Adhesive Compositions Research Articles

Study of various adhesive systems’ bond strength for bracket placement

Relevance . Today, the dental market offers a large selection of adhesive systems developed based on various concepts. Improving adhesive technology in orthodontic practice is aimed at simplifying methods of use, improving the composition and ability of adhesion of orthodontic elements to the tooth structure. The aim of this study is to compare the shear bonding strength of different generations of adhesive systems for metal brackets placement. Materials and Methods . The study sample consisted of 40 recently extracted human upper premolars. The premolars were divided into four groups 10 each. The first group used the bond Transbond XT 3M Unitek (USA), the second - Beauty Ortho Bond (Japan), the third - Tetric N bond Universal (Vivapen) (USA) with acid etching with phosphoric acid (LI), the fourth - Tetric N bond Universal (Vivapen) (USA) without acid etching with phosphoric acid. The study used metal brackets for upper premolars (Gemini Bracket MBT, 3M Unitek, USA) with a micro-patterned base, the area of which was defined as 10.61 mm2. Mechanical shear strength tests were carried out using the Instron Universal Test machine (USA). One-way analysis of variance and the TUKEY test were used to examine significant differences in adhesive strength and shear strength between study groups. Results and Discussion. The highest adhesive shear strength was established when using the Transbond XT adhesive system (12.28 MPa) and the Tetric N Bond Universal system using the total etching (12.66 MPa) and self-etching (11.44 MPa) techniques; statistically significant differences between these adhesives were not detected. The second group of Beauty Ortho Bond (5.34 MPa) demonstrated the lowest adhesion force among the studied adhesives, with a statistically significant difference from the other groups. Conclusion : This study concluded that there are no notable differences in the comparison of the universal system with or without etching with the Transbond system. Regarding the use of the beauty Ortho bond, it obtained the lowest strength with significant difference from the remaining groups.

Molecular design and hygrothermal resistance of high‐toughness polysiloxane–polyurethane block copolymer composite adhesives

AbstractWith the development of new energy sources, the demand for aluminum composite films for power batteries is expanding; at the same time, higher requirements have been put forward for aluminum composite films and adhesives. Polyurethane, as the binder of aluminum composite films, strongly affects the performance of aluminum composite films when exposed to moisture and high temperature and can lead to delamination. This thesis prepares a polyurethane and silicone block copolymer composite adhesive by adjusting the ratio of hard and soft polyurethane segments to obtain polyurethane (PU) with excellent flexibility. On the basis of block copolymerization with bis‐amino‐terminated organosiloxane (ATPS), obtained excellent flexibility, high peel strength, moisture resistance, and heat resistance from a polysiloxane‐based polyurethane composite adhesive (PUSR). The properties are also tested using tensile tests and peel strength tests. The test results show that by adjusting the ATPS content, the flexibility and hydrophobicity of the PUSR composite adhesive further improved, with a tensile strength of 36 MPa, an elongation at break of 757%, and bonding performance of 11 N/15 mm. Additionally, the damp heat resistance of 6 N/15 mm, exceeding the international standard of 3 N/15 mm, in the power battery soft package aluminum–plastic film has potential application prospects.

Process optimization and performance verification of CFRP laser surface modification

AbstractAdhesive bonding has gradually replaced mechanical connections as the primary method for composite material bonding, with surface quality being the key factor determining the effectiveness of composite material adhesion. Laser surface treatment, known for its green and precise characteristics, has garnered widespread attention from both academia and industry. However, the process parameters of laser surface treatment are complex, efficiency is low, and the mechanism remains unclear. This paper, based on the response surface methodology (RSM), investigates the influence of laser secondary parameters on the resin removal rate of carbon fiber reinforced polymer/plastic (CFRP) surfaces and the impact of defocusing on surface treatment efficiency. The results indicate that when the total laser energy density (Et) is 69 J/cm2, the overlap ratio in the warp direction (OLs) is 76%, and the overlap ratio in the weft direction (OLh) is 85%, the surface tensile shear strength increases by 90.59% and 27.77% compared to the original surface and polished surface, respectively. When the defocus distance is +8 mm, the efficiency of laser surface treatment is 2.25 times that of non‐defocus, with minimal impact on mechanical performance. The surface treatment mechanism, with changes in Et, primarily involves the pure thermal decomposition of the resin matrix in an oxygen‐free environment, oxidative decomposition, and the synergistic action of the decomposition products' oxidation. Through the coupled optimization of laser process parameters, this work enhances the efficiency and effectiveness of composite material adhesive surface treatment, promoting the engineering application of laser technology.Highlights By establishing a response surface model, the study elucidated the impact patterns of laser secondary parameters (overlap rates in the warp and weft directions, total energy density) on the resin removal rate of CFRP surfaces. Based on the laser surface treatment phenomena at different total energy densities, the study analyzed and revealed the mechanism of near‐infrared (1064 nm) laser resin removal from CFRP surfaces. By increasing the spot size through defocusing, the efficiency of laser surface treatment was enhanced, and the impact on the interfacial properties of CFRP after defocused treatment was validated.

