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Bangi, Malaysia

Salih A.M.,University Putra Malaysia | Ahmad M.B.,University Putra Malaysia | Ibrahim N.A.,University Putra Malaysia | HjMohd Dahlan K.Z.,Polycomposite SDN Bhd | And 3 more authors.
Molecules | Year: 2015

Over the past few decades, there has been an increasing demand for bio-based polymers and resins in industrial applications, due to their potential lower cost and environmental impact compared with petroleum-based counterparts. The present research concerns the synthesis of epoxidized palm oil acrylate (EPOLA) from an epoxidized palm oil product (EPOP) as environmentally friendly material. EPOP was acrylated by acrylic acid via a ring opening reaction. The kinetics of the acrylation reaction were monitored throughout the reaction course and the acid value of the reaction mixture reached 10 mg KOH/g after 16 h, indicating the consumption of the acrylic acid. The obtained epoxy acrylate was investigated intensively by means of FTIR and NMR spectroscopy, and the results revealed that the ring opening reaction was completed successfully with an acrylation yield about 82%. The UV free radical polymerization of EPOLA was carried out using two types of photoinitiators. The radiation curing behavior was determined by following the conversion of the acrylate groups. The cross-linking density and the hardness of the cured EPOLA films were measured to evaluate the effect of the photoinitiator on the solid film characteristics, besides, the thermal and mechanical properties were also evaluated. Source

Salih A.M.,University Putra Malaysia | Ahmad M.B.,University Putra Malaysia | Ibrahim N.A.,University Putra Malaysia | Dahlan K.Z.H.M.,Polycomposite SDN Bhd | And 3 more authors.
AIP Conference Proceedings | Year: 2014

Palm oil based-polyurethane acrylate (POBUA)/clay nanocomposites were prepared via in-situ intercalative polymerization using epoxidized palm oil acrylate (EPOLA) and 4,4' methylene diphenyl diisocyante (MDI). Organically modified Montmorillonite (ODA-MMT) was incorporated in EPOLA (1, 3 and 5%wt), and then subjected to polycondensation reaction with MDI. Nanocomposites solid films were obtained successfully by electron beam radiation induced free radical polymerization (curing). FTIR results reveal that the prepolymer was obtained successfully, with nanoclay dispersed in the matrix. The intercalation of the clay in the polymer matrix was investigated by XRD and the interlayer spacing of clay was found to be increased up to 37 Å, while the structure morphology of the nanocomposites was investigated by TEM and SEM. The nanocomposites were found to be a mixture of exfoliated and intercalated morphologies. The thermal stability of the nanocomposites was significantly increased by incorporation of nanoclay into the polymer matrix. DSC results reveal that the Tg was shifted to higher values, gradually with increasing the amount of filler in the nanocomposites. Tensile strength and Young's modulus of the nanocomposites showed remarkable improvement compared to the neat POBUA. © 2014 AIP Publishing LLC. Source

Houmani Z.M.M.,National University of Malaysia | Majid A.A.,National University of Malaysia | Radiman S.,National University of Malaysia | Ahmad Z.,Nuclear Malaysia
Malaysian Journal of Analytical Sciences | Year: 2012

The ratio of equilibrium radionuclide concentration in the solid phase to the concentration in soil solution i.e. the distribution coefficient (Kd) can be used for quantification of a radionuclide' s migration potential in the subsurface. Kd is one of the main parameter that describes soil absorbability for any radionuclide. In this study, distribution coefficients (Kd,s) of 137Cs were measured by a batch technique for five Malaysian soil series samples to evaluate the absorbability of 137Cs. The five Malaysian soils series samples i.e. Durian, Rengam, Holyrood, Segamat and Selangor were collected systematically at different depths (0-20 cm, 20-40 cm and 40-60 cm), at five different sites in Malaysia. The calculated Kd values for Durian, Holyrood, Rengam, Segamat and Selangor soil series were in the range of 958 to 3231 ml g-1, 273 to 1349 ml g-1 (mean: 853 ± 444 ml g-1), 202 to 1739 ml g-1 (mean: 754 ± 724 ml g-1), 216 to 546 ml g-1 (mean: 388 ±113 ml g-1) and 3389 to 5919 ml.g-1 (mean: 4657 ± 918 ml g-1), respectively. Thus this study indicated that the 137Cs Kd values of the soils varies with type and depth of the soil and can be used as a good backfill choice for final disposal sites for retarding migration of 137Cs. Source

