ± 0.2 MPa) after aging under extreme humidity and temperature conditions (70 °C and 100% R.H. for 4 weeks). The chemical treatment reported in this work is a very simple method to produce durable joints.

Social mating systems in birds: resource-defense polygamy-but not lekking-is a macroevolutionarily unstable trait.

Our understanding of the evolution of social mating systems is largely based on an atemporal ecological framework, whereas macroevolutionary and phylogenetic perspectives looking at the causes of mating systems variation are less developed. Here, we present analyses of the evolution of social mating systems in birds at an unprecedented scale, including 66% of the world's birds and using trait-dependent speciation and extinction models. We found that lekking (no social bond between the sexes) is very rarely lost, in accordance with the hypothesis that a male shifting to investing in one rather than multiple mates would suffer a severe fitness cost. In contrast, resource-defense polygamous lineages (with a weak, transient socio-sexual bond) frequently revert back to monogamy (strong, durable socio-sexual bond) and have an elevated extinction fraction. We tentatively attribute this to the impossibility of females settling on an optimal parental care strategy under this system. Finally, we found that most gains of lekking have been directly from monogamy rather than through an intermediate stage of resource-defense polygamy.

Evaluation of shear strength and durability of adhesive bond in cross-laminated timber (CLT) panels made from Nigerian Gmelina arborea timber

This study investigates the shear strength and durability of wood-adhesive bonds in Cross-Laminated Timber (CLT) panels made from Nigerian grown Gmelina arborea using one-component Polyurethane (PUR) and two-component Epoxy Resin (ER) adhesives. The block shear test and delamination test, conducted in accordance with EN 14080 (2015) and EN 16351 (2015), were employed to assess the bond quality and durability. The maximum shear strengths observed were 3.37 MPa for PUR and 2.78 MPa for ER, with respective minimum values of 2.88 MPa and 2.45 MPa. Wood failure percentage (WFP) analysis indicated that ER exhibited slightly better adhesive performance under dry conditions, while PUR demonstrated superior performance after delamination. A moderate positive correlation (r ≈ 0.579) was found between shear strength and WFP for PUR, whereas ER showed a very weak correlation (r ≈ 0.015), suggesting differing performance characteristics between the adhesives. The delamination test results showed PUR generally outperformed ER, particularly in smaller CLT-60 panels, indicating better bond durability. A strong positive correlation (r ≈ 0.984) between total delamination (Dtot) and maximum delamination (Dmax) was identified, while no significant correlation was found between delamination and WFP. The findings suggest that while PUR offers higher shear strength and better durability, ER provides more consistent adhesive performance. Panel size was also found to influence the bonding performance, with smaller panels exhibiting lower delamination percentages. Overall, PUR appears more suitable for applications requiring high durability, particularly in smaller panels, while ER might be preferable for larger panels where consistent bond quality is critical.

Provides Efficient Shear Bond Strength and Durability Between Lithium Disilicate Glass-ceramic and Resin Cement: A Potential Alternative to the Conventional Hydrofluoric Acid Protocal

Objectives: This study investigated the effects of two surface treatment protocols on the shear bond strength, bond durability, and failure mode at the interface between lithium disilicate glass-ceramic and resin cement. The protocols compared were a self-etching ceramic primer and the conventional hydrofluoric acid (HF) etching followed by silane. Methods: Fifty lithium disilicate specimens were randomly divided into five surface treatment groups (n=10 each). A control group received no treatment. The remaining 4groups included: 5% HF etch with Monobond Plus thermocycled and non-thermocycled, Monobond Etch &amp; Prime (MEP), thermocycled and non-thermocycled. Microshear bond strength (microSBS) was assessed before and after thermocycling to evaluate bond durability. Failure modes (adhesive, mixed, cohesive in resin/ceramic) were recorded under a stereomicroscope. Results: Both surface treatment protocols exhibited comparable microSBS for both pre- and post-thermocycling results. Moreover, bone durability obtained from the two treatment protocols seemed to be comparable. Most groups displayed adhesive/mixed failures. Notably, the self-etching ceramic primer group showed cohesive failure in half of the specimens initially, persisting in 20% after thermal aging. Conclusions: Compared with the conventional HF protocol, the self-etching ceramic primer protocol provided similar microSBS and bond durability between lithium disilicate glass-ceramic and resin cement. The data suggest a self-etching ceramic primer is a viable option for the conventional HF protocol in bonding to glass-ceramic, minimizing the HF hazard and simplifying the clinical procedure.

