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"Sebuah penelitian sistematis telah dilakukan untuk mengetahui penyebab utama rendahnya tingkat kristalinitas nanopartikel titania (TiO2) di dalam nanokomposit TiO2-PMMA hasil proses sol-gel. Dari hasil investigasi diketahui bahwa fasa TiO2 amorfus di dalam nanokomposit disebabkan oleh pembentukan cepat dari jaringan kaku Ti-OH selama tahapan hidrolisis dan kondensasi."

"Sebuah penelitian sistematis telah dilakukan untuk mengetahui penyebab utama rendahnya tingkat kristalinitas nanopartikel titania (TiO2) di dalam nanokomposit TiO2−PMMA hasil proses sol−gel. Dari hasil investigasi diketahui bahwa fasa TiO2 amorfus di dalam nanokomposit disebabkan oleh pembentukan cepat dari jaringan kaku Ti-OH selama tahapan hidrólisis dan kondensasi, yang diperburuk dengan efek perangkap dari matrik PMMA. Sebuah metode kombinasi pra-anil dan pasca-hidrotermal berhasil meningkatkan tingkat kristalinitas fasa TiO2 secara signifikan , dengan tetap mempertahankan integritas matrik polimer di dalam nanokomposit. Analisis evolusi nano struktural TiO2 dalam nanokomposit dilakukan dengan pengujian XRD, spektroskopi FTIR dan TEM. Peningkatan kristalinitas nanopartikel TiO2 meningkatkan sifat-sifat optis linier dan nonlinier lapisan tipis transparan nanokomposit TiO2−PMMA

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A systematic investigation has been conducted to understand the mechanisms responsible for the low nanocrystallinity of TiO2 nanoparticles in sol−gel derived TiO2 −PMMA nanocomposites. On the basis of investigation, it is found that the largely amorphous TiO2 state is caused by the fast development of stiff Ti−OH networks during hydrolysis and condensation, worsened by the PMMA entrapment effect. A combined method involving a pre-annealing and a post -hydrothermal treatment has been successfully devised to enhance TiO2 nanocrystallinity, while maintaining the integrity of polymer matrix. The nanostructural evolution of TiO2 in nanocomposites were carried out with x-ray diffraction, Fourier Transfor Infra-Red (FTIR) spectroscopy and High -Resolution Transmission Microscope (HRTEM). The functional properties of the TiO2−PMMA nanohybrids have been correlated to their nanostructures, where both linear and nonlinear optical responses are shown to increase with the enhancement of TiO2 nanocrystallinity."

"Nanokomposit Perak, Titanium dioksida, dan Mangan (II,III) oksida (Ag/TiO2/Mn3O4) dengan berbagai rasio molar telah disintesis menggunakan metode hidrotermal. Pengukuran difraksi sinar-X (XRD) mengkonfirmasi struktur nanokomposit Ag/TiO2/Mn3O4 yang terdiri dari struktur kubik Ag, TiO2 anatase, dan Mn3O4 tetragonal. Rasio komposisi unsur nanokomposit Ag/TiO2/Mn3O4 diselidiki dengan fluoresensi sinar-X (XRF). Efek sinergis Ag, TiO2 dan Mn3O4 dapat meningkatkan efisiensi nanokomposit sebagai fotokatalis. Peningkatan efisiensi ditunjukkan dengan melebarnya rentang absorbansi pada hasil pengukuran UV-Vis Diffuse Reflectance. Pengukuran adsorpsi-desorpsi nitrogen menunjukkan bahwa penambahan geraham TiO2 mengakibatkan penurunan luas permukaan spesifik nanokomposit Ag/TiO2/Mn3O4, sedangkan hasil sebaliknya diberikan dengan penambahan geraham Mn3O4. Pada uji fotokatalitik, hasil terbaik ditunjukkan oleh nanokomposit Ag/TiO2/Mn3O4 dengan dominasi Mn3O4 untuk radiasi UV dan cahaya tampak. Pada kondisi optimum, nanokomposit Ag/TiO2/Mn3O4 mampu mendegradasi metilen biru hingga 91% dengan penyinaran selama 2 jam. Uji scavenger mengidentifikasi lubang sebagai spesies yang berkontribusi paling besar pada proses fotokatalitik ini. Uji reusabilitas dan stabilitas pada nanokomposit Ag/TiO2/Mn3O4 menunjukkan hasil positif.

