Effect of Template Removal on Synthesis of Organic-Inorganic Hybrid Mesoporous MCM-48

Ya Nan Zhao, San Xi Li,Chong Soo Han,San Xi Li 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

Post-synthesis is used to synthesize organic hybrid inorganic mesoporous sieves. In this method, the activity and structure of the base sieve are crucial to obtain the definable hybrid materials. The chemical and physical properties of the base can be largely changed either by the final step of its synthesizing processes, by template removal which is accomplished with the oxidative thermal decomposition (burning) method or by solvent extraction method. In this paper we compared two methods for the post-synthesis of organic hybrid MCM-48. When the template was extracted with HCl/alcohol mixture, the final product showed larger pore size, larger pore volume and better crystallinity compared to the case of the thermal decomposition. The reactivity of the surface silanol group of template free MCM-48 was also checked with an alkylsilylation reagent CH2=CHSi(OC2H5)3. Raman and 29Si NMR spectra of MCM-48 in the test reaction indicated that more of the organic group was grafted to the surface of the sample after the template was removed with the solvent extraction method. Direct synthesis of vinyl-MCM-48 was also investigated and its characteristics were compared with the case of post-synthesis. From the results, it was suggested that the structure and chemical reactivity can be maintained in the solvent extraction method and that organic grafting after the solvent extraction can be a good candidate to synthesize a definable hybrid porous material.

Electrochemical Polymerization of Methoxy Polyethylene Glycol Acrylate on Carbon Fiber for Improved Interfacial Properties

Qiu Li,Ai-ling Zhang,Meng Zhang,Fang-fang Li,Song Wang,San-xi Li,Yong-jiang Li,Ze-fei Sun 한국섬유공학회 2019 Fibers and polymers Vol.20 No.12

Methoxy polyethylene glycol acrylate (MPGA) was electrochemical polymerized on carbon fiber (CF) by usingcyclic voltammetry (CV) to enhance the surface properties of CF. Fourier transform infrared spectroscopy (FTIR), scanningelectron microscopy (SEM) and thermogravimetry analysis (TGA) investigations confirmed that MPGA electropolymerizedon CF (MPGA-CF) was obtained. The low frequency capacitance of MPGA-CF (CLF=5.85 mF·cm-2) was higher thanCF(CLF=4.75 mF·cm-2) based on the result of electrochemical impedance spectroscopy(EIS) and the data obtained fitted withan R(Q(R(Q(R(CR))))) equivalent circuit model. Contact angle experiment showed that the contact angle between water andMPGA-CF is significantly lower than that between water and CF. Mechanical experimental results indicated that theinterlaminar shear strength (ILSS) of MPGA-CF/epoxy resin composites (32.24 MPa) has improved by 134.81 % comparewith the CF/epoxy resin composites (13.73 MPa), which significantly enhanced interfacial properties of epoxy resincomposites.

Effect of Aging Precipitate on Ductility Anisotropy and Low Cycle Fatigue Behavior of AA2195 Al-Li Alloy

Gui Wang,Ben Lin,Ding‑ding Lu,San‑xi Deng,Guang‑jun Zeng,Xu‑feng Cai,Jin‑feng Li,Dan‑yang Liu 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.8

The mechanical properties and low-cycle fatigue behavior of the hot-rolled AA2195 Al-Li alloy taken along the longitudinaldirection and transverse direction were investigated. The anisotropy ductility of the alloy with the short-term naturalaging (T4-SN), long-term natural aging (T4-LN), and T6 artificial aging alloy is mainly related to the grain structure andgrain boundaries, whereas the weakened anisotropy of ductility is attributed to the appearance of PFZs. The T4-SN andT4-LN specimens present the cyclic hardening phenomenon due to the interaction of dislocations with dislocations or theGuinier–Preston zone. The cyclic softening phenomenon in T6 specimens is attributed to that the dislocations cut throughthe T1precipitates, and some dislocations bypass the non-shearable precipitates, which activates more potential slip systemsto shear the T1precipitates.

