Ahmad Zuraida

Micromechanical Property Investigations of Poly(lactic acid)–Kenaf Fiber Biocomposites

In this research, investigation on the interfacial shear strength of poly(lactic acid)–kenaf fiber biocomposite was investigated using microbond tests. Tensile properties and fracture behaviors of single kenaf fiber are tested via in situ monitoring with acoustic emission (AE). During tensile loading, acoustic signal recorded higher amplitude of above 20 dB up to the maximum force, which corresponds to breakage of single kenaf fiber. Based on microbond tests and AE evaluation, a correlation has been established on failure of kenaf fiber, which is due to debonding of filament and internal structure, cracking of fiber and breakage of fiber.

Fourier Transform Infrared Study on Sol-Gel Derived Manganese-Doped Hydroxyapatite

Manganese is one of metallic elements which appear in biological apatite like bone and teeth. Its important effect on the growth and development of bone has been well known. Here, we have synthesized manganese-doped hydroxyapatite (HA) via sol-gel method. White ammoniacal solution of monomers were refluxed until white gel formed, followed by drying and calcination at 500 – 900°C. Four different concentration of manganese (2, 5, 10 and 15 mol%) were successfully incorporated into HA crystals. XRD analysis showed that the crystallinity increased with the increased amount of manganese. SEM measurement also showed that individual particles become bigger with the increasing content of Mn. Tricalcium phosphate appeared as an additional phase when calcined at 800°C. It was also proven that the incorporation of manganese reduced the peak intensity of tricalcium phosphate. FTIR analysis is in good agreement with the results from XRD measurement where the peaks of OH (630 cm-1) and PO4 3- (565 cm-1, 601 cm-1, 960 cm-1, 1020 cm-1 and 1100 cm-1) bands of HA phase show higher intensity with the increasing concentration of manganese. FTIR measurement also showed that the presence of HPO4 2- (880cm-1) decreased in intensity with the increased Mn content, showing that the anion exist in less crystalline phase of HA.

Properties of Sago Starch-Nanoclay Biocomposites Film

This paper reported on properties of sago starch that was compounded with montmorillonite (MMT) nanoclay to form biodegradable composites film. The film was fabricated via film casting method with glycerol as a plasticizer. The investigated biocomposites film was prepared at starch-glycerol/MMT weight fraction of 90/10, 85/15, 80/20 and 75/25. The physical properties of the film, namely thickness and density were studied and results show that incorporation of nanoclay as filler affects the biocomposites physical properties. Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to analyze the film’s morphological properties and chemical characteristics, respectively. SEM shows that less clay content in the film produces homogenous phase and well dispersed of clay platelets within the starch matrix. FTIR summarizes that MMT nanoclay is able to form hydrogen bonding with starch.

The Study of Glycerol Plasticized Thermoplastic Sago Starch

Thermoplastic sago starch (TPSS) was produced by plasticizing with glycerol through melt blending before being compression moulded. The investigated TPSS was prepared at glycerol/starch weight fraction of 40/60, 35/65 and 30/70. The functional groups composition, tensile strength, density, moisture content and water absorption were evaluated and compared at different glycerol/starch ratio. The compatibility of the glycerol as the plasticizer in the TPSS was proven by Fourier transform infrared spectroscopy (FTIR) where glycerol could form stable hydrogen bond with sago starch. This preliminary study demonstrated that the stress at maximum load was only applicable for lower glycerol/starch ratio of 30/70. The density of TPSS was inversely proportional to the increment of glycerol/starch ratio whereas moisture content and water absorption had opposite relationship.

Interfacial shear strength of Polylactic Acid-Kenaf fibre biocomposites

This paper reported the interfacial shear strength (IFSS) between kenaf fibre (KF) and polylactic acid (PLA) matrix which was measured using microbond tests device. The value of IFSS obtained in PLA-KF is comparable to other polymer with natural fibre reinforcements. The properties of single kenaf fibre was determined from tensile tests and also described in this paper. From single kenaf fibre properties, various mechanical properties can be estimated for various applications.

