62 research outputs found

    EFFECT OF AGING ON THE MICROSTRUCTURES AND MECHANICAL PROPERTIES OF C102 COPPER ALLOY

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    Aging of copper alloy was studied at different temperature and times. Tensile test and metallurgical investigation were carried out to study the effect on mechanical properties and the microstructures of copper alloy. It was observed that peak strength was obtained by specimen aged for 4 hours at 450 oC, with yield strength of 542.38 MPa and ultimate tensile strength of 559.69 MPa. Peak strength was achieved with an increased strain field in the structure produced by coherent precipitates. The finer grain structure was observed in this stage which led to strain hardening. Lowest strength was recorded on specimen aged for 8 hours at 450 oC, with yield strength of 441.66 MPa and ultimate tensile strength of 452.24 MPa. The reduction of strength was the effect of overaging, which was due to coarsening of grain structure and elimination of precipitation coherency

    Thermal, mechanical, and physical properties of seaweed/sugar palm fibre reinforced thermoplastic sugar palm Starch/Agar hybrid composites

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    The aim of this research is to investigate the effect of sugar palm fibre (SPF) on the mechanical, thermal and physical properties of seaweed/thermoplastic sugar palm starch agar (TPSA) composites. Hybridized seaweed/SPF filler at weight ratio of 25:75, 50:50 and 75:25 were prepared using TPSA as a matrix. Mechanical, thermal and physical properties of hybrid composites were carried out. Obtained results indi- cated that hybrid composites display improved tensile and flexural properties accompanied with lower impact resistance. The highest tensile (17.74 MPa) and flexural strength (31.24 MPa) was obtained from hybrid composite with 50:50 ratio of seaweed/SPF. Good fibre-matrix bonding was evident in the scan- ning electron microscopy (SEM) micrograph of the hybrid composites’ tensile fracture. Fourier transform infrared spectroscopy (FT-IR) analysis showed increase in intermolecular hydrogen bonding following the addition of SPF. Thermal stability of hybrid composites was enhanced, indicated by a higher onset degradation temperature (259 ◦C) for 25:75 seaweed/SPF composites than the individual seaweed com- posites (253 ◦C). Water absorption, thickness swelling, water solubility, and soil burial tests showed higher water and biodegradation resistance of the hybrid composites. Overall, the hybridization of SPF with seaweed/TPSA composites enhances the properties of the biocomposites for short-life application; that is, disposable tray, plate, etc

    Effect of seaweed on physical properties of thermoplastic sugar palm starch/agar composites

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    The aim of this paper is to investigate the physical properties of thermoplastic sugar palm starch/agar (TPSA) blend when incorporated with seaweed. The ratio of starch, agar, and glycerol for TPSA was maintained at 70:30:30. Seaweed with various contents (10, 20, 30, and 40 wt.%) were mixed with TPSA matrix via melt mixing before compression were molded into 3 mm plate at 140oC for 10 minutes. The prepared laminates were characterized for moisture absorption, water absorption, thickness swelling, water solubility, and density. The results showed that increasing seaweed loading from 0 to 40 wt% has led to a drop in moisture content from 6.50 to 4.96% and 9% reduction of the density. TPSA matrix showed 52.5% water uptake and 32.3% swelling whereas TPSA/seaweed composites (40 wt% loading) showed 97% water uptake and 74.8% swelling respectively. Higher water solubility was also shown by TPSA/seaweed composites (57 wt%) compared to that of the TPSA matrix (26 wt%). After 16 days of storage, the equilibrium moisture content for TPSA and TPSA/seaweed (40 wt% loading) were 23.2 and 25.2% respectively. In conclusion, TPSA/seaweed composites show good environmental friendly characteristics as a renewable material. In future, the properties of this material can be further improved by hybridization with more hydrophobic fillers for better resistance against water

    Characteristics of Eucheuma cottonii waste from East Malaysia: physical, thermal and chemical composition

