Now showing 1 - 10 of 21
  • Publication
    Comparison between the Tensile, Water Absorption and Flammability Properties of Recycled High-Density Polyethylene/Rice Husk Composite from Twin-Screw Extruder and Heated Two-Roll Mill
    This study compares the mechanical properties of recycled high-density polyethylene (r-HDPE)/rice husk (RH) composites from a twin-screw extruder and a heated two-roll mill, and the effect of different filler loadings using different melt blending processes on the mechanical properties of r-HDPE/RH composites. Polyethylene-graft-maleic anhydride (MAPE) acts as the coupling agent to enhance interfacial bonding between the fibre and the polymer matrix. The filler loading used was in the range of 10-40 wt. %. In this work, r-HDPE/RH blends were prepared using a twin-screw extruder and a heated two-roll mill. The ratio of 70/30 twin-screw extruder compounded composites significantly showed higher tensile based on improved to about 45.5% at 11 MPa compared to those compounded in the heated two-roll mill. The same ratio showed an increment almost up to 9% of elongation at break. It has also been verified that the higher filler loading used reduced the tensile strength and elongation at break, while the Young's modulus increased. The result was evidenced by the increase in water absorption and longer burning time as the filler loading increased.
  • Publication
    The study and preparation of polyaniline-graphene oxide as robust counter electrode for dye-sensitized solar cells
    ( 2022-05-18) ;
    Shukor A.A.
    ;
    ;
    Nawawi W.I.
    ;
    ;
    Badri A.
    The study of alternative materials and platinum-free counter electrodes (CE) for the development of dye- sensitized solar cells (DSSC) has been highlighted nowadays. Polyaniline (PANI) is one of the most common conducting polymers applied in electrochemical energy storage and conversion technologies such as supercapacitors, rechargeable batteries and fuel cells. However, PANI counter electrodes lack long-term stability due to their low surface area and large volume changes during the release of ions. In that regard, this research work focused on the modification of protonated PANI with graphene oxide (GO) at various weight percentages (wt%) in order to obtain robust CE in DSSC. The structure and formation of PANI, GO and PANI/GO were characterized by Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analyses. The absorption spectra showed all the characteristic bands of GO, PANI(ES) and PANI/GO. Meanwhile, the incorporation of GO into PANI has enhanced the crystallinity of the composite. As a result, power conversion efficiency (PCE%) of the device with PANI/GO 3 wt% as the counter electrode reaches 6.39%. The excellent photoelectric properties, simple preparation procedure and inexpensive cost allow the PANI/GO electrode to be a credible alternative for DSSCs.
      2  29
  • Publication
    The role of Nitrogen-Doped TiO2 supported by platinum catalyst synthesized via various mode preparations for photocatalytic nnhancement
    ( 2022-11-01)
    Natar N.S.
    ;
    Ghani N.I.A.
    ;
    Hamzah S.R.
    ;
    Rosli M.A.
    ;
    Muhamad N.A.
    ;
    Azami M.S.
    ;
    Ishak M.A.M.
    ;
    ;
    Nawawi W.I.
    The limitations of TiO2 as a photocatalyst such as the larger bandgap energy, which only activates under the UV region, give a lower photocatalytic activity. This study reports the role of the N and Pt co-dopant on the modification of the TiO2 photocatalyst for photocatalytic degradation of methylene blue dye under different mode preparations, i.e., sequential and vice-versa modes. The sequential mode preparation of the N and Pt co-dopant TiO2 photocatalyst consisted of the initial preparation of the N-doped TiO2 (N-TiO2) under the calcination method, which was then further doped with platinum (Pt) through the photodeposition process labeled as NPseq-TiO2, while the vice-versa mode was labeled as PNrev-TiO2. About 1.58 wt.% of N element was found in the NPseq-TiO2 photocatalyst, while there was no presence of N element detected in PNrev-TiO2, confirmed through an elemental analyzer (CHNS-O) and (EDX) analysis. The optimum weight percentage of Pt for both modes was detected at about ±2.0 wt.%, which was confirmed by inductively coupled plasma-emission spectroscopy (ICP-OES). The photoactivity under methylene blue (MB) dye degradation of the NPseq-TiO2 photocatalyst was 2 and 1.5 times faster compared to the unmodified TiO2 and PNrev-TiO2, where the photodegradation rates were, ca., 0.065 min−1 and 0.078 min−1, respectively. This was due to the N elements being incorporated with the TiO2 lattice, which was proven by UV-Vis/DRS where the bandgap energy of NPseq-TiO2 was reduced from 3.2 eV to 2.9 eV. In addition, the N generated a stronger PL signal due to the formation of oxygen vacancies defects on the surface of the NPseq-TiO2 photocatalyst. The higher specific surface area as well as higher pore volume for the NPseq-TiO2 photocatalyst enhanced its photocatalytic activity. Moreover, the NPseq-TiO2 showed the lowest COD value, and it was completely mineralized after 7 h of light irradiation. The preparation order did not affect the Pt dopant but did for the N element. Therefore, it is significant to investigate different mode preparations of the N and Pt co-dopant for the modification of TiO2 to produce a good-quality photocatalyst for photocatalytic study under the photodegradation of MB dye.
