Fabrication of an Ultrastrong Formaldehyde-Free Wood Adhesive with an Organic-Inorganic Cross-Linking Network.

The wood industry faces challenges in producing eco-friendly, high-performance, and formaldehyde-free adhesives. In this study, carboxylated styrene-butadiene rubber (XSBR) was blended with polyamidoamine-epichlorohydrin (PAE) resin, and a controlled amount of CaCO3 powder was incorporated to create an adhesive with exceptional strength. The resulting three-layer plywood demonstrated remarkable dry and wet shear strengths of 3.09 and 2.36 MPa, respectively, and of 2.27 MPa after boiling water tests, comparable to that of phenolic resins. Additionally, the adhesive exhibited strong adhesion across various materials including glass, metal, etc. This exceptional performance was due to two primary factors: (1) the high-density chemical cross-linking reaction and the physical entanglement between XSBR and PAE; (2) the organic-inorganic hybrid involving metal ion complexation developed by CaCO3, which fostered molecular chain connections and enhanced the adhesive-material interface. These findings offer valuable references for further research in the field of wood adhesives.

Study on the Properties of FEVE Modified with Ag2O/OH-MWCNTS Nanocomposites for Use as Adhesives for Wooden Heritage Objects.

The durability of wooden heritage objects and sites can be affected by external environmental factors, leading to decay, cracking, and other forms of deterioration, which might ultimately result in significant and irreversible loss. In this study, a FEVE resin was modified with Ag2O/OH-MWCNTS (MA), denoted as MAF, where three concentrations were prepared using in situ precipitation, and the resulting composite adhesive was characterized by a high viscosity and effective bacteriostatic properties, demonstrating a better viscosity and thermal stability, as well as antibacterial properties, than pure FEVE resin. The results show that MAF adhesives present good thermal stability, as evidenced by a lower mass loss rate following treatment at 800 °C compared to the pure FEVE resin. At a consistent shear rate, the viscosity of MAF demonstrates a notable increase with the proportion of MA, which is better than that of FEVE. This suggests that the nano-Ag2O particles in MA act as physical crosslinking agents in FEVE, improving the viscosity of the composite adhesive MAF. The adhesion strength between MAF and wood exhibits a similar trend, with wooden samples showing higher shear strengths as the proportion of MA increases in comparison to FEVE. Simultaneously, the antibacterial effects of the MAF adhesive exceeded 1 mm for Trichoderma, Aspergillus niger, and white rot fungi. The antibacterial activity of the MAF adhesive exhibited a direct correlation with the concentration of Ag2O/OH-MWCNTS, with the most pronounced inhibitory effect observed on Trichoderma. The MAF adhesive demonstrates promising prospects as an adhesive for wooden heritage artifacts, offering a novel approach for the rapid, environmentally friendly, and efficient development of composite adhesives with superior adhesive properties.

Valorization of sewage sludge for facile and green wood bio-adhesives production.

A method is presented herein for the design of wood bio-adhesives using sewage sludge extracts (SSE). SSE was extracted from SS using deep eutectic solvents and processed with glycerol triglycidyl ether (GTE) to disrupt the secondary structure of proteins. An additive was also used to improve mechanical performance. The resulting bio-adhesive (SSE/GTE@TA) had a wet shear strength of 0.93 MPa, meeting the Chinese national standard GB/T 9846-2015 (≥0.7 MPa). However, the high polysaccharide content in SSE would weaken the mechanical properties of wood bio-adhesives. The key to improve bio-adhesive quality was the formation of a strong chemical bond via Maillard reaction as well as higher temperatures (140 °C) to reduce polysaccharide content via dehydration. This approach has lower environmental impact and higher economic efficiency compared to incineration and anaerobic digestion of sewage sludge. This work provides a new perspective on the high-value utilization of SS and offers a novel approach to developing bio-adhesives for the wood industry.

High Hardness, Excellent Hydrophobicity, and Favorable Corrosion Resistance of Plasma-Sprayed FeCrMoSi Amorphous Coatings on 304 Stainless Steel.

