Hakimah Osman
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Preferred name
Hakimah Osman
Official Name
Hakimah, Osman
Alternative Name
Osman, Hakimah
Osman, H.
Main Affiliation
Scopus Author ID
7005733143
Researcher ID
AAT-9920-2020

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  • Publication
    Synthesis and Characterization of a Novel Nanosized Polyaniline
    ( 2023-12-01)
    Banjar M.F.
    ;
    Joynal Abedin F.N.
    ;
    Fizal A.N.S.
    ;
    Muhamad Sarih N.
    ;
    Hossain M.S.
    ;
    Hakimah Osman
    ;
    Khalil N.A.
    ;
    Ahmad Yahaya A.N.
    ;
    Zulkifli M.
    Polyaniline (PANI) is a conductive polymer easily converted into a conducting state. However, its limited mechanical properties have generated interest in fabricating PANI composites with other polymeric materials. In this study, a PANI–prevulcanized latex composite film was synthesized and fabricated in two phases following chronological steps. The first phase determined the following optimum parameters for synthesizing nanosized PANI, which were as follows: an initial molar ratio of 1, a stirring speed of 600 rpm, a synthesis temperature of 25 °C, purification via filtration, and washing using dopant acid, acetone, and distilled water. The use of a nonionic surfactant, Triton X-100, at 0.1% concentration favored PANI formation in a smaller particle size of approximately 600 nm and good dispersibility over seven days of observation compared to the use of anionic sodium dodecyl sulfate. Ultraviolet–visible spectroscopy (UV-Vis) showed that the PANI synthesized using a surfactant was in the emeraldine base form, as the washing process tends to decrease the doping level in the PANI backbone. Our scanning electron microscopy analysis showed that the optimized synthesis parameters produced colloidal PANI with an average particle size of 695 nm. This higher aspect ratio explained the higher conductivity of nanosized PANI compared to micron-sized PANI. Following the chronological steps to determine the optimal parameters produced a nanosized PANI powder. The nanosized PANI had higher conductivity than the micron-sized PANI because of its higher aspect ratio. When PANI is synthesized in smaller particle sizes, it has higher conductivity. Atomic force microscopy analysis showed that the current flow is higher across a 5 µm2 scanned area of nanosized PANI because it has a larger surface area. Thus, more sites for the current to flow through were present on the nanosized PANI particles.
  • Publication
    Effect of blowing agent on compression and morphological properties of natural rubber latex foam
    ( 2020-09-21)
    Syahrin S.M.
    ;
    Zunaida Zakaria
    ;
    Hakimah Osman
    ;
    Syarifah Nuraqmar Syed Mahamud
    Sodium bicarbonate (NaHCO3) was used as a blowing agent in natural rubber latex foam (NRLF) in this study. At fixed vulcanization temperature and time in an air-circulating oven, the NRLF was prepared via the Dunlop method by whipping until frothing and adding NaHCO3 in latex compounds with different loading (i.e., 0, 3, 9 and 12 phr). An alternative formulation for the inclusion of NaHCO3 in NRLF was used. The effect of different blowing agent loading on the physical characteristics of NRFL such as relative foam density was investigated. Observation of cell diameter was performed using an optical microscope (OM). The result of NRLF's compression strength was also evaluated, which correlated with the foam's physical characteristics. The relative foam density was increased with an increase in the amount of NaHCO3. However, the average cell diameter was shown to decrease as the loading of the blowing agent increased. The outcomes of the NRLF's compression strength were also enhanced as the loading of the blowing agent increased following the physical characteristics of the foam respectively.