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Silver, Titanium dioxide, and Manganese (II,III) oxide (Ag/TiO2/Mn3O4) nanocomposites with various molar ratios have been synthesized using the hydrothermal method. X-ray diffraction (XRD) measurements confirmed the structure of the Ag/TiO2/Mn3O4 nanocomposite consisting of a cubic structure of Ag, TiO2 anatase, and tetragonal Mn3O4. The elemental composition ratio of Ag/TiO2/Mn3O4 nanocomposite was investigated by X-ray fluorescence (XRF). The synergistic effect of Ag, TiO2 and Mn3O4 can increase the efficiency of nanocomposites as photocatalysts. The increase in efficiency is indicated by the widening of the absorbance range on the measurement results of UV-Vis Diffuse Reflectance. The nitrogen adsorption-desorption measurements showed that the addition of TiO2 molars resulted in a decrease in the specific surface area of ​​the Ag/TiO2/Mn3O4 nanocomposite, while the opposite result was given by the addition of Mn3O4 molars. In the photocatalytic test, the best results were shown by the Ag/TiO2/Mn3O4 nanocomposite with the dominance of Mn3O4 for UV radiation and visible light. Under optimum conditions, Ag/TiO2/Mn3O4 nanocomposite was able to degrade methylene blue up to 91% with irradiation for 2 hours. The scavenger test identified pits as the species that contributed most to this photocatalytic process. Reusability and stability tests on Ag/TiO2/Mn3O4 nanocomposites showed positive results."

"Aplikasi serat alam terus berkembang di berbagai sektor industri. Serat kenaf merupakan serat alam yang digunakan dalam penelitian ini karena memiliki sifat mekanik yang cukup tinggi. Busa poliuretan (PU) banyak digunakan sebagai lapisan inti dalam konstruksi komposit sandwich untuk menghasilkan suatu material ringan. Penelitian ini bertujuan menganalisa hasil karakterisasi nanoselulosa dari serat kenaf, menganalisa pengaruh nanoselulosa / Cellulose Nanofiber (CNF) serat kenaf sebagai pengisi (filler) dalam komposit busa PU-CNF, serta merumuskan formulasi komposit busa PU-CNF yang memberikan sifat mekanik terbaik sebagai material kuat dan ringan dalam aplikasi struktural. Nanoselulosa merupakan nanomaterial alami yang dapat diekstrak dari dinding sel tanaman yang memiliki sifat-sifat menarik seperti kekuatan yang tinggi, kekakuan yang sangat baik, dan luas permukaan yang tinggi. Variasi berat CNF yang ditambahkan ke dalam busa PU adalah 0, 3, 5, 7, dan 10 wt%. Proses ekstraksi CNF dari serat kenaf dimulai dengan pre-treatment serat meliputi proses alkalisasi dengan natrium hidroksida dan proses bleaching dengan natrium hipoklorit lalu selanjutnya diberikan perlakuan mekanik dengan alat Ultra Fine Grinder untuk menghasilkan suspensi CNF. Fabrikasi komposit PU-CNF menggunakan metode in-situ polimerization. Karakterisasi CNF meliputi TEM, XRD, dan FT-IR. Hasil TEM pada CNF mengkonfirmasi dimensi berskala nano dari CNF yaitu memiliki diameter pada kisaran 40-70 nm. Hasil FT-IR yang menunjukkan tidak adanya puncak pada daerah panjang gelombang 1700–1740 cm-1 menyatakan pre-treatment pada serat kenaf berhasil mengurangi kandungan non-selulosa. Hasil XRD menunjukkan bahwa kritastalinitas CNF setelah perlakuan mekanik adalah menjadi 75,22%. Karakterisasi komposit busa PU-CNF meliputi uji tekan, uji lengkung-3-titik, dan SEM. Nilai kuat tekan optimal diperoleh pada komposit busa KFCNF3/PU dengan nilai kuat tekan dan modulus tekan optimal masing-masing adalah 284,434 kPa dan 7,32 MPa. Nilai kuat lengkung-3-titik optimal juga diperoleh pada komposit busa PU berpenguat 3wt% CNF yaitu 734,145 kPa. Komposit busa PU berpenguat 3 wt% CNF merupakan komposit terbaik yang memiliki nilai optimum dari hasil uji tekan dan uji lengkung-3-titik.

