Displaying publications 61 - 80 of 317 in total

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  1. Hau Hong DL, Mohammed BS, Al-Fakih A, Wahab MMA, Liew MS, Amran YHM
    Materials (Basel), 2020 Jun 24;13(12).
    PMID: 32599798 DOI: 10.3390/ma13122831
    Engineered cementitious composite (ECC) was discovered as a new substitute of conventional concrete as it provides better results in terms of tensile strain, reaching beyond 3%. From then, more studies were done to partially replace crumb rubber with sand to achieve a more sustainable and eco-friendlier composite from the original ECC. However, the elastic modulus of ECC was noticeably degraded. This could bring potential unseen dangerous consequences as the fatigue might happen at any time without any sign. The replacement of crumb rubber was then found to not only bring a more sustainable and eco-friendlier result but also increase the ductility and the durability of the composite, with lighter specific gravity compared to conventional concrete. This study investigated the effects of crumb rubber (CR) and graphene oxide (GO) toward the deformable properties of rubberized ECC, including the compressive strength, elastic modulus, Poisson's ratio, and drying shrinkage. Central composite design (CCD) was utilized to provide 13 reasonable trial mixtures with the ranging level of CR replacement from 0-30% and that of GO from 0.01-0.08%. The results show that GO increased the strength of the developed GO-RECC. It was also found that the addition of CR and GO to ECC brought a notable improvement in mechanical and deformable properties. The predicted model that was developed using response surface methodology (RSM) shows that the variables (compression strength, elastic modulus, Poisson's ratio, and drying shrinkage) rely on the independent (CR and GO) variables and are highly correlated.
    Matched MeSH terms: Tensile Strength
  2. Siva R, Valarmathi TN, Palanikumar K, Samrot AV
    Carbohydr Polym, 2020 Sep 15;244:116494.
    PMID: 32536404 DOI: 10.1016/j.carbpol.2020.116494
    In recent days, there is an increasing use of green composites in composite manufacturing, where cellulosic natural fibers have been started using for this purpose. In line with this, a novel cellulose fiber was extracted from the Kigelia africana fruit and its physical, chemical and thermal properties, crystallography and surface morphology analysis were studied and reported in this investigative research paper. The physical analysis revealed the mean tensile strength as 50.31 ± 24.71 to 73.12 ± 32.48 MPa, diameter as 0.507 ± 0.162 to 0.629 ± 0.182 mm and density as 1.316 g/cm³ for the Kigelia africana fiber. The proximate chemical analysis estimated the cellulose percentage to be 61.5 % and the existence of different basic components like cellulose, hemicellulose and lignin are confirmed by Fourier transform infrared spectroscopy analysis. Thermogravimetric analysis establishes the thermal stability of the fiber as 212 ⁰C. The crystallinity index, 57.38 % of the fiber was determined by X-ray diffraction. Surface morphology by field emission scanning electron microscopy reveals the presence of protrusions in fiber which aid in the better adhesion with the matrix in composite manufacturing.
    Matched MeSH terms: Tensile Strength
  3. Sinniah, Saraswathy D., Jones, Steven P., Georgiou, George, Cunningham, Susan J., Petrie, Aviva
    Compendium of Oral Science, 2016;3(1):17-24.