The FeCrMoSi amorphous coatings were fabricated on the surface of a 304 stainless steel (SS) base material using atmospheric plasma spraying. A comprehensive investigation was carried out to evaluate the structure, morphology, adhesion to base material, hardness, hydrophobicity, interfacial contact resistance, and corrosion resistance of the coatings. The results show a remarkable hardness of 1180.1 HV, a strong bond strength of up to 64.3 N/mm2, and excellent hydrophobicity with a water contact angle reaching 141.2°. Additionally, in an acidic environment with fluoride ions (0.5 M H2SO4 + 2 ppm HF, 80 °C), the FeCrMoSi amorphous coating demonstrated superior corrosion resistance compared with 304 SS while maintaining similar electroconductibility. Detailed analysis of the structural characteristics and corrosion resistance of FeCrMoSi amorphous coatings provided valuable insights into their mechanics. These promising results signify a bright future for FeCrMoSi amorphous coatings in various industrial sectors, including transportation, petroleum, and electric power industries.

Electronic Modification by Transitional Metal Dopants to Tune the Oxidation Activity of Pt-CeO2-Based Catalysts.

While utilization of transitional metals as a promoter has been extensively studied to enhance the activity of Pt-based catalysts for the oxidation of formaldehyde (HCHO), there is still a lack of well elucidated property-function relationship for the rational selection of a promoter in catalyst design. Herein, we modified a Pt/CeO2 catalyst with two transitional metal dopants (i.e., Mn and Cu) that showed negligible influence on the physical structure of the Pt-CeO2 matrix but distinct effects on the activity of the catalyst. Complementary characterizations combined with density functional theory modeling revealed that the transitional metal dopants significantly modified the electronic structure of the catalyst and shifted the d-band of Pt to higher energy with different extents, which may tune the bonding strength of HCHO/intermediates with the Pt-CeO2 interface domain. The catalyst with moderate bonding strength (i.e., Pt-Mn/CeO2) displayed the highest reactivity under the ambient condition, while Pt-Cu/CeO2 with the highest bonding strength showed a dramatically decreased activity. No correlation was observed between the abundancy of the active oxygen and catalytic activity, likely due to the oxygen supply having a much higher rate than the rate-determining step. This work contributes to the elucidation about the property-function relationship of a transitional metal dopant in Pt-based catalysts for the oxidation of HCHO.

Effects of different frequencies of Er:YAG laser on the bonding properties of zirconia ceramic.

The effects of Er:YAG laser with different frequencies on zirconia ceramic's bonding properties were studied. In total, 42 Y-TZP (yttrium-stabilized tetragonal zirconia polycrystals, UPCERA ST) with 3 mm × 3 mm × 2 mm divided into 6 groups (n = 7): control (C), sandblasting (SB), and Er:YAG laser (A1-A4), which the frequencies correspond to 5 Hz, 10 Hz, 15 Hz, and 20 Hz, IPS e.max Press ceramics were B. Scanning electron microscope (SEM) images were recorded. The ceramics were bonded to enamel from extracted teeth. After being constantly stored at 37 ℃ for 24 h, the shear test was performed with a universal testing machine. Stereomicroscope evaluated fracture modes. Stereomicroscope evaluated fracture modes. Data were analyzed by SPSS26.0 statistical software; the standard was P = 0.05. (1) The SEM showed the surface of A1-A4 became rough compared with C. (2) The shear test showed that the highest bonding strength for B was 13.15 ± 2.97 MPa, followed by SB was 7.78 ± 0.97 MPa, and A2 was 7.13 ± 0.75 MPa. However, there was no significant difference between SB and A2 (P > 0.05). Fracture modes of C were the interface fracture of Y-TZP and resin adhesive; most of A1-A4 and SB also were interface fracture, a few mixed fractures, and cohesion fracture of resin adhesive; B were all mixed fracture. Er:YAG laser with 10 Hz could be used as an alternative to sandblasting with Al2O3 for surface modification of Y-TZP to increase the bonding strength.

Effect of Er:YAG laser pretreatment on glass-ceramic surface in vitro.

