Adhesive Agent Research Articles

Multifunctional 3D-MXene/PDMS nanocomposites for electrical, thermal and triboelectric applications

Highly conductive and flexible materials have many applications in the electrical and electronic fields, while the realization of high electrical/thermal conductivity by a green, simple and efficient approach is still challenging. Herein a simple method was proposed to construct three-dimensional Ti3C2Tx (3D-MXene) skeleton without using adhesive agents. After incorporated into polydimethylsiloxane (PDMS) matrix, the resultant 3D-MXene/PDMS nanocomposites exhibited excellent electrical conductivity of 5.5 S/cm, which was nearly 14 orders of magnitude higher than that of the neat PDMS. On the other hand, the nanocomposites show a thermal conductivity enhancement of about 220% at a low MXene content of 2.5 vol% in comparison with neat PDMS. Moreover, the output current of 3D-MXene/PDMS based triboelectric nanogenerators (TENGs) was greatly enhanced because of the significantly decreased electrical resistance. This finding can be applied to TENGs with capacitor structures and can also widen the practical applications of MXene in the field of thermal management, sensors and energy harvesters.

MANAGEMENT OF REFRACTORY LARGE MACULAR HOLE WITH AUTOLOGOUS NEUROSENSORY RETINAL FREE FLAP TRANSPLANTATION.

To investigate the morphological and functional outcome of refractory large macular hole (MH) with autologous neurosensory retinal free flap transplantation. This case series enrolled 10 patients suffering from refractory large MH at Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. All eyes underwent pars plana vitrectomy, a neurosensory retinal free flap with a 1.5 to 2-MH diameter was harvested. We used an adhesive agent such as whole blood or Viscoat to assist the stabilization of the retinal free flap and then use tamponade silicone oil to tamponade the vitreous cavity. Silicone oil was removed 6 months postoperatively. Main outcome measures including closure of MH and change in best-corrected visual acuity change were recorded. The mean age was 64.9 ± 11.5 years. Before presentation, all cases had received at least two vitreoretinal procedures including vitrectomy, internal limiting membrane peeling, and fluid-gas exchange. At last visit, closure of the MH was achieved in 9 of 10 (90%) cases. The mean preoperative best-corrected visual acuity and that after 12 months of surgery improved from 1.65 ± 0.43 logarithm of minimum angle of resolution to 0.88 ± 0.49 logarithm of minimum angle of resolution (P < 0.001). For eyes with refractory or large MH, autologous neurosensory retinal free flap under silicone oil tamponade may provide a new option to improve the anatomical and function outcome, especially in cases where insufficient internal limiting membrane is left.

HBO2 as an adhesive agent for the multi-step fabrication of all-solid-state sodium batteries

Spark plasma sintering (SPS) is a convenient technique to assemble electrode composites of positive and negative electrode active materials and inorganic solid electrolyte with similar sintering temperatures. Here, a new process is proposed to combine the separate sintering steps of positive and negative electrode composite pellets, and their subsequent assembling step with metaboric acid (HBO2). All-Solid-State Na Batteries using Na4Co3(PO4)2P2O7 (NCPP) and Na3V2(PO4)3 (NVP) were assembled as positive and negative electrodes, respectively. The NCPP and the NVP electrode composite powders were sintered at individual appropriate temperatures and pressures with solid electrolyte, Na3Zr2(SiO4)2PO4(NZSP) layers. The NZSP layers of the prepared pellets were successfully joined with heated HBO2 sandwiched between both pellets (NVP electrode composite/NZSP and NZSP/NCPP electrode composite). The fabricated all-oxide-powder type battery has demonstrated a discharge capacity of 73 mAh g−1 at 200 °C.

