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.
In this work, the wear behavior of the mechanical coupling between the biomedical polymer ultrahigh molecular weight polyethylene (UHMWPE) and the titanium-aluminum-vanadium alloy pin (Ti4Al6V) manufactured by electron beam melting (EBM) is investigated. Pure and oxidized graphite fillers is added to the UHMWPE matrix to boost the wear resistance. The tribological test is performed in dry and under the action of various lubricating media (distilled water [DW], simulated synovial fluid [SSF], and natural bovine serum [NBS]) in order to investigate their effects on wearing. The physical-mechanical characterization results show a progressive increase in wear resistance of more than 60% in the nanocomposite (UHMWPE/GO) with the addition of paraffin oil (PO) compared to the UHMWPE and higher under NBS lubricant (more than 80%). The observed wear action is reduced in the order Dry > DW > SSF ≥ NBS, thereby lowering the debris production.
Water-soluble polymers are becoming increasingly important in various applications, such as stabilizer fluids and drilling muds. These materials are used as viscosifiers and filtration control agents, flocculants, and deflocculants due to their superior properties in increasing viscosity and gelling ability in the presence of crosslinkers. In general, studying the rheological behavior of drilling fluids is of paramount importance to ensure successful well drilling operations. Partially hydrolyzed polyacrylamide is one of the polymers widely used in water-based muds. The main objective of this study is to optimize the rheological properties of drilling muds through a characterization study of various parameters, including rheological behavior, viscosity, temperature (23 °C, 40 °C, and 60 °C), salinity using KCl and NaCl contents, aging, pH, solubility, and structural analysis using infrared of partially hydrolyzed polyacrylamide. The study aims to demonstrate the importance of using polymers in drilling muds. The findings revealed that a rate of 3% of HPAM gave better rheological behavior, the influence of KCl (1.5%, 3%, and 4.5%) was greater than that of NaCl (1.5%, 3%, and 4.5%) on polymers, and the aging test showed that the different formulations are stable and maintain their behavior up to 110 °C. The solubility test results confirmed the maximum amount absorbed by polyacrylamide ([CHPAM] = 66.42 g/L) in order to avoid aggregation, gelification, and enhance the drilling mud by utilizing the prescribed contents.
The addition of treated nanoclay as the reinforcement agent modifies the melt behavior of PP/PA66 nanocomposites, but also profoundly decreases the burning rate of reinforced formulations. To modify the flammability of PP/PA66 nanocomposites, various amounts (0-6 wt%) of treated nanoclay were added to improve the fire performance of PP/PA66 nanocomposites. Horizontal flame test according UL94 was used to evaluate the fire performance of the reinforced formulations, and the results proved that the addition of more than 2 wt% treated nanoclay lead the improvements in flame retardancy through the reduced burning rate. The melt behavior of PP/PA66/Nanoclay nanocomposites was also investigated. It is proposed that, in the presence of clay, the combustion surface changed to a compact carbonaceous-silicate structure. When the clay content was 4-6 wt%, the layered silicates became enriched on part of the surface and formed an island-like structure; the islands displayed a loose cinder structure with much higher silicon content, in contrast to a surface with low silicon content in the surrounding polymers substrate. As the clay content continued to increase, the char covered most of the combustion surface and more clay accumulated on the burning surface. In addition, the clay particles promoted the formation of the carbonaceous-silicate structure. The melt behavior of the PP/PA66 nanocomposites was affected with increasing addition of clay. J.
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