    MyJurnal
    used with bonded retainers. Setting: Department of Orthodontics, UCL Eastman Dental Institute, United Kingdom. Methods: Flowable composite resins (Transbond TM Supreme LV, StarFlowTM and Tetric EvoFlow®) and non -flowable control resin (TransbondTM LR) were made into cylinders prior to bonding to hydoxyapatite discs. They were then mounted into jigs and tested in the InstronTM Universal Testing Machine in both shear and tensile modes. Results: The highest mean shear bond strength was seen with StarFlow TM (14.09 MPa), which was significantly higher than both TransbondTM LR (9.48 MPa) and TransbondTM Supreme LV (8.20 MPa). The mean shear bond strength of Tetric EvoFlow® (11.86 MPa) was also significantly higher than TransbondTM Supreme LV. The highest mean tensile bond strength was seen with Tetric EvoFlow® (2.14 MPa), which was significantly higher than TransbondTM LR (1.15 MPa) and TransbondTM Supreme LV (0.61 MPa) but not significantly different to StarFlowTM (1.47 MPa). For shear loading, StarFlowTM had the highest 50th percentile survival estimate at 15.10 MPa, followed by Tetric EvoFlow® (13.00 MPa) and TransbondTM Supreme LV (7.50 MPa). TransbondTM LR had a 50th percentile estimate at 9.00 MPa. For tensile loading, Tetric EvoFlow® had the highest 50th percentile survival estimate at 2.50 MPa, followed by StarFlowTM (1.30 MPa) and TransbondTM Supreme LV (0.50 MPa). TransbondTM LR had a 50th percentile estimate at 1.00 MPa. Conclusions: Mean shear bond strengths for all of the resins were significantly higher than the mean tensile bond strengths. StarFlowTM and Tetric EvoFlow® could potentially be suitable clinical alternatives to TransbondTM LR due to its low viscosity flow characteristics and adequate shear and tensile bond strengths.
    Matched MeSH terms: Tensile Strength
  4. Ahmad Mahmood, Aws H. Ali Al-Kadhim, Zaripah Wan Bakar, Adam Husein
    Malaysian Dental Journal, 2011;32(1):12-16.
    MyJurnal
    Evaluation of the mechanical behaviour of restoration dental materials is essential to understand their performance under different load conditions and to estimate their durability under clinical oral function. Restorative materials and dental tissues like other materials by having specific mechanical properties, such as static strength (i.e. compressive strength, tensile strength, flexural strength) and dynamic strength (i.e. fatigue strength). The selection of proper mechanical test type depends on the goals that the study claims to define. On such basis, the mechanical test can be chosen correctly. Laboratory studies should be designed as replications of the clinical oral circumstances to measure the mechanical and physical properties of a material and any arbitrary choices in the design of the study may result in large variations of data.
    Matched MeSH terms: Tensile Strength
  5. Nordin, N. I. A. A., Ariffin, H., Hassan, M.A., Ibrahim, N. A., Shirai, Y., Andou, Y.
    MyJurnal
    The objective of this study was to evaluate the effects of milling methods on tensile properties of polypropylene (PP) / oil palm mesocarp fibre (OPMF) biocomposites. Two types of mills were used; Wiley mill (WM) and disc mill (DM). Ground OPMF from each milling process was examined for its particle size distribution and aspect ratio by sieve and microscopic analyses, respectively. Results showed that DM-OPMF had smaller diameter fibre with uniform particle size compared to the WM-OPMF. Surface morphology study by SEM showed that DM-OPMF had rougher surface compared to WM-OPMF. Furthermore, it was found that PP/DM-OPMF biocomposite had higher tensile strength compared to PP/WM-OPMF, with almost two-fold. Thus, it is suggested that small diameter and uniform size fibre may improve stress transfer and surface contact between the fibre and polymer matrix and cause well dispersion of filler throughout the polymer resulted in better tensile strength of PP/DM-OPMF Compared to PP/WM-OPMF biocomposite. Overall, it can be concluded that disc milling could serve as a simple and effective grinding method for improving the tensile properties of biocomposite.
    Matched MeSH terms: Tensile Strength
  6. Mustapha SNH, Wan JS
    Food Chem, 2022 Mar 30;373(Pt B):131440.
    PMID: 34731804 DOI: 10.1016/j.foodchem.2021.131440
    The objective of this work was to develop a plastic film from food sources with excellent thermal, mechanical, and degradability performance. Corn starch (CS)/nata de coco (NDC) were hybridized with addition of glycerin as plasticizer at different weight ratio and weight percent, respectively. Sample analysis found that the hybridization of CS with NDC improved the film forming properties, mechanical and thermal, degradation properties, as well as hydrophobicity and solubility of the film up to 0.5:0.5 wt hybrid ratio. The properties of the films were highly affected by the homogeneity of the sample during hybridization, with high NDC amount (0.3:0.7 wt CS:NDC) showing poor hydrophobicity, and mechanical and thermal properties. The glycerin content, however, did not significantly affect the hydrophobicity, water solubility, and degradability properties of CS/NDC film. Hybridization of 0.5:0.5 wt CS/NDC with 2 phr glycerin provided the optimum Young's modulus (15.67 MPa) and tensile strength (1.67 MPa) properties.
