Siti Zaleha Sa'ad

Effect of Annealing Temperature on the Crystallinity, Morphology and Ferroelectric of Polyvinylidenefluoride- Trifluoroethylene (PVDF-TrFE) Thin Film

The annealing temperature for 250 nm PVDF-TrFE (70:30 mol %) spin coated thin films were varied at solvent evaporation (Ts = 79 °C), Curies transition (Tc= 113 °C), till melting temperature (Tm = 154 °C). XRD measurement showed that, there was an improvement in the crystallinity of the annealed films, consistent with the increased in the annealing temperatures. Morphological studies of the annealed PVDF-TrFE thin films as observed with Field Emission Scanning Electron Microscope (FESEM) (100k magnification), showed enhanced development of elongated crystallite structures known as ferroelectric crystal. However, thin film annealed at 160 °C (AN160) showed fibrous-like structure with appearance of nanoscale separations, which suggested high possibility of defects. Ferroelectric characterization indicated an improvement in the remnant polarization of annealed PVDF-TrFE thin films with the exception to AN160 in which leakage of current was inevitable due to the presence of cracks on the film surface.

Different surface morphology of annealed PVDF-TrFE thin films and the effect on its ferroelectric properties

The different morphology of 250 nm PVDF-TrFE (70:30 mol%) thin films were observed in relation to its ferroelectricity. The annealing temperatures were varied from solvent evaporation (Ts), Curies transition (Tc), up to melting temperature (Tm). It was found that the annealing process promoted the development of elongated crystallite structure also known as ferroelectric crystal, which significantly improved the ferroelectric properties of PVDF-TrFE (70:30 mol%) thin films. However, the presence of nanoscale separations on the thin film annealed over Tm (AN160) suggested high possibility of defects, and hence a reduction in ferroelectric properties of thin films.

Tensile properties of chrome tanned leather waste short fibre filled unsaturated polyester composite

Waste leather from industries was commonly disposed via land filling or incineration where the oxidation of Cr III to Cr VI by oxidants (such as peroxides and hypohalide) can easily occur. Cr VI is well known as carcinogenic and mutagenic element where the excessive exposure to this element can be very harmful. As an alternative way, the leather waste from footwear industry was utilised as filler in unsaturated polyester composite (UPC). The leather waste was ground using 0.25 mm mesh size and used without any chemical treatment. The sample was fabricated via castingtechnique and the study was carried out at 1 wt%, 2 wt% and 3 wt% filler loading. The leather waste filled composites showed lower tensile strength and Young’s modulus than the unfilled composite. The increasing loading amount of leather waste led to the decreased in tensile strength and Young’s modulus. The tensile results was supported by the decreasing pattern of density result which indicates the increasing of void content as the filler loading increased. The results of glass transition temperature are also parallel to the tensile properties where the increasing filler loading had decreased the glass transition temperature. Based on the morphological observation on the fractured tensile sample, much severe filler agglomerations and higher amount of voids was observed at higher filler loading compared to the lower filler loading.Waste leather from industries was commonly disposed via land filling or incineration where the oxidation of Cr III to Cr VI by oxidants (such as peroxides and hypohalide) can easily occur. Cr VI is well known as carcinogenic and mutagenic element where the excessive exposure to this element can be very harmful. As an alternative way, the leather waste from footwear industry was utilised as filler in unsaturated polyester composite (UPC). The leather waste was ground using 0.25 mm mesh size and used without any chemical treatment. The sample was fabricated via castingtechnique and the study was carried out at 1 wt%, 2 wt% and 3 wt% filler loading. The leather waste filled composites showed lower tensile strength and Young’s modulus than the unfilled composite. The increasing loading amount of leather waste led to the decreased in tensile strength and Young’s modulus. The tensile results was supported by the decreasing pattern of density result which indicates the increasing of void content as the filler lo...

Ferroelectric Properties of Polyvinylidenefluoride-Trifluoroethylene (PVDF-TrFE) Annealed Thin Film

The annealing temperature for 250nm PVDF-TrFE (70:30 mol %) spin coated thin films were varied at solvent evaporation (Ts = 79°C), Curies transition (Tc= 113°C) till melting temperature (Tm = 154°C). From the XRD measurement, there was an improvement in the crystallinity of the annealed films, consistent with the increased in the annealing temperatures. Morphological studies of the annealed PVDF-TrFE thin films as observed with Field Emission Scanning Electron Microscope (FESEM) (100k magnification), showed enhanced development of elongated crystallite structures better known as ferroelectric crystal. However, the AN160 thin film showed fibrous-like structure with appearance of nanoscale separations, which suggested to posed high possibility of defects. Ferroelectric characterization indicated an improvement in the remnant polarization of annealed PVDF-TrFE thin films with the exception to AN160 in which leakage of current was inevitable due to the presence of cracks on the film surface.

