Mohamad Kahar Ab Wahab
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Preferred name
Mohamad Kahar Ab Wahab
Official Name
Mohamad Kahar, Ab Wahab
Alternative Name
Kahar, Ab Wahab M.
Mohd Kahar, Ab Wahab
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Scopus Author ID
54793162000
Researcher ID
CYR-1062-2022

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  • Publication
    Dynamic vulcanization of Polypropylene / natural rubber blends filled with Cyperus Odoratus
    (IOP Publishing, 2020)
    Norfatulikmah Zainal Abidin
    ;
    Mohamad Kahar Ab Wahab
    A new thermoplastic blend was developed using polypropylene (PP) with natural rubber (NR) as the base material. The natural filler is added to enhance the properties of PP/NR blend. The first series was to compare the properties of PP/NR blend with different filler loading. Second series was to investigate the effect of dynamic vulcanization on the properties of PP/NR blend filled with Cyperus Odoratus with the intention of improving the blend properties. Process development, tensile properties, thermal analysis, FTIR analysis and morphological characterization of blends were investigated with the variation of the conditions of the blend. The increasing filler loading decrease the tensile properties of the PP/NR blend and it shows in the morphology study of the blend. Dynamic vulcanization of the blend resulted in improved tensile and thermal properties compared to unvulcanized counterpart. This result is confirmed by the SEM study that showed better dispersion of NR in the PP matrix and improved adhesion between the two phases.
      2  17
  • Publication
    Effect of dynamic vulcanization on properties of linear low density polyethylene/natural rubber filled with Calcium Carbonate
    (IOP Publishing Ltd, 2020)
    Loh Annie
    ;
    Mohamad Kahar Ab Wahab
    ;
    Elammaran Jayamani
    The effect of dynamic vulcanization with different loading of calcium carbonate (CaCO3) on linear low density polyethylene/natural rubber using N,N'-m-phenylene bismaleimide (HVA-2) vulcanized and dicumyl peroxide (DCP) vulcanized as a cross-linker were investigated. Optimum ratio of LLDPE/NR blends was chosen is 70/30 in this study. Calcium carbonate loading was varied at 0wt%, 5wt%, 10wt% and 20wt% as filler in LLDPE/NR blends. The study showed that the tensile properties of the un-vulcanized LLDPE/NR blends were deteriorated with increasing in CaCO3 content. The dynamic vulcanization approach by using the HVA-2 and DCP dynamic vulcanization agents was applied on the LLDPE/NR blends in order to compensate the deterioration properties caused by the incorporation of CaCO3. According to the results, the addition of HVA-2 and DCP showed the composites were better in water resistance and tensile properties as compared to the standardized counterpart. The morphological analysis by using the scanning electron microscopy (SEM) found out that the interfacial adhesion and dispersion of CaCO3 was improved in both vulcanization systems.
      2  15
  • Publication
    The effect of modified Jackfruit (Artocarpus Heterophyllus Lam.) seed starch on the properties of poly lactic acid
    (IOP Publishing, 2020)
    Nur Amira Sahirah Abdullah
    ;
    Mohamad Kahar Ab Wahab
    This work investigates the effect of the modified jackfruit seed starch with silane coupling agent on the properties of polylactic acid (PLA). Jackruit seed starch will converted into thermoplastic like in the presence of glycerol as plasticizer. The physicochemical properties and thermal stability of the native and modified jackfruit seed starch blends with PLA were comparatively investigated. The structural changes after modification was analyzed by using Fourier Transmission Infra-red technique. Its confirmed the successful of the silane treatment from the newly peak observed at 1020 cm-1 and 1105 cm-1 for Si-O-Si and starch-O-Si bonds, respectively. For tensile strength, the value shows slightly decrese with the increasing of jackfruit seeds starch content. However the tensile properties for silane treatment shows the better improvement as compared to untreated counterpart. In the case of plasticized jackfruit seed starch, the elongation at break value increase with filler loading due to the ductile behavior of the blends system. The modification of the starch with silane coupling agent gives better interfacial adhesion between starch and PLA matrix while the glycerol gives the ductility and hydrophobicity to the starch and gives better elongation at break for the PLA/starch blends. The thermal stability of the silane treated PLA/starch blends was also improved as compared to the native PLA/starch blends.