    Matched MeSH terms: Tensile Strength
  7. Taharuddin NH, Jumaidin R, Mansor MR, Hazrati KZ, Hafila KZ, Md Yusof FA
    Int J Biol Macromol, 2024 Oct;277(Pt 1):133852.
    PMID: 39025171 DOI: 10.1016/j.ijbiomac.2024.133852
    The potential of Hylocereus polyrhizus peel (HPP) as a new eco-friendly reinforcement for thermoplastic sago starch/agar composite (TPSS/agar) was investigated. The integration of HPP into TPSS/agar composite aimed to enhance its mechanical and thermal characteristics. The study employed Fourier transform-infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC), as well as mechanical, physical properties and soil burial testing to analyse the composites. The results showed a favourable miscibility between the matrix and filler, while at higher concentrations of HPP, the starch granules became more visible. The tensile and impact properties of the composites improved significantly after incorporating HPP at 20 wt%, with values of 12.73 MPa and 1.87 kJ/m2, respectively. The glass transition temperature (Tg) and initial decomposition temperature (Ton) decreased with the addition of HPP. The density of the composites reduced from 1.51 ± 0.01 to 1.26 ± 0.01 g/cm3 as the HPP amount increased. The environmental properties indicated that the composites can be composted, with weight loss accelerating from 35 to 60 % and 61 to 91 % by the addition of HPP in 2- and 4-weeks' time, respectively. The study demonstrates the potential of TPSS/agar/HPP composites as eco-friendly materials for various applications.
    Matched MeSH terms: Tensile Strength
  8. Xu X, Deng S, Essawy H, Lee SH, Lum WC, Zhou X, et al.
    Int J Biol Macromol, 2024 Oct;277(Pt 1):133784.
    PMID: 39084972 DOI: 10.1016/j.ijbiomac.2024.133784
    In this study, various chitosan-based films such as chitosan (C), chitosan-condensed tannin (CT), chitosan-casein (CC), and chitosan-casein-condensed tannin (CCT) films were prepared for the purpose of food packaging. In order to improve the hydrophobicity of these films, carnauba wax was blended into CCT to produce CCTW film. Properties such as morphology, UV resistance, water solubility, barrier performance, tensile strength, antioxidant, antibacterial and its performance as food packaging were evaluated. Compared with other chitosan-based films, CCTW films exhibited higher UV resistance, tensile strength, thermal stability and hydrophobicity. The addition of both condensed tannin and carnauba wax has significantly decreased the water vapor and oxygen permeability of the CCTW films. The CCTW films were proved capable of repelling most daily consuming liquids. Besides, CCTW films displayed outstanding free radical scavenging rate and antibacterial properties. Meanwhile, bananas wrapped with CCTW films remained fresh for seven days without any mold growth and outperformed other types of films. Apart from that, the CCTW films also showed biodegradable characteristics after exposure to Penicillium sp. These distinguished characteristics made the CCTW films a promising packaging material for long-term food storage.
    Matched MeSH terms: Tensile Strength
  9. Bairwan RD, Sukeksi L, Khalil HPSA, Hosny KM, Baradwan M, Rizg WY, et al.
    Int J Biol Macromol, 2025 Apr;304(Pt 2):140985.
    PMID: 39952528 DOI: 10.1016/j.ijbiomac.2025.140985
    This study explores the potential of crude lignin, extracted from coir fibers, an agricultural byproduct, as a sustainable filler in Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biodegradable blends. To enhance compatibility with the PHBV matrix, lignin was chemically modified using acetic anhydride (AL) and propionic anhydride (PL). These modifications were confirmed through FTIR, XRD, FE-SEM, EDX, and TGA analyses. The blends were prepared via melt compounding in a twin-screw extruder, followed by compression molding, with lignin microfillers incorporated at 1, 3, 5, and 7 wt% of dried PHBV. The addition of modified lignins improved the physical, mechanical, and thermal properties of the blends, with the optimal performance observed at 5 wt%, attributed to enhanced interfacial bonding. Two-way ANOVA with Tukey tests (p ≤ 0.05) confirmed statistical significance. However, at 7 wt%, all blends exhibited reduced performance due to lignin agglomeration, confirmed by morphology and tensile tests. Both modifications provided desirable multi-functional properties, but propionylated lignin-based blends outperformed those with acetylated and raw lignins, due to more effective substitution of non-polar groups, which improved filler-matrix miscibility. Fracture surface analysis, topography, and thermal evaluations validated these observations. These findings highlight chemically modified lignins, as effective, sustainable fillers for eco-friendly biopolymer composites suitable for packaging applications.