This study investigated the feasibility of using an Er:YAG laser to pretreat glass-ceramic surface and evaluate the effect of the treatment on the bonding strength and marginal adaptation between glass-ceramic and dentin. Glass-ceramic samples (CEREC Blocs) and third molars were cut into 6 mm × 6 mm × 2 mm plates. Thirty ceramic plates were randomly divided into 5 groups: group A (control), group B (pretreated with 9.6% hydrofluoric acid [HF]), group C (pretreated with the Er:YAG laser at 300 mJ and 15 Hz), group D (pretreated with the Er:YAG laser at 400 mJ and 15 Hz), and group E (pretreated with the Er:YAG laser at 500 mJ and 15 Hz). The surface morphologies of the samples in each group were studied under a scanning electron microscope, and the sample displaying optimal etching parameters was selected for subsequent experiments. Based on the surface treatments, 30 ceramic and dentin plates were randomly allocated into 3 groups: the control, laser, and acid-etching groups. After bonding a ceramic plate to a dentin plate, the microleakage and bonding strength were measured, and the pretreatment effects of the Er:YAG laser and 9.6% HF were compared. Group E exhibited an etching effect that was more pronounced and uniform than that in groups C and D. Microleakage and bonding strength analyses revealed that the laser and acid-etching groups differed significantly from the control group in dye penetration depth and shear strength (P < 0.05), although the laser and acid-etching groups did not differ from each other. Both 9.6% hydrofluoric acid and Er:YAG laser pretreatments can coarsen glass-ceramic surfaces, improve the marginal adaptation and bonding strength between the glass-ceramic and dentin, and decrease microleakage of the materials. The two treatments showed no apparent differences in pretreatment outcomes.

Effect of antimicrobial photodynamic therapy with different photosensitizers and adhesion protocol on the bond strength of resin composite to sound dentin.

OBJECTIVES: The aim of this study is to evaluate the influence of the antimicrobial photodynamic therapy with phycocyanin and toluidine blue on the bond strength of resin composite to the sound dentin. MATERIALS AND METHODS: The samples include 120 tooth blocks taken from 60 human extracted sound third molar teeth. They were randomly divided into 12 groups and disinfected with two different photosensitizers (Phycocyanin and Toluidine blue) activated by 635 nm diode laser for aPDT procedure. Then two different protocols (total-etch and self-etch) of universal adhesive system (G-Premio BOND, GC Dental Products CORP. Japan) were applied. The samples then filled with resin composite (Gradia® Direct, GC Dental Products CORP. Japan). After 10000 cycles of thermocycling, all samples were subjected to the micro shear bond strength (µSBS) test using a universal testing machine (1 mm/min). The data were analyzed with One Way ANOVA. RESULTS: The effect of aPDT using both photosensitizers (phycocyanin and toluidine blue O) on the bonding strength to dentin was not significant (P>0.05). However, the bonding strength of total etch groups was reduced significantly (P<0.05) after aPDT using both photosensitizers. Phycocyanin self-etch group showed the greatest bonding strength (19.48 ± 3.89 MPa) in comparison to other aPDT groups. No significant reduction after thermocycling in dentin bond strength was observed in all groups (P>0.05), with exception of control total etch groups, which showed significant difference (P<0.05). CONCLUSION: aPDT using toluidine blue O and phycocyanin has no adverse effect on bonding to sound dentin when using universal adhesive in self-etch protocol. CLINICAL RELEVANCE: Phycocyanin is more recommended to be used in aPDT in comparison to toluidine blue as a natural photosensitizer.

[Evaluation of the effect of sodium hypochlorite gel on composite bonding strength to enamel of primary teeth after salivary contamination: in vitro study]. / Primenenie gelya gipokhlorita natriya dlya uluchsheniya stsepleniya kompozitnogo materiala s emal'yu vremennykh zubov pri slyunnoi kontaminatsii.

