Maizlinda Izwana Idris

Short review of ultrafiltration of polymer membrane as a self-cleaning and antifouling in the wastewater system

This paper focuses on ultrafiltration polymer membrane for wastewater systems as a self-cleaning and antifouling. Fouling is one of the most important problems in almost all membrane processes. In this review, membrane antifouling and self-cleaning properties can be improved by using titanium dioxide (TiO2) particles and UV radiation on membrane structure and surface. Coating TiO2 particles on membrane surface is an advanced method to minimize membrane fouling. Hence, these properties can be improved the membrane performance.

Passive Damage Detection of Natural Fibre Reinforced Composites Using Sensor Response Data

This paper presents the detection of impact damage in a natural fibre reinforced composite plate under low velocity impact damage. Lead Zirconate Titanate (PZT) sensors were placed at ten different positions on each plate in order to record the response signals. The response signals captured from each sensor were collected for impacts performed by a data acquisition system. The impacted plates were examined with optical microscope to examine the damaged areas. It was found that the damaged size grew proportionally with impact force. The results also revealed that PZT sensors can be used to detect the damage extent with the waveform of sensor signals implying the damage initiation and propagation which detected above the damage force of 150N.

Properties of polyurethane foam/coconut coir fiber as a core material and as a sandwich composites component

This research focuses on the fabrication and characterization of sandwich composite panels using glass fiber composite skin and polyurethane foam reinforced coconut coir fiber core. The main objectives are to characterize the physical and mechanical properties and to elucidate the effect of coconut coir fibers in polyurethane foam cores and sandwich composite panels. Coconut coir fibers were used as reinforcement in polyurethane foams in which later were applied as the core in sandwich composites ranged from 5 wt% to 20 wt%. The physical and mechanical properties found to be significant at 5 wt% coconut coir fiber in polyurethane foam cores as well as in sandwich composites. It was found that composites properties serve better in sandwich composites construction.

Biomimetic Bone-Like Apatite Coating on Anodised Titanium in Simulated Body Fluid under UV Irradiation

Low temperature deposition techniques of bioceramics coatings are now being researched and developed to avoid deficiencies inherent in high temperature techniques. Biomimetic coatings is a solution-based method conducted at ambient temperature to deposit bioactive coatings on the surface. The current study aims to investigate the effect of ultraviolet (UV) irradiation on the coating of bone-like apatite on the anodised surface. High purity titanium foils were anodised with an applied voltage of 350 V, current density of 70 mA.cm-2 in mixture of 0.04 M β-glycerophosphate disodium salt pentahydrate (β-GP) and 0.4 M calcium acetate (CA) for 10 min. After anodic oxidation, UV light treatment was conducted in pH-adjusted distilled water for 12 hours with ultraviolet light A (UVA) irradiation. Subsequently, the UV-treated anodised titanium foils were soaked in SBF for 7 days with/without UVA irradiation. After SBF immersion for 7 days, anodised titanium with combination of UV light treatment and UV irradiation during in vitro testing was fully covered by highly crystalline bone-like apatite at maximal thickness of 2.8 μm. This occurred mainly due to the formation of large amounts of Ti-OH groups which act as nucleation sites for bone-like apatite. This study also revealed that UV irradiation during in vitro testing is superior in promoting growth of bone-like apatite compared to UV light treatment. The suggested mechanism for bone-like apatite formation on anodised titanium under different UV irradiation conditions is illustrated in this article. The findings of this study indicated that biomimetic bone-like apatite coating with assistance of UV irradiation is an effective method in accelerating the formation of bone-like apatite.

Investigation of Surface Properties of Titanium Treated with Combined Alkali and Sodium Removal Treatments

Recent studies revealed the incorporation of sodium removal treatment in between alkali and heat treatments to prepare a sodium-free bioactive surface on titanium. This method has been reported to be more effective than conventional alkali and heat treatments to promote titanium osteointegration. This study aims to investigate the surface properties of high purity titanium after subjected to alkali treatment and subsequent sodium removal treatment. High purity titanium foils were immersed in 5 M NaOH at 60 °C for 24 hours followed by immersion in diluted HCl acid and/or distilled water at 40 °C for a period of time. The surface morphology and composition were examined using Field Emission Scanning Electron Microscope/Energy-Dispersive X-Ray Spectroscopy (FESEM/EDS). The surface wettability was evaluated by water contact angle. The surface functional groups were analysed using Fourier Transform Infrared Spectroscopy (FTIR). It was revealed that alkali and subsequent sodium removal treatments have rendered these samples high wettability and surface energy with the introduction of hydroxyl groups. Furthermore, diluted HCl treatment, water treatment and combination of both treatments removed sodium from the surfaces of alkali-treated titanium effectively (<5wt% Na) without altering existing hydroxyl groups.

Effect of Bath Temperature on Surface Properties of Anodised Titanium for Biomedical Application

Anodic oxidation is an electrochemical method to deposit ceramic coatings on the metals substrate to improve the bioactivity. This study aims to investigate the effect of bath temperature on the surface properties of anodised titanium. High-purity titanium foil was modified by anodising in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA). The experiments were carried out at 350 V, 30 mA.cm-2 for 10 minutes at different bath temperature (4-100 °C). Field emission scanning electron microscopy (FESEM), glancing angle X-ray diffractometer (GAXRD) and goniometer were used to characterise the surface morphology, mineralogy and wettability of anodised titanium, respectively. The results showed that porosity and crystallinity of surface decreased as increasing of bath temperature. Interestedly, the α-tricalcium phosphate (α-TCP) was deposited on the samples which anodisation at higher bath temperature (≥ 60 °C) and resulted high hydrophilicity behaviour even the surface was found relatively smooth.

