An emphasis on dynamic mechanical properties of novel stilbene containing copolymer/organo-MMT nanocomposites fabricated via in situ interlamellar copolymerization

The objective of the present study is to synthesis and characterize the novel functional stilbene containing copolymer-clay nanocomposites, make clear the influence of organo-clay on peculiarities of the nanocomposites and emphasis on the dynamic mechanical properties. For this purpose, poly(acrylamide-co-trans-stilbene)-organo-MMT [poly(AAm-co-Stb)-O-MMT] nanocomposites were synthesized by in situ interlamellar solution copolymerization with organically modified montmorillonite (O-MMT) clay due to its superior properties gives to copolymer. The effect of different amounts of O-MMT clay incorporation to the nanocomposite structure and properties of copolymer/O-MMT clay nanocomposites were characterized by X-ray diffraction (XRD), Attenuated Total Reflectance-Fourier Transform Infrared, Thermogravimetric Analysis, Differential Scanning Calorimeter, Dynamic mechