Fauziah Abdul Aziz

Cellulose Microfibril Angle in Wood and Its Dynamic Mechanical Significance

The orientation of the cellulose microfibrils in the S2 layers of the cell walls of softwood has a significant influence on the mechanical properties of wood. The angle between the cellulose fibrils and the longitudinal cell axis, the microfibril angle, MFA was found to be a critical factor in determining the physical and mechanical properties of wood (Cave, 1997). For this reason, considerable effort has been directed towards the measurement of the cellulose MFA. Direct measurement of MFA has been made by highlighting microfibrils in individual cell walls with iodine staining, but the most widely adopted techniques use either wideangle X-ray diffraction or small-angle X-ray scattering The pioneering work of Cave (1966) and Meylan (1967) led to the use of the ‘T’ parameter derived from the curve distribution of the intensity diffracted by the (002) planes of the cellulose fibrils.

Regression models on the age-affecting and microfibril angle of Acacia mangium

Diffraction patterns arising from crystal planes of various sample forms of wood trees had attracted scientific research in determining the crystallographic measurements. As such the tropical hard wood in Sabah, Acacia mangium was chosen for experimental data. Age-contributing factors were measured; the angle of reflection (θ), relative intensity, full width at half maximum (FWHM), the nearest between two neighbouring atoms in the crystalline structure (d-spacing) and the peak height, had been taken into account at different ages, pith and bark of tree. Regressions were done in comparing the microfibril angle, MFA at different ages using the least-square method and cubic-spline interpolation. The latter was able to interpolate a polynomial up to the third order. The range of the optimum angle was found to have benefited foresters in deciding the time for tree cropping and harvesting.

Nanocellulose: a promising material for engineering - an overview

Nanocellulose from abundant sources is attracting attention because it offers excellent properties. There are a number of sources that can be used to extract cellulose such as algae, bacteria, non-wood and wood materials. Numerous methods were established in order to isolate nanocellulose and each method produced different types of nanocellulose. However, there are some limitations in merging nanocellulose into polymeric material due to the presence of the hydrophilic group in nanocellulose structure. In order to overcome the limitations, surface modification method was introduced and may improve the homogeneity and interfacial interaction between nanocellulose and polymeric material. Utilising nanocellulose as reinforcement filler has successfully proved the hypothesis, where properties of the composite were enhanced according to several studies.

Isolation of Microfibrillated Cellulose (MFC) from Local Hardwood Waste, Resak (Vatica spp.)

Micrifibrillated cellulose (MFC) is generally can be prepared either by acid hydrolysis, chemical treatments, or by a high pressure refiner. In this study, the MFC of Resak’s hardwood waste with high degree of crystallinity has been obtained by an acid hydrolysis using mineral acid H2SO4. The microstructures of the MFC were characterized via X-ray diffraction (XRD) and Field emission scanning electron microscope (FESEM).

The Treated Cellulose Micro/Nano Fibers (CMNF) from Bioresources in Malaysia

Cellulose Micro/Nano fibers (CMNF) from various plants which is Resak (Vatica spp.) waste, Merbau (Intsia bijuga) waste, banana (Musa acuminata) pseudo-stem and pineapple (Ananas comosus) leaf fibers have been isolated and characterized. Isolation of microfibril cellulose from raw fibers was achieved using alkaline treatment and bleaching. The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Characterizations of treated and untreated samples were compared. The comparison between those treated and untreated samples giving different crystallite size, crystallinity, arrangement of CMNF and surface morphology from different plants. Hence, with these information different nanocomposite from CMNF can be constructed and manipulated for various application.

X-Ray Diffraction (XRD) Analysis of Cellulose from Banana (Musa acuminata) Pseudo-Stem Waste

Alkali treatment and bleaching have been applied on banana fibers obtained from harvested pseudo-stem of the banana plant Musa acuminata collected in Banting, Selangor, Malaysia. The structure and morphology of the fibers have been found to be affected by the used of alkaline treatment and bleaching. The crystallite size and percentage crystallinity of the untreated (raw banana fibers) and treated (microfibrils cellulose) fibers were investigated using X-Ray Diffraction (XRD). XRD studies shows that the treated cellulose prepared by such chemical treatment (alkali and bleaching treatment) were more crystalline than the untreated banana fibers.