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Natural fiber applications continue to grow in various industrial sectors. Kenaf fiber is a natural fiber that was used in this study because it has high mechanical properties. Polyurethane (PU) foam is widely used as a core layer in sandwich composite construction to produce a lightweight material. The objective of this research was to analyze the results of nanocellulose characterization from kenaf fibers, to analyze the effect of nanocellulose / Cellulose Nanofiber (CNF) kenaf fiber as a filler in PU-CNF foam composites, and to formulate a PU-CNF foam composite formulation that provided the best mechanical properties as strong and lightweight materials in structural applications. Nanocellulose is a natural nanomaterial that can be extracted from plant cell walls which has attractive properties such as high strength, excellent stiffness and high surface area. The CNF weight variations in PU foam were 0, 3, 5, 7, and 10 wt%. The CNF extraction process from kenaf fiber started with fiber pre-treatment including alkalization with sodium hydroxide and bleaching with sodium hypochlorite and then mechanical treatment with an Ultra Fine Grinder to produce CNF suspension. PU-CNF composites were fabricated using in-situ polymerization method. CNF characterization included TEM, XRD, and FT-IR. TEM results on CNF confirmed that the CNF diameter was in the range of 40-70 nm. FT-IR results showed that no peaks in the 1700-1740 cm-1 wavelength region and this confirmed that pre-treatment on kenaf fibers succeeded in reducing the non-cellulose content. XRD results showed that the crystallinity of CNF after mechanical treatment was 75.22%. The PU-CNF foam composite characterization included compressive test, 3-point bending test, and SEM. The optimal compressive strength values obtained in the PU foam reinforced 3 wt% CNF composites with the optimal compressive strength and modulus values were 284,434 kPa and 7,32 MPa, respectively. The optimal 3-point bending strength value was also obtained in the PU foam reinforced 3 wt% CNF composites, which was 734.145 kPa. PU foam reinforced 3 wt% CNF composites were the best composites that have the optimum value from the results of the compressive and 3-point-bending tests."

"Material Perovskite-like layered structrure (PLS) La2Ti2O7 merupakan material feroelektrik yang sangat aplikatif dengan didasarkan pada sifat piezoelektrik, piroelektrik, dan elektro optik yang dimilikinya. Feroelektrik dikatakan unggul ketika memiliki sifat dielektrik yang tinggi yang dapat diaplikasikan untuk DRAM (Dynamic Random Access Memory) pada kapasitornya. PLS La2Ti2O7 dengan substitusi Zn2+ di situs Ti (La2Ti2- xZnxO7) dengan x = 0.0, 0.1, 0.2 berhasil disintesis menggunakan metode sol-gel yang dilanjutkan dengan proses sintering. Karakterisasi sampel telah dilakukan untuk mempelajari sifat struktur dengan data hasil XRD, SEM-EDS, UV-Vis dan sifat listrik dengan metode sprektoskopi impedansi. Hasil uji XRD menunjukkan bahwa semua sampel La(Ti,Zn)O single phase dan memiliki struktur stabil monoklinik dengan space group P21. Jari-jari atom doping Zn2+ (0.74 Ǻ) yang lebih besar dari atom Ti4+(0.61 Ǻ) menyebabkan pergeseran sudut 2θ lebih rendah sehingga parameter kisi akan lebih besar dan sebanding dengan volumenya. Hasil uji SEM menunjukkan bahwa penambahan konsentrasi Zn2+ menyebabkan grain size menurun yang konsisten dengan hasil yang diperoleh XRD yang mengkonfirmasi terjadinya penurunan cristalllite size seiring dengan kenaikan konsentrasi doping. Hasil EDX menunjukkan pada sampel murni tidak terdapat Zn di dalamnya dengan nilai persen atomic dan persen berat unsur Ti4+ menurun dan menunjukkan kenaikan pada unsur Zn2+ seiring kenaikan konsentrasi x. Hasil uji UV- Vis dengan data absorbansi diplot menggunakan metode tauc dan menghasilkan nilai energy band gap yang meningkat seiring kenaikan konsentrasi x. Hasil ini dikonfirmasi dengan hasil uji listrik yang menunjukkan nilai konstanta dielektrik yang meningkat dan konduktivitas yang meningkat seiring peningkatan konsentrasi x dikarenakan ada banyak kekosongan oksigen yang berkorelasi dengan hasil SEM.