    Matched MeSH terms: Tensile Strength
  10. Wan Yahaya WA, Mohd Azman NA, Hashim NA, Abdul Mudalip SK, Gimbun J
    Int J Biol Macromol, 2025 Apr;303:140605.
    PMID: 39914533 DOI: 10.1016/j.ijbiomac.2025.140605
    This paper introduces a novel active carrageenan film designed for meat preservation, featuring the release of antioxidants eugenol (Eu) and α-tocopherol (Tp). The film is composed of semi-refined carrageenan, plasticized with 0.9 % glycerol, and reinforced with 10 % cellulose nanofibers derived from waste biomass. Lipid oxidation was measured through TBARS and percent metmyoglobin to evaluate the film's effectiveness in extending the shelf-life and maintaining the quality of meat. The film containing 0.4 % Tp demonstrates superior mechanical properties and thermal stability, achieving a tensile strength of 66.79 MPa and an elongation at break of 46.54 %. Notably, it exhibits a significant antioxidant release rate over 25 days, with TBARS and percent metmyoglobin values of 0.652 and 35.98 %, respectively. These results suggest that this biodegradable packaging solution not only prolongs meat shelf-life but also aligns with sustainable practices in food preservation. The release profiles of Eu and Tp follow a first-order kinetic model, indicating a controlled and sustained release mechanism. Overall, these findings highlight the potential of active films in enhancing food packaging solutions while promoting eco-friendliness.
    Matched MeSH terms: Tensile Strength
  11. Gaaz TS, Sulong AB, Ansari MNM, Kadhum AAH, Al-Amiery AA, Nassir MH
    Materials (Basel), 2017 Jul 10;10(7).
    PMID: 28773134 DOI: 10.3390/ma10070777
    The advancements in material science and technology have made polyurethane (PU) one of the most important renewable polymers. Enhancing the physio-chemical and mechanical properties of PU has become the theme of this and many other studies. One of these enhancements was carried out by adding starch to PU to form new renewable materials called polyurethane-starch composites (PUS). In this study, PUS composites are prepared by adding starch at 0.5, 1.0, 1.5, and 2.0 wt.% to a PU matrix. The mechanical, thermal, and morphological properties of PU and PUS composites were investigated. Scanning electron microscope (SEM) images of PU and PUS fractured surfaces show cracks and agglomeration in PUS at 1.5 wt.% starch. The thermo-mechanical properties of the PUS composites were improved as starch content increased to 1.5 wt.% and declined by more starch loading. Despite this reduction, the mechanical properties were still better than that of neat PU. The mechanical strength increased as starch content increased to 1.5 wt.%. The tensile, flexural, and impact strengths of the PUS composites were found to be 9.62 MPa, 126.04 MPa, and 12.87 × 10(-3) J/mm², respectively, at 1.5 wt.% starch. Thermal studies showed that the thermal stability and crystallization temperature of the PUS composites increased compared to that of PU. The loss modulus curves showed that neat PU crystallizes at 124 °C and at 127 °C for PUS-0.5 wt.% and rises with increasing loading from 0.5 to 2 wt.%.
    Matched MeSH terms: Tensile Strength
  12. Yusuf NK, Lajis MA, Ahmad A
    Materials (Basel), 2017 Aug 03;10(8).