Modeling Microfibril Angle and Tree Age in Acacia Mangium Wood Using X-Ray Diffraction Technique

 Abstract—The term microfibril angle (MFA) in wood refers to the angle between the spiralling cellulose fibrils and the long axis of the tracheid cell wall. Diffraction patterns arising from crystal planes of various sample forms of wood trees had attracted scientific research in determining the crystallographic measurements. Acacia mangium classified as a hardwood was chosen for experimental data. Age- contributing factors were measured; the angle of reflection (θ), relative intensity, full width at half maximum (FWHM), the nearest between two neighbouring atoms in the crystalline structure (d-spacing) and the peak height, had been taken into account at different ages, pith and bark of tree. Regressions were done in comparing the microfibril angle, MFA at different ages using the least-square method and cubic-spline interpolation. The latter was able to interpolate a polynomial up to the third order. The range of the optimum angle was found to have benefited foresters in deciding the time for tree cropping and harvesting.

Preparation of Cellulose Microfibrils from Banana (Musa acuminata) Pseudo-Stem Waste

Cellulose microfibril from banana pseudo-stem fiber waste has been isolated and characterised. Isolation of microfibril cellulose from raw fibers was achieved using alkaline treatment and bleaching. The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Characterizations of treated and untreated samples were compared. XRD studies shows that the treated cellulose prepared by alkaline and bleaching treatment was more crystalline than the untreated banana fiber. Surface morphological studies using FESEM shows there was a reduction in fiber diameter during the chemical treatment.

A facile hydrothermal approach for catalytic and optical behavior of tin oxide- graphene (SnO2/G) nanocomposite

A cost-effective, facile hydrothermal approach was made for the synthesis of SnO2/graphene (Gr) nano-composites. XRD diffraction spectra clearly confirmed the presence of tetragonal crystal system of SnO2 which was maintaining its structure in both pure and composite materials’ matrix. The stretching and bending vibrations of the functional groups were analyzed using FTIR analysis. FESEM images illustrated the surface morphology and the texture of the synthesized sample. HRTEM images confirmed the deposition of SnO2 nanoparticles over the surface of graphene nano-sheets. Raman Spectroscopic analysis was carried out to confirm the in-plane blending of SnO2 and graphene inside the composite matrix. The photocatalytic performance of the synthesized sample under UV irradiation using methylene blue dye was observed. Incorporation of grapheme into the SnO2 sample had increased the photocatalytic activity compared with the pure SnO2 sample. The electrochemical property of the synthesized sample was evaluated.

One pot synthesis of hybrid ZnS–Graphene nanocomposite with enhanced photocatalytic activities using hydrothermal approach

In this work, a facile, one pot hydrothermal approach was undertaken to synthesize ZnS/Graphen hybrid nanocomposites. X-ray powder diffraction analysis was carried out to identify the structure and crystalline phase of the prepared sample. Scanning electronic microscopic analysis (SEM) was carried out to observe the surface texture and the Particle shape and size of the developed nanocomposite samples were analyzed using Transmission electronic microscopic analysis (TEM). The elemental composition of the prepared sample was determined using EDS spectrum. The functional groups for pure and ZnS coated Graphene nanocomposites were confirmed using FTIR spectrum. The peak shifts for the individual composite materials were observed using Raman spectroscopic analysis. The optical properties of the samples were examined using UV–Vis reflectance and photoluminescence spectroscopic analysis (PL). The sample showed enhanced photocatalytic performance compared to pure ZnS which is attributed to the reduction of photoinduced electron–hole pair recombination persuaded by incorporation of nanoporous graphene inside the nanocomposite matrix.