The Effect of Surface Modification on Physical Properties and Morphology of Oil Palm and Rice Husk Fibres

This study focuses on surface modification of local made fibres for use as reinforcement in the area of polymer matrix composite. Modified oil palm and Rice husk fibres were prepared by using alkaline treatment and the samples were investigated by using Helium pycnometry, Fourier transform infrared spectroscopy (FT-IR), Energy dispersive X-ray fluorescence (ED-XRF) and Field emission scanning electron microscope (FESEM). The oil palm fruit bunch and rice husk fibres were treated with 6.0 w.t % Sodium Hydroxide (NaOH). In order for the treated fibre to be compared, fibres without alkaline treatment were prepared. All the prepared samples were crushed and a sieving machine was used to prepare 100μm particles sizes. The changes in composition of the both fibres due to leakage of original elements as well as the changes in density have been successfully determined by these techniques. Density for both oil palm (OP) and rice husk (RH) fibres decreased after treated. A series of FT-IR spectra confirmed the reduction of the Hemicelluloses and Lignin content after the treatment. The significant changes between untreated and treated fibres were also discussed, whereby the rough surface of fibres becomes smooth due to elimination of impurities. ED-XRF analysis confirmed the percentage of Silica (Si) content for both fibres and proved the reduction of elements present in the composition.

Adsorption of Cu (II) by using modified SBA-15

SBA-15 (Santa Barbara Amoprhous 15) was functionalized by using three different organosilane comprised of different functional group, namely 3-aminopropyltriethoxysilane (APTES), 3-mercaptopropyltriethoxysilane (MPTS) and triethoxyvinylsilane (TEVS). Materials were characterized by using X-ray Diffractor (XRD), Fourier Transform Infrared Specrometer (FT-IR) and Field Emission Scanning Electron Microscopy (FESEM). Batch adsorption study was done to determine the effect of variable parameters, like contact time, temperature, pH and agitation towards adsorption. Adsorption was found to be highly dependent on effects of variable parameters of heavy metal ions aqueous solution. Kinetic adsorption study was carried out by using three models, namely pseudo first order, pseudo second order and intraparticle diffusion. Adsorption rate was found to be fast and well presented by using pseudo second order.

Comparison study of Cu (II) adsorption by using aminopropyl and vinyl functionalized MCM-41

MCM-41 functionalized with aminopropyl and vinyl group were studied as potential adsorbent for removal of Cu (II). Materials were characterized by using XRD, FT-IR and TGA. Standard structure of MCM-41 at [100] planar was retained after functionalization. Batch adsorption study was carried out to determine effect of variable parameters (i.e. initial concentration, pH and adsorbent dosage) towards adsorption of Cu (II) from aqueous solution. Cu (II) adsorption was found to be dependent on variable parameters. Adsorption of Cu (II) was also found to fit Langmuir isothermal compared to Freundlich isothermal model. Regeneration of adsorbent by using disodium EDTA and acid base treatment showed that percentage of metal recovery is higher when using disodium EDTA.

Optimization of Annealing Temperature for PVDF-TrFE (70:30 mol %) Thin Film

The annealing temperature of 250nm PVDF-TrFE (70:30 mol%) spin coated thin films were optimized. The annealing temperature were varies starting from solvent evaporation (Ts), Curies transition (Tc), up to melting temperature (Tm). The result shows that the dielectric constant increases with the increasing of annealing temperature. Supported with the XRD observation indicating there were an improvement in crystallinity consistently with the increasing of the annealing temperature. Morphological properties of the annealed PVDF-TrFE thin films were observed by utilizing Field Emission Scanning Electron Microscope (FESEM) at 100k magnification. It can be found that, the annealing temperature promotes the development of elongated crystallite structure which known as ferroelectric crystal. However, the presence of nanoscale cracks on the thin film annealed at 160°C (AN160, over Tm) suggesting high possibility to posed defects while in device applications.

Comparison study of amino-functionalized and mercaptopropyl-functionalized mesoporous silica MCM-41

The ability to decorate silicate surface with different organoalkoxysilanes creates powerful new capabilities for catalyst, adsorbents and chemical separation. Mesopororus silica, MCM-41 was modified by grafting of amino and mercaptopropyl functional group. The structures of these materials were characterized by using Fourier Transform Infrared Spectroscopy (FT-IR), and X-Ray diffraction (XRD). The samples were found to exhibit structural properties similar to those reported earlier. Significant functional groups of the modified mesoporous silicates were found in the spectrum of FT-IR. Standard structure of mesoporous silicates were found to be preserved at planar [100] of XRD difractogram of mesoporous silicates. Adsorption of Cu (II) ions were done under different temperatures, initial concentrations and pH. Adsorption process also was determined from kinetic point of view and was found to be better fitted to pseudo second order of kinetic model.