Advanced Materials Research Vol. 1134

Abstract: This paper investigated the effect of density and thickness on flexural strength and dimensional stability of laminated floor panel. The focus of this research is to acknowledge the suitability of Kenaf fibres as raw material for floor panel. The evaluated floor panel samples consist of high density fibreboard as a core of floor panel and resin impregnated paper as lamination. The core was made up from Kenaf (Hibiscus cannabinus) bast fibres that were used to fabricate dry-formed fibreboard at three different board densities (850, 960 and 1000 kg/mʒ) with the thickness of 8mm and 12mm for each board. Bending modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA) and thickness swelling (TS) were measured for each panel in accordance to BS EN standard. The overall result showed increasing density and thickness increased were MOE, MOR, TS and WA. Density and thickness were significantly affecting all the panels’ properties except for MOR, TS and WA.

Abstract: The enhancement of ferroelectric and dielectric properties of PVDF-TrFE by incorporating various percentages of Magnesium Oxide (1 – 7%) for spin coated nanocomposite thin film was demonstrated. Observations showed uniform distribution and low agglomeration of MgO in the PVDF-TrFE nanocomposite thin film, especially for 3% MgO. Additionally, the 3% MgO incorporated into PVDF-TrFE had generated the highest P_r (88 mC/m²) and dielectric constant (13.6) in comparison other percentage compositions. However, the addition of more than 3% MgO filler loading caused a reduction in the ferroelectric and dielectric properties of the nanocomposite thin films.

Abstract: The impact of surface plasma modification on PVDF-TrFE film with different exposure time was investigated using X-ray photoelectron spectroscopy (XPS). The main emphasis of this study was to optimize the exposure time of argon plasma on the surface of PVDF-TrFE films The surface of spin coated PVDF-TrFE film was modified with argon plasma at exposure time of 1, 3, 5, 7 and 9 min/s. Prior to modification, only small amount of atomic percent (1.92 %) of O1_s peak was observed at 540.8 eV, but upon modification, the atomic percent for O1_s peak was found to increase to 8.8 %. Meanwhile, the atomic percent for F1_s peak observed at 695.3 eV was found to decrease from 70.6 % to 61.2 %. This phenomenon is an indication that plasma modified PVDF-TrFE films were readily oxidized. Importantly, most of the fluorine elements were removed from the modified PVDF-TrFE film surface, which rendered the film favourable for adhesion with other material for coating aplications.

Abstract: Poly (vinylideneflouride)/nanomagnesium oxide (PVDF/MgO) film with MgO loading percentage of 7% were annealed with various annealing temperatures ranging from 70°C to 170°C. The PVDF/MgO(7%) thin films were fabricated using spin coating technique with metal-insulator-metal (MIM) configuration and the dielectric constant of PVDF/MgO(7%) with respect to annealing temperatures was studied. The PVDF/MgO nanocomposite thin films annealed at temperature of 70°C (AN70) showed an improvement in the dielectric constant of 27 at 10³ Hz compared to un-annealed sample (UN), which is 21 at the same frequency. As the annealing temperatures were increased from 90°C (AN90) to 150oC (AN150), the dielectric constant of PVDF/MgO(7%) were found to gradually decreased from 25 to 12 respectively, interestingly lower than the UN thin films. AN70 also produced low value of tangent loss (tan δ) at frequency of 10³ Hz. The resistivity value of AN70 was also found to increase from 3.08×10⁴Ω.cm (UN-PVDF) to 1.05×10⁵Ω.cm. The increased in dielectric constant, with low tangent loss and high resistivity value suggests that 70°C was the favourable annealing temperature for PVDF/MgO(7%) for application in electronic devices such as low frequency capacitor.

