In this paper, nanocomposites of polyethylene terephthalate (PET) including polyesteramide-based hyperbranched polymer, or PET/Hyperbranched polymer nanocomposites, have been prepared via melt blending method with different hyperbranched polymer contents. In addition, morphology, surface structure, and thermal properties of these nanocomposites and virgin PET were studied by atomic force microscopy, attenuated total reflection fourier transform infrared spectroscopy and differential scanning calorimetry (DSC), respectively. Dynamic mechanical analysis experiments in solid state were carried out to follow the effect of hyperbranched polymer on the dynamic mechanical properties of these nanocomposites. The structure of the nanostructured hyperbranched polymer was also studied by small-angle X-ray scattering. The rheometric mechanical spectroscopy results showed that the hyperbranched polymer as a modifier decreased the complex viscosity and enhanced liquid-like behavior. This happened more significantly by increasing the content of hyperbranched polymer. The DSC analysis results revealed that crystallinity and glass transition temperature decreased by adding the amount of hyperbranched polymer.

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Response surface methodology coupled with the central composite design (CCD) was employed to optimise the significant parameters in the synthesis of silver nanoparticles (AgNPs) by chemical reduction method to obtain smaller average particle size. Different parameters such as the ethylene glycol (EG) concentration as reducing agent, the polyvinyl pyrrolidone (PVP) content as stabiliser and the pH were selected as they have the dominant effects on the particle size of AgNPs. Each of these parameters was studied at three levels. The average particle size of AgNPs was considered as the response value and determined by dynamic light scattering (DLS) analysis. The statistical analysis showed that the pH emerged as the most significant parameter influencing the average particle size and after that, the PVP content was also a significant parameter. The AgNPs synthesised under optimal conditions (6.88 M of EG, 0.5% of PVP and pH = 11) were characterised by UV-vis spectroscopy, X-ray diffraction (XRD), DLS, zeta potential, field emission scanning electron microscope and energy dispersive X-ray analysis. The XRD pattern showed the face-centred cubic silver and the average crystallite size of AgNPs was 30 nm. The average particle size of AgNPs was 37.35 nm according to DLS analysis, which was in good agreement with the predicted value (37.65 nm) by CCD.

This work reports the synthesis of silver nanoparticles (AgNPs) from Ag nitrate (AgNO 3) using the gallic acid (GA) as a green methodology without utilisation of hazardous chemicals. The effects of variables such as AgNO 3 concentration, GA concentration, and pH on the average particle size of AgPs were optimised through response surface methodology based on the central composite design at three levels to obtain the desired response, i.e. minimum average particle size. The formation of AgNPs at each experiment was characterised by ultraviolet-visible (UV-vis) spectroscopy and the average particle size was measured by dynamic light scattering (DLS). To evaluate the significance of factors on the response and their quantitative effects, analysis of variance was carried out. The results indicated that the pH was the most effective factor on the response. The AgNPs synthesised at optimised conditions (5.42 mM of AgNO3, 6.25 mM of GA, and pH = 9.02) were characterised by X-ray diffraction, DLS, field-emission scanning electron microscope, energy dispersive X-ray, transmission electron microscopy, UV-vis spectroscopy, and Fourier-transform infrared spectroscopy. On the basis of the DLS, the average particle size of AgNPs obtained 8 nm, which was in satisfactory agreement with the predicted value (7.51 nm) by model.

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