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Perovskite-like layered structure (PLS) La2Ti2O7 is a highly applicable ferroelectric material based on its piezoelectric, pyroelectric, and electro-optic properties. Ferroelectric is said to be superior when it has high dielectric properties that can be applied to DRAM (Dynamic Random Access Memory) in the capacitor. PLS La2Ti2O7 with Zn2+ substitution at the B-site (La2Ti2-xZnxO7) with x = 0.0, 0.1, 0.2 was successfully synthesized using the sol-gel method followed by a sintering process. Sample characterization was carried out to study the structural properties using XRD, SEM-EDS, UV-Vis, and electrical properties using impedance spectroscopic methods. XRD test results showed that all samples of La(Ti,Zn)O were single phase and had a stable monoclinic structure with space group P21. The atomic radius of Zn2+ doped (0.74 ) which is larger than that of Ti4+ (0.61 ) causes a lower 2θ angular shift so that the lattice parameters (a, b, c) will be larger and proportional to the volume. The SEM test results show that the addition of Zn2+ concentration causes the grain size to decrease which is consistent with the results obtained by XRD which confirms a decrease in crystallite size along with the increase in doping concentration. The EDX results show that in the pure sample there is no Zn in it with the atomic percent and weight percent values of Ti4+ decreasing and showing an increase in Zn2+ as the concentration of x increases. The results of the UV-Vis test with absorbance data plotted using the tauc method and resulted in an energy band gap value that increased with the increase in x concentration. This result was confirmed by the electrical test results which showed an increasing dielectric constant value and an increasing conductivity with an increase in x concentration due to the presence of many oxygen vacancies which correlated with the SEM results."

"Pada penelitian ini nanokomposit Natrium Alginat-Bentonite-TiO2 telah berhasil disitesis. Hasil sintesis yang diperoleh dilakukan karakterisasi menggunakan FTIR, XRD, SEM, EDX dan TEM untuk mengetahui sifat dari nanokomposit yang diperoleh. Nanokomposit yang telah disintesis memiliki bandgap 3.01 eV dengan distribusi ukuran partikel TiO2 kurang dari 500 nm. Nanokomposit diaplikasikan untuk uji adsorpsi dan fotokatalisis dalam pengurangan limbah zat warna Methylene Blue MB . Persen degradasi yang didapat yaitu sebesar 95,01 dalam kondisi optimum pada pH 8, waktu adsorpsi 30 menit dan massa adsorben 30 mg. Isotherm adsorpsi dari proses yang terjadi mengikuti isotherm Langmuir dengan nilai R2 yaitu 0.971. Untuk proses fotokatalisis, telah dipelajari studi kinetika dimana reaksi yang berjalan mengikuti kinetika orde satu dengan nilai R2 yaitu 0.9420 dan konstanta lanju k sebesar 0.008.

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In this study, sodium alginate Bentonite TiO2 nanocomposite has been successfully synthesized in this study. The synthesis results obtained were characterized using FTIR, XRD, SEM, EDX and TEM to determine the properties of the acquired nanocomposites. The synthesized nanocomposite has a 3.01 ev bandgap with a particle size distribution of TiO2 less than 500 nm. Nanocomposites were applied for the adsorption and photocatalysis tests in the reduction of methylene blue MB dye waste. The percentage of degradation was 95,01 under optimum pH condition of 8, optimal adsorption time of 30 minutes, and the optimal adsorbent mass of 30 mg. The adsorption isotherm of the process that follows Langmuir isotherm with R2 value is 0.971. For the process of photocatalysis, kinetic studies have been studied in which the reaction follows the first order kinetics with the R2 value of 0.9420 and the rate constant k of 0.008."

