Poly(Lactic Acid) (PLA)-reinforced Kenaf Bast Fiber Composites: The Effect of Triacetin

In this article, the mechanical, morphological, and dynamic-mechanical properties of the blends of PLA and kenaf bast short fiber were investigated. The composites, with different fiber loading and triacetin content, were prepared by melt blending techniques using a Brabender internal mixer at 60 rpm and 170�C for 10 min and their properties were examined. Pure PLA was used as a reference for the biocomposite samples. Triacetin was used as a plasticizer for PLA and PLA/kenaf composites in order to study the improvement in tensile properties. The tensile strength and stiffness of unplasticized biocomposite materials decreased with the addition of kenaf bast fibers but improved with the addition of triacetin. The optimum fiber loading was 30wt% kenaf fibers in the PLA matrix with the addition of 5% triacetin. The dynamic mechanical analyses showed that triacetin improved the thermal stability of the biocomposites. The triacetin increased the storage modulus and gave a lower softening temperature for plasticized biocomposites. The micrographs of the tensile specimens and their fractured surfaces, which were examined by scanning electron microscopy, demonstrated that better adhesion between the fibers and the matrix was achieved with the addition of the plasticizer

Optimization of TiO2 thin film thickness for dye sensitized solar cell applications

Dye sensitized solar cells (DSSCs) rely on the absorption of photons by the dye molecules which are transported to the conduction band of the TiO2 electrode. The microstructure, energy gap and the absorption spectra of the TiO2 electrodes highly affects the efficiency of the cell. In this paper, the absorption spectra and energy gap has been studied by varying the thickness of the TiO2 paste. Nanocrystalline TiO2 thin films were deposited on ITO glass substrate with three different thickness (4.54μm, 7.12μm and 12.3μm) by using doctor blade method. After deposition all the samples were sintered at 450°C after deposition to enhance the particle bonding and for achieving better adhesion. The samples were characterized by UV-VIS spectra for determining the absorption spectra and Scanning Electron Microscopy (SEM) for investigating the thickness and the surface morphology. Fabricating the electrodes with different thickness showed significant changes in the energy gap and from the results it can be concluded that the energy gap increases with the increased thickness. The highest energy gap of 2.25ev and absorption 3.791 was achieved by 12.3μm thick sample. The absorption spectra also shows better absorption throughout the whole visible light range but the SEM images suggests that 12.3μm thick sample shows cracks all over the deposited region which will cause current leakage when the cell is assembled. Therefore, the optimum result was achieved by 7.12μm thick sample providing 1.9 ev energy gap and 3.91 absorption peak

RIGS16-176-0340/The studies on environmentally safe biopolymer derived from natural based algae

In the efforts to sustain the environment, biodegradable plastic has become a great alternative to replace conventional plastic. Hence, this study focuses on a potential biodegradable plastic. In the current study, the properties of algae (matrix) were investigated by adding acetic acid and cinnamon powder as filler and antimicrobial agent. The amount of acetic acid varies from 0.1, 0.3 and 0.5%, while, the cinnamon content between 1, 3 and 5%. The film was fabricated using the solution casting method. Upon fabrication, the physical and mechanical properties of the films were characterized using tensile test, Fourier Transform Infrared Spectrometry (FTIR) analysis, Scanning Electron Microscopy (SEM) analysis and biodegradation test. Based on the results, the addition of acetic acid and cinnamon are capable of affecting the tensile property of the algae film. Initially, it indicated that the acetic acid reduced the tensile property and affected the elongation at break of the algae film. However, the tensile strength of the film was altered by adding a certain amount of cinnamon. The maximum tensile strength was achieved by the addition of 5% cinnamon which exhibited a good intermolecular interaction between the algae and cinnamon molecules. The tensile strength which was measured at 4.80 MPa correlated with the morphological structure. The latter was performed using SEM, where, the surface showed the absence of a separating phase between the algae and cinnamon blend. Moreover, the addition of acetic acid into the algae film clearly indicated that the acetic acid molecules affect the adjacent molecules by increasing the distance and reducing the internal force giving more flexibility to the film. This was evidenced by the Fourier Transform Infrared (FTIR) analysis which confirmed the occurrence of no chemical reaction between the algae and acetic acid. The C-H stretching due to the formation of intermolecular and intramolecular bonds between algae and carboxylic acid groups corresponds to the water-related absorbance. As for the biodegradable analysis, the addition of acetic acid into cinnamon, demonstrated low moisture absorption thus decelerating the degradation due to low swelling rate and microorganism activity. In conclusion, good tensile properties and longer degradation rate are achievable with the addition of 0.3% of acidic acid with 5% of cinnamon blended with the algae matrix

Bio-polymer chitosan and corn starch with extract of hibiscus rosa-sinensis (hibiscus) as PH indicator for visually-smart food packaging

This study is focusing on the presence of pigments called anthocyanin in hibiscus, can be used as pH indicator as the pigments react with OH- ions before changing its color depending on the acidity or alkalinity of the surroundings. Hence, a system for pH monitoring based on chitosan, corn starch and phytochemical extract from Hibiscus rosa-sinensis (hibiscus), all inexpensively obtained from renewable sources is developed. Chitosan, corn starch and hibiscus extract were used to produce biopolymer pH indicator for smart food packaging. The system is then characterized by using FTIR, as well as light microscopy. In order to validate the use of this system as a meat spoilage detection sensor, application tests were conducted with chicken breasts. The results show that the system has good optical and morphological properties and is very sensitive to pH variations. During the application test, the system visually indicated pH changes. This shows a clear response to pH variation of the samples. Therefore, it has potential to be used as a visual indicator of the storage and consumption conditions of food

Determination of some properties of used cooking oil using AAS, bomb calorimeter and GC-MS techniques