A Study of Russian-Made Adhesive Compositions for Gluing Rubber to Metal during the Vulcanization Process Compared with Imported Analogues

A Study of Russian-Made Adhesive Compositions for Gluing Rubber to Metal during the Vulcanization Process Compared with Imported Analogues

Spectroscopic Characterization of the Chemical Changes Occurring in Soy Wood Composite Adhesives When Exposed to Moisture

Abstract Solid-state surface attenuated total reflectance Fourier transform infrared spectroscopy (SATR-FTIR) and solid-state nuclear magnetic resonance spectroscopy (SSNMR) were used to characterize the physiochemical changes in solid soy-flour adhesives upon exposure to water. Comparisons were made between adhesives that were prepared with and without the crosslinking chemical polyamideamine-epichlorohydrin (PAE). Comparisons were also made between neat monolithic adhesive films, and adhesives that were laminated to yellow poplar (Liriodendron tulipifera). FTIR data revealed that the relative surface concentration of water-soluble components on neat monolithic adhesives was higher prior to water-exposure as compared with the adhesive laminated to wood. Moreover, the chemical composition of the water-soluble extract was affected by PAE. After soaking in water, the water-soluble components were observed to dissolve and disappear from the surfaces of the adhesives, as well as from the surfaces of water-soaked wood-laminate specimens. Similarly, SSNMR results corroborated with the dissolution and disappearance of the water-soluble components from the neat monolithic adhesives after water soaking. Moreover, it was discovered that the water-soluble components have a plasticization effect when PAE is used as a crosslinker. The implications of these findings as they pertain to the mechanism of adhesion will be discussed.

Simple surface modification of barium sulfate for improving the interface of polymer composites and its x‐ray shielding properties

AbstractRadiation shielding materials have been researched using Pb and metal oxide particles, and composites of resin and barium sulfate (BaSO4) have been reported. In addition, multiwalled carbon nanotubes (MWCNTs) have often been used as a nanomaterial to improve the mechanical strength of resin–BaSO4 composites. The literature includes no examples of these two materials—BaSO4 and MWCNTs—being used at the interface of composites. We effectively modified the surface of BaSO4 by a simple process involving strong electrostatic interaction between positively charged barium and negatively charged functional groups on the MWCNT surface. The process is simple and can form large amounts of MWCNTs that coat BaSO4 surfaces. As a result, MWCNTs remained on the BaSO4 surface even after the MWCNT‐coated BaSO4 was washed with a solvent and subjected to melt mixing. The physical anchoring of MWCNTs onto the BaSO4 surface improved the interfacial adhesion and mechanical properties of the resultant composites. The originality of this research is that MWCNTs can be coated onto the surface by only electrostatic interaction without using a polymer adhesive. In addition, the x‐ray shielding performance of the MWCNT‐containing composites was the same as that of composites prepared without the MWCNTs.Highlights MWCNTs were coated onto the surface of BaSO4 by electrostatic interaction. Interfacial adhesion of PS composites was improved by coating MWCNTs. The MWCNTs did not affect the x‐ray shielding performance.

