scholarly journals EFFECT OF CHEMICAL TREATMENT WITH OXIDANTS ON THE MECHANICAL PROPERTIES OF LUFFA SPONGE/UNSATURATED POLYESTER COMPOSITES

2021 ◽  
Vol 55 (1-2) ◽  
pp. 159-167
Author(s):  
NOURI LAIB ◽  
AZZEDINE BENYAHIA ◽  
ALI REDJEM ◽  
NADIR DEGHFEL

This study investigates a synergistic treatment comprising alkali, permanganate, dichromate, silane and bleaching pretreatment on Luffa sponge (LF) fibers intended to be used as reinforcement in an unsaturated polyester (UP) matrix to improve the mechanical properties of Luffa sponge fibers reinforced unsaturated polyester composites. Treatment effects by NaOH (5 wt%), K2Cr2O7 (0.2 wt%), KMnO4 (0.0125 wt%), NaClO (13°) and silane (0.5 wt%) on the performance of the prepared composites were evaluated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), SEM and mechanical tests (flexural strength and modulus). The results of the analyses indicated that composites reinforced with treated fibers have higher flexural strength than composites reinforced with untreated fibers.

2021 ◽  
Vol 10 (2) ◽  
pp. 129-138
Author(s):  
. Fatma ◽  
. Desnelli ◽  
Fahma Riyanti ◽  
Mustafa Kamal ◽  
Muhammad Ramdan Abdul Mannan ◽  
...  

Eggshell is a solid waste that is available in abundance but is being left unused. Eggshell containing calcium in a high amount. Calcium can be used as a precursor for hydroxyapatite (HAp). Modification of HAp with SiO2 is expected to improve its low mechanical properties for biomedical applications. In this study, HAp is synthesized from the eggshell. Then, it was modified by adding SiO2 utilizing the coprecipitation method with concentrations of 10%, 20%, 30%, and 40%, respectively. The HAp and HAp/SiO2 were characterized using; X-ray diffraction and Fourier transform infrared spectroscopy. The analysis HAp and HAp/SiO2 were density, compressive strength, and hardness. The best mechanical properties of HAp/SiO2 were characterized using SEM-EDS. The HAp were prepared successfully with a ratio of Ca/P was 1.673, close to the theoretical 1.67. The addition of SiO2 caused a decrease in crystallite size and density but increased compressive strength and hardness. The best mechanical properties of HAp/SiO2 were obtained with SiO2 of 30% and 40% with similar values.


BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8631-8647
Author(s):  
Dongliang Zhao ◽  
Haibiao Yu ◽  
Xiuchun Bao ◽  
Jinwei Liu ◽  
Haoqiang Yuan ◽  
...  

Poplar and pine wood were extracted with water, 1% NaOH (wt%) solution, and benzene:ethanol solution (V1 : V2, 2 : 1) to investigate the governing factors and mechanism by which extractives affect wood structure and mechanical properties. The structure, pore distribution, crystal structure, and mechanical properties of samples were analyzed by Fourier transform infrared spectroscopy (FTIR), adsorption of N2 gas, X-ray diffraction (XRD), and mechanical testing, respectively. The results demonstrated that cellulose, hemicellulose, and lignin were degraded to some extent in the course of the dissolution of the extractives. This degradation had a great influence on the structure and quantity of pores. The extraction treatment did not change the crystallization type of the wood, but it increased the crystallinity of the wood, and the length and width of the crystallization area changed. In addition, the mechanical properties of wood were changed when the content of the extractives was reduced.


Author(s):  
T Narendiranath Babu ◽  
E Rajkumar ◽  
George George ◽  
Jefferson Jobai ◽  
D Rama Prabha

The focus of our study was to evaluate and compare the mechanical properties, namely tensile and bending strength of natural fibre composites. Natural fibre composites are composites consisting of fibres made from plants and animals. The natural fibre chosen for this study was Tampico fibre. The moulds were made according to ASTM D638 and D790 standards for both tensile and bending specimens. The first set of composites were arranged in three different orientations namely uniaxial, biaxial and criss-cross. The moulds were prepared using the hand-lay-up technique. These fibres were combined with Epoxy LY-556 pitch and Hardener HY-951 in a specific proportion to make the composite. The second set of composites included an additional variant in the form of biaxial E-glass fibres of 270GSM density, to compare the differences in the mechanical strength. The X-ray diffraction and Fourier-transform infrared spectroscopy were performed on the specimen to understand the lattice structure and prevalent bonds formed within the composites.