Most of the used cooking oil from households and catering premises in Malaysia will eventually ends up in wastewaters. It will be discharged to the surface of waters because no alternative steps were taken to overcome the waste from used cooking oil. As a component of wastewater, oil is classified together with fats and waxes as grease. This trend results in the generation of a vast waste stream that needs to be properly managed to avoid environmental damage. Thus, the information regarding on the waste cooking oil properties is needed to contribute knowledge for future research where the waste may reformed to value added product. Preliminary analysis of used cooking oil properties via GCMS using capillary column shows n-Hexadecanoic acid and Oleic acid as the major compounds present in the used frying oil. The analysis for determination of volatile and moisture content with 3 replicates show an average of 0.02% moisture and volatile content, which the experimental procedure was based on MPOB Test Methods

FTIR and TGA analysis of biodegradable poly(lactic acid)/ treated kenaf bast fibre: effect of plasticizers

A biodegradable composite (PLA/KBF blends) was prepared using melt blending technique in a brabender mixer and characterized with FTIR and TGA analyzer. Five percent of triacetin and glycerol contents were used as plasticizers to plasticise PLA matrix. KBF was treated with 4% NaOH solution, while 30 wt% of fibre loading was used constantly for all the composite samples. From the FTIR analysis, the additions of triacetin and glycerol to PLA composites did not produce any significant difference, and there were no chemical changes in both the plasticized PLA with the treated and untreated KBF, respectively. Observation done on the TGA analysis revealed that both plasticizers did improve the thermal stability of the composites, and this might be due to the modification on the fibre surfaces, which further led to the delay in the degradation of the PLA matrix and to significant stabilization effect

The role of tin and magnesium in assisting liquid phase sintering of aluminum (Al)

This study aims to investigate the effect of tin (Sn) and magnesium (Mg) on the sintering response of sintered Al. Although this topic has been extensively reported, details on the combined effect of Sn and Mg that function as sintering additives are still limited. The current study discusses the effect of the combined use of Sn and Mg to assist aluminium (Al) in liquid phase sintering via the powder metallurgy technique. The results demonstrated that the densities of sintered Al increased from 2.5397 to 2.575 g/cm3 as the Sn content increased from 1.5 to 2.5 wt. % respectively. Accordingly, the physical characteristics of sintered Al were transformed from black to silver, which confirmed the reduction in the oxygen content (oxide layer reduction) from 0.58 to 0.44 wt. % respectively. Additionally, the microstructure of the resultant sintered Al demonstrated that effective wetting by Sn addition was obtained at its maximum content of 2.5 wt. % with a greater micro pores reduction and better metallurgical bonding between Al particles. Therefore, the introduction of different Sn content, along with Mg element, was found to further improve the sintering response of the resultant sintered Al that consequently improved its densities and physical characteristics

Preliminary development of porous aluminum via powder metallurgy technique

Porous aluminum has been extensively studied, particularly in the field in which lightweight and high stiffness properties are essential. In this study, a preliminary investigation is performed to determine the optimum sintering temperature to develop porous aluminium by a powder metallurgy technique, using polymethylmethacrylate as a space holder. The effects of the sintering temperatures on the physical characteristics, oxidation level, microstructure and sintered density of the porous specimen are systematically evaluated. Based on the results, an increase in the sintering temperature from 580 °C to 600 °C changes the colour of the porous aluminum body from a silver‐like colour to a gold‐like colour, with some of the specimens encountering severe cracking, spalling and even collapsing. As such, the oxygen content is significantly increased from 0.45 wt.% to 2.14 wt. %, suggesting the oxidation phenomenon. In line with this, an obvious appearance of particle boundaries with less macro‐pores formation is also observed. Additionally, the sintered density of the porous specimen is found to reduce from 1.305 g/cm3 to 0.908 g/cm3. Therefore, fabrication of the resultant porous aluminium at 580 °C is an ideal condition in this study, owing to the ideal combination of physical characteristics, microstructure, oxidation level and sintered densit

Mechanical properties of gracilaria lichenoides reinforced bioplastic film

In this study, the mechanical properties of gracilaria lichenoides with additional of plasticizer and filler were evaluated. For samples with the addition of 5.5% of plasticizer, produced low tensile strength and this results is vice versa with elongation at break results. The tensile strength of the bioplastic continuously decreases from 14.8 to 2.7MPa as the plasticizer increases up from 1.5% to 5.5%. This phenomenon was analyses under scanning electron microscope (SEM), it shows that, the formation of pores and crystal agglomeration at sample with 5.5% glycerin. To alter these flaws, squid bone is introduce as filler to the bioplastic. Based on the analysis, additional of 6% filler content did alter the tensile strength up to 8 MPa with 3% of the elongation at break

Characterization of poly (lactic acid) _ poly (ethylene) glycol blends prepared for melt drawn spinning process

In this study, PLA/PEG blends were prepared using solvent (chloroform) casting methods. PEG was incorporated with increments of 5 wt.% up to 30 wt.% into PLA. Multiple test methods were used to characterize the thermal and structural properties of these blends; Differential Scanning Calorimeter (DSC), Thermogravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR) and optical microscopy (OM). DSC thermograms showed that the incorporation of PEG significantly decreases the glass transition temperature from 55.56°C to 37.35°C and crystallization temperature from 97.14°C to 79°C of the blend. TGA thermograms indicated that the initial and maximum decomposition temperatures for all composition shifted systematically to lower temperature compared to the pure PLA. As the incorporation of PEG into PLA increases, the values of –CH stretching, C=O, C-O wavenumber shifted to lower wavenumber. Lastly, smooth and uniformed fibers were then successfully drawn using an in-house built mini fiber-drawing equipment with an average diameter ranging from 27 to 50 μm