Improved adhesion of rubber composites by developing environmentally friendly fiber impregnation coatings with good interfacial modulus transition gradients

Polyester (PET) fibers must undergo impregnation with a resorcinol-formaldehyde-latex (RFL) solution to ensure efficient adhesion with rubber. However, the harmful, carcinogenic resorcinol-formaldehyde (RF) resin in RFL impregnation solution negatively affects human health. In this paper, PET was pretreated with blocked isocyanate and epoxy resins to activate the fibers, and a new environmentally friendly fiber impregnation coating was developed. In the new impregnation coatings, ethylene glycol diglycidyl ether (EGDE) and m-xylylenediamine (MXDA) were applied to replace the resorcinol and formaldehyde. Moreover, glycidyl methacrylate (GMA) containing epoxy groups and double bonds was introduced to enhance interaction with rubber further, and then styrene-butadiene-vinyl-pyridine (VP) latex was mixed. The results show that the peel strength of the impregnated PET/rubber composites with the new impregnation coatings can reach 14.0 N/mm, representing an increase of 30.8 % compared to that of the sample with the pure RFL impregnation coatings, whose peel strength is only 10.7 N/mm. Furthermore, the mechanism for enhancing the interfacial adhesive properties of PET/rubber composites was performed by analyzing the chemical composition and morphological changes of the impregnated PET surface, as well as the change of sulfur content at the interface of the impregnated PET/rubber composites and the transition gradient of interfacial modulus.

Fully Printable and Reconfigurable Hufu-type Electroluminescent Devices for Visualized Encryption.

Hufu, serving as evidence of imperial authorization in ancient China, comprises two parts in the form of tiger-shaped tallies that only become effective when matched. Drawing inspiration from the concept of Hufu, a reconfigurable electroluminescent (EL) device is designed by separating conventional integral devices into two parts that contain the EL layer (part A) and the transparent electrode (part B), respectively. The key to realizing such strategy is employing an adhesive and stretchable polymer gel composite as the transparent electrodes for the EL devices. The polymer gel composite facilitates robust yet reversible contact between the EL layer and transparent electrode, enabling high-performance and stretchable EL devices that can be readily disassembled and reassembled: the EL devices can maintain ≈81% of their initial luminance after 1000 times of repeated disassembly and reassembly. Moreover, the precursor ink of the polymer gel composite is compatible with a wide variety of coating and printing technologies, such as spin-coating, inkjet printing, dispensing, and brush painting. Importantly, the reconfigurable feature of the devices opens up a new path to encryption display systems, and as a proof-of-concept, EL encrypted password, and content-changeable digital clock are demonstrated.

Performance evaluation of asphalt binders incorporating surface-modified diatomite and bio-oil: A value-added utilization of natural resource

To study the effect of surface-modified diatomite (SMD) on bio-asphalt performance, the asphalt binders incorporating SMD and bio-oil (SMDB) was prepared with different dosages. The high-temperature characteristics of SMDB were assessed by consistency test, viscosity test, and dynamic shear rheometer (DSR). Meanwhile, the low-temperature characteristics of SMDB were evaluated by bending beam rheometer (BBR) and ductility test. The compatibility of SMDB was assessed by a storage stability test and a Fluorescence microscope (FM). The adhesion and chemical composition of SMDB were analyzed using the sessile drop method and Fourier transform infrared (FTIR) spectroscopy, respectively. Finally, the moisture stability and high-temperature properties of the SMDB mixture were studied using the tensile strength ratio (TSR) test and wheel track test, respectively. The preliminary results of this work show that the addition of SMD increases the viscosity, softening point, fatigue index, and rutting factor of asphalt and reduces the penetration. It is found that SMD improves the anti-aging performance, adhesion performance, and high-temperature stability of SMDB. Although SMD has a negative effect on the low-temperature properties and fatigue resistance of asphalt, the characteristics of SMDB at low temperatures are still superior to those of virgin asphalt. SMD at low content had little effect on the fatigue resistance of the bio-asphalt. Moreover, it is found that SMD is better than the original diatomite in enhancing bio-asphalt properties more significantly. In addition, the blending among SMD, asphalt matrix, and bio-oil is the physical modification, and the mixture has excellent storage stability. Finally, the mixture property testing results indicate that SMD improves the rutting and moisture resistance of the SMDB mixture.