The influence of external and internal factors on ensuring adhesive interaction of a polymeric sealant with a substrate surface (a review)

This paper analyzes literature data on the influence of various factors affecting the strength and durability of adhesive bonds, as well as presents a characterization of the methods described in the literature for conducting relevant studies. It is shown that one of the main characteristics of adhesive joints is the interaction at the interface between the substrate and the adhesive. The adhesive capability of a sealant largely depends on the structure of the polymer component, as well as the presence of components in the sealant that enhance this property. The structure and condition of the substrate surface significantly affect the nature of the interaction between the adhesive and the substrate. Various methods are used to determine the strength of the adhesive bond, differing in the type of applied loads and the nature of the surface fracture. An important indicator is the determination of the wetting angle of the substrate by the sealant, which characterizes the surface energy. The durability of adhesive bonds is significantly influenced by environmental factors as well as operational conditions. Moisture, atmospheric oxygen, ultraviolet radiation, and microorganisms have a particularly strong effect on the properties of polymeric sealants.

Deformation-Resistant Underwater Adhesion in a Wide Salinity Range.

Conventional adhesives experience reduced adhesion when exposed to aqueous environments. The development of underwater adhesives capable of forming strong and durable bonds across various wet substrates is crucial in biomedical and engineering domains. Nonetheless, limited emphasis placed on retaining high adhesion strengths in different saline environments, addressing challenges such as elevated osmotic pressure and spontaneous dimensional alterations. Herein, a series of ionogel-based underwater adhesives are developed using a copolymerization approach that incorporates "dynamic complementary cross-linking" networks. Synergistic engineering of building blocks, cross-linking networks, pendant groups and counterions within ionogels ensures their adhesion and cohesion in brine spanning a wide salinity range. A high adhesion strength of ≈3.6MPa is attained in freshwater. Gratifyingly, steady adhesion strengths exceeding 3.3MPa are retained in hypersaline solutions with salinity ranging from 50 to 200gkg-1, delivering one of the best-performing underwater adhesives suitable for diverse saline solutions. A combination of outstanding durability, reliability, deformation resistance, salt tolerance, and self-healing properties showcases the "self-contained" underwater adhesion. This study shines light on the facile fabrication of catechol-free ionogel-based adhesives, not merely boosting adhesion strengths in freshwater, but also broadening their applicability across various saline environments.

Evaluation of the Bond Strength, Durability, and Enamel Demineralization Potential of Orthodontic Adhesives on Bracket Bonding

ABSTRACT Objective: To evaluate the effects of incorporating titanium tetrafluoride (TiF4) into orthodontic primers on shear bond strength (SBS), bond durability, and enamel demineralization potential compared to conventional adhesive systems. Materials and Methods: In total, 120 extracted human premolars were divided into three groups (n = 40 each): Group A (Resin-based, Transbond XT), Group B (Glass ionomer-based, Fuji Ortho LC), and Group C (2 Wt.% TiF4-containing modified Transbond XT system). Standard edgewise premolar brackets were bonded to the teeth. Half of each group underwent immediate SBS testing, while the remaining specimens were thermocycled before testing. The Adhesive Remnant index was assessed post-debonding. Enamel demineralization was evaluated using quantitative light-induced fluorescence before bonding and after debonding. Results: Group C exhibited the highest mean SBS values both immediately (19.5 MPa) and after thermocycling (17.9 MPa). This group also showed the least enamel demineralization. Conclusions: The incorporation of 2 Wt.% TiF4 into the orthodontic primer resulted in improved bond strength and reduced enamel demineralization compared to conventional adhesive systems.

Competitive inhibition of family GH11 Aspergillus fumigatus endo-xylanase A by Oryza sativa xylanase inhibitor protein: Investigating key interface residues and non-covalent interactions

Glycoside hydrolase (GH) family 11 Aspergillus fumigatus endo-xylanase A (AfXylA11) was recombinantly expressed in Pichia pastoris X33 and secreted into culture medium. Hydrolysis of beechwood xylan by recombinant AfXylA11 (reAfXylA11) predominantly generated xylooligosaccharides (XOs), chiefly comprising xylotriose (X2) and xylotetraose (X3). These hydrolysates demonstrated significant antioxidant capabilities. Competitive inhibition of reAfXylA11 was observed in the presence of the Oryza sativa xylanase inhibitor protein (OsXIP), with an inhibition constant (Ki) of 120.98 nM. Molecular dynamics (MD) simulations and conformational analyses of the AfXylA11-OsXIP complex revealed that the extended loop (Lα4β5, K150-V158) of OsXIP penetrated the active groove of AfXylA11, thereby obstructing xylan from interacting with catalytic sites. The R153 at the bottom of the U-shaped loop, was found to form durable hydrogen bonds with E197 (acid/base catalyst) and Y97 of AfXylA11. Additionally, OsXIP established stable interactions with the “cord” and “thumb” regions of AfXylA11 during MD simulations. The binding free energy of the AfXylA11-OsXIP complex was determined to be -74.3 ± 7.6 kcal/mol, with electrostatic interactions and van der Waals forces being the predominant contributors to enzyme-inhibitor interaction. Further MD simulations demonstrated that the mutation of Y116A or S120A in the “cord” region of AfXylA11 significantly reduced its binding affinity to OsXIP by weakening interface residue interactions. Delving into the conformational dynamics of the AfXylA11-OsXIP complex yields insights into the molecular mechanisms dictating their competitive inhibition. This investigation offers useful basis for engineering mutant xylanases that resist to the inhibitory protein yet retain high catalytic efficacy.