OBJECTIVE: The study investigated the effect of 2%s odium hypochlorite gel application after post-etching salivary contamination on composite bonding strength to primary teeth enamel. MATERIAL AND METHODS: The sample consisted of 79 primary human teeth that were extracted no more than one month ago. The sample was randomly divided into four groups: (1) the control group (A) comprised 10 primary teeth, and composites were applied in the traditional manner without any salivary contamination; (2) the second group (B) consisted of 23 primary teeth in which salivary contamination was conducted after etching followed by re-etching and follow-up; (3) the third group (C) comprised 23 primary teeth in which saliva contamination was done after etching followed by washing, drying, and follow-up; and (4) the fourth group (D) comprised 23 primary teeth, in which salivary contamination was conducted after etching followed by application of sodium hypochlorite gel and follow-up. The samples were tested using the Testometric Tensile Strength Device (Testometric M350-10 kN, Testometric Ltd., UK) to measure the composite bonding strength to enamel of primary teeth. RESULTS: The arithmetic mean strength values in the research sample were ordered as followed: (A=13.39 MPa) > (D=11.82 MPa) > (C=8.07 MPa) > (B=6.15 MPa). The application of sodium hypochlorite gel after salivary contamination significantly improved the composite bonding strength to primary teeth enamel when compared with re-etching or only washing and drying. CONCLUSION: 15 s exposition of sodium hypochlorite gel with subsequent rinse and drying is recommended in case of saliva contamination of etched primary tooth enamel surface.

Improving Tabletability of Excipients by Metal-Organic Framework-Based Cocrystallization: a Study of Mannitol and CaCl2.

PURPOSE: To improve tabletability of pharmaceutical excipient mannitol by forming cocrystal with metal-organic framework (MOF) structure. METHODS: Mannitol was cocrystallized with CaCl2 by slurry method and solvent evaporation method. The obtained cocrystal was characterized by SCXRD, PXRD, and thermal analysis. Comparative study on tabletability between cocrystal and ß-mannitol were then conducted. Differences in tabletability were subsequently analyzed using the bonding area-bonding strength (BA-BS) model and correlated with their crystal structures. RESULTS: The prepared cocrystal contains mannitol, CaCl2 and water in molar ratio of 1:1:2 (i.e. mannitol·CaCl2·2H2O) and all the Ca2+ in the cocrystal are linked together by mannitol molecules through an infinite coordination network, demonstrating a typical MOF structure. Compared with ß-mannitol, such MOF-based cocrystal showed improved tabletability (~2-fold increased tensile strength) and reduced lamination tendency (~3-fold increased minimum compaction pressure to occur lamination). The tabletability improvement of cocrystal was dominated by its higher BS, which is attributed to stronger intermolecular interactions. The reduced lamination tendency was attributed to its lower in-die elastic recovery than ß-mannitol. CONCLUSIONS: MOF-based cocrystallization will be a promising and valuable approach to tailor mechanical properties of pharmaceutical materials in order to achieve better pharmaceutical performance.

Molecular Origin of the Distinct Tabletability of Loratadine and Desloratadine: Role of the Bonding Area - Bonding Strength Interplay.

PURPOSE: To explain the different tabletability of two structurally similar H1-receptor antihistamine drugs, loratadine (LOR) and desloratadine (DES), based on the molecular basis of bonding area and bonding strength. METHODS: LOR and DES were characterized by powder X-ray diffractometry, thermal analysis, and dynamic water sorption. The compressibility, tabletability, compactibility, and Heckel analysis of their bulk powders and formulations were evaluated. A combined energy framework and topological analysis was used to characterize the crystal structure - mechanical property relationship. Surface energy of bulk powder was assessed by contact angle measurement using the Owens/Wendt theory. RESULTS: Both LOR and DES bulk powders are phase pure and stable under compaction. The superior tabletability of LOR is attributed to both larger bonding area (BA) and higher interparticle bonding strength (BS). The larger BA of LOR results from its experimentally established higher plasticity, which is explained by the presence of more densely packed molecular layers with smooth surface topology. The higher BS of LOR corresponded to its significantly higher dispersive component of the surface energy. CONCLUSIONS: This work provides new insights into the molecular origins of BA and BS, which can be applied to improve mechanical properties and tableting performance of drugs through appropriate crystal engineering.

Minimum Interfacial Bonding Strength for Bilayer Tablets Determined Using a Survival Test.