Precipitation of Hydroxyapatite on Pure Titanium Substrate via Single Step Anodic Oxidation

Anodic oxidation is an electrochemical method that deposits ceramic coatings on the metal substrates to improve the bioactivity of implant. In this study, a novel approach was proposed to precipitate hydroxyapatite (HAP) directly on the surface of pure titanium through anodic oxidation approach. As part of the proposed approach, a new formulation of electrolyte was introduced, which consists of 0.04 M β-glycerophosphate (β-GP), 0.4 M calcium acetate (CA) and 1.0 M sulphuric acid (H2SO4). The approach herein only requires a single step to precipitate the HAP directly on the surface of titanium through anodisation process within the electrolyte. High purity titanium foils were anodised in 0.04 M β-GP + 0.4 M CA + 1.0 M H2SO4 at 350 V and 70 mA.cm-2 for 10 minutes at varying fractions of mixture volumes of H2SO4 (0-100 vol%). The surface properties of anodised titanium were characterised by using several methods, namely the field emission scanning electron microscopy (FESEM), glancing angle X-ray diffractometer (GAXRD) and goniometer. The outcome of the characterisation showed that the needle-like HAP was precipitated on the titanium, whereby anodising in electrolyte contains 12.5 vol% H2SO4. Combinations of anatase, rutile, titanium, tricalcium phosphate (Ca3O8P2) and calcium diphosphate (Ca2O7P2) elements were detected within the anodised titanium, whereby the anodising in electrolyte contains 50 vol% H2SO4.

Surface properties, crystallinity and optical properties of anodised titanium in mixture of β-glycerophosphate (β-GP) and calcium acetate (CA)

Anodic oxidation is an electrochemical method for the production of ceramic films on a metallic substrate. It had been widely used to deposit the ceramic coatings on the metals surface. This method has been widely used in surface modification of biomaterials especially for dental implants. In this study, the surface morphology, crystallinity and optical properties of titanium foil was modified by anodising in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA). The experiments were carried out at high voltage (350 V), different anodising time (5 and 10 minutes) and current density (10-70 mA.cm−2) at room temperature. Anodised titanium was characterised by using field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), and UV-Vis spectrometry. The result of the experiment showed that surface morphology, crystallinity and optical properties depended strongly on the current density and anodising time. More porous surface and large amount...

Effect of applied voltage on surface properties of anodised titanium in mixture of β-glycerophosphate (β-GP) and calcium acetate (CA)

Anodic oxidation is a surface modification method which combines electric field driven metal and oxygen ion diffusion for formation of oxide layer on the anode surface. This method has been widely used to modify the surface morphology of biomaterial especially titanium. This study aimed to investigate the effect of applied voltage on titanium. Specifically, the titanium foil was anodised in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA) with different applied voltage (50-350 V), electrolyte concentration (0.04 M β-GP + 0.4 M CA), anodising time (10minutes) and current density (50 and 70 mA.cm−2) at room temperature. Surface oxide properties of anodised titanium were characterised by digital single-lens reflex camera (DSLR camera), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM). At lower applied voltage (≤150 V), surface of titanium foils were relatively smooth. With increasing applied voltage (≥250 V), the oxide l...

Mechanism of Bone like Apatite Formation on Anodised Titanium under UV Irradiation

Anodic oxidation is an electrochemical method for the production of ceramic films on a metallic substrate. It had been widely used to deposit the ceramic coatings on the metals surface. UV light was used to accelerate the bone-like apatite formation on the anodised titanium in this study. The processing was composed of two steps which were UV light treatment after anodic oxidation, and UV light illumination during simulated body fluid (SBF). This study aims to study the mechanism of bone-like apatite formation on the surface of anodised titanium under UV irradiation. High purity titanium foils were anodised at 350 V, 70 mA.cm in electrolytic solution containing glycerophosphate disodium salt pentahydrate (βGP) and calcium acetate monohydrate (CA) for 10 minutes. UV light treatment was conducted in pH-adjusted distilled water (pH 1) for 12 hours. Next, SBF was carried out by illuminating with UV lamp for 1 week. Anodised titanium foils were characterised by using field emission scanning electron microscopy (FESEM) and fourier transform infrared spectroscopy (FTIR). The results showed that bone-like apatite started to form at concave surface due to the presence of nucleation site. The surface of anodised titanium was fully covered by bone-like apatite after soaking in SBF for 4 days. Denser bone-like apatite was formed after 7 days immersion in SBF. The mechanism of the growth of bone-like apatite was illustrated. The FTIR results showed that carbonated bone-like apatite was formed on the surface on anodised titanium. The result indicated that the anodised titanium in mixture of β-GP + CA possess excellent apatite-forming ability under UV irradiation. Keywords— anodic oxidation, titanium, titanium dioxide, UV irradiation, simulated body fluid, bone-like apatite.