The current work predicted the permeance of COsub.2 across a ZIF-L@PDMS/PES composite membrane using two different models. The membrane was fabricated by dipping a PES hollow fiber membrane in a ...coating solution made using PDMS that contained ZIF-L. First, flat sheet ZIF-L@PDMS membranes were fabricated to verify the role of ZIF-L on the gas separation performance of the membrane. Based on the data, the presence of ZIF-L in the PDMS matrix allowed enhancement of both permeability and selectivity of COsub.2, where the maximum value was obtained at 1 wt% of ZIF-L. The performance of ZIF-L@PDMS layer, as a function of ZIF-L loading, was well-predicted by the Cussler model. Such information was then used to model the COsub.2 permeance across ZIF-L@PDMS/PES composite membrane via the correction factor, which was introduced in the resistance in series model. This work discovered that the model must consider the penetration depth and the inorganic loading (in the case of ZIF-L@PDMS/PES). The error between the predicted COsub.2 permeance and the experimental results was found to be minimal.
Microbial adhesion on dental restorative materials may jeopardize the restorative treatment long-term outcome. The goal of this in vitro study was to assess Candida albicans capability to adhere and ...form a biofilm on the surface of heat-cured dental composites having different formulations but subjected to identical surface treatments and polymerization protocols. Three commercially available composites were evaluated: GrandioSO (GR), Venus Diamond (VD) and Enamel Plus HRi Biofunction (BF). Cylindrical specimens were prepared for quantitative determination of C. albicans S5 planktonic CFU count, sessile cells CFU count and biomass optical density (ODsub.570 nm). Qualitative Concanavalin-A assays (for extracellular polymeric substances of a biofilm matrix) and Scanning Electron Microscope (SEM) analyses (for the morphology of sessile colonies) were also performed. Focusing on planktonic CFU count, a slight but not significant reduction was observed with VD as compared to GR. Regarding sessile cells CFU count and biomass ODsub.570 nm, a significant increase was observed for VD compared to GR and BF. Concanavalin-A assays and SEM analyses confirmed the quantitative results. Different formulations of commercially available resin composites may differently interact with C. albicans. The present results showed a relatively more pronounced antiadhesive effect for BF and GR, with a reduction in sessile cells CFU count and biomass quantification.
This study describes the synthesis of a hydroxyl silane coupling agent (HO‐silane) through a click reaction between SH in 3‐(trimethoxysilyl)propane‐1‐thiol (KH‐590) and CC in 2‐hydroxyethyl ...methacrylate (HEMA). This coupling agent was subsequently employed in the synthesis of silane‐modified polyurethane (SPU) resin which could be moisture‐cured at room temperature. The influence of r values (the molar ratio of NCO and OH) on the characteristics of SPU resins was investigated. These results reveal that an increase in the r value leads to a reduction in viscosity from 4.9 × 105 to 1.9 × 105 mPa·s, a rise in tensile strength from 0.88 to 0.98 Mpa followed by a decline to 0.69 MPa, and a reduction in extension at fracture from 236% to 94%. A SPU resin with a viscosity of approximately 3.6 × 105 mPa·s, tensile strength of 0.98 MPa, and elongation at break of 218% can be produced when the r value is 1.8. In addition, a silane‐modified polyurethane (MS) sealant with a tensile strength of 1.6 MPa in addition to elongation at break at 336% could be produced using the aforementioned SPU resin.
A strategy to prepare hydroxyl silane coupling agent (HO‐silane) was developed based on a click reaction and used to prepare silane‐modified polyurethane resins. These resins have been successfully used in the manufacture of modified silane sealant.
In this study, a series of nano-Alsub.2Osub.3 reinforced polyimide (PI) composites were fabricated using the hot compression method. A silane coupling agent was used to modify the surface of ...nano-Alsub.2Osub.3 powder to enhance the PI/Alsub.2Osub.3 interface compatibility. The effects of Alsub.2Osub.3 contents on the microstructures, thermal behavior and mechanical properties of PI/Alsub.2Osub.3 composites were investigated. The results suggested that chemical reactions occurred during in situ modification. The nano-Alsub.2Osub.3 was cross-linked to the PI matrix, which reduced the mobility of PI chains and improved the elastic modulus of the composites. When the Alsub.2Osub.3 content was 30 wt.%, the compressive strength of composites reached the maximum value of 313 MPa and increased by 26.5% than that of the PI matrix.
This work investigated the effects of 3-aminopropyl triethoxy silane (APTES) hydrolysis time on the physicochemical properties of the resulting starch/epoxidized soybean oil (ESO) bioplastics ...comprehensively. FTIR analysis confirmed that APTES hydrolyzed for 4 h had the best modification effect on starch. The results of XRD and TGA demonstrated the successful silylation of starch by APTES despite hydrolysis time. Silylation treatment reduced the thermal stability of starch slightly, but enhanced the thermal stability of the resultant bioplastics, revealing better interaction between silylated starch and ESO. The interfacial adhesion of starch and ESO in the bioplastics was obviously enhanced when APTES was hydrolyzed for 2–24 h. The bioplastics with APTES hydrolyzed for 2–4 h showed more desirable tensile properties as the silane hydrolysis was complete and self-condensation of hydrolyzed silanes was avoided. The bioplastics containing silylated starch still showed superior opacity and biodegradability.