Study on processing galvanized steel/PA6 sandwich composites by hot-pressing: Influence of interface properties and surface treatment on the adhesion strength

Steel/polymer/steel sandwich structures have a high potential in weight reduction at high stiffness values. The aim of this study is to investigate the adhesion properties of galvanized steel/Polyamide 6 sandwich composites, which are produced by hot pressing following a parametric design of experiments plan at varied temperatures, times and pressures. One of the most interesting phenomenon hindering a good adhesion strength was the formation of sub-millimeter sized bubbles during the hot pressing. Possible reasons and methods to avoid these bubbles were investigated using scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, ultraviolet photoelectron spectroscopy, metastable induced electron spectroscopy and X-ray diffraction. The proposed solution is to apply a heat treatment on the galvanized sheet prior to pressing, where varied treating regimes were applied. To improve the adhesion quality, mechanical/physical treatments were utilized as well. Furthermore, a compatible adhesive agent was applied in combination with the different surface treatments, where the lap shear strength reached at least 23 MPa, high enough for a delamination-free shaping afterwards.

Development and characterization of allicin using palm stearin as a binder on urea granules

The potency of allicin as a urease inhibitor has been discovered and the demand for using a biodegradable material as a coating is increasing. The loss of nitrogen can be reduced, and the efficiency of the fertilizer can be increased by utilizing a coating. The objective of this study was to determine the compatibility of allicin and urea with palm stearin as an adhesive agent in the coating process. Four treatments were used in this study; urea as the control, urea coated with palm stearin (UPS), urea coated with allicin and palm stearin (UPSA) and urea coated with NBPT (UNBPT). The treatments were analyzed for thickness, chemical structure, total N content, dissolution rate in water and hardness. Results from FT-IR and SEM images demonstrated that palm stearin was compatible with allicin and urea with smoother coated layer. The efficiency of coated urea with allicin and plam stearin was enhanced by reducing 70% of urea release in 24 hours as compared to the urea. The crushing strength was significantly improved by using palm stearin as the binder. Coating urea with palm stearin and allicin appears to increase the efficiency of urea.

Restauración de pavimentos: adherencia entre capas con interposición de geosintético de diferente abertura de malla

Generally, a deteriorated concrete pavement is restored by a layer of asphalt reinforcement. Currently, an appropriate intervention consists of interposing a geosynthetic material to delay the growth of existing fissures in the old pavement towards the new upper layer. The dilemma raised is the adherence that is achieved between the layers of the old and new pavement by interposing a geosynthetic, because the effective operation of a pavement occurs when the layers that make it work together. Previous work experiences showed problems in the adhesion with the interposition of geosynthetics. Therefore, the study of the adhesion between a layer of Portland Cement Concrete and a layer of Conventional Asphalt Mixture is proposed, interposing a geogrid with different mesh opening, using as an adhesion agent an asphalt emulsion modified with polymer. It is found that the mesh opening geogrid that offers the best adhesion performance is that which has a mesh size of 40x40 mm. It is also observed that whatever the mesh size of the material, it generates a benefit compared to the system that does not consider the material, that is, to the intimate contact between concrete-asphalt by emulsion.

Use of adhesive cream ‘Aphtofix’ for oral mucosa in dentistry

The article discusses the effectiveness of the use of the adhesive agent Aftofiks in the complex treatment of diseases of the oral mucosa. The positive effect of Aftofix adhesive on the timing of epithelization of wound surfaces of the oral mucosa, pain reduction, ease of application of the drug and its safety have been studied.

Lignin Particles for Multifunctional Membranes, Antioxidative Microfiltration, Patterning, and 3D Structuring.

We introduce a new type of particle-based membrane based on the combination of lignin particles (LPs) and cellulose nanofibrils (CNF), the latter of which are introduced in small volume fractions to act as networking and adhesive agents. The synergies that are inherent to lignin and cellulose in plants are re-engineered to render materials with low surface energy (contact angle measurements) and can be rendered water-resistant with the aid of wet-strength agents (WSAs). Importantly, they are most suitable for antioxidative separation (ABTS•+ radical inhibition): membranes with uniform porous structures (air permeability and capillary flow porosimetry) allow effluent oxidation at 95 mL/cm2, demonstrating, for the first time, the use of unmodified lignin particles in flexible membranes for active microfiltration. Moreover, the membranes are found to be nonfouling (protein adhesion and activity rate). The inherent properties of lignin, including UV radiation blocking capacity (UV transmittance analysis) and reduced surface energy, are further exploited in the development of tailorable and self-standing architectures that are almost entirely comprised of nonbonding LP (solids content as high as 92 w/w%). Despite such composition, the materials develop high toughness (oscillatory dynamic mechanical analysis), owing to the addition of minor amounts of CNF. Multifunctional materials based on thin films (casting), 3D structures (molding), and patterned geometries (extrusion deposition) are developed as a demonstration of the potential use of lignin particles as precursors of new material generation. Remarkably, our observations hold for spherical LPs since a much poorer performance was observed after using amorphous powder, indicating the role of size and shape in related applications.