PURPOSE: To identify the minimum interfacial bonding strength (IBS) required for bilayer tablets to sustain the stresses experienced during manufacturing, transportation, and handling. METHODS: Bilayer tablets of a number of formulations with systematically varied IBS were prepared on a materials testing macine. Five bilayer tablets with the same IBS were repeatedly dropped at a fixed height in a friabilator and integrity of the interface was periodically examined. The number of tablets free from observable defects at the interface was plotted as a function of the number of drops. The IBS for all five tablets to remain intact after 1000 drops was taken as the minimum IBS for a given formulation. RESULTS: The minimum IBS depends on both layer composition and tablet size. For bilayer tablets made with more brittle materials or a larger size, a higher minimum IBS is required to pass the survival test. The incorporation of HPMC leads to a lower minimum IBS. An IBS of 0.26 MPa is sufficient for all bilayer tablet formulations and sizes to pass the survival test in this work. CONCLUSIONS: A minimum IBS of 0.26 MPa is recommended as a tentative criterion for bilayer tablets of most materials to avoid quality issues arising from inadequate IBS.

Comparison of the different retention appliances produced using CAD/CAM and conventional methods and different surface roughening methods.

The purposes of this study are to conduct an in vitro comparison of the shear bond strength, breakage mode, and wire deformation of three different types of retainers and to compare the subsequent enamel surface changes. Two hundred seventy intact lower incisor teeth were embedded in acrylic blocks in pairs. Dead wire and CAD/CAM-fabricated and fiber-reinforced wires were applied to the teeth roughened with acid and Er:YAG or Er,Cr:YSGG laser. The surface roughness was observed by scanning electron and atomic force microscopy. The samples were analyzed for shear bonds. The dead wire and acid group were found to have the highest bonding strength and the strengths for all groups in which acid was used as an agent were found to be higher than others. Deformation of retainers was most noted in the dead wire-acid group. Among all the groups, the CAD/CAM-fabricated wire group showed the least deformation, with no deformation observed. In this study, it was determined that there is a significant correlation between ARI scores and agents. Consequently, acid etching was found to create more enamel surface roughness than laser groups. It was also seen that the combined use of the acid method and dead soft wire had the highest bond strength, even though it was not statistically significant. It was concluded that CAD/CAM-fabricated wire provides the opportunity for reuse in clinical applications due to its lack of deformation, being more conservative for the patient, and being more advantageous for the clinician in terms of session time, considering the residual adhesive amount left on the enamel surface.

Monitoring of Epoxy-Grouted Bonding Strength Development between an Anchored Steel Bar and Concrete, Using PZT-Enabled Active Sensing.

Anchored steel bars have been widely used in retrofitting of existing concrete structures. The bonding strength between the anchored steel bar and the concrete is critical to the integrity of the strengthened concrete structure. This paper presents a method to monitor epoxy-grouted bonding strength development by using a piezoceramic-enabled active sensing technique. One concrete beam with an anchored steel bar was involved in the monitoring test, and two concrete beams with six anchored steel bars were used in the pull-out test. To enable the active sensing, a Lead Zirconate Titanate (PZT) patch was bonded to the surface of the exposed end, and piezoceramic smart aggregates were embedded in each concrete specimen. During the monitoring experiment, signals from PZT sensors and smart aggregates were acquired at intervals of 0, 20, 40, 60, 80, and 100 min. In addition, a pull-out test was performed on each of the remaining six anchored steel bars in the two concrete beams, while the signal was recorded in the test. Furthermore, a wavelet packet analysis was applied to analyze the received signal energies to investigate the bonding strength development between the concrete and the anchored steel bar during the epoxy solidification process. The test results demonstrate the effectiveness of the proposed method in monitoring the bonding strength development between the anchored steel bar and the concrete, using the PZT-enabled active sensing.

Effect of Bonding and Rebonding on the Shear Bond Strength of Two-Piece Implant Restorations.

