Papers by Keyword: Microporous

Abstract: In this research, smooth commercial Ti grade 2 corroded by ErCl₃.6H₂O under an electrochemical process with difference electrochemical current ranging from 0.5 – 4A, providing a rougher surface conducive to the adsorption on the Ti surface. A thin layer of TiO₂ nanotubes synthesized via the anodization method on microporous Ti surfaces for application in the biomedical field. The results reveal that the smooth titanium surface was completely corroded, resulting in the formation of a microporous structure, with a thin layer of TiO₂ successfully formed on the microporous titanium surfaces. The digital optical images obtained using digital microscope (VHX) showed that the micropore depth is around 41.94 - 55.83 µm. On the other hand, the SEM results revealed that the diameter of TiO₂ nanotubes ranged from 50 – 80 nm. The EDS and XRD techniques indicated that no impurities were present, and the TiO₂ phase was successfully formed. SEM images show positive results regarding the formation of a bone-like CaP mineral layer after 14 days of immersion in simulated body fluid (SBF), indicating suitability for biomedical applications.

Abstract: Copper-based metal-organic framework (MOF-199, also known as Cu-BTC and HKUST-1) materials were successfully synthesized by hydrothermal method using renewable straight-chain fatty alcohol with eight carbon chain length (i.e. octyl alcohol). The addition of palm oil derived fatty alcohol (PODFA) was suggested to act as porogen (structure directing agent) that aided the particle formation and flexible porous structure. This synthesis approach was environmental-friendly and sustainable by utilizing the fatty alcohols originated from biomass such as palm oil. The resulting MOF-199 materials exhibited single crystalline octahedral morphology structure by X-ray diffraction analyses and SEM images. The optimum ratio of octyl alcohol exhibited well-defined single octahedral particles at size range of ca. 10-50 µm and reduced by-product formation of cuprous oxide at high temperature synthesis. The nature of MOF-199 having apparently high surface area, high pore volume and low density provided the possibility in carbon capture storage. The CO₂ adsorption capacity of MOF-199 investigated using high pressure volumetric analyser (HPVA-II) at ambient temperature (i.e. 25 °C) was found to be at maximum working capacity.

Abstract: In this study, a three-dimensional (3D) copper-based metal-organic framework (MOF-199) is a microporous materials with structural formula Cu₃(BTC)₂ (1,3,5-benzene tricarboxylate) were successfully synthesized using nonsurfactant templating method. The preparations of MOF-199 utilized different length of straight carbon chain (oleochemical) fatty alcohols derived from palm oil were similar to those reported earlier by our group with some modifications [1]. This new method led to unique structure and properties of as-synthesized MOF-199. The addition of fatty alcohols such as octyl (C8) and decyl (C10) alcohol act as renewable template onto MOF-199 generating the required carbon template for microporous crystalline structure [2]. The MOF-199 had been synthesized using conventional hydrothermal method with the present of fatty alcohols to analyse the resulting MOF-199 in terms of structure, morphology, surface area and adsorption isotherm. MOF-199 synthesized in this study exhibited single crystal orthorhombic morphology at ca. 30 micron. The crystallinity of MOF-199 materials was improved by the addition of fatty alcohols as observed in the X-Ray Diffraction patterns.

Abstract: A three-dimensional (3D) copper-based metal-organic frameworks or MOF-199 were successfully synthesized by utilizing palm oil based fatty alcohols that acted as renewable template. The synthesis of MOF-199 employed different length of straight chain of fatty alcohols namely octyl, decyl, lauryl, myristyl and cetyl alcohols derived from palm oil using similar method to those reported earlier with some modifications. The microstructure of MOF-199 exhibited single particles with fine octahedral morphology at various particle sizes in the range of ca. 15-60 μm. The nitrogen adsorption isotherms were conducted to estimate the surface area and pore volume of the materials and were at ca. 400 – 1100 m²g^-1 and 0.17 – 0.43 mLg^-1 respectively. The surface area and pore volume of the materials decreased with longer straight chain fatty alcohol possibility due to mobility of the long carbon chain.