Effect of Decontamination Treatments on Micro-Shear Bond Strength between Blood-Saliva-Contaminated Post-Etched Dentin Substrate and Composite Resin.

Blood–saliva contamination negatively affects the bonding potential of adhesive agents. The study aimed to assess the effect of various cleaning protocols on micro-shear bond strength (μSBS) between blood–saliva-contaminated post-etched dentin and composite resin in total-etch and self-etch adhesives. The cleaning methods tested were water rinsing, 37.5% phosphoric acid (H3PO4) re-etching, 6% sodium hypochlorite (NaoCl), 2% chlorhexidine gluconate (CXG), isopropyl alcohol (IPA), and pumice. Nono-hybrid composite cylinders with a 3-mm diameter and 2-mm height were directly cured over the dentin substrate, stored for 24 h, and subjected to 12,000 thermocycles. The shear force was exerted with a 200-μm knife-edged chisel-shaped head from a universal testing machine. The type of failure was assessed with stereomicroscope magnified images. The obtained data were evaluated by Kruskal–Wallis and Mann–Whitney U post-hoc tests. Water-rinsed contaminated dentin surfaces showed substantially reduced μSBS in the total etch from 25.93 to 20.29 Mpa and the corresponding values for the one-step self-etch adhesive were 10.10 to 8.8. Re-etching with 37.5% H3Po4 resulted in a recovery of bonding potential in both total-etch (24.58 Mpa) and self-etch adhesive (9.23 Mpa). Alternately, NaoCl and pumice cleaning showed promising results for the total-etch (23.51 Mpa) and self-etch (7.79 Mpa).

Heat and sound insulation applications of pineapple aerogels from pineapple waste

Given the harmful effects of agricultural waste residues on the environment and the abundance of pineapple byproducts after harvest, converting pineapple waste into a high-engineering value product for practical applications is one of the solutions toward sustainable development in developing countries. For the first time, flexible cellulose aerogels from raw pineapple-leave fibers (PALF) are developed successfully by using an adhesive agent, polyvinyl alcohol (PVA), and deionized (DI) water as a solvent, followed by a freeze-drying process. The effects of the pineapple fiber (PF) concentration on the heat and acoustic insulation properties are also investigated. The PF aerogels show high porosities of nearly 99%, ultra-low densities of (0.013–0.033) g/cm3, and a microporous structure which are determined by FE-SEM, BET and XRD analysis. They have very low thermal conductivities of (0.030–0.034) W/mK, indicating their excellent suitability for heat insulation applications. Indeed, the thermal jacket using a PF aerogel as filler wrapped around a water bottle can maintain the water temperature below 0 °C for 6 h (initial temperature of −3 °C), and above 40 °C for 2.5 h (initial temperature of 90 °C). The heat insulation capacity of the thermal jacket is about three times better than that of a commercially available product. With the same thickness, the noise reduction coefficient of 2.0 wt% PF aerogel samples is greater than that of a commercial absorber Basmel, which demonstrates their potential in acoustic insulation applications.