Predicting lifetime of adhesive bonds for naval steel by time-temperature superposition

There is a lack of knowledge about the long-term behaviour of adhesive joints in the marine environment, and for hence, its reliability. The life cycle expected for a ship is twenty-five years and conduct duration tests would last decades. The importance and originality of this study are that it provides a methodology for predicting the durability of adhesive bonds. For this purpose, three adhesives for bonding naval steel were tested at several temperatures for determination of their shear strength on standard single-lap-joint specimens. Subsequently, using the time temperature superposition principle, these results were combined into one master curve for each adhesive that can be considered as a prediction method of the durability in a long-term period. The usual parametric models of Arrhenius and Williams-Landel-Ferry were used to obtain the master curve for each adhesive by manual shifting. The results were compared with those obtained applying an open-source software developed by the authors in R language, which specifically implements a non-parametric methodology based on the shift of the first derivative curves, following parameters of Explainable Artificial Intelligence. It was found a good correlation between both methodologies, supporting the durability lifetime obtained and therefore the applicability on ships of this adhesive technology.

Comparative evaluation of the strength of adhesion by push-out bond strength tests on endodontic posts cemented with different resinous types of luting cements: An in vitro study

INTRODUCTION. Endodontic posts play a vital role in strengthening debilitated teeth. They are luted into the radicular space using dental cements that are generally resinous. Given that the forces faced by human teeth are loading in nature and the stresses are accumulative, the bond strength of the interfaces at both the radicular dentin and luting agent and the endodontic post and the luting agent needs to be evaluated. Micro pushout bond strength (POBS) testing is done to determine these strengths. This experimental, in vitro study evaluated the adhesion strength of endodontic posts cemented with different resin-based luting agents using micro-POBS.MATERIALS AND METHODS. A total of 30 human lower incisors were selected and divided into three groups (n=10), based on the type of adhesive resin cement used for luting. Prefabricated endodontic fiber posts were inserted into the root canals of each tooth, and different resin types of cement – Estecem II, Multilink Automix, and Relyx Ultimate. were used to cement the fiber posts. The micro-POBS test measured the bond strength of the cemented pins to the root canal dentin.RESULTS. The results showed that the mean POBS of Group B was higher than that of Group A and Group C. The difference between the mean POBSs of Group A and Group C was not statistically significant (p&gt;0.05).CONCLUSION. The resin adhesive cement used can affect the POBS of endodontic posts to root canal dentin. Clinicians should choose the appropriate resin cement for cementing endodontic posts to ensure a strong and durable bond for a good clinical prognosis.

Optimized Microporous Surfaces Increase Bond durability of NPJ-printed zirconia

Optimized Microporous Surfaces Increase Bond durability of NPJ-printed zirconia

The effects of optimized microstructured surfaces on bond strength and durability of NPJ-printed zirconia

ObjectivesThis study was to investigate the effects of optimized microstructured surfaces on bond strength and bond durability of the latest nanoparticle jetting (NPJ)-printed zirconia. MethodsZirconia microstructured surfaces with different geometries and void volume were analyzed through three-dimensional finite element analysis for surface micromorphology optimization. Zirconia disks and cylinders were additively manufactured by an NPJ 3D printer (N = 128). They were randomly divided into four groups based on surface micromorphology optimization and airborne-particle abrasion (APA) treatment before they were bonded using 10-methacryloloxydecyl dihydrogen phosphate (MDP) containing resin cement (Clearfil SA luting cement). The shear bond strengths (SBSs) were tested before and after 10,000 thermocycles and were analyzed by one-way ANOVA analysis. Failure modes were determined by optical microscopy. Zirconia surfaces were analyzed with X-ray diffraction, scanning electron microscopy, and three-dimensional interference microscopy. ResultsThe optimized microstructured surface was characterized by circular microstructures with 60 % void volume, about 20 µm of depths, about 10 µm of undercuts, and consistent beam widths. The optimized microstructured surface combined with APA treatment and MDP-containing resin cement possessed the highest SBSs both before and after thermocycling aging (P＜0.05). The greater reductions of zirconia bond strengths occurred when the zirconia were not treated with APA (P＜0.05). SignificanceThe optimized microstructured zirconia surface with circular microstructures and 60 % void volume fabricated by the latest NPJ printing technology could greatly enhance the zirconia bond strength and durability in combination with APA treatment and application of MDP-containing resin cement, which might be promising for adhesively bonded indirect restorations of NPJ-printed zirconia.