      4  11
  • Publication
    Structural and dimensional analysis of LDPE/TPS blend filled with calcium carbonate
    (IOP Publising, 2020)
    Anis Adila Ab Halim
    ;
    Mohamad Kahar Ab Wahab
    This study aims to investigates the changes in structural, thermal stability and water absorption properties of thermoplastic starch (TPS) before and after modification with citric acid and ascorbic acid. The first stage of study involved the preparation of TPS from native potato starch. Starch will be converted into thermoplastic like in the presence of glycerol as plasticizer. For the second stage, LDPE was blended with TPS to produce LDPE/TPS blend with and without modification. Then, the influence of calcium carbonate as particulate filler on the properties of LDPE/TPS blends was also investigated. Structural findings based on the FTIR analysis showed the formation of new ester bond on the TPS backbone after the modification, which correspond to the formation of crosslinking network in TPS phase. Water absorption test was used to determine the effectiveness of TPS modification in term of physical interaction between the phases.
      1  29
  • Publication
    Effect of glycerol as plasticizer on the tensile properties of chitosan / microcrystalline cellulose films
    ( 2021-05-03)
    Lau S.
    ;
    Mohamad Kahar Ab Wahab
    ;
    Yusrina Mat Daud
    The chitosan/microcrystalline cellulose (MCC) film was produced through solution casting with different composition of MCC and the presence of plasticizer. This chitosan /MCC film is a biodegradable polymer due to all the ingredient was natural resources. MCC and chitosan can be found abundantly in the earth, thus, can be obtained easily. One testing was conducted which was tensile test. The optimum ratio of chitosan/MCC was 97:3 (chitosan:MCC). At this ratio, chitosan /MCC film has the highest tensile strength which was 14.73 MPa without adding any plasticizer. By the addition of plasticizer, properties of chitosan /MCC film was improved. Glycerol was used in chitosan /MCC film as plasticizer. Higher tensile strength and elongation at break follow by lower Young's modulus were the result showing that with the addition of glycerol, their film properties were able to be enhanced. About 13.57% increment in tensile strength and 47.66% in elongation at break of optimum ratio for plasticized chitosan/MCC films compared to unplasticized films.
      1  20
  • Publication
    Preparation and characterization of LDPE/TPS blend filled with calcium carbonate
    (IOP Publishing Ltd, 2020)
    Anis Adila Ab Halim
    ;
    Mohamad Kahar Ab Wahab
    The measurement of low-density polyethylene / thermoplastic starch (LDPE/TPS) composite with different loading of calcium carbonate (CaCO3) as filler was conducted under several testing such as the tensile test and scanning electron microscopy. The preparation of LDPE/TPS/CaCO3 composite was divided into three stages. The first stage involved the preparation of TPS with and without modification with carboxylic acid. The second stage, LDPE was blended with TPS to produce LDPE/TPS blend. LDPE/TPS blends with blend ratio of 100:0, 90:10, 80:20, 70:30, 60:40 and 50:50 was prepared. Each composition will undergo tensile testing to analyze their mechanical properties. The optimum LDPE/TPS blend ratio was chosen for subsequent study. Third stage involved the compounding of the chosen LDPE/TPS blend ratio with CaCO3. The result indicate that LDPE/TPS with incorporation of CaCO3 gave higher value of tensile properties as compared to LDPE/TPS blend. Based on the SEM micrograph, treated TPS with citric acid and ascorbic acid performed better interfacial phase as compared to untreated TPS, with no agglomeration and voids formation.
      4  12
  • Publication
    Morphological analysis on crosslinked plasticized starch filled with microcrystalline cellulose
    ( 2021-05-03)
    Foong J.Y.
    ;
    Mohamad Kahar Ab Wahab
    ;
    Mohd Fairul Sharin Abdul Razak
    ;
    Yusrina Mat Daud
    This work investigates the effect of the photo and peroxide crosslinked thermoplastic starch on the morphological properties of thermoplastic starch (TPS) / microcrystalline cellulose (MCC) films. Granulated starch will converted into thermoplastic like in the presence of glycerol as plasticizer. The amount of MCC filler carried out in this research is 0 %, 3 %, 6 %, 9 % and 12 % of the dry weight of starch. The morphological properties of photo-crosslinked TPS and peroxide crosslinked TPS were were analysed by using scanning electron microscope (SEM) and optical microscope for soil burial and weathering test. Each formulation has undergone tensile test to study their stress-strain properties and the optimum formula is obtained for subsequent studies. The increasing MCC loading increase the tensile properties of the TPS/MCC up to 6% MCC as support by morphology study. The increament in tensile strength was confirmed by the SEM study that showed better dispersion of MCC in the TPS matrix and exhibited coarser surfaces as compared to uncrosslinked counterpart. The TPS/MCC films also can last more than 20 days under soil burial test. The thermoplastic starch films will start to degrade after placed under normal weathering conditions for 20 days while the addition of rainfall will also accelerate the degradation process.
      1  19