    PMID: 28771207 DOI: 10.3390/ma10080902
    Meltless recycling technique has been utilized to overcome the lack of primary resources, focusing on reducing the usage of energy and materials. Hot press was proposed as a novel direct recycling technique which results in astoundingly low energy usage in contrast with conventional recycling. The aim of this study is to prove the technical feasibility of this approach by characterizing the recycled samples. For this purpose, AA6061 aluminium chips were recycled by utilizing hot press process under various operating temperature (Ts = 430, 480, and 530 °C) and holding times (ts = 60, 90, and 120 min). The maximum mechanical properties of recycled chip are Ultimate tensile strength (UTS) = 266.78 MPa, Elongation to failure (ETF) = 16.129%, while, for surface integrity of the chips, the calculated microhardness is 81.744 HV, exhibited at Ts = 530 °C and ts = 120 min. It is comparable to theoretical AA6061 T4-temper where maximum UTS and microhardness is increased up to 9.27% and 20.48%, respectively. As the desired mechanical properties of forgings can only be obtained by means of a final heat treatment, T5-temper, aging after forging process was employed. Heat treated recycled billet AA6061 (T5-temper) are considered comparable with as-received AA6061 T6, where the value of microhardness (98.649 HV) at 175 °C and 120 min of aging condition was revealed to be greater than 3.18%. Although it is quite early to put a base mainly on the observations in experimental settings, the potential for significant improvement offered by the direct recycling methods for production aluminium scrap can be clearly demonstrated. This overtures perspectives for industrial development of solid state recycling processes as environmentally benign alternatives of current melting based practices.
    Matched MeSH terms: Tensile Strength
  13. Omar FN, Hafid HS, Samsu Baharuddin A, Mohammed MAP, Abdullah J
    Planta, 2017 Sep;246(3):567-577.
    PMID: 28620814 DOI: 10.1007/s00425-017-2717-5
    MAIN CONCLUSION: X-ray microtomography results revealed that delignification process damaged the oil palm fibers, which correlated well with reduction of lignin components and increase of the phenolic content. Biodegradation investigation of natural fibers normally focuses on physico-chemical analysis, with less emphasis on physical aspect like fiber structures affect from microbial activity. In this work, the performance of Pycnoporus sanguineus to delignify oil palm empty fruit bunch fibers through solid-state fermentation utilizing various ratio of POME sludge was reported. In addition to tensile testing, physico-chemical and X-ray microtomography (µ-CT) analyses on the oil palm fibers were conducted to determine the effectiveness of the degradation process. The best ratio of fiber to fungi (60:40) was chosen based on the highest lignin loss and total phenolic content values and further investigation was performed to obtain fermentation kinetics data of both laccase and manganese peroxidase. µ-CT results revealed that delignification process damaged the pre-treated and untreated fibers structure, as evident from volume reduction after degradation process. This is correlated with reduction of lignin component and increase of the phenolic content, as well as lower stress-strain curves of the pre-treated fibers compared to the untreated ones (from tensile testing). It is suggested that P. sanguineus preferred to consume the outer layer of the fiber, before it penetrates through the cellular structure of the inner fiber.
    Matched MeSH terms: Tensile Strength
  14. Rahman AM, Jamayet NB, Nizami MMUI, Johari Y, Husein A, Alam MK
    J Prosthodont, 2019 Jan;28(1):36-48.
    PMID: 30043482 DOI: 10.1111/jopr.12950
    PURPOSE: This systematic review aims to identify and interpret results of studies that evaluated the changes in the physical properties of maxillofacial prosthetic materials (1) without aging, (2) after natural or artificial accelerated aging, and (3) after outdoor weathering.

    METHODS: Relevant articles written in English only, before January 15, 2017, were identified using an electronic search in the PubMed, Scopus, and Google Scholar databases. Furthermore, a manual search of the related major journals was also conducted to identify more pertinent articles. The relevancy of the articles was verified by screening the title, abstract, and full text if they met the inclusion criteria. A total of 37 articles satisfied the criteria, from which data were extracted for qualitative synthesis.

    RESULTS: Among the 37 included articles, 14 were without aging, 15 were natural or artificial accelerated aging, 7 were outdoor weathering, and 1 contained both artificial aging and outdoor weathering. Only 4 studies out of the 14 without aging had significant observations; whereas 9 articles with natural or artificial aging published significant results, and 3 out of 7 outdoor weathering articles showed significant changes in the evaluated silicone elastomers.