The Study of Biodegradable Thermoplastics Sago Starch

The motivation of this work is to lessen the dependence on non-degradable plastic packaging which can lead to waste disposal problems. In this paper, the alternative biodegradable material developed by using local available sago starch in the present of biodegradable glycerol as plasticizer, as well as a set of composition added with citric acid as co-plasticizer is reported. Starch was added with 15-30 w/w% of glycerol to prepare workable bioplastics. The samples were characterized by Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) and tested for mechanical properties. The results reveale that, the tensile strength of the bioplastic is increasing with the increasing of glycerol until the optimum amount of 30 w/w%. The similar trend is also observed upon the addition of the citric acid. The decrease of the strength after the optimum point, however is obvious in the specimens with the addition of citric acid which is about 50% lower than the specimen without citric acid.

Egg Yolk as Pore Creating Agent to Produce Porous Tri-Calcium Phosphate for Bone Implant Application

Porous tri-calcium phosphate which is to be applied as artificial bone was prepared via protein consolidation method and egg yolk is used to give binding effect as well as to create porosity. In this experiment, fractions of egg yolk is controlled from 50 wt%, 60 wt%, 70wt% and 80 wt% and the mixture of egg yolk and tri-calcium phosphate powder were dried at 60 °C before undergone uniaxial compaction method. Subsequently, pressure of 68.5 MPa is given to the mold to produce cylindrical shape samples with diameter to height ratio of 1:2. Samples were then sintered at 1100°C to achieve porous tri-calcium phosphate. This method produces porous tri-calcium phosphate with desired porosity of 20-54.5% and acceptable compressive strength between 0.7-0.07 MPa. Besides, microporosity of 0.4-1μm and macroporosity in the range of 100-800μm were successfully obtained from this method.

Application of Low Cost Polyurethane (PU) Foam for Fabricating Porous Tri-Calcium Phosphate (TCP)

Porous tri-calcium phosphate, well-known for its use as artificial bone, was prepared via sponge polymeric method by the application of low cost polyurethane (PU) foam as a structural guide. In this experiment, fractions of tri-calcium phosphate (TCP) are controlled at 12, 13, 14, 15 and 16 grams and mixed with distilled water (fixed at 25 grams) to produce slurries. Subsequently, rectangular shaped PU foam was immersed in the slurry and dried for three days. Samples were then sintered at 1100°C to obtain porous tri-calcium phosphate. This method produces porous tri-calcium phosphate with porosity between 31-44% and the compressive strength in the range of 0.17-1.02 MPa. The macroporosity of the tri-calcium phosphate, observed through SEM, was in the range of 100 µm to 900 µm.

Properties of Montmorillonite-Reinforced Thermoplastic Sago Starch Composites

In this work, biodegradable polymer was prepared from thermoplastic sago starch (TPSS) plasticized with glycerol. In order to improve the properties of the TPSS, Montmorillonite (MMT), a kind of reinforced additive was used in the preparation of montmorillonite-reinforced thermoplastic sago starch (MTRSS) composites via hot pressing method. The fabricated samples were investigated through X-ray diffractometry, Fourier transform infrared (FT-IR) as well as thermal and morphological properties. FT-IR patterns show that in the MTRSS composites, the C-O groups of sago starch molecules shifted to higher wave number, while the reactive hydroxyl groups of MMT shifted to the lower wavenumber. On the other hand, X-ray diffraction revealed that MMT restrained the crystallization of MTRSS and intercalated in TPSS. Thermogravimetric analysis (TGA) revealed that the thermal stability of MTRSS was better than those of TPSS. In addition, the scanning electron micrograph results show that MMT were uniformly dispersed in the TPSS.

Cotton Reinforced Biopolymer Matrix Composite: Effect of Curing and Aging Conditions on its Mechanical Properties

The attention in natural fiber reinforced biopolymer composite materials has been rapidly growing both in terms of industrial applications and basic research. This study investigated on the effect of aging time on mechanical properties and morphological structure of thermoset protein-based composites from egg albumen reinforced by natural cotton fibres. The cotton/albumen composites (CAC) were fabricated by hands lay-up technique with 10 w/w % of fiber content. The samples were cured and aged at room temperature for different aging time from 7 to 32 days. The cotton fibres have contributed in a significant improvement in mechanical strength and toughness of the composites. Tensile strength of the composites achieved the optimum strength of 9 MPa after 21 days of aging time and constant till 32 days. As the aging time increased, impact strength of the composites also improved to some value of 20 kJ/m2. Thereby after 21 days observation, the composites show an equilibrium moisture content of 6-9 wt%, and the strength remains stable at room condition with 50-60% relative humidity (RH). Morphology studied using SEM justify that the moisture content after aging time influenced mechanical properties of the composites.