PURPOSE: To evaluate the rebonding strength of ceramics to titanium alloy after disassembling by heat treatment. MATERIALS AND METHODS: A total of 40 titanium alloy (titanium-6 aluminum-4 vanadium) disks (4.0 × 6.6 mm) and 20 zirconia (Lava Plus) disks were manufactured using computer-aided design and computer-aided manufacturing (CAD/CAM) technology. Twenty heat-pressed lithium disilicate glass-ceramic (IPS e.max Press LT) disks were fabricated and used as controls. Bonding protocol for each specimen surface was performed according to manufacturer's instructions. Specimens (n = 10) of zirconia/titanium alloy (ZR) and lithium disilicate/titanium alloy (LD) were bonded using adhesive resin cement (RelyX Ultimate) and then subjected to a heat treatment (HT, 320°C, 2 minutes) to disassemble the bonding complex, cleaned with aluminum oxide airborne-particle abrasion, and rebonded following the initial protocol, group ZRHT and group LDHT, respectively. After 5000 cycles of thermal cycling, a shear bond test was conducted. A universal testing machine was used at a 5 mm/min crosshead speed. Failed specimens were examined with stereomicroscopy at 10× magnification to identify the mode of failure. One-way ANOVA and Tukey HSD tests were applied for statistical analysis of the shear bond strength data, with statistical significance at α = 0.05. RESULTS: The mean ± SD bond strength values ranged from 28.3 ± 7.2 to 45.9 ± 9.7 MPa. Statistically significant lower shear bond strength values were obtained from the LD group (p = 0.002, F = 5.89), while no statistically significant differences in bond strength were observed between the ZR and ZRHT groups (p > 0.05). Failure mode was predominantly mixed-type failure pattern for all specimens. CONCLUSIONS: Heat and abrasion surface treatment increased the bond strength of lithium disilicate glass-ceramics cemented to titanium alloy, but no effect was observed on zirconia/titanium alloy bonding.

The effectiveness of erbium: Yttrium-aluminum-garnet laser on enamel conditioning: An In vitro study.

OBJECTIVES: The purpose of this in vitro study was to investigate the effect of three different enamel surface conditioning procedures on the bonding strength of two resin-based filled fissure sealants. MATERIAL AND METHODS: Freshly extracted, 48 third molar teeth were used in this study. Teeth were randomly divided into three main groups as the phosphoric acid etched, erbium: Yttrium-aluminum-garnet (ER: YAG) laser etched, and the phosphoric acid plus ER: YAG laser-etched groups. The main groups further divided into two subgroups as Clinpro or Fissurit FX applied. After preparation of the enamel surfaces and application of the sealants, the samples were subjected to shear bond strength test. RESULTS: According to statistical analysis with one-way ANOVA, the bonding strength values of the phosphoric acid groups were found significantly higher than those values obtained from the ER: YAG laser and ER: YAG laser plus phosphoric acid groups (P < 0.001). CONCLUSION: As a result of the study, it has been concluded that the laser application alone has no additional benefit to the acid application in terms of bonding strength.

The Effect of Surface Preparation of Acrylic Teeth.

PURPOSE: To investigate whether the chemical bond between acrylic teeth and heat polymerized PMMA can be altered by chemical and/or mechanical treatment. MATERIALS AND METHODS: One hundred fifty acrylic teeth were divided in groups of 10. Their ridge lap surface underwent mechanical and/or chemical treatments: 1) no treatment, 2) air-abrasion with Al2O3 particles, 3) acid etching with phosphoric acid, 4) application of composite resin bonding agent, 5) application of MMA and ethylmethylketone bonding agent, 6) PMMA monomer application. The teeth were then placed in heat polymerized acrylic resin. Each specimen was compressed with a universal testing machine. Descriptive statistics, one-way ANOVA (α=0.05) and Tukey's HSD test were used. A scanning electron microscope (SEM) was also used to study the fracture areas. RESULTS: Statistically significant differences (p⟨0.001) in the bond strength were found. The strongest bond (239.41 N), was noted in the group treated with sandblasting followed by PMMA monomer application. CONCLUSIONS: Mechanical and/or chemical preparations affect significantly the bond strength between the acrylic resin denture teeth and the PMMA denture base. Air abrasion was the most effective treatment, either alone or combined with other treatments.

A critical Examination of the Phenomenon of Bonding Area - Bonding Strength Interplay in Powder Tableting.