    CONCLUSIONS: Despite the varying research, it seems that the single "ideal" maxillofacial prosthetic material that can provide sufficient resistance against different aging conditions is yet to be identified. Therefore, it is imperative for standardization organizations, the scientific community, and academia to develop modified prosthetic silicones possessing improved physical properties and color stability, limiting the clinical problems regarding degradation of maxillofacial prostheses.

    Matched MeSH terms: Tensile Strength
  15. Lazar PJL, Sengottuvelu R, Natarajan E
    Materials (Basel), 2018 Nov 05;11(11).
    PMID: 30400592 DOI: 10.3390/ma11112186
    The principal objective of this research work was to investigate the results of impregnating epoxy matrix-glass fibre composite laminates with nanosilica as secondary reinforcement. 0.5, 0.75, 1 and 3 wt% nanosilica was used and thereafter properties of composites were assessed through tensile, three point bending, quasi static indentation tests and dynamic mechanical analysis. Scanning electron microscope examinations were done on fracture surfaces and failure modes were analyzed. The internal failures of the composite due to quasi-static indentation were evaluated through C-Scan. Among samples of different weight fractions, 0.75 wt% nanosilica reinforced composite laminates exhibited substantial increase of 42% in tensile strength and 39.46% in flexural strength. The reduction in glass transition temperature (Tg), increase in storage modulus (E'), loss modulus (E″) and damping factor (tan δ) were also observed. Quasi-static indentation assessments revealed that energy absorption property was enhanced significantly by 53.97%. Hence nanosilica up to 0.75 wt% can be used as a potential candidate for secondary reinforcement in epoxy composite laminates.
    Matched MeSH terms: Tensile Strength
  16. Abdullah, M.A.A., Mamat, M., Rusli, S.A., Kassim, A.A.
    ASM Science Journal, 2018;11(101):96-104.
    MyJurnal
    Considering its excellent thermal stability, alkyl phosphonium surfactant: triisobutyl(methyl)phosphonium
    (TIBMP) was used in this research as an intercalant for surface
    modification of Na+-MMT via ion exchange process forming organomontmorillonite
    (OMMT). The OMMT was then used as filler in poly(methyl methacrylate) (PMMA) via
    melt intercalation technique. OMMT decomposed at a higher temperature than commercial
    alkyammonium modified MMT. Exfoliated and intercalated types of nanocomposites
    are obtained from PMMA/OMMTs at low and high content of OMMT loading, depending
    on the space of those clay platelets had to disperse in PMMA. The ability of OMMT to
    carry a certain load applied in PMMA matrix enhances the tensile strength in all composites.
    TIBMP are compatible with PMMA matrix, and significantly improves the tensile
    properties of PMMA composites.
    Matched MeSH terms: Tensile Strength
  17. Razali, M.H., Ismail, N.A., Osman, U.M., Amin, K.A.M.
    ASM Science Journal, 2018;11(101):158-165.
    MyJurnal
    The aim of this work was to investigate the effect of glycerol concentration on mechanical
    and physical properties of gellan gum (GG) biofilm. The biofilm was prepared using solvent
    casting method and the effective glycerol concentration was found to be within 30-50%
    w/w (based on GG weight). At 60 and 70 w/w% of glycerol, the films started to distort
    because the films was flexible and brittle. As glycerol concentration was increased the tensile
    strength (TS) and Youngs modulus (E) of films decreased. Somehow, elongation at break
    (EAB), water vapor transmission rate (WVTR) and swelling of films was increased. Glycerol
    plasticized GG biofilm was thermally stable and flexible, proposed its can be exploited as
    film-forming material and with optimized glycerol concentration it has good mechanical and
    physical properties for edible biofilm.
    Matched MeSH terms: Tensile Strength
  18. Tan, L.S., Leila, M., Rabeta, M.S.
    Food Research, 2018;2(1):68-75.