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    The aim of this paper was to examine the characteristics of Eucheuma cottonii waste in order to analyse its potential as renewable material. The morphology of Eucheuma cottonii (raw and wastes) was investigated through scanning electron microscopy (SEM), the thermal behaviour through thermogravimetric analysis (TGA) and the physical properties through FT-IR, XRD, gas pycnometer, particle size analyser, water absorption and moisture content analysis. The chemical compositions were determined by using acid detergent fibre (ADF), neutral detergent fibre (NDF) and acid detergent lignin (ADL) analysis. It was found that Eucheuma cottonii wastes have better thermal stability, higher crude fibre content, lower moisture content and similar density to the raw Eucheuma cottonii, which suggests that these biomass wastes have good potential as renewable filler material

    Thermoplastic sugar palm starch composites

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    Chapter 9 discusses the development of biodegradable materials derived from sugar palm starch. Due to the increasing environmental problems arising from the disposal of non-biodegradable plastics, the development of biopolymers has gained increasing attention from researchers as substitutes for conventional petroleum-based plastic. Among biopolymers, starch has been considered the most promising material because it is low in cost, highly abundant, renewable and fully biodegradable. This biopolymer can be transformed into thermoplastic starch in the presence of heat and plasticizer. Recent research has focused on the development of thermoplastic starch utilizing a new source of starch, sugar palm (Arenga pinnata). Unfortunately, thermoplastic sugar palm starch presents some drawbacks, such as poor mechanical properties, high sensitivity to moisture, and low thermal degradation. Therefore, various studies have been carried out to overcome these drawbacks, such as blending thermoplastic sugar palm starch with other biopolymers and reinforcement with various natural fibers to enhance the properties of this bio-based material

    Thermal Analysis Of Carbon Fibre Reinforced Polymer Decomposition

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    The increasing number of carbon fibers reinforced polymer (CFRP) waste disposed of in landfills is creating environmental concerns due to the potential release of toxic by-products and the need for recycling. This research work investigates the influence of atmosphere (single and combination of nitrogen and oxygen) and heating rate (5 and 10 °C min-1) on the thermal decomposition of CFRP to recover the reclaimed-cf The samples were heated up to 420 °C in a nitrogen atmosphere followed by heating in the oxygen atmosphere from 420 °C until the final heating temperature at different heating rates. The thermal decomposition behavior of the CFRP waste was compared by thermogravimetric analysis (TGA). Morphological, chemical and structural analysis of reclaimed-CF was performed using SEM, FT-IR and Raman spectroscopy respectively. A nitrogen atmosphere was significance at the early temperature (<420 °C) to decompose smaller molecules of epoxy resin components, while oxygen atmosphere is needed to achieve a complete separation of reclaimed-CF from their matrix. Thermal decomposition at lower heating rate (5 °C min-1) was found efficiently to eliminate the complex epoxy resin and retain the structure of reclaimed-cf The particular thermal decomposition technique that leads to a lower final heating temperature (540 °C) is present to recover valuable reclaimed-CF from complex CFRP industrial waste

    Extraction and characterization of potential biodegradable materials based on Dioscorea hispida tubers

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    This study was driven by the stringent environmental legislation concerning the consumption and utilization of eco-friendly materials. Within this context, this paper aimed to examine the characteristics of starch and fibres from the Dioscorea hispida tuber plant to explore their potential as renewable materials. The extraction of the Dioscorea hispida starch and Dioscorea hispida fibres was carried out and the chemical composition, physical, thermal, morphological properties, and crystallinity were studied. The chemical composition investigations revealed that the Dioscorea hispida starch (DHS) has a low moisture t (9.45%) and starch content (37.62%) compared to cassava, corn, sugar palm, and arrowroot starches. Meanwhile, the Dioscorea hispida fibres (DHF) are significantly low in hemicellulose (4.36%), cellulose (5.63%), and lignin (2.79%) compared to cassava, corn hull and sugar palm. In this investigation the chemical, physical, morphological and thermal properties of the Dioscorea hispida fibre and Dioscorea hispida starch were examined by chemical composition investigation, scanning electron microscopy (SEM), particle size distribution, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), and Fourier transform infrared (FTIR), respectively. It was found that Dioscorea hispida waste is promising alternative biomass and sustainable material with excellent potential as a renewable filler material for food packaging applications
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