Advanced Materials Research Vol. 812

Abstract: With blooming interests in the research of biodegradable polyesters produced from microorganisms as well as polymer processing and technology, this study is intended to reveal the influence of thermal treatment on the molecular weight of poly (3-hydroxybutyrate-co-3 mol% 3-hydroxyhexanoate)/P(3HB-co-3 mol% 3HHx), a copolymer of polyhydroxyalkanoates (PHA). P(3HB-co-3 mol% 3HHx) was thermally treated using Differential Scanning Calorimeter and analyzed using Gel Permeation Chromatography and Attenuated Total Reflectance-Fourier transform infrared (ATR-FTIR) spectrometer. Results from gel permeation chromatography suggest a major reduction of molecular weight up to 50 % when P(3HB-co-3 mol% 3HHx) is exposed to 180 °C for 30 mins. The half-time degradation of P(3HB-co-3 mol% 3HHx) treated at 170 °C and 180 °C is 14.1 and 9.9 mins, respectively. FTIR spectroscopy shows an increase absorbance intensity of P(3HB-co-3 mol% 3HHx) after thermal treatment, indicating a formation of more alkenyl and carboxylic end-group in polymer chains due to random chain scissions.

Abstract: A vulcanized epoxidized natural rubber (ENR) based electrically conductive compound was successfully prepared by using the combination of internal mechanical mixing and open milling devices. This compound was developed based on a formula with at least 73.0 wt % of petro-chemical free ingredients. The vulcanizate of this compound showed good physical properties, high electrical conductivities and also complied with Malaysia Standard 1097 [. As a result, this newly formulated compound can be targeted for making antistatic tire tread of commercial vehicles.

Abstract: The aim of this study is to determine the effect of alkali treatment on water absorption and tensile properties of non-woven kenaf polyester composite. Kenaf fiber mat was treated with 2, 4 and 6% of different sodium hydroxide (NaOH) concentration. The composite was fabricated using compression molding technique. It was found that treatment reduced the overall water uptake of composites. The 6% treated fibre composite was greater in moisture resistance as compared to untreated. The tensile strength of the composites was substantially improved after alkali treatment, and it was similar with the tensile modulus.

Abstract: Thermally reduced graphene oxide (graphene) filled natural rubber (NR) composites were fabricated by melt mixing method. Dielectric constant, dielectric loss and a.c conductivity data of the NR composites are reported. Highest conductivity of 3 x 10^-4 S/m was obtained for the composite with 3 wt. % graphene with initial electrical percolation at a loading of 0.5 wt. %. High conductivity in the composite with 3 wt. % graphene is accounted by its homogeneity as observed in SEM micrographs.

Abstract: Thin films of poly (ethylene oxide) (PEO), poly (methyl methacrylate) (PMMA) and selected blends of PEO/PMMA with and without the addition of LiClO₄ were prepared using solution casting technique. The presence of a single T_g which corresponds closely to that of the Gordon Taylor equation confirms the miscibility of both the salt-free and salt-doped blends. The T_gs and the ion conductivity (σ) at room temperature of PEO, PMMA and the PEO/PMMA blends generally increase with ascending salt concentration (Y). Variations in the σ value as a function of Y for all the three systems correlate closely with their respective T_g results. PMMA-salt complex records the lowest σ value at all salt concentrations. PEO/PMMA/LiClO₄ blend with 75 wt% PEO exhibits the highest σ value of 5 x 10^-7 S cm^-1 at Y = 0.10. The σ value of the blend-salt system is observed to be slightly lower than that of the PEO-salt system. This is due to reduced segmental motion cause by increased T_g of the blend and a decrease in free ions in the amorphous phase of PEO as a small amount of the salt is solvated by PMMA in the blend. Therefore, the percolation path lies in the amorphous PEO rich phase of the blend.

Abstract: The introduction of the eco-core sandwich panel composite is contributing a new approach to the designer to achieve high performance and light weight. In this research project, the new kenaf eco-core sandwich panel will be developed and then laminated with galvanized steel. The final goal is to find the optimum eco-core metal matrix composite sandwich structure with maximum mechanical properties such as stiffness and buckling. Kenaf eco-core sandwich will be fabricated and study on the interaction between eco-core sandwich panel and metal faces will be performed. The characterization of the eco-core sandwich panel will be done using different analytical tools. This study would provide a way to enhance the application of this new eco-core metal matrix composite sandwich structure.The amount of sample used was approximately 12 mg. The temperature profile was from 27°C to 1000°C at a heating rate of 10°C/min. In this study, result shows that degradation of composites starts to occur at about 180°C. Increasing the kenaf percent ratio will decrease the percent residue.

Abstract: In this study, palm oil-based polyols were prepared and characterized. In order to prepare the polyol, Epoxidized palm oil (EPO) was reacted with glycerol and undergoes ring opening reaction. The synthesized oil was characterized by oxygen oxirane content titration (OOC), hydroxyl value test (HV), fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR). Based on the FTIR spectrum of polyols, the disappearance of epoxy groups at 825cm^-1, 843cm^-1 and the emergence of hydroxyl group at 3394cm^-1 are obvious indicating that hydroxyl group of the polyols formed. In NMR, the presence of new signal at δ 3.46ppm (-CH-OH) showed the attachment of hydroxyl group onto the epoxidized palm oil.