Browsing by Author "Hachaichi, Amina"

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    Development and characterization of bio-nanocomposite mixture reinforced by natural reinforcement (elaboration and characterization)
    (Université M'Hamed Bougara : Faculté de Technologie, 2022) Hachaichi, Amina; Kouini, Benalia(Directeur de thèse)
    Date palm fiber (Phoenix dactylifera L.) is a natural fiber rich in lignocellulosic components. Its high cellulose content lends them to the extraction of tiny particles like microcrystalline cellulose and nanocrystalline cellulose. These cellulose-derived small size particles can be used as an alternative biomaterial in wide fields of application such as automobile production, biomedical, food packaging and membrane applications, that's due to their renewability and sustainability. In the present work, microcrystalline cellulose and nanocrystalline cellulose were isolated and characterized, the extraction of microcrystalline cellulose from bunch branches of Algerian date palm trees was passed via serial chemical treatments, including alkaline, bleaching and acid hydrolysis process. Also, different hydrolysis time of 60 min and 90 min were used to isolate the nanocrystalline cellulose from microcrystalline cellulose. The implemented characterization shows that altered and irregular shaped morphology of microfibrils with slightly rougher surface was observed for microcrystalline with greater thermal stability, that revealed the effectiveness in removing substantial amorphous components of lignin and hemicellulose from date palm fibers. In addition, the features of both nanoparticle samples are very interesting with their elongated shape of nanostructures that imparted them with high aspect ratio (diameter/length), Many studies suggested that it can give a strong stiffness to the nanoparticle network and thus achieve high reinforcing effect in polymer matrices. The degree of crystallinity has been improving from 68% to 71% with prolonged hydrolysis time. At later stage, a selective nanocrystalline cellulose sample of 90 min was used as reinforcing material to develop polylactic acid bionanocomposite. Bionanocomposite of PLA reinforced with different loadings of NCC were prepared via casting solution method by using chloroform solvent, as examined from characterization, nanocrystalline cellulose filled polyacid lactic showed organized and high porous structure as beehive, also, a great thermal stability and mechanical strength were observed. Therefore, the experimental work mentioned can be used in future to produce microcrystalline cellulose, nanocrystalline cellulose from date palm wastes, and can be used to produce nanocrystalline cellulose reinforced polylactic acid bionanocomposite
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    Experimental and numerical study of the effect of the presence of a geometric discontinuity of variable shape on the tensile strength of an epoxy polymer
    (Sciendo, 2023) Saada, Khalissa; Amroune, Salah; Zaoui, Moussa; Houari, Amin; Madani, Kouider; Hachaichi, Amina
    The presence of geometric discontinuity in a material reduces considerably its resistance to mechanical stresses, therefore reducing the service life of materials. The analysis of structural behaviour in the presence of geometric discontinuities is important to ensure the proper use, especially if it is regarding a material of weak mechanical properties such as a polymer. The objective of the present work is to analyse the effect of the notch presence of variable geometric shapes on the tensile strength of epoxy-type polymer specimens. A series of tensile tests were carried out on standardised specimens, taking into account the presence or absence of a notch. Each series of tests contains five specimens. Two notch shapes were considered: circular (hole) and elliptical. The experimental results in terms of stress-strain clearly show that the presence of notches reduces considerably the resistance of the material, where the maximum stress for the undamaged specimen was 41.22 MPa and the lowest stress for the elliptical-notched specimen was 11.21 MPa. A numerical analysis by the extended finite element method (XFEM) was undertaken on the same geometric models; in addition, the results in stress-strain form were validated with the experimental results. A remarkable improvement was obtained (generally an error within 0.06%) for strain, maximum stress, Young's modulus and elongation values. An exponential decrease was noted in the stress, strain, and Young's modulus in the presence of a notch in the material
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    Extraction and characterization of microcrystalline cellulose from date palm fibers using successive chemical treatments
    (Springer, 2021) Hachaichi, Amina; Kouini, Benalia; Kian, Lau Kia; Asim, Mohammad; Jawaid, Mohammad
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    Nanocrystalline cellulose from microcrystalline cellulose of date palm fibers as a promising candidate for bio-nanocomposites : isolation and characterization
    (MDPI, 2021) Hachaichi, Amina; Kouini, Benalia; Kian, Lau Kia; Asim, Mohammad; Fouad, Hassan; Jawaid, Mohammad; Sain, Mohini
    Date palm fiber (Phoenix dactylifera L.) is a natural biopolymer rich in lignocellulosic components. Its high cellulose content lends them to the extraction of tiny particles like microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC). These cellulose-derived small size particles can be used as an alternative biomaterial in wide fields of application due to their renewability and sustainability. In the present work, NCC (A) and NCC (B) were isolated from date palm MCC at 60 min and 90 min hydrolysis times, respectively. The isolated NCC product was subjected to characterization to study their properties differences. With the hydrolysis treatment, the yields of produced NCC could be attained at between 22% and 25%. The infrared-ray functional analysis also revealed the isolated NCC possessed a highly exposed cellulose compartment with minimized lignoresidues of lignin and hemicellulose. From morphology evaluation, the nanoparticles’ size was decreased gradually from NCC (A) (7.51 nm width, 139.91 nm length) to NCC (B) (4.34 nm width, 111.51 nm length) as a result of fragmentation into cellulose fibrils. The crystallinity index was found increasing from NCC (A) to NCC (B). With 90 min hydrolysis time, NCC (B) showed the highest crystallinity index of 71% due to its great cellulose rigidity. For thermal analysis, NCC (B) also exhibited stable heat resistance, in associating with its highly crystalline cellulose structure. In conclusion, the NCC isolated from date palm MCC would be a promising biomaterial for various applications such as biomedical and food packaging applications