Effect of Sub-Structure and Precipitation Behavior on Mechanical Properties of Al–xCu–Li Alloys

Yu‑zhuo Li,Guang‑jun Zeng,Ding‑ding Lu,Zhen‑zhen Liu,San‑xi Deng,Peng‑cheng Ma,Yong‑lai Chen,Rui‑feng Zhang,Jin‑feng Li 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.11

The tensile properties and microstructure of extruded and cold rolled 2A55 Al–Li alloys with different Cu content werestudied. After solution treatment, the strength of extruded sheets is slightly higher than that of cold rolled sheets due to strongdeformation texture and high density of substructure. However, the strength change order is different with the increase of Cucontent with T6-24 h. The extruded sample with higher Cu content have higher strength due to many dense T1precipitates. The δ′/θ′/δ′ composite precipitates and θ′ precipitates suppress the formation of T1precipitates, which cause cold rolled samplewith higher Cu content shows lower strength. Additionally, many fine T1precipitates nucleate at the sub-grain boundariesformed in the extrusion process, which have a significant effect on the mechanical property.

Effect of Template Removal on Synthesis of Organic-Inorganic Hybrid Mesoporous MCM-48

Zhao, Ya Nan,Li, San Xi,Han, Chong-Soo Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

Post-synthesis is used to synthesize organic hybrid inorganic mesoporous sieves. In this method, the activity and structure of the base sieve are crucial to obtain the definable hybrid materials. The chemical and physical properties of the base can be largely changed either by the final step of its synthesizing processes, by template removal which is accomplished with the oxidative thermal decomposition (burning) method or by solvent extraction method. In this paper we compared two methods for the post-synthesis of organic hybrid MCM-48. When the template was extracted with HCl/alcohol mixture, the final product showed larger pore size, larger pore volume and better crystallinity compared to the case of the thermal decomposition. The reactivity of the surface silanol group of template free MCM-48 was also checked with an alkylsilylation reagent $CH_2=CHSi(OC_2H_5)_3$. Raman and $^{29}Si$ NMR spectra of MCM-48 in the test reaction indicated that more of the organic group was grafted to the surface of the sample after the template was removed with the solvent extraction method. Direct synthesis of vinyl-MCM-48 was also investigated and its characteristics were compared with the case of post-synthesis. From the results, it was suggested that the structure and chemical reactivity can be maintained in the solvent extraction method and that organic grafting after the solvent extraction can be a good candidate to synthesize a definable hybrid porous material.

Photocatalytic degradation of Rhodamine B using CaCu3Ti4O12 embedded polyethersulfone hollow fiber membrane

Tunmise Ayode Otitoju,Dafu Jiang,Yuanyuan Ouyang,Mohammed Ahmedelbadawi Mohammed Elamin,San-xi Li 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.83 No.-

In this study, CaCu3Ti4O12 (CCTO) modified polyethersulfone (PES) HF membranes were prepared via drywetphase inversion by adding different concentration of CCTO particles (0–4 wt.%) in the dope solution. The synthesized PES/CCTO composites were characterized by viscosity measurement, scanning electronmicroscope, X-ray diffraction, contact angle, pore size, and pore size distribution. Theflux and thephotocatalytic activity of CCTO entrapped PES membranes were subsequently evaluated by crossflowultrafiltration and the photodegradation of Rhodamine B (RhB) under UV irradiation, respectively. Thepure water permeability of the composite membranes improved considerably upon the addition of CCTOowing to its slightly improved hydrophilicity and moderate pore size. The results also show that the PES/CCTO composite exhibited a higher photocatalytic activity, which was mainly attributed due to thecrystallite size of CCTO particles.

Advanced ceramic components: Materials, fabrication, and applications

Tunmise Ayode Otitoju,Patrick Ugochukwu Okoye,Guanting Chen,Yang Li,Martin Onyeka Okoye,San-xi Li 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.85 No.-

The global demand for ceramic materials with wide-ranging applications in the environment, precisiontools, biomedical, and electronics, and environmentalfields is on the increase. Several ceramic materialsand methods of fabrication have been developed with task-specific properties. The material, thefabrication methods, and processing conditions impel characteristics including corrosion-resistant,outstanding optical and electrical properties, hardness and anti-aging. In this review, various materialsfor the preparation of ceramics and ceramic composites components were investigated to demonstratethe contribution of the materials and different fabrication methods to the properties of the ceramicscomponents. The material properties, sintering temperature, casting technique, and pressure influencesthe ceramics grain size and porosity, which have an explicit effect on mechanical strength, corrosionresistant,and optical properties of the ceramic components. Thefinishing of the ceramic componentsinto a machinable shape requires careful attention to avoid defects. However, most conventionalfinishing methods are cost-intensive, hence, the need to commercialize 3-D printing for large scale andlong-run applications. It is hoped that this review would propagate wider research on low cost andenergy effective pathways to produce ceramics with dynamic properties, which can be applied in severalfields with outstanding performance.