Shear bond strength of universal adhesives to human enamel and dentin.

The composition of universal adhesives is highly diverse. The purpose of this in vitro study was to compare the shear bond strength of a composite with five different universal adhesives to human enamel and dentin. The shear bond strength of a composite (G-aenial Universal Injectable) to human enamel and dentin was tested in selective enamel etching mode before and after thermocyclic aging (10,000 cycles) using five different universal adhesive systems (Adhese Universal VivaPen, Clearfil Universal Bond Quick, G-Premio Bond, Prime&Bond active, and Scotchbond Universal Plus). Two-bottle systems (OptiBond FL and G2-Bond Universal) were used as control. Scanning electron microscopy was conducted of the bonding interface. Significant differences in shear bond strength values were found among the five evaluated universal adhesives. Lowest shear bond strength values were observed for 2-hydroxyethylmethacrylate (HEMA)-free systems. Thermocyclic aging did not significantly reduce shear bond strength values indicating that the initial bond remains stable. The clinical use of universal adhesives Adhese Universal VivaPen, Clearfil Universal Bond Quick, and Scotchbond Universal Plus can be encouraged as they provided comparable or even better shear bond strength values than the two-bottle controls. Universal adhesives that were developed for the same indication and approved for clinical use demonstrated variety in shear bond strength values. When applied in the selective enamel etching mode, a stable bond can be expected from adhesives containing HEMA and monomers with phosphate groups.

Influence of Talc on the Properties of Silicone Pressure-Sensitive Adhesives.

The article describes new silicone self-adhesive adhesives modified with the addition of talc. The obtained self-adhesive materials were characterized to determine their adhesive properties (adhesion, cohesion, and adhesion) and functional properties (pot life of the composition, shrinkage, and thermal properties of adhesives). Novel materials exhibited high thermal resistance above 225 °C while maintaining or slightly reducing other values (adhesion, cohesion, shrinkage, and tack). Selected composition: T 0.1 was used to prepare self-adhesives in industrial-scale production. Moreover, conducted test results revealed that the addition of talc delayed the thermal decomposition of the adhesive and provided reduced intensity of smoke emissions during combustion as well as the flammability of the adhesive layer.

Preparation of thermally stable and flame‐retardant sugarcane bagasse‐ammonium dihydrogen phosphate/epoxy composites and their performance

AbstractEpoxy resin was often applied in fiber‐reinforced composite materials, adhesives, and encapsulation materials. However, epoxy was easily flammable and limited its usage in certain applications. The study recycled and reused agricultural waste sugarcane bagasse to prepare a halogen‐free bio‐based intumescent flame retardant and then mixed with epoxy resin to prepare a composite containing polymer with improved thermal properties and flame retardancy of the materials. The work followed the concept of circular economy and sustainability. Bagasse‐ammonium dihydrogen phosphate (ADP) flame retardant was added to an epoxy resin to prepare epoxy/bagasse‐ADP composites, an effective flame‐retarding composite material through hydrothermal method. Adding bagasse‐ADP increased the thermal stability and flame retardancy of the composite materials compared with that of pure epoxy. For the material with 30 wt% added bagasse‐ADP, the char yield was 32.3 wt%, which was 18.2 wt% higher than that of pure epoxy (14.1 wt%) through thermogravimetric analysis. In addition, the limiting oxygen index increased from 21% to 30%, and the UL‐94 classification improved from “Fail” to “V‐0.” This performance was attributed to the nitrogen, phosphorus, and silicon content of the flame retardant.

Dentin adhesion of bulk-fill composites and universal adhesives in class I-cavities with high C-factor