2006 ◽  
Vol 530-531 ◽  
pp. 709-714 ◽  
Author(s):  
Edcleide Maria Araújo ◽  
Amanda D. de Oliveira ◽  
Renata Barbosa ◽  
Tomás Jefférson Alves de Mélo

In this work, polyethylene/montmorillonite clay nanocomposites were produced by melt intercalation. The clays were treated with quaternary ammonium salts and then treated and untreated clays were introduced in polyethylene. The clays were characterized by X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). The nanocomposites were characterized by mechanical and flammability properties. The results showed that the mechanical properties were improved by introduction of organoclay in polyethylene matrix. By adding only 3wt% montmorillonite, the burning rate of the nanocomposites was reduced by 17% in relation to PE matrix.


2012 ◽  
Vol 476-478 ◽  
pp. 1031-1035
Author(s):  
Wei Min Liu ◽  
Xing Ai ◽  
Jun Zhao ◽  
Yong Hui Zhou

Al2O3-TiC-ZrO2ceramic composites (ATZ) were fabricated by hot-pressed sintering. The phases and microstructure of the composites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relative density and mechanical properties (flexural strength, fracture toughness and Vicker’s hardness) of the composites were tested. The results show that the microstructure of the composites was the gray core-white rim. With the increase of sintering temperature, the relative density and mechanical properties of the composites increased first and then decreased. The composite sintered at 1705°C has the highest synthetical properties, and its relative density, flexural strength, fracture toughness and Vickers hardness are 98.3%,970MPa,6.0 MPa•m1/2and 20.5GPa, respectively.


2012 ◽  
Vol 476-478 ◽  
pp. 2059-2062
Author(s):  
Chen Wang ◽  
Ya Dong Li ◽  
Gu Qiao Ding

Tributyl borate was first adopted for the introduction of boron in the preparation of bioactive borosilicate xerogel by sol-gel method. The xerogel reacted continuously in 0.25M K2HPO4 solution with a starting pH value of 7.0 at 37 °C for 1day. The structural, morphologies and compositional changes resulting from the conversion were characterized using X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. The results indicated that speed of formation of HA was cut way back on the time with the addition of boron and the induction period for the HA nucleation on the surface of the borosilicate xerogel was short than 1 days. The conversion mechanism of the borosilicate xerogels to hydroxyapaptite was also discussed.


2019 ◽  
Vol 29 (2) ◽  
Author(s):  
Mutia Dewi Yuniati ◽  
Feronika Cinthya Mawarni Putri Wawuru ◽  
Anggoro Tri Mursito ◽  
Iwan Setiawan ◽  
Lediyantje Lintjewas

Magnesite (MgCO3) is the main source for production of magnesium and its compound. In Indonesia, magnesite is quite rare and can be only found in limited amount in Padamarang Island, Southeast Sulawesi Provence. Thus the properties of magnesite and the reactivity degree of the obtained product are of technological importance. The aim of this work was to analyze the characteristics of Padamarang magnesite under calcination and hydrothermal treatment processes. The processes were carried out at various temperatures with range of 150-900°C for 30 minutes. The solids were characterized with respect to their chemical and physical properties by using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). SEM image indicates that magnesite was formed from thin and flat hexagon sheets. The FTIR and XRD analysis disclose that MgO formed at temperature above 300°C, where as the magnesite sample also lost its mass around 50%. These results demonstrate that Padamarang magnesite decomposes to magnesium oxide and carbon dioxide at high temperature.Magnesit (MgCO3) merupakan sumber utama untuk produksi magnesium dan senyawa-senyawanya. Di Indonesia, magnesit cukup jarang dan hanya dapat ditemukan dalam jumlah yang terbatas di Pulau Padamarang, Propinsi Sulawesi Tenggara. Oleh karena itu sifat magnesit dan derajat reaktivitas dari produk-produk magnesit penting untuk diketahui. Penelitian ini bertujuan untuk menganalisis karakteristik magnesit Padamarang dengan perlakuan kalsinasi dan hidrothermal.  Proses dilakukan pada temperatur yang bervariasi dari 150-900°C selama 30 menit. Sifat kimia dan fisika dari magnesit dikarakterisasi dengan menggunakan scanning electron microscopy dengan energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FTIR), dan X-ray diffraction (XRD). Gambar dari analisis SEM menunjukkan bahwa magnesit terbentuk dari lembaran-lembaran heksagonal yang tipis dan datar. Hasil analisis dengan FTIR dan XRD menunjukkan bahwa MgO terbentuk pada temperatur diatas 300°C, dimana sampel magnesit juga kehilangan massanya sekitar 50% pada suhu tersebut. Hal ini menunjukkan bahwa Magnesit Padamarang terdekomposisi menjadi magnesium oksida dan karbon dioksida pada temperatur tinggi.


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