      13  26
  • Publication
    Extraction of silica content from the Cymbopogan citratus (lemon grass) and its performance as reinforcement for polymers
    ( 2017-07-21)
    Nur Firdaus Mohamed Yusof
    ;
    Hakimah Osman
    ;
    Hendrik Simon Cornelis Metselaar
    ;
    Rozyanty Rahman
    Silica is widely used as sources for adsorption materials, medical additives and fillers in composite and rubber industries. The manufacturing process of commercial silica use in various industries is very expensive and energy extensive. Therefore, agricultural waste material such as lemon grass is seen as a potential alternative silica sources for replacement of commercial silica which is currently available in the industry. In this research, a simple method based on the acid leaching treatment with hydrochloric acid (HCl) was developed to produce purified silica from lemon grass, followed by thermal combustion at 600°C. Acid leaching temperatures of 33, 50, 80 and 110°C were used. The silica content, shape and texture of the lemon grass ash was characterized using scanning electron microcopy -energy-dispersive X-ray (SEM-EDX) analysis. The SEM analysis indicated the presence of tubular-shaped porous aggregates, spherical and fibrous shapes of untreated and treated lemon grass at 33°C to 110°C. The highest silica content recorded was 73.46% for lemon grass treated at the highest leaching temperature of 110°C. The thermal stability of lemon grass ash was examined by using a thermogravimetric analysis (TGA) instrument. The TGA analysis shows that the untreated and treated lemon grass ash start to decompose at lower temperature (90 to 100°C). Lemon grass treated at the highest leaching temperature 110°C exhibit the highest thermal stability.
      20  3
  • Publication
    Evaluation and Enhancement of Polylactic Acid Biodegradability in Soil by Blending with Chitosan
    ( 2023-06-01)
    Nor Helya Iman Kamaludin
    ;
    Ismail H.
    ;
    Rusli A.
    ;
    Sam Sung Ting
    ;
    Hakimah Osman
    This study highlights the soil burial degradation of polylactic acid/chitosan (PLA/Cs) biocomposites prepared by the melt compounding technique. The effect of various Cs loadings (2.5, 5, 7.5, 10 parts per hundred parts of polymer (php)) and soil burial periods (0, 2, 6, 12 months) on visual observation, weight loss, changes in functional groups, as well as tensile, thermal, and morphological properties were analyzed. The PLA/Cs biocomposites became brittle and showed more fragmentation with increasing Cs content and buried time. The result correlates with a remarkable increase in weight loss percentage of about ~ 192%, with Cs addition from 2.5 to 10 php at the end of soil degradation. Besides, a decrement in peak intensity at 1751 cm−1 and 1087 − 1027 cm−1 after 12 months signifies the breakdown of PLA ester bonds due to the hydrolytic degradation. This correlates to a significant drop of 60% and 55% in tensile strength and elongation at break, respectively, in the 2.5 php sample, whilst further Cs addition resulted in the broken of the biocomposites at the end of the soil degradation. Yet, no significant difference was observed in the tensile modulus. A consistent stiffness in the biocomposite suggests the degradation occurs in the amorphous region and leaves the crystalline part. This is proven by the 70% increment in crystallinity degree in all samples after 12 months of soil burial. Moreover, surface morphology showed numerous and extended crack formations. It proposes a notable deterioration effect of the biocomposite due to biodegradation. The hydrophilicity of Cs enhances water-polymer interaction, thereby accelerating the biodegradation of polymer components. Therefore, Cs could be a good candidate for facilitating PLA biodegradation in the natural soil environment.
      1  25
  • Publication
    Effect of Different Foaming Temperature on Properties of NaHCO3 – Natural Rubber Latex Foam
    ( 2023-01-01)
    Smail M.S.
    ;
    Zunaida Zakaria
    ;
    Hakimah Osman
    ;
    Masa A.
    ;
    Leemsuthep A.
    High volatile fatty acid natural rubber latex foam (H-VFA NRLF) was prepared via the Dunlop process using sodium bicarbonate, NaHCO3 as the blowing agent. The influence of different foaming temperatures (140 ℃, 150 ℃, 160 ℃, 170 ℃, and 180 ℃) on relative foam density, average cell size, cell size distribution frequency and compression stress-strain of H-VFA NRLF were studied. The average cell sizes were related to the relative foam density of H-VFA NRLF. As the temperature increased, the relative foam density increased, and eventually the average cell size decreased due to high amount of gas generated by blowing agents simultaneously. Meanwhile, smaller cell sizes were distributed as the temperature increased. It was found that the optimum temperature for H-VFA NRLF was 150 ℃ due to the lowest relative foam density and significantly larger uniform cell size were produced. Thus, the lowest compression stress up to 60% of strain was found at 150 ℃ and increased with increasing temperature. The mechanical properties were correlated with the morphology and physical properties of the H-VFA NRLF, respectively.
      1  25