ObjectivesThe aim of this study was to compare the dentin adhesion of bulk-fill composites in high C-factor class I-cavities before and after thermocycling to a control group using incremental layering technique. MethodsA standardized class I-cavity was prepared into 195 human molars, then different universal adhesives were applied either in self-etch or etch & rinse mode, and the cavity was filled according to each materials application protocol. The material combinations used were a conventional layered composite as control, the respective bulk-fill product, two other bulk-fill composites made by different manufacturers, with one of them being tested using two different polymerization times. Furthermore, one thermoviscous bulk-fill composite and one self-adhesive restorative were examined of which the latter can only be applied in self-etch mode. In each group the dentin adhesion to the cavity bottom was measured using microtensile bond strength test initially (24 h water storage) and after thermocycling. All results were statistically analyzed using STATA 17.0. ResultsThe statistical analysis showed significant differences between the control and the experimental groups (p < 0.001). The highest mean bond strength before (14.8 ± 10.7 MPa) and after aging (14.2 ± 11.5 MPa) was measured for the etch & rinse-control group. Among the bulk-fill groups, the etch & rinse technique consistently showed higher bond strengths. Bond strength of groups with shortened polymerization did not exceed 2.1 MPa. The bond strength of the self-adhesive restoration material was low before and after thermocycling (2.7 MPa/ 0.0 MPa). Groups with low bond strength values showed a high number of pre-testing-failures. ConclusionsBulk-fill materials used in high C-factor class I-cavities showed lower bond strength during self-etch application. The same applies for a shortened polymerization regime, which cannot be recommended for high C-factor cavities. Clinical significanceToday, a large variety of materials and application techniques can be used when placing an adhesive restoration. Whether new instead of established procedures should be applied in high C-factor cavities has to be critically assessed, as they are a demanding scenario for adhesive restorations.

Experimental and numerical investigation of impact behavior in honeycomb sandwich composites

This paper presents an experimental and numerical study on the low-energy impact fatigue and bending behavior of sandwich panels reinforced with composite laminate glass and carbon fabric facesheets, supported by a honeycomb core made of Nomex. The crushing behavior of honeycomb sandwich specimens subjected to the impact test was compared and discussed. Our results indicate that the carbon composite facesheets have a significant effect on the impact, resulting in an increase in impact resistance and a 157.14% increase in crack depth in the elastic region compared to glass facesheets reinforcement. This increase serves as an indicator of the laminate's ability to resist damage initiation and impact fracture mechanisms. Also, an increasing in flexural strength about 45.72% was observed in carbon facesheets honeycomb specimens compared to glass facesheets reinforcement. Microscopic illustration of the damaged honeycomb sandwich specimens was conducted to evaluate the interfacial characteristics and describe the damage mechanics of the composite facesheets and core adhesion under the impact test. The numerical approach proves to be efficient in terms of accuracy and simplicity compared to existing methods for predicting the damage mechanisms of honeycomb sandwich structures. It was noted that results of numerical study show best agreements with experiment results and the model can be used to predict the low-energy impact fatigue.

Characterization of Novel Cell-Adhesive Peptides for Biomaterial Development.

In previous studies, my group developed cell-adhesive peptide-polysaccharide complexes as biomaterials for tissue engineering. Having a wide variety of cell-adhesive peptides is important as the biological functions of peptide-polysaccharide complexes are highly dependent on the biological activity of peptides. This paper reviews the biological activities of two types of recently characterized cell-adhesive peptides. The first is peptides rich in basic amino acids originating from octaarginine. We analyzed the relationships between the amino acid composition of basic peptides and cell adhesion, elongation, and proliferation and identified the most suitable peptide for cell culture. The second was arginine-glycine-aspartic acid (RGD)-containing peptides that promote the adhesion of induced pluripotent stem cells (iPSCs). We identified the RGD-surrounding sequences necessary for iPSC adhesion, clarified the underlying mechanism, and improved cell adhesion by modifying the structure-activity relationships. The novel cell-adhesive peptides identified in our previous studies may aid in the development of novel peptide-based biomaterials.

Polyacrylic acid-reinforced organic-inorganic composite bone adhesives with enhanced mechanical properties and controlled degradability.