Adhesive-free joining and application for flexible devices - a review

Interface has been recognized for a long time as a part of materials such as surface and grain boundary in bulk in spite of the fact that interface gives decisive influences on the performance and durability of devices in practical use. Interface is also well known to have four principal performances and roles such as mechanical, electrical, magnetic and optical properties. Here, I will at first review the interface behavior with special emphasis on materials science and then introduce typical examples of case study. Mechanical behavior of interface can be attributed to joining of different materials in particularly at low temperature and intrinsic defects introduced in the process of joining caused by difference in thermal expansion. Defects thus introduced is known to result in work hardening of interface. Recently, an epoch-making method of joining to utilize water gas adsorption layer as an adhesive agent. This gas adsorption joining (GAJ) was demonstrated in cycloolefin polymer (COP) film and borosilicate glass system. Both surfaces were first modified by atmospheric pressure plasma, followed by close lamination to reaction distance and heated at about 100°C to result in the formation of a strong covalent bond for joining. Durability thus formed system was found to remain unchanged even after weathering test in 60°C, 95%RH for 2000 hrs. Joining mechanism can be explained in terms of an increase in density of functional molecules at the interface, followed by dehydration. Thickness of joining layer was confirmed by X-ray photoelectron spectroscopy and STEM and EELS to be 1∼2nm. Sealing performance of GAJ was examined by measuring Water Vapor Transmission Rate (WVTR) by MOCON system using joined PET films on which high barrier layer was coated. The WVTR of line sealing with 1 mm width and 1-2 nm thick was found to be better than 5 x 10−4 g/m2/day. Practical applications of thus developed GAJ for joining and sealing are now in progress for flexible film devices such as OLED display, solar cells, and healthcare devices. Finally, roles of interface in materials science in future will be critically discussed.

Metal-free rGO/GO hybrid microelectrode array for sensitive and in-situ hydrogen peroxide sensing

Microelectrode array (MEA) has recently attracted significant research interest in biomedical applications due to its high sensitivity, mass production and fast response. However, the previous MEA with precious metal-based nanomaterials for electro-catalysis may induce toxicity to cells. In this work, we present a metal-free graphene/graphene oxide (rGO/GO) hybrid MEA for precise and in-situ H2O2 secretion detection. The configuration and size of rGO/GO hybrid MEA can be well designed and controlled by combining the convenient lithography and electrochemistry method, where the GO region with abundant oxygen functionalized groups has good biocompatibility, so as to play as the adhesion and growth agent of pheochromocytoma cells (PC12 cells). Whereas, the rGO region with higher electro-catalytic activity can favor high sensitive in-situ H2O2 secretion detection that is released from the stimulated PC 12 cells at GO region, but with the cell filopodia extended to the rGO region. Besides, the rGO/GO hybrid MEA presented herein is compatible with the micro-fabrication technique and can be integrated into the lab-on-chip devices, which may shed useful insights for the design and fabrication of high performance biosensors.

KARAKTERISASI BAKTERI PENGHASIL EKSOPOLISAKARIDA ASAL RHIZOSFER TANAMAN KENTANG SEBAGAI PROMOTOR PERTUMBUHAN TANAMAN

Utilization of Exopolisakarida Bacteria as adhesive agent and binder soil structure so that the structure of the soil becomes steady. EPS bacteria play a role in stabilizing soil aggregates through augmentation techniques in potato plant rhizosphere.This study aims to characterize the bacteria producing eksopolisakarida (EPS) obtained from the rizosphere of highland potato plants which are focussed as promoters of plant growth. There are 3 sample sampling locations that are distinguished by the height of the sea level: 1200, 1500 and 1800 m above sea level in in Malino, South Sulawesi. Soil samples were diluted and cultured on ATCC medium No. 14 and the specific medium of exopolisakarida-producing bacteria Mac Concay medium. After testing there were 15 EPS bacterial isolates that had the potential to produce exopolysaccharides and all the bacteria were grouped in gram-negative bacteria. Isolates P3T (63) yielded an IAA ( Indole Acetic Acid) value of 21.14 ppm and as a phosphate solvent of 20, 59 ppm. While Isolate P3T (50) has the ability to fix Nitrogen of 1, 42 ppm, and produce EPS of 1,07 mg/mg protein with the best carbon source for producing exopolysaccharides is Sucrose. Keywords : Exopolysaccharide, Promoters, IAA, Phosphate solvent, Nitrogen Fixation

Preparation of Stick Type Solid Glue as Paper Adhesive Using Mixed Seaweed Extract