Houmani Z.M.M.,National University of Malaysia | Majid A.A.,National University of Malaysia | Radiman S.,National University of Malaysia | Ahmad Z.,Nuclear Malaysia
Malaysian Journal of Analytical Sciences | Year: 2012

In this study, the adsorption of 137Cs in soil samples were quantified using the distribution coefficient (Kd-value). The distribution coefficients (Kd) of 137Cs in Rengam and Selangor soil series were determined by a batch technique. The Malaysian soil series (Rengam and Selangor soil series) were collected systematically at three different depths (0-20 cm, 20-40 cm and 40-60 cm) at two different sites in Malaysia. The batch Kd tests were used with deionized water that was spiked with 137Cs tracer to the soil sample and the activities of 137Cs in the supernatant solution were measured by a low background but high efficiency well-type HPGe detector. Several physicochemical soil properties were also characterised for each soil type. Pearson's correlation and stepwise multiple regression models were applied at 0.05 level of significance throughout all analysis to determine the relationships and influences between distribution coefficients (Kd-value) of 137Cs with physicochemical soil properties of each soil type. The calculated Kd-value for Rengam and Selangor soil series at several depth were determined to be in the range of 202 to 1739 ml.g-1 and 3389 to 5919 ml.g-1 respectively. The results indicate that the stepwise multiple regression model incorporating pH and porosity influence the Kd-value of 137Cs in Rengam Soil Series and exhibits an R2 equal to 0.922 indicating that 92.2% of total variation has been explained by the regression model. The regression model also reveals that cation exchange capacity, bulk density, porosity and free manganese oxide (Mn2+) have influence on the Kd-values of 137Cs in Selangor soil series and exhibits an R2 equal to 0.997 indicating 99.7% of total variation. Therefore, the sorption coefficients in relation to the environmental factors including physicochemical properties can be used to predict and design the radionuclide transport and safety assessment models. Source

Naher U.A.,University Putra Malaysia | Othman R.,University Putra Malaysia | Shamsuddin Z.H.J.,University Putra Malaysia | Saud H.M.,University Putra Malaysia | And 2 more authors.
Australian Journal of Crop Science | Year: 2011

Biological Nitrogen Fixation (BNF) is an energy involving process. A 15N tracer study was conducted under growth chamber and glasshouse conditions to determine the effect of glucose, galactose and arabinose (common sugars found in root environments) on BNF by two diazotrophs, Rhizobium sp. Sb16 and Corynebacterium sp. Sb26, previously isolated from rice genotypes (Mayang Segumpal and MR219). Diazotrophs have preferences for specific sugar utilization and plant association. Sb16 showed high preference for galactose, and Sb26 preferred arabinose. Application of 10 mM sugar in the experimental pot (5 kg soil), either galactose or arabinose, to the respective rice genotype enhanced diazotroph population growth, N 2 fixation activity and simultaneously plant growth. Mayang inoculated with Sb16 applied with galactose increased plant N concentration 4.2 ± 0.07 %, whereby, 42 ± 1.06 % of the N was derived from the atmosphere. About 40 ± 1.29 % of the N concentration of MR219 inoculated with Sb26 and arabinose was obtained from BNF. The association between Mayang with Sb16 increased 195 ± 40 % of plant biomass as compared to control, and 36 ± 19.8 % over 60 kg ha-1 of N-fertilizer. On the other hand, the association of MR219 with Sb26 resulted in 108 ± 37.07 % biomass increment as compared to control, and 89 ± 22.34 % over fertilized-N in different sugar treatments. The association between the plant-diazotrophs along with sugar significantly increased photosynthetic activity. The study indicated that growth and N2 fixation activity of rice can be increased by increasing the availability of specific sugars in the rhizosphere. Source

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