Abstract: In this study, several batches of natural rubber (SMR L) were compounded with three different types of accelerators, which were N-cyclohexylbenzothiazole-2-sulphenamide (CBS), diphenylguanidine (DPG) and zinc diethyldithiocarbamate (ZDEC). ZDEC is known as an ultrafast accelerator. The rubber compounds were cured at 140°C, 130°C, 120°C, 110°C and 100°C in accordance with the temperature gradients observed within the thick rubber block. The main aim of this study is to cure the rubber at each temperature region to the same cure time as that of the outermost region (20 minutes at 140°C). The amount of sulfur and accelerator were adjusted accordingly at each curing temperature to match the state of cure at 140°C. The state of cure of of the vulcanized rubbers were measured using hardness and tensile strength. The same state of cure is achieved if the hardness and tensile strength value are within ±2 IRHD and ±3 MPa, respectively with that of the control vulcanized rubber (hardness and tensile strength cured at 140°C). The results shows that the hardness and tensile strength of the vulcanized rubber at each temperature region are within the expected margins. The results clearly indicated that the type and amount of accelerators, and the amount of sulfur were correctly chosen at each temperature.

Abstract: Spectrophotometric determination of hydroxymethylfurfural (HMF) based on p-toluidine as a reagent has been studied. The absorption intensities were measured at a wavelength range of 250 to 500 nm to record the absorption spectra before and after reaction with the HMF. The solution response was obtained at pH 3. The concentration of HMF was 5 × 10^-3 M, whereas for p-toluidine was 8 × 10^-3 M .The relative standard deviation (R.S.D.) of reproducibility was 3.33% when concentration of p-toluidine 3 × 10^-3 M was used .The photostability was found to be good with 1.9 %. M was used . The photostability was found to be good with 1.9 %.

Abstract: In this paper, three type of natural-fibre reinforced polyethylene were produced. They are the coconut coir reinforced polyethylene (RPCC), kenaf reinforced polyethylene (RPKC) and bamboo reinforced polyethylene (RPBC). Water absorption test, thickness swelling test and tensile test of the different natural fibre composites were carried-out. The mass of HDPE and natural fibre were based on percentage of filler loading. Each board types were produced with two fibre ratios which are at fourty percent and thirty percent. The preparation of the test sample is according to ASTM D1037 and ASTM D638. The tensile modulus of elasticity, tensile stress, water absorption and thickness swelling of kenaf and bamboo reinforced polyethylene composites were found to increase with increasing fibre weight fraction. Kenaf and bamboo composites showed compatible result for tensile stress and tensile modulus of elasticity while coconut coir appears to be otherwise. However, coconut coir fibre composites displayed comparable results to kenaf and bamboo for both water and thickness swelling. There were significant differences in both tensile properties and the percentage of the water absorption among composites.

Abstract: This study employed 7 weight percent (wt.%) of untreated and treated MgO nanofillers incorporated into PVDF polymer. The effects of coupling agents (chlorotrimethylsilane and triacetoxyvinylsilane) on the polymorphism of PVDF/MgO nanocomposite were investigated. The PVDF/MgO nanocomposite thin films of untreated and treated MgO nanofillers, with and without the addition of coupling agents were produced via spin coating technique. The average thickness recorded for these films was 300 nm thick. ATR-FTIR was conducted to investigate the changes in polymorphism of PVDF/MgO nanocomposite thin films. The results shows that PVDF/MgO (Chlorotriemethylvinylsilane) indicates better compatibility than PVDF/MgO, with sharp and distinguished absorption band at 840 cm^-1, indicating high content of PVDF, β-crystals.

Abstract: The role of surfactants in the formation of active Poly (vinylidene fluoride) (PVDF) ultrafiltration (AUF) membranes was studied. The effect combination of surfactants that are Sodium dodecyl sulfate (SDS)/Tween 80 and Tween 80/Triton X-100 formulations on performance and morphological structures were investigated for the first time. The influence of surfactants blends on the membrane pores was also examined. Experimental data showed that combination of Tween 80/Triton X-100 give the highest BSA permeation flux which value 285.51 Lm^-2h^-1. With combination of SDS/Tween 80, the AUF membrane showed the highest protein rejection up to 93% and 79% for Bovine Serum Albumin (BSA) and Egg Albumin (EA), respectively. Moreover, membranes characterization demonstrated that the addition of SDS/Tween 80 and Tween 80/Triton X-100 were found to affect the performance, surface morphologies and membrane pores of AUF PVDF membranes.