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All Journal Teknomekanik Journal of Engineering and Technological Sciences
Rahman, M. Mahbubur
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Aerospace Engineering Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Electrical & Electronics Engineering Mechanical Engineering

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The conversion of nata de coco bacterial cellulose into cellulose nanofibers using high shear mixer with eco-friendly fluid dynamics method Amri, Amun; Putri, Diana Eka; Febryza, Dhina; Voadi, Salsabilla Diva; Utami, Syelvia Putri; Miran, Hussein A.; Rahman, M. Mahbubur
Teknomekanik Vol. 7 No. 2 (2024): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/teknomekanik.v7i2.32972

Abstract

Nanocellulose is widely applied in various fields due to its superior characteristics. Several methods have been developed to synthesize it, but they still have limitedness as being non-eco-friendly and inefficient use. Therefore, the synthesis of nanocellulose from sustainable sources is being developed using a simple and eco-friendly method. This study successfully produced a low viscosity gel suspension of cellulose nanofibers (CNF) from bacterial cellulose (BC) derived from Nata de Coco using a high shear mixer (HSM). The mixture of BC and water in a 1:1 ratio was processed with various rotational speeds and times in the HSM. The suspension result was characterized using an Ostwald viscometer, UV-vis spectrophotometer, lux meter, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), particle size analyzer (PSA), and x-ray diffraction (XRD). Based on the characterization, it was confirmed that higher rotational speeds and extended processing times reduced the suspension viscosity and increased light transmittance, indicating a reduction in BC size to the submicron/nanometer scale. The best light transmittance was achieved with the HSM at 4500 rpm for 180 min, resulting in a viscosity drop from 232.67 mPa.s to 1.45 mPa.s. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis showed that the CNF retained its fibrous structure with nanometer-scale widths and high porosity without significant changes in crystallinity.
Facile and Environmentally Friendly Synthesis of Low-defect Few-Layers Graphene (FLG) Using Combined Shear Exfoliation Methods Amri, Amun; Wulandari, Revika; Fabryza, Dhina; Sunarno, Sunarno; Heltina, Desi; Bahri, Syaiful; Sarma, Deki; Miran, Hussein A.; Rahman, M. Mahbubur; Altarawneh, Mohammednoor; Jiang, Zhong Tao
Journal of Engineering and Technological Sciences Vol. 57 No. 5 (2025): Vol. 57 No. 5 (2025): October
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2025.57.5.4

Abstract

This study presents an environmentally friendly and scalable method for synthesizing high-quality few-layer graphene (FLG) through a combination of turbulence-assisted shear exfoliation (TASE) and high shear exfoliation (HSE) techniques. By systematically varying the high-shear mixer (HSM) speed (3000–5000 rpm) and processing time (1–3 hours), we precisely controlled key material attributes, including the number of graphene layers, crystallinity, lateral size, and defect density. Optimal conditions (5000 rpm, 3 hours) resulted in FLG with ~2–3 layers, confirmed by a symmetric 2D peak with a full-width at half-maximum (FWHM) of ~35 cm⁻¹ and a high I2D/IG ratio (~0.6), indicating excellent structural integrity. The ID/IG ratio (~0.1) further verified the presence of minimal defects, predominantly edge vacancies rather than oxidative disruptions. Raman imaging revealed a dominance of zigzag edge chirality, while TEM and PSA analyses demonstrated control over lateral size (~396.5 nm) and particle uniformity. The application of household dishwashing liquid as a green surfactant innovatively enabled selective and pure exfoliation. This work highlights how precise modulation of shear parameters can directly influence graphene quality, paving the way for sustainable large-scale production of low-defect FLG.
Co-Authors Altarawneh, Mohammednoor Amun Amri Desi Heltina Fabryza, Dhina Febryza, Dhina Jiang, Zhong Tao Miran, Hussein A. Putri, Diana Eka Sarma, Deki Sunarno Sunarno SYAIFUL BAHRI Syelvia Putri Utami Voadi, Salsabilla Diva Wulandari, Revika