      1  9
  • Publication
    Effect of polyethylene glycol and sodium dodecyl sulphate on microstructure and self-cleaning properties of graphene oxide/TiO2 thin film
    In this study, a sol gel procedure for preparation of TiO2 thin films with graphene oxide (GO) was developed. The effect of PEG and SDS addition on the microstructure of the films as well as the photocatalytic activity of the thin film was also investigated. The morphology and surface structure of the films were studied by SEM and AFM while the photocatalytic activity of the films was analyzed by measuring the degradation of methylene blue under sunlight irradiation using UV-Vis spectrophotometer. It was found that GO/TiO2 thin film with PEG shows a smaller and porous particle while GO/TiO2 thin film with SDS formed a very smooth surface and very fine particles. Therefore, in AFM analysis reveals that surface roughness decreases with the addition of PEG and SDS. Finally, the photocatalytic activity showed that GO/TiO2 thin film with SDS have the most effective self-cleaning property which degrade 64% of methylene blue that act as model of contaminants.
      1
  • Publication
    Preparation and characterization of NE-7150 and NE-7170 silicone rubber blend with different ratios and curing agents loading
    ( 2022-05-18)
    Chew Jie Yi
    ;
    Mohamad Kahar Abdul Wahab
    ;
    Nur Afikah Zulkeply
    ;
    Hayeemasae N.
    ;
    Silicone rubbers are elastomers which are composed of silicone, carbon, hydrogen and oxygen. It is widely used in industry and many applications in our daily life. Basically, silicone rubbers can be divided into solid or liquid form. Uncured rubbers are required to undergo vulcanization process with a curing agent or cross-linking agent to produce useful products. Silicone rubbers can be molded into many shapes and designs due to its ease of processing. In this research project, silicone rubbers NE-7150 and NE-7170 were used in the blend in different types of curing agents. Two different vulcanization systems were involved which were peroxide C-15 vulcanization system and platinum C-25A & C-S5B catalysts hydrosilylation. Platinum can offer the silicone rubbers to cure with higher cross-linking density and result in good swelling and mechanical properties. However, as the cross-linking density increases and the rubbers become harder, the percentage elongation at break of the rubbers will drop. Fourier Transform Infrared Spectroscopy (FTIR) test was carried out to investigate the structure formation of silicone rubbers. The uncured and cured rubbers showed similar results as the curing of rubbers only happened within the C-C bonds. In Scanning Electron Microscopy (SEM), the surface morphology of the rubber samples was obtained and the existence of rough surfaces on the platinum cured rubbers indicate it cured with more cross-links than peroxide cured rubbers.
      7  18
  • Publication
    Preparation of a Visible light Active N-doped TiO2Photocatalyst using Microwave Irradiation Technique
    ( 2020-11-24)
    Nawawi W.I.
    ;
    ;
    Fazeri
    The dye wastewater which directly discharges without treatment process will affect the environment. The semiconductor like titanium dioxide (TiO2) has gained attention as most potential material for photocatalysis process to treat the dye wastewater with act as photocatalyst. However, this semiconductor has their limitation toward the photodegradation under visible light irradiation. In this study, TiO2 has been modified by doping with nitrogen (N) to improve the effectiveness under visible light irradiation. This simple prepared N-doped TiO2 was prepared by mixing of TiO2 powder with urea as N precursor under microwave irradiation instead of using muffle furnace as heating media. The nitogen was chemically bonded with TiO2 as proven by XPS analysis. N-doped TiO2 sample show active under visible light irradiation due to lower band gaps energy of sample observed by UV/Vis-DRS. An active photo response under visible light was observed from N-doped TiO2 with 80 minutes time irradiation to complete the reactive red 4 (RR4) color removal, while no photocatalytic degradation was observed from unmodified TiO2 under the same irradiation.
      1
  • Publication
    Synergistic effect of agarose biopolymer gel electrolyte with modified TiO2 for low-cost electrochemical device applications
    ( 2023-09-01)
    Badri A.
    ;
    ;
    Nawawi W.I.
    ;
    ; ;
    Abul Shukor A.
    The effect of different concentrations of agarose gel electrolyte in a low-cost fabrication of DSSC system was investigated. The modified DSSC was fabricated by a sandwiched method using ITO glass plates as substrates. TiO2-Graphene-coated glass plate was used as the working electrode while PANI-GO-coated glass plate works as a counter electrode, respectively. Both electrodes were separated by agarose gel mixture with KI solution as gel biopolymer electrolyte. The FTIR result showed that peaks of agarose are well observed in the KI-agarose spectra. In the XRD analysis, the combination of KI-agarose has reduced the crystallinity of agarose which was good for ionic conductivity value. The addition of agarose in KI solution also produced a fine channel to facilitate the ionic transfer in electrolyte. The behaviour of electrochemical properties of the system was observed using AC impedance spectroscopy based on the Nyquist plot. From the plot, three semicircles were observed as the responses at different frequencies. It was observed that the 5 wt% agarose electrolyte in DSSC system was selected as the optimum loading exhibiting the lowest resistivity ensuring the faster electron transfer and giving the ionic conductivity of 9.04 × 10−1 S/cm. The ionic conductivity of the system was dropped at 2.21 × 10−1 S/cm as the percentage of agarose was increase to 6 wt%.