Seaweed extracts, namely carrageenan obtained from Grateloupia elliptica and algin obtained from Laminaria, were employed as adhesive agents to synthesize solid adhesives for paper. Carrageenan from Grateloupia elliptica with the highest adhesive strength and lgin from Laminaria with the highest compressive strength was selected. The selected carrageenan and algin were mixed in a ratio of 7:3, and the mixture was employed as an adhesive agent. At a high temperature, sodium stearate(used as a solidifying material) oxidized the seaweed extracts. Consequently, carrageenan and algin were added to the final manufacturing process. The adhesive strength of the final synthesized solid adhesive is found to be 3.02 MPa and the compressive strength is found to be 30.5 N. Compared to the adhesive strength (2.95 MPa) and compressive strength (30.11 N) of commercial solid adhesives, the obtained results indicate superior adhesion characteristics. Furthermore, the proposed adhesive is environment-friendly because the presence of volatile organic compounds, formaldehyde, and heavy metals(such as chromium, lead, and cadmium) were not detected. Moreover, when used, the flatness of paper was twice that of commercial solid paper adhesives. Hence, the proposed adhesive can provide excellent adhesion, stability, and usability.

Nitrogen-doped carbon networks derived from the electrospun polyacrylonitrile@branched polyethylenimine nanofibers as flexible supercapacitor electrodes

Nitrogen-doped carbon nanofibers (NCNFs) are important electrode materials that have received tremendous attention in terms of their capacity to store energy. At present, it is still desirable to fabricate high-performance NCNFs for supercapacitors. Here, for the first time, polyacrylonitrile@branched polyethylenimine (PAN@bPEI) composite nanofibers are proposed as precursors to prepare freestanding NCNFs, which can then be used directly in flexible supercapacitors. The single electrode based on the resultant NCNFs with unique chemical composition exhibits electrochemical properties that are superior to those of the polyacrylonitrile-derived CNFs electrode. In addition, a quasi-solid-state symmetric supercapacitor assembled without the use of any adhesive or conductive agent also shows a comparable energy density, favorable cycling durability, and mechanical stability, indicating that bPEI is an effective nitrogen source with which to construct nitrogen-doped carbon fibers for energy storage applications.

Synchrotron IR-microspectroscopy-based visualization of molecular and chemical interactions between dental cement, biomimetic composite and native dental tissue

The low affinity of composite materials for the hard tissue of human teeth poses a challenge to restorative dentists. This study was undertaken to explore molecular and chemical characteristics of the interface between the dental cement, the buffer layer formed from a next generation biomimetic material that mimics the organic mineral composition of human enamel and dentin, and the intact native hard dental tissue. Seven plane-parallel dental slices were analyzed using synchrotron IR microspectroscopy. The obtained absorption spectra of functional molecular groups were organized into cluster maps. This allowed us to identify the intact tissue, the adhesive agent and the biomimetic layer at their interface and to localize and measure concentrations of functional groups involved in the integration of the biomimetic composite into the hard tissue of the human tooth. The proposed biomimetic material is based on nanocrystal carbonate-substituted calcium hydroxyapatite synthesized from a biogenic calcium source and a complex of basic polar amino acids copying the composition of the human tooth and can form a functional bond with hard dental tissue.

Prepless Direct Midline Diastema Closure in a Single Visit: 18 months Follow-up Report

Maxillary midline (major) diastemas are common aesthetic problems for the patients. Recently, it is easier to get rid of those unwilling spaces aesthetically with the help of newly developed restorative materials. Major diastema may frequently occur due to high frenulum junctions thus causing unaesthetic outlook for some patients. In this case report a maxillary major diastema due to high frenulum was closed non-invasively with direct, prepless composite resin restorations. In this case frenectomy, office bleaching and direct prepless restorations was respectively planned. Six weeks were waited for periodontal tissue healing after frenectomy operation and then bleaching procedure was done using 40% hydrogen peroxide gel ( Opalescence Xtra Boost, Ultradent, USA ). Following vital bleaching; after 2 weeks, universal adhesive agent (Universal bond, Kuraray Noritake, Japan) was applied to the etched enamel surfaces (36% phosphoric acid etching with DeTrey Conditioner 36, Dentsply, Germany). Direct composite resin restorations was done using “A1B” and “NE” shades ( Estelite Asteria, Tokuyama Dental, Japan ). Polishing discs (SofLex, 3M ESPE, USA), interdental strips (Epitex, GC, Japan) and two spiral polishing twists (Twist Dia, Kuraray, Japan) was used during the finishing and polishing stages. The success of the final restorations were assessed in 3 month, 9 month and 18 month follow ups.