•Effect of silane hydrolysis on structures and properties of bioplastics was explored.•Silane hydrolyzed for 4 h had the best silylation effect.•The interfacial adhesion of starch and epoxidized oil was obviously enhanced.•Silylation enhanced the thermal stability of the resultant bioplastics.•Bioplastics with silane hydrolyzed for 2–4 h showed the best tensile properties.
Objective: The objective of this study was to evaluate the resin-ceramic adhesion of a long-carbon-chain silane (LCSI)-containing resin cement. Methods: Polished lithium disilicate ceramic discs were ...etched with hydrofluoric acid and randomly assigned into four groups; (PSAP), cemented using a silane-free resin cement with no prior priming; (PSAP-S), primed using a silane-containing primer before cementation using a silane-free resin cement; (PSAU), cemented using a LCSI-containing resin cement with no prior priming; (PSAU-S), primed as for the group (PSAP-S) and cemented using a LCSI-containing resin cement. The cemented blocks were sectioned into microbeams. The resin-ceramic microtensile bond strength (μTBS) was measured at 1 week and after thermocycling. The failure modes of the tested microbeams were evaluated. Results: The μTBS of the LCSI-containing and silane-free resin cements, either with or without a prior priming step, did not significantly differ. The adhesion of the LCSI-containing resin cement to lithium disilicate ceramic, either with or without a prior priming step, did not significantly deteriorate after artificial aging. Conclusions: The long-carbon-chain silane (LCSI) monomer incorporated in the resin cement eliminated the need for a silane priming step of a hydrofluoric acid-etched lithium disilicate ceramic.
Silane pre‐functionalized carbon dots, arbitrarily doped (0–100% scale) carbon dot nanohybrid gel glasses and macrostructures with high luminescence (quantum yields = 47% and 88%, respectively) and ...broadband optical limiting properties (532 and 1064 nm) are reported. These glasses are optically, thermally, and mechanically stable, as well as highly transmissive (ca. 90%) in the 400–1350 nm region.
Stimuli-responsive Pickering emulsions are recently being progressively utilized as advanced catalyzed systems for green and sustainable chemical conversion. Hierarchically porous metal-organic ...frameworks (H-MOFs) are regarded as promising candidates for the fabrication of Pickering emulsions because of the features of tunable porosity, high specific surface area and structure diversity. However, COsub.2-switchable Pickering emulsions formed by hierarchically porous zirconium-based MOFs have never been seen. In this work, a novel kind of the amine-functionalized hierarchically porous UiO-66-(OH)sub.2 (H-UiO-66-(OH)sub.2) has been developed using a post-synthetic modification of H-UiO-66-(OH)sub.2 by (3-aminopropyl)trimethoxysilane (APTMS), 3-(2-aminoethylamino)propyltrimethoxysilane (AEAPTMS) and 3-2-(2-aminoethylamino)ethylaminopropyl-trimethoxysilane (AEAEAPTMS), and employed as emulsifiers for the construction of Pickering emulsions. It was found that the functionalized H-UiO-66-(OH)sub.2 could stabilize a mixture of toluene and water to give an emulsion even at 0.25 wt % content. Interestingly, the formed Pickering emulsions could be reversibly transformed between demulsification and re-emulsification with alternate addition or removal of COsub.2. Spectral investigation indicated that the mechanism of the switching is attributed to the reaction of COsub.2 with amino silane on the MOF and the generation of hydrophilic salts, leading to a reduction in MOF wettability. Based on this strategy, a highly efficient and controlled Knoevenagel condensation reaction has been gained by using the emulsion as a mini-reactor and the emulsifier as a catalyst, and the coupling of catalysis reaction, product isolation and MOF recyclability has become accessible for a sustainable chemical process.
A new hydrogenated nitrile butadiene rubber (HNBR) material filled with silane-modified nano-Alsub.2Osub.3 is developed in this work. Influence of the nano-Alsub.2Osub.3 and its contents on friction ...and wear performances of the HNBR materials is investigated. The nano-Alsub.2Osub.3 particles with different contents are added into the HNBR composites. Then, friction and wear tests are conducted using a pin-on-disk tribometer. Scanning electron microscope (SEM) is used to observe wear topography of the HNBR composite surfaces. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy is used to investigate mechanism of nano-Alsub.2Osub.3 reinforcing HNBR. Results show that the filled nano-Alsub.2Osub.3 and its contents significantly affect friction and wear performances. Presence of the nano-Alsub.2Osub.3 obviously decreases friction coefficient and volume wear rate. Friction coefficient and volume wear rate of the composites reduce initially with the increase of nano-Alsub.2Osub.3 content and then increase with further increasing the nano-Alsub.2Osub.3 content. The HNBR material filled by the nano-Alsub.2Osub.3 with the content of 15phr shows better antifriction and wear performances. SEM results indicate that the HNBR material filled by the nano-Alsub.2Osub.3 of 15phr presents the best topography of wear surface compared with the HNBR materials filled by other nano-Alsub.2Osub.3 contents in this study. ATR-FTIR results show that mechanism of the nano-Alsub.2Osub.3 reinforcing HNBR for wear resistance is due to the graft reaction between the modified nano-Alsub.2Osub.3 and HNBR to form cross-linking networks around the Alsub.2Osub.3 nanoparticles, and self-polymerization of unsaturated groups on the surface of the nano-Alsub.2Osub.3 to form interpenetrating polymer networks with the HNBR molecular main chains.
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