Abstract: Basing on coal and the oxygen evolving complex theory, the method of study on the spontaneous combustion by analysis the microporous in coal has been established in this article. By the electron microscope, the process of microporous volume changeing with the temperature gradually increased is observed. It is believe that the process of spontaneous combustion reaction should be carried out in the microporous. Finally, under the help with finite element analysis , the temperature field surrounding microporous has been analyzed and the distribution regularity of the temperature field has been obtain. It make the conclusion that coal surface microporous can be used as evidence of coal spontaneous combustion reaction.

Abstract: In this present work we could show that a microporous β-TCP ceramic with interconnected porosity and 5 μm median pore diameter is a useful delivery vehicle for drugs and growth factors. However, it is necessary to combine the ceramics with degradable biopolymers, like hydrogels for retarded release. So the drug release could be increased by the factor 7 from 3 up to 21 days with concentrations having an antimicrobial activity. Concerning the growth factor, the release period was prolonged significantly.

Abstract: The development of CaP ceramics involved a better control of the process of resorption and bone substitution. Micro Macroporous Biphasic CaP, (MBCP+) is a concept based on an optimum balance of the more stable phase of HA and more soluble TCP. The material is soluble and gradually dissolves in the body, seeding new bone formation as it releases Ca and P ions into the biological medium. The MBCP+ is selected for tissue engineering in a large European research program on osteoinduction and mesenchymal stem cell technology (REBORNE 7^th EU frame work program, Regenerative Bone defects using New biomedical Engineering approaches, www.reborne.org). We have optimized the matrices in terms of their physical, chemical, and crystal properties, to improve cell colonization and to increase kinetic bone ingrowth. The fast cell colonization and resorption of the material are associated to the interconnected macropores structure which enhances the resorption bone substitution process. The micropore content involves biological fluid diffusion and suitable adsorption surfaces for circulating growth factors. The bioceramics developed for this project was fully characterized using X-Ray diffraction, FTIR, X-rays micro tomography, Hg porosimetry, BET specific surface area, compressive mechanical test, and SEM. Preclinical tests on the optimized scaffold were realized in critical size defects in several sites of implantation and animals (rats, rabbits, goats, dogs).The smart scaffold has a total porosity of 73%, constituted of macropores (>100µm), mesopores of 10 to 100µm and high micropores (<10µm) content of more or less 40%. The crystal size is <0.5 to 1 µm and the specific surface area was around 6m²/g. The in vivo experiment indicated higher colonization by osteogenic cells demonstrating suitable matrices for tissue engineering. The HA/TCP ratio of 20/80 was also more efficient for combination with total bone marrow or stem cell cultivation and expansion before to be implanted.

Abstract: In this work, microporous membrane biomaterials based on high weight molecular polylactide (PLA) and low molecular weight poly(ethylene glycol) (PEG) using rapid solvent evaporation method were prepared and investigated. The effect of PEG segments added on the thermal and degradation behaviors was studied. According to the results, produced PLA/PEG biomaterial has lower glass transition temperature (Tg)in comparison with neat PLA. It was also found that the degradation rates of the PLA/PEG biomaterials were significantly increased with adding of PEG, which explained by increasing hydrophilic groups. For better porous fixation, CL-blocked polyisocyanate (CL-bp), which was synthesized from reaction of isophorone diisocyanate (IPDI) with dimethylol propionic acid (DMPA) and Trimethylolpropane (TMP) followed by addition of caprolactam (CL), were introduced. The microporous forms were observed by the scanning electron microscope (SEM), which showed the mean diameters of prepared PLA/PEG microporous were around 10μm.

Abstract: Lamellas important for micropores were well formed during extrusion and annealing process in melt-spinning and stretching method. This unusual crystalline structure and its changing during annealing and stretching process were well studied in term of lamellar size, lamellar crystallite orientation, degree of lamellar and observation of morphology. Lamellar and microfibril model was accepted as mechanism of making micropore for this process. Gas permeability and porosity testing experimental were used to characterize membrane properties.

Abstract: Mullite can be prepared as lightweight refractories for its low thermal conductivity, advanced volume stability at high temperature environment. Using industrial alumina and nature silica powders as starting materials, the mullite aggregates with microporous structure were synthesized by adding some burning-out materials as pore forming agents. The effects of burning-out materials on the pore size distribution, mullite contents and microstructure of microporous mullite have been investigated. The results show that the effects on the mullite contents and microstructure of microporous mullite are significant. All the burning-out materials have a similar effect for the pore size distribution.