FEATURES FOR OPTIMISING THE PROPERTIES OF COMPOSITE MATERIALS BASED ON ACRYLIC MONOMERS

Further development of research in the field of acrylic composites is aimed at creating modifiers with specified properties that will improve the characteristics of composites in specific application conditions; developing optimal ratios of composite components to ensure the required properties; developing universal mathematical models that will predict the properties of composites depending on the composition and curing conditions; searching for new applications for acrylic composites, such as industrial and civil engineering. Among all organic compounds, acrylic compounds demonstrate the highest rate of strength gain over a wide temperature range. This is due to the low activation energy of the polymerisation process of acrylic monomers, which is triggered by special initiators. Due to this feature, acrylic composites can cure even at low temperatures and gain high strength in a short time. However, despite the obvious advantages, there are a number of questions that require further research: how does the rate of strength gain and other properties of acrylic composites change at different temperatures? How does changing the ratio of composite components (pliable, filler, initiator) affect its properties? How does the curing process of acrylic composites work at the molecular level? Determining the answers to these questions will make it possible to select the optimal ratio of components to obtain a material with the required properties, control the rate of strength gain of the composite by changing the temperature and composition, and use acrylic composites in a wider range of temperature conditions. Thus, a deep understanding of the processes that occur during the curing of acrylic composites is a prerequisite for their effective use in various industries and construction. The aim of the study is to comprehensively study the properties of composite materials based on methyl methacrylate (MMA) for the purpose of their effective use. Research objectives: determination of the optimal temperature regime to achieve maximum composite strength in the shortest possible time (1.5-2 hours). Study the effect of various fillers and other components on the strength, durability and other properties of the material. Identification of effective ways to modify MMA to increase the strength of the composite. Development of methods for controlling the rate of strength gain to ensure optimal operation. Assessment of the durability of the adhesive bond under various operating conditions. Comparison of the properties of the developed composites with existing materials. The results of the study will make it possible to develop new, more efficient composite materials for repair work that will be widely used in construction, industry and other sectors. Keywords: acrylic composites, modification, methyl methacrylate, strength, temperature, curing, repair.

Advances in Adhesive Bonded Joints for Composite Materials: A Comprehensive Review

Adhesive bonded joints have become increasingly significant across various high-tech industries, including aerospace, automotive, marine, and construction. This growing importance is largely due to their efficiency in joining lightweight composite materials, which are integral to modern engineering applications. In this review paper, we offer a comprehensive update on the latest advancements in adhesive bonded joints specifically for composite materials. The paper delves into several critical aspects of adhesive bonding, beginning with surface preparation. Proper surface preparation is crucial for achieving optimal bond strength and durability, and this paper explores the latest techniques and best practices in this area. It also examines current testing methods used to evaluate the performance of adhesive joints, ensuring that they meet stringent industry standards. Durability is another key focus of the review. We discuss various considerations related to the long-term performance of adhesive bonded joints, including environmental factors, load-bearing capacity, and resistance to aging and degradation. The paper also highlights recent innovations in adhesive technologies. These advancements include new formulations and types of adhesives that enhance bonding capabilities and overall joint performance. Additionally, we cover the latest developments in surface treatments, which play a critical role in improving adhesion by modifying the surface properties of composite materials. In summary, this review offers a thorough and up-to-date examination of adhesive bonded joints for composite materials, highlighting both recent advancements and ongoing challenges, while providing valuable insights into future research directions

Antibacterial Dental Adhesive Containing Cetylpyridinium Chloride Montmorillonite.

Oral bacteria cause tooth caries and periodontal disease. Much research is being conducted to prevent both major oral diseases by rendering dental materials' antimicrobial potential. However, such antimicrobial materials are regarded as 'combination' products and face high hurdles for regulatory approval. We loaded inorganic montmorillonite with the antimicrobial agent cetylpyridinium chloride, referred to below as 'CPC-Mont'. CPC-Mont particles in a 1, 3 and 5 wt% concentration were added to the considered gold-standard self-etch adhesive Clearfil SE Bond 2 ('CSE2'; Kuraray Noritake) to render its antibacterial potential (CSE2 without CPC-Mont served as control). Besides measuring (immediate) bonding effectiveness and (aged) bond durability to dentin, the antibacterial activity against S. mutans and the polymerization-conversion rate was assessed. Immediate and aged bond strength was not affected by 1 and 3 wt% CPC-Mont addition, while 5 wt% CPC-Mont significantly lowered bond strength and bond durability. The higher the concentration of the antimicrobial material added, the stronger the antimicrobial activity. Polymerization conversion was not affected by the CPC-Mont addition in any of the three concentrations. Hence, adding 3 wt% CPC-Mont to the two-step self-etch adhesive rendered additional antimicrobial potential on top of its primary bonding function.