      2  20
  • Publication
    Surface Modification of GO/TiO2 Thin Film by Sodium Dodecyl Sulphate for Photocatalytic Applications
    Photocatalyst material titanium dioxide (TiO2) and graphene oxide (GO) were used to improve the self-cleaning properties of thin films. The sol–gel spin-coating method was successfully used to synthesize GO/TiO2 thin films. Surface modification was applied to optimize the self-cleaning capabilities by adding several concentrations of sodium dodecyl sulfate (SDS) (0.1 w/v%, 0.2 w/v%, 0.3 w/v%, 0.4 w/v%, and 0.5 w/v%) to the parent solution. The synthesized thin films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, UV-visible spectroscopy, water contact angle analysis, and photocatalytic analysis. The AFM and SEM images revealed that as the SDS amount increased, the particles became less agglomerated, and the roughness of the surface reduced from 2.54 × 102 nm to 0.83 × 102 nm. The wettability analysis showed that when SDS increased to 0.4 w/v%, the water contact angle dropped to 15.30°, implying that the thin film exhibits hydrophilic qualities. A decrease in the GO/TiO2 band gap was obtained linearly with the increase in SDS addition from 3.17 eV to 2.75 eV. Finally, the improvement of the surface coating and reduction of the band gap enhanced the photocatalytic activity, which degraded 78.97% of methylene blue, which was obtained by 0.4SDS.
      2
  • Publication
    Preparation of water-base immobilized N doped TiO2 using DSAT technique for photocatalytic degradation of methylene blue dye
    ( 2022-01-01)
    Natar N.S.
    ;
    Ikhwan S.
    ;
    Nazeri N.S.
    ;
    Hamzah S.R.
    ;
    Rosli M.A.
    ;
    Ghani N.I.
    ;
    Ishak M.A.M.
    ;
    ;
    Azami M.S.
    ;
    Nawawi W.I.
    Photocatalytic degradation of TiO2 photocatalyst under suspension mode has widely been studied among researchers. However, the application is limited due to the complexity in separation and non-recyclability of photocatalyst. Immobilization is one of the promising methods to overcome this problem. Most of the prepared immobilization modes showed lower photocatalytic activity compared with the suspension due to the chemical reaction of solvent with modified TiO2. Therefore, a free solvent or water-base preparation of immobilized TiO2 is critical in retaining its photocatalytic activity. Immobilization via double-sided adhesive tape (DSAT) was introduced previously by our research team, it works the best of others in replacing polymer binder in immobilization system making it a free solvent preparation process. The aim of this research is to prepare immobilized unmodified TiO2 and N doped TiO2 by using water-base DSAT technique. The presence of N element was detected for all modified N doped TiO2 samples confirmed by FTIR and EDX analysis. The N incorporated in modified TiO2 has reduced the band gap energy from 3.0 to 2.8 eV as observed by UV–Vis/DRS analysis. This explained the photoactivity under MB dye degradation is 2.1 times faster under N doped TiO2 where the photodegradation rate for unmodified and optimum N doped TiO2 (TN1-45) were 0.065 and 0.138 min−1 respectively. Immobilized TiO2/DSAT and TN1-450/DSAT have shown a significant photocatalytic performance where it was only reduced to 15% from suspension to immobilized mode. It can be considered higher performance as compared to the normal immobilization under solvent. It also better than suspension mode by considering of its reusability that able to sustain the photoactivity of immobilized TN1-450/DSAT for at least for 12 cycles.
      1
  • Publication
    The study and preparation of polyaniline-graphene oxide as robust counter electrode for dye-sensitized solar cells
    ( 2022-05-18) ;
    Amira Abul Shukor
    ;
    ;
    Nawawi W.I.
    ;
    ;
    Afzalina Badri
    The study of alternative materials and platinum-free counter electrodes (CE) for the development of dye- sensitized solar cells (DSSC) has been highlighted nowadays. Polyaniline (PANI) is one of the most common conducting polymers applied in electrochemical energy storage and conversion technologies such as supercapacitors, rechargeable batteries and fuel cells. However, PANI counter electrodes lack long-term stability due to their low surface area and large volume changes during the release of ions. In that regard, this research work focused on the modification of protonated PANI with graphene oxide (GO) at various weight percentages (wt%) in order to obtain robust CE in DSSC. The structure and formation of PANI, GO and PANI/GO were characterized by Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analyses. The absorption spectra showed all the characteristic bands of GO, PANI(ES) and PANI/GO. Meanwhile, the incorporation of GO into PANI has enhanced the crystallinity of the composite. As a result, power conversion efficiency (PCE%) of the device with PANI/GO 3 wt% as the counter electrode reaches 6.39%. The excellent photoelectric properties, simple preparation procedure and inexpensive cost allow the PANI/GO electrode to be a credible alternative for DSSCs.
      1