PURPOSE: Although the bonding area (BA) and bonding strength (BS) interplay is used to explain complex tableting behaviors, it has never been experimentally proven. The purpose of this study is to unambiguously establish the distinct contributions of each by decoupling the contributions from BA and BS. METHODS: To modulate BA, a Soluplus® powder was compressed into tablets at different temperatures and then broken following equilibration at 25°C. To modulate BS, tablets were equilibrated at different temperatures. To simultaneously modulate BA and BS, both powder compression and tablet breaking test were carried out at different temperatures. RESULTS: Lower tablet tensile strength is observed when the powder is compressed at a lower temperature but broken at 25°C. This is consistent with the increased resistance to polymer deformation at lower temperatures. When equilibrated at different temperatures, the tensile strength of tablets prepared under identical conditions increases with decreasing storage temperature, indicating that BS is higher at a lower temperature. When powder compression and tablet breaking are carried out at the same temperature, the profile with a maximum tensile strength at 4°C is observed due to the BA-BS interplay. CONCLUSION: By systematically varying temperature during tablet compression and breaking, we have experimentally demonstrated the phenomenon of BA-BS interplay in tableting.

Comparative evaluation of bonding strength of computer aided machined ceramic, pressable ceramic, and milled metal implant abutment copings and effect of surface conditioning on bonding strength: An in vitro study.

BACKGROUND/PURPOSE: The aim of this study was to compare the shear bond strength of computer aided design/computer aided machined ceramic (CAD/CAM), pressable ceramic, and milled metal implant copings on abutment and the effect of surface conditioning on bonding strength. MATERIALS AND METHODS: A total of 90 test samples were fabricated on three titanium abutments. Among 90 test samples, 30 copings were fabricated by CAD/CAM, 30 by pressable, and 30 by milling of titanium metal. These 30 test samples in each group were further subdivided equally for surface treatment. Fifteen out of 30 test samples in each group were surface conditioned with airborne particle abrasion. All the 90 test samples were luted on abutment with glass ionomer cement. Bonding strength was evaluated for all the samples using universal testing machine at a crosshead speed of 5 mm/min. The results obtained were compared and evaluated using one-way ANOVA with post-hoc and unpaired t-test at a significance level of 0.05. RESULTS: The mean difference for CAD/CAM surface conditioned subgroup was 1.28 ± 0.12, for nonconditioned subgroup was 1.20 ± 0.11. The mean difference for pressable surface conditioned subgroup was 1.18 ± 0.04, and for nonconditioned subgroup was 0.75 ± 0.28. The mean difference for milled metal surface conditioned subgroup was 2.57 ± 0.58, and for nonconditioned subgroup was 1.49 ± 0.15. CONCLUSIONS: On comparison of bonding strength, milled metal copings had an edge over the other two materials, and surface conditioning increased the bond strength.

Preparation and characterization of PVDF-glass fiber composite membrane reinforced by interfacial UV-grafting copolymerization.

A novel inorganic-organic composite membrane, namely poly(vinylidene fluoride) PVDF-glass fiber (PGF) composite membrane, was prepared and reinforced by interfacial ultraviolet (UV)-grafting copolymerization to improve the interfacial bonding strength between the membrane layer and the glass fiber. The interfacial polymerization between inorganic-organic interfaces is a chemical cross-linking reaction that depends on the functionalized glass fiber with silane coupling (KH570) as the initiator and the polymer solution with acrylamide monomer (AM) as the grafting block. The Fourier transform infrared spectrometer-attenuated total reflectance (FTIR-ATR) spectra and the energy dispersive X-ray (EDX) pictures of the interface between the glass fiber and polymer matrix confirmed that the AM was grafted to the surface of the glass fiber fabric and that the grafting polymer was successfully embedded in the membrane matrix. The formation mechanisms, permeation, and anti-fouling performance of the PGF composite membrane were measured with different amounts of AM in the doping solutions. The results showed that the grafting composite membrane improved the interfacial bonding strength and permeability, and the peeling strength was improved by 32.6% for PGF composite membranes with an AM concentration at 2wt.%.