"Nanokomposit CeO2/SnO2 telah disintesis melalui proses hidrotermal dan pola difraksi XRD nanokomposit yang dihasilkan masih memuat impuritas selain SnO2 dan CeO2, dan belum menunjukkan terjadinya kristalisasi. Weight loss di 250oC dan 600 oC yang berhubungan dengan hilangnya molekul air dan terjadinya kristalisasi pada nanokomposit diketahui dari hasil pengukuran TGA (Thermal Gravimetric Analysis). Proses kalsinasi terhadap nanokomposit untuk tiga variasi suhu, yaitu 500 oC, 600 oC, dan 700 oC selama 2 jam, menghasilkan pola difrasi XRD (X-Ray Diffraction) dengan hilangnya impuritas dan kristalisasi yang baik. Indentifikasi nanokomposit menggunakan XRF (X-Ray Fluoroscene) menunjukkan elemen Sn dan Ce tetap hadir setelah proses kalsinasi. Kehadiran ikatan oksigen dengan Ce (~460 cm-1) dan Sn (~630 cm-1) diketahui dari pengukuran Raman. Perhitungan celah pita optik nanokomposit dari hasil reflektansi UV-VIS DRS (UV-Visible Diffuse Reflectance Spectroscopy) berada diantara CeO2 dan SnO2, dan tidak menunjukkan perubahan yang besar dengan perlakuan kalsinasi. Sifat permukaan nanokomposit CeO2/SnO2 dengan dan tanpa kalsinasi menunjukkan macropores yang berbentuk slit-shaped pores. Nanokomposit CeO2/SnO2 yang dikalsinasi pada suhu 600 oC menunjukkan kinerja fotokatalitik terbaik untuk cahaya tampak, dengan dosis 0.2 g/L, dan pH 13 dalam mendegradasi MB (Methylene Blue). Bertambahnya waktu rekombinasi elektron-hole dengan penggabungan CeO2 dan SnO2 yang berbeda celah pita optik, yang berkontribusi dalam degradasi maksimum MB, dengan hole sebagai species yang berperan aktif untuk paparan pada cahaya tampak.

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The CeO2/SnO2 nanocomposites have been synthesized through the hydrothermal process and the nanocomposites XRD diffraction pattern produced still contains impurity other than SnO2 and CeO2, and have not shown crystallization. Weight loss at 250 oC and 600 oC which is related to the loss of water molecules and the occurrence of crystallization in nanocomposites is known from the results of TGA (Thermal Gravimetric Analysis) measurements. The process of calcination of nanocomposites for three variations of temperature, namely 500 oC, 600 oC, and 700 oC for 2 hours, produces XRD (X-Ray Diffraction) diffraction patterns with impurity loss and good crystallization. Identification of nanocomposites using XRF (X-Ray Fluoroscene) shows the elements Sn and Ce remain present after the calcination process. The presence of oxygen bonds with Ce (~ 460 cm-1) and Sn (~ 630 cm-1) is known from Raman measurements. Calculation of nanocomposite optical band gap from the results of UV-VIS DRS (UV-Visible Diffuse Reflectance Spectroscopy) is between CeO2 and SnO2, and does not show a large change with calcination treatment. Surface properties of CeO2 / SnO2 nanocomposites with and without calcination showed macropores in the form of slit-shaped pores. CeO2 / SnO2 nanocomposites calcined at 600 oC showed the best photocatalytic performance for visible light, at a dose of 0.2 g / L, and pH 13 in degrading MB (Methylene Blue). Increased electron-hole recombination time by combining CeO2 and SnO2 with different optical band gaps, which contributes to the maximum degradation of MB, with holes as species that play an active role for exposure to visible light.