Effective use of the endoscopic vacuum system in the comprehensive treatment of a patient with a defect in the abdominal segment of the esophagus after gastrectomy

In oncosurgery esophago-intestinal anastomotic leak as well as defects of the abdominal segment of the esophagus are serious complications associated with prolonged hospital stay and increased mortality rate. A choice of management tactics for each patient is individual. Treatment of esophageal anastomotic leak without separation provides the best result by reducing the time of rehabilitation, improving the quality of life and reducing mortality. Conservative treatment requires an adequate drainage when conducting enteral feeding and adequate antibiotic therapy. The indications for separation of the anastomosis include a large defect size, necrosis of the graft uncontrolled purulent-septic complications and a failure of conservative therapy. In recent decades a number of methods for endoscopic treatment of anastomotic leaks in the gastrointestinal tract have been elaborated, including the use of adhesive agents, self-expanding stents, clipping, and endoscopic vacuum system. These methods have several advantages over surgical and conservative management. Despite the accumulated experience, at present there is no single systemic approach to the use of endoscopic methods for closure of defects of anastomosis as well as defects of the abdominal segment of the esophagus. This is mainly due to a relatively small number of publications. One of the promising methods for endoscopic treatment of anastomotic leak is currently the Endoscopic Vacuum System (EndoVAC therapy). The article provides the clinical case of a patient with stomach cancer who was given transperitoneal gastrectomy with D2-lymphadenectomy which was complicated by a defect in the abdominal segment of the esophagus with peritonitis. To treat those complications relaparotomy, sanitation and drainage of the abdominal cavity was performed. In order to achieve closure of the fistula more quickly the vacuum system was used resulting in a marked decrease in fluid exudation, which in turn contributed to closure of the fistula.

Fatigue performance of distributed optical fiber sensors in reinforced concrete elements

In this paper, the authors present the results of a laboratory test where two reinforced concrete beams were instrumented with Distributed Optical Fiber Sensors (DOFS) to allow the monitoring g of strain in four different longitudinal segments bonded to their bottom surface. The test objective was to confirm the ability and good performance of the DOFS to monitor bridge structures in a long-term basis. To this end, the two specimens were submitted to a fatigue test up to 2million load cycles. The amplitude of the stress range applied during the fatigue test was representative of what is expected on a standard highway bridge under vehicular traffic. Additionally, each of the four DOFS segments was bonded using a different adhesive to also investigate on the fatigue performance of the adhesive agents normally used. Finally, the collected data is checked against the data recorded with strain gauges also deployed on the beam specimens.

Enhanced antistatic properties of polyethylene film/polypropylene-coated non-woven fabrics by compound of hot-melt adhesive and polymer antistatic agent

In this paper, the compound hot-melt adhesives were prepared by blending alkyl sulfonate polymer antistatic agent with modified rosin hot-melt adhesive and used for the preparation of polyethylene film/polypropylene-coated non-woven fabrics. The effects of the amount of antistatic agent on the melt viscosity, softening point, and thermal stability of the compounded hot-melt adhesives were studied. Then, the antistatic properties and its washing fastness of the coated non-woven fabrics were tested and analyzed. The results showed that the softening point and the melt viscosity of the hot-melt adhesives decreased after compounding, and the thermal stability of the compound hot-melt adhesives decreased in the high temperature range, which was not affected before 200℃. The surface inductive voltage, half-life, and specific resistance of the coated non-woven fabrics prepared from the compound adhesives decreased gradually with the increase of the amount of the antistatic agent, indicating that the antistatic property of the prepared fabrics was gradually improved. In addition, the fabrics still exhibited antistatic properties after soaping for several times. The influence of compound adhesive on the wettability of fabric surface was consistent with that of antistatic property. Finally, the mechanism of the hot-melt adhesive and antistatic agent compounding technology to improve the antistatic performance of the coated non-woven fabrics was elaborated, and the reason for its excellent soaping durability was also explained.