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All Journal Jurnal Rekayasa Material, Manufaktur & Energi Indonesian Journal of Chemical Studies (Indones. J. Chem. Stud.) Sorption Studies
Nareswari, Vania Agatha
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Aerospace Engineering Chemical Engineering, Chemistry & Bioengineering Chemistry Control & Systems Engineering Electrical & Electronics Engineering Energy Engineering Materials Science & Nanotechnology

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Reaction Mechanism in Standardized α-Cellulose Content Test: Study from Boehmeria nivea Fiber Rahmawati, Fani; Basuki, Rahmat; Fahri, Mirad; Apriliyanto, Yusuf Bramastya; Kurniadi, Tedi; Nareswari, Vania Agatha; Sandri, Azzahra; Istiqomah, Tiara
Indonesian Journal of Chemical Studies Vol. 3 No. 1 (2024): Indones. J. Chem. Stud., June 2024
Publisher : Indonesian Scholar Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55749/ijcs.v3i1.45

Abstract

In defense industry, α-cellulose is the main component of nitrocellulose propellant. However, a detailed description of the reaction mechanism of each treatment step in SNI 0444-2009 is still very scarce. This study addresses this gap by presenting the reaction mechanisms of each treatment and the symbols used in the SNI 0444-2009 procedure. The separation of lignin from α-cellulose occurred by breaking the C‒O bond linking them. This bond was broken by the ‒OH group of NaOH via a hydrolysis reaction. The reaction was initiated with the elimination of a hydrogen atom from the lignin structure by the hydroxyl ion (‒OH), and the C‒O bond was broken by a hydrolysis reaction. The breaking of this bond was indicated by the disappearance of the IR peaks at wavenumbers 1049 and 1190 cm–1 in the filtrate after extraction. The SNI 0444-2009 method for the α-cellulose content test was carried out by a redox back titration of Cr(VI) with Fe(II) from ferrous ammonium sulfate. This titration was conducted to calculate the amount of Cr(VI) ions in potassium dichromate or Cr(VI) that did not react with lignin or beta cellulose in the filtrate. Understanding the contribution and reaction mechanisms of each compound involved in the SNI 0444-2009 procedure contributed to obtaining accurate data on α-cellulose content. In this study, the calculated α-cellulose content of the flax fiber was 96.75%. Furthermore, the detailed mechanism of the redox reaction was discussed in detail in this paper.
Sintesis BaM/PAni Doping Cu Optimasi Sifat Radar Absorbing Material Pada Aplikasi Pelapisan Alpalhankam Aritonang, Sovian; Xaviera, Allodya Nadra; Devina, Ardelia; Br Panjaitan, Thesalonika; Nareswari, Vania Agatha
Rekayasa Material, Manufaktur dan Energi Vol 7, No 1: Januari 2024
Publisher : Fakultas Teknik UMSU

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30596/rmme.v7i1.17317

Abstract

Defense technology known as stealth technology aims to reduce the response of electromagnetic waves emitted by radar so that the position or location of an object is not detected. Barium Hexaferite has properties as a Radar Absorbing Material (RAM). Research on radar absorbing matrial from barium hexaferite already exists, but those using cu doping do not yet exist. In order to increase the effectiveness of its absorption, Barium Hexaferite is doped with Cu metal synthesized by coprecipitation method. Aniline polymerization was carried out with BaM to form BaM/PAni composite. Characterization of composite synthesis samples and coating results were carried out by SEM, FTIR, LCR-meter, and VNA to identify chemical bonds, electrical conductivity properties, microstructure, and reflection loss properties of RAM composite samples. Based on the results of previous research, the optimal absorption of multilayer coatings on steel with a reflection loss of -49.028 dB was obtained with an absorption frequency of 8.2 GHz. The addition of Cu doping is expected to improve the material's ability to absorb radar waves and reduce object reflections.
Radar Absorber Composite Graphene Oxide/Magnetite/Zinc Oxide in Polypyrole Matrix Xaviera, Allodya Nadra; Nareswari, Vania Agatha; Ananda, Dea Dwi; Azzahra, Hazzha; Tarigan, Thessa Ocatvia Joyetta; Yulita, Tiara Rizki; Sasongko, Nugroho Adi; Basuki, Rahmat
Sorption Studies Vol. 1 No. 1 (2025): Sorption Studies, Vol. 1 No. 1 June 2025
Publisher : Indonesian Scholar Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55749/ss.v1i1.80

Abstract

The development of stealth technology in modern defense systems demands superior radar absorbing material (RAM) innovation. This study aims to synthesize and characterize Fe₃O₄/ZnO modified carbon-based RAM composites in a polypyrrole (PPy) matrix using graphite oxide (GiO). The composites were synthesized via a modified Hummer method as well as a one-pot technique, and characterized using FTIR, XRD, SEM-EDX, and VNA. The FTIR characterization results showed that the C=C peak decreased in intensity after the oxidation process, indicating the breaking of the aromatic double bond and the formation of new functional groups such as C–O and C=O. This change was detected in both pGiO and kGiO samples. XRD data showed a shift in the main peaks to 2θ = 11.25° and 42.20° for pGiO and 2θ = 11.56° and 42.40° for GiO-k, respectively. This shift indicates the formation of a more amorphous graphite oxide structure compared to the original graphite.The results show that GiO/Fe₃O₄/ZnO has the highest reflection loss value of -9.20 dB at 10.91 GHz (GiO-p/Fe₃O₄/ZnO 66%-PPy) with an absorption value of 88.03% and rGO/Fe₃O₄/ZnO/PPy the highest RL value reached -7.51 dB at 11.57 GHz (rGO-k/Fe₃O₄/ZnO 66%-PPy) with an absorption value of 82.21%. This research proves that Fe3O4/ZnO modified carbon-based composites in a polypyrrole matrix have high potential as an efficient radar absorbing material and can support the needs of domestic defense technology.
Co-Authors Ananda, Dea Dwi Aritonang, Sovian Azzahra, Hazzha Br Panjaitan, Thesalonika Devina, Ardelia Fahri, Mirad Istiqomah, Tiara Kurniadi, Tedi Nugroho Sasongko Jati, Nugroho Sasongko Rahmat Basuki Rahmawati, Fani Sandri, Azzahra Tarigan, Thessa Ocatvia Joyetta Xaviera, Allodya Nadra Yulita, Tiara Rizki Yusuf Bramastya Apriliyanto