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"Epoxy-organo clay nanocomposite materials are constructed from a polymer as a matrix and an organoclay as filler. Epoxy-organo clay nanocomposites have been synthesized using various curing agents. The aim of this research was to study the influence of the curing agent and the organoclay contents to the structure and mechanical properties of nanocomposites materials. Epoxy-organo clay nanocomposites were synthesized using cycloaliphatic amine as a curing agent and a montmorillonite organoclay (MMT) as filler through an in situ polymerization method. XRD and TEM technique provide more detail information to understand the structure that relates to the mechanical properties of the materials. Tensile test, compressive test and hardness test were conducted based on ASTM and JIS standards. The fracture surfaces after tensile tests were analyzed using SEM. The nanocomposite properties were compared to glass-fiber composites which were synthesized using wet-laminating method.It was found that the curing agent is influence to the nanocomposites structure which was shown by the change of d-spacing before and after the addition of the agent curing. XRD and TEM techniques showed that both intercalated and exfoliated structure have been formed. TEM image also exhibited that the number of intercalated structure was higher when the organoclay content was higher. It can be said that TEM techniques provides a better understanding of the nanocomposites structure and the number intercalated structure increase as the organoclay increases.The organoclay contain also influences to mechanical properties of nanocomposite materials. The addition of 10.5 wt.% organoclay improved the tensile modulus by 185% but and decreased tensile strength by 186% and 49%, and these values are lower of 36% and 90% compared to glass fiber composites. These decreases in the strength may be attributed to the fact that agglomerate and void was formed. From compression test, the addition of 3.1 wt.% organoclay demonstrated a 102% increase in compression strength and a 93% increase in load maximum compare to epoxy resin. But, that compression strength value lower of 11% compared to glass fiber composites. For the maximum load, the addition of 3.1 wt.% organoclay improved 246% compared to glass fiber composites. Addition of 7.3 wt.% organoclay demonstrated an increase of modulus of the epoxy resin by 93% and 2% compare to glass fiber composites. Meanwhile, the addition of 10.5% organoclay cause decreasing in yield compression up to 31%, but this higher value equal to 406% from is glass fiber composites. While that, result of hardness test do not show the make-up of value meaning in comparison with epoxy matrix."

"Nanokomposit selulosa asetat telah disintesis dengan menggunakan nanofiller organoclay yang dimodifikasi dengan TiO2. Bentonit Tapanuli yang sebelumnya dikenai proses purifikasi dan penyeragaman kation dimodifikasi dengan ditambahkan TiO2 dengan persen berat yakni 0%, 1%, 3%, 5%, dan 10% terhadap total komposit. Analisis FTIR menunjukkan interkalasi surfaktan telah berhasil dilakukan dengan adanya pita serapan baru dari HDTMABr pada 2636 cm-1 dan 2569 cm-1. Pembuatan nanokomposit dilakukan dengan menggunakan aseton sebagai pelarut dan metode solvent casting sebagai teknik untuk pembuatan film nanokomposit. Aplikasi nanokomposit berupa uji fotodegradasi pada penyinaran sinar matahari langsung, lampu UV, dan tanpa penyinaran selama tiga puluh hari. Diketahui, semakin banyak TiO2 semakin besar komposit yang terdegradasi. Persen penurunan berat hasil uji aplikasi pada penyinaran lampu UV sebesar 4,02% , 13,45%, 18,66%, 22,35%, 27,86%, pada penyinaran langsung sebesar 2,15%, 8,49%, 13,85%, 14,70%, 15,02%, dan pada tanpa penyinaran sebesar 0,16%, 0,16%, 0,18%, 0,20%, 0,26%. Modifikasi nanokomposit dengan penambahan TiO2 sebagai agen fotokatalitik menambahkan sifat baru berupa kemampuan fotodegradas.

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Nanocomposite cellulose acetate has been synthesized using organoclay nanofiller modified with TiO2. Tapanuli Bentonite were previously subjected to processes of purification and unification of cations then modified with TiO2 that was added as much 0%, 1%, 3%, 5%, 10% weight of the total composite. FTIR analysis showed intercalation with surfactant was successfully carried out in the presence of HDTMABr, indicated by new absorption band at 2636 cm-1 and 2569 cm-1. Fabrication of nanocomposite film was carried out using acetone as solvent and through solvent casting method.

Nanocomposite application in photodegradation test was carried out under direct sunlight radiation, UV light, and without irradiation for thirty days. It's found that the greater the presence amount of TiO2 in the composites, the more weight loss occured due to photodegredation. Percent weight loss in the UV light irradiation are 4,02% , 13,45%, 18,66%, 22,35%, 27,86%, while under direct irradiation, the weight loss was 2,15%, 8,49%, 13,85%, 14,70%, 15,02%, and while without light irradiation was 0,16%, 0,16%, 0,18%, 0,20%, 0,26%. Modification of nanocomposite with the addition of photocatalytic TiO2 as photocatalytic agent has shown the ability of self photodegradation of nanocomposit."