    MyJurnal
    Formulation 2 (1 g w/w) was the most favourable and was chosen for further analyses to
    compare its composition with that of a control (0 g w/w). Total phenolic content (TPC) of
    the fresh noodles remained higher than that of the control even after cooking. However,
    after cooking, the carbohydrate and protein contents showed significant increases. The
    results showed that the lemuni-supplemented noodles have a longer shelf life compared to
    the control. The colour parameters L* and a* also showed significant differences as the
    lightness decreased, and the redness increased after the substitution. The L*, a* and b*
    values decreased significantly after the noodles of both formulations were cooked. The
    tensile strength, adhesiveness, and hardness of the lemuni noodles were significantly
    higher than those of the control. Thus, the Vitex negundo Linn. leaf has the potential to
    increase the health benefits of food products.
    Matched MeSH terms: Tensile Strength
  19. Ishak Ahmad, Mohd Khairil Saat, Ibrahim Abdullah, Azizah Baharum
    Blends of fibre-reinforced rubber based on natural rubber-thermoplastic (NR/LLDPE) reinforced by aramid fibre have been done using melt blending process. Two different processing methods were used; internal mixer and extrusion compounding in twin screw extruder. Twaron loading in the system was varied from 0 to 30%. It was found that increasing the amount of aramid fibre led to an increase in the tensile strength, tensile modulus and hardness of the composites while the strain decreased rapidly. The results showed that the optimum composition of filler loading in NR/LLDPE blend is 20%. The ,echanical behaviour was caused by the strong Twaron-matrices interaction in the composites and effective stress concentrating function of Twaron. Composites prepared using the twin-screw extruder have a higher tensile strength and tensile using the twin-screw extruder have a higher tensile stength and tensile modulus but lower impact strength compared to those prepared using internal mixer. Study of the fracture surface by scanning electron microscopy showed that the composite prepared using the internal mixer produced random fiber orientation while the twin-screw extruder produced the fibers aligned to the longitudinal direction. The results indicate that the mechanical properties of the composite were significantly influenced by the processing technique.
    Penyediaan komposit getah asli termoplastik daripada NR/LLDPE yang diperkuat gentian Twaron telah dijalankan melalui proses adunan leburan. Dua kaedah penyediaan yang berbeza digunakan iaitu menggunakan mesin pencampur dalaman manakala kaedah kedua menggunakan pengekstrud skru kembar. Kandungan Twaron di dalam komposit telah diubah daripada 0 hingga 30%. Keputusan menunjukkan bahawa penambahan Twaron telah meningkatkan nilai tegasan maksima, modulus Young dan kekuatan hentaman komposit tetapi menurunkan nilai terikan maksima. Kandungan Twaron yang optimum adalah 20%. Kehadiran Twaron telah membentuk satu jaringan saling tindak gentian-matriks menyebabkan kekuatan regangan komposit meningkat. Twaron juga berfungsi sebagai penyerap hentaman yang berkesan. Penyediaan komposit menggunakan pengekstrud skru berkembar telah menghasilkan nilai kekuatan regangan yang lebih tinggi berbanding penggunaan pencampur dalaman sebaliknya kekuatan hentaman yang lebih rendah. Kajian morfologi menggunakan mikroskop imbasan elektron mendapati komposit yang disediakan menggunakan pencampur dalaman menghasilkan gentian dengan orientasi rawak manakala pengekstrud skru kembar menghasilkan orientasi gentian yang selari. Keputusan ini menunjukkan bahawa sifat mekanik komposit NR/LLDPE yang diperkuat Twaron sangat dipengaruhi oleh teknik pemprosesan.
    Matched MeSH terms: Tensile Strength
  20. Chai CK, Md. Soot Ahmad, Wan Manshol W. Zin
    Electron beam vulcanization of natural rubber latex has been developed as an alternative to the conventional sulphur vulcanization method. This study aimed at determining the effect of electron beam dose, beam current and centrifugation to the tensile properties of field natural rubber latex. Irradiation dose and beam current ranged from 50 to 300 kGy and 1 to 15 mA respectively. The determination of tensile properties were done on cast film prepared from irradiated field latex before and after centrifugation. It was found that tensile properties increased with radiation dose but decreased with beam current. Rubber films made from centrifuged irradiated field latex were softer and showed higher tensile strength.
    Matched MeSH terms: Tensile Strength
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