For the purpose of the development of poly(lactic acid)/ graphene oxide composites with improved tensile properties, a stearic acid compatibilizer was used to enhance the compatibility of the graphene oxide sheets with the poly(lactic acid) polymer matrix. Graphene oxide was modified with stearic acid at different mass ratios of 1:1, 1:3, and 1:5 prior to forming the composites with poly(lactic acid). Characterization showed positive effects of stearic acid attached to GO in every mass ratio and also enhanced compatibility with the poly(lactic acid) matrix. Stearic acid could strengthen the interfacial interactions between the flat graphene oxide sheets and the poly(lactic acid) matrix resulting in improved tensile strength. The tensile strength of the poly(lactic acid)/graphene oxide/ stearic acid composite with a mass ratio of graphene oxide and stearic acid 1:1 increased by 32% compared to poly(lactic acid) alone. Based on these results, the graphene oxide/stearic acid composites show potential for use as nanosheet fillers for tensile strength enhancement in poly(lactic acid). POLYM. COMPOS., 38:2272-2282, 2017

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AbstractThe Lysimachia foenumgraecum Hance extract (LHE) was used for silver nanoparticles (AgNPs) synthesis. In this study, the herbal plant of Lysimachia foenumgraecum Hance (LH) was extracted with deionized water and we are the first to successfully use LHE as reducing and stabilizing agents for the green synthesis of AgNPs. The concentration of LHE used in this study was in the range of 0.003 to 1.0 wt%. Aqueous colloidal solutions of AgNPs reduced and stabilized by LHE show long-term stability due to the steric stabilization effect. This can be confirmed by zeta potential measurements which afforded values approximately of 0 mV, indicating the steric stability of AgNPs colloidal solutions synthesized by LHE. Furthermore, the obtained AgNPs colloidal solutions show superior antibacterial effect to gram-positive bacteria (Staphylococcus aureus) comparing to Chloramphenicol (positive control). AgNPs with LHE 0.003 wt% affords the highest antibacterial effect to S. aureus showing an inhibition zone diameter of 19.08 ± 0.67 mm; which is superior to Chloramphenicol.

. (2013). Facile synthesis of reduced graphene oxide/MWNTs nanocomposite supercapacitor materials tested as electrophoretically deposited films on glassy carbon electrodes. Journal of Applied Electrochemistry, 43 (9), 865-877.Facile synthesis of reduced graphene oxide/MWNTs nanocomposite supercapacitor materials tested as electrophoretically deposited films on glassy carbon electrodes AbstractThis paper reports on a facile synthesis method for reduced graphene oxide (rGO)/multi-walled carbon nanotubes (MWNTs) nanocomposites. The initial step involves the use of graphene oxide to disperse the MWNTs, with subsequent reduction of the resultant graphene oxide/MWNTs composites using l-ascorbic acid (LAA) as a mild reductant. Reduction by LAA preserves the interaction between the rGO sheets and MWNTs. The dispersion-containing rGO/MWNTs composites was characterized and electrophoretically deposited anodically onto glassy carbon electrodes to form high surface area films for capacitance testing. Pseudo capacitance peaks were observed in the rGO/MWNTs composite electrodes, resulting in superior performance with capacitance values up to 134.3 F g-1 recorded. This capacitance value is higher than those observed for LAA-reduced GO (LAA-rGO) (63.5 F g-1), electrochemically reduced GO (EC-rGO) (27.6 F g-1), or electrochemically reduced GO/MWNTs (EC-rGO/MWNTs) (98.4 F g-1)-based electrodes. AbstractThis paper reports on a facile synthesis method for reduced graphene oxide (rGO)/multi-

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Green synthesis of nanoparticles (NPs) has received much attention due to biocompatibility and being facile and eco-friendly.Caesalpinia sappanLinn. (CS) is a plant found in Southeast Asia and is commonly known as sappan wood. In this research, we are the first to successfully use CS extract as reducing and stabilizing agents for the green synthesis of gold NPs (AuNPs). Colloidal solutions of AuNPs after reduction show natural red-wine and dark purple color depending on the size of AuNPs, without the interference of the orange/reddish-orange color from the CS extract. The concentration of CS was investigated for the formation and stabilization of AuNPs in colloidal solution (i.e. morphology, size and zeta potential). It was found that the optimized concentration of the reducing agent for the green synthesis of AuNPs was in the range of 0.004–0.04 wt% of CS. As the concentration of CS was increased, the sizes of AuNPs decreased due to the adsorption and stabilizing effect of CS. Transmission electron microscopy (TEM) analysis showed differences in size and shape of the NPs with earthworm and quasi-spherical characteristics. The zeta potential of AuNPs synthesized in the presence of CS was approximately in the range of −10 mV to −20 mV, indicating the stability of AuNPs synthesized by CS.

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