Bone adhesives, as alternatives to traditional bone fracture treatment methods, have great benefits in achieving effective fixation and healing of fractured bones. However, current available bone adhesives have limitations in terms of weak mechanical properties, low adhesion strength, and inappropriate degradability, hindering their clinical applications. The development of bone adhesives with strong mechanical properties, adhesion strength, and appropriate degradability remains a great challenge. In this study, polyacrylic acid was incorporated with tetracalcium phosphate and O-phospho-L-serine to form a new bone adhesive via coordination and ionic interactions to achieve exceptional mechanical properties, adhesion strength, and degradability. The bone adhesive could achieve an initial adhesion strength of approximately 3.26 MPa and 0.86 MPa on titanium alloys and bones after 15 min of curing, respectively, and it increased to 5.59 MPa and 2.73 MPa, after 24 h of incubation in water or simulated body fluid (SBF). The compressive strength of the adhesive increased from 10.06 MPa to 72.64 MPa over two weeks, which provided sufficient support for the fractured bone. Importantly, the adhesive started to degrade after 6 to 8 weeks of incubation in SBF, which is beneficial to cell ingrowth and the bone healing process. In addition, the bone adhesives exhibited favorable mineralization capability, biocompatibility, and osteogenic activity. In vivo experiments showed that it has a better bone-healing effect compared with the traditional polymethyl methacrylate bone cement. These results demonstrate that the bone adhesive has great potential in the treatment of bone fractures.

Adhesive composition based on epoxide cooligomer functionalized with acetamide

Adhesive composition based on epoxide cooligomer functionalized with acetamide

Assessment of cytotoxicity, odontoblast-like differentiation, shear bond strength, and microhardness of four orthodontic adhesive composites.

To determine and compare the cytotoxicity, odontoblast-like differentiation, shear bond strength (SBS) and Vickers microhardness of four commercial light-cured orthodontic adhesives. The orthodontic resins selected were Transbond XT - GI, Transbond Plus Color Change - GII (both from 3M Unitek), Enlight - GIII and Blugloo - GIV (both from Ormco). Samples were prepared, and leached monomers were obtained. Cytotoxicity was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and deposited calcium was analyzed using Alizarin red staining (ARS). SBS and the adhesive remnant index (ARI) were determined using 120 human premolars. The Vickers microhardness test was performed on the resin discs. All adhesives showed moderate to severe cytotoxicity (21-37%) and promoted similar formation of calcium deposits. A SBS of 6-8 MPa was achieved only by Blugloo (7.1 ± 2.4 MPa), and Enlight showed the lowest Vickers hardness score (40 ± 2.5 HV). Transbond Plus Color Change (score 0 = 42.9%) and Blugloo (score 0 = 46.4%) showed better ARI scores than Transbond XT (score 0 = 7.1%) and Enlight (score 0 = 3.6%). On the basis of the properties evaluated, Blugloo seems to be the best option.

Environmentally friendly adhesive composition containing nitrogen

Environmentally friendly adhesive composition containing nitrogen

Treatment of a Patient With Closed Liver Injury Using Interventional Methods:&#x0D; a Case Study

Background. Mechanical injury occupies a leading position among the causes of mortality in the working-age population. Diagnosis and treatment of isolated and combined abdominal traumas accompanied by bleeding appear to be a specific challenge. Due to difficulties in diagnosis and treatment, they are characterized by frequent complications and an increased mortality rate.Currently, there is no uniform tactics for diagnosing and treating patients with liver damage. In Russia and globally, new approaches are being actively introduced for the treatment of patients with closed liver traumas using minimally invasive techniques.The aim of study was to present a clinical case of a patient with a closed liver injury treated using interventional methods, such as angiography and embolization.Materials and methods. According to conventional techniques, the patient had to undergo laparotomy with complex manipulations to stop intra-abdominal bleeding from a ruptured liver, which would inevitably worsen her condition in the context of a presenting severe injury.Multiple studies reported that the number of postoperative complications after laparotomy is up to 41%, and in case of combined trauma 10-35% of complications can be one of the causes of death [6, 7, 8]. In order to avoid more traumatic treatment approaches, we applied tactics using minimally invasive high-tech diagnostic and treatment options.Results. To stop intra-abdominal bleeding from a liver rupture, which was previously diagnosed during multislice computed tomography (MSCT) with intravenous contrast, using interventional options, selective embolization of the segmental branch of the right hepatic artery was performed with an adhesive composition. The post-traumatic period proceeded without complications; in 14 days after the injury, the patient was discharged in satisfactory condition.Conclusion. Minimally invasive and conservative treatment of patients with closed abdominal traumas using interventional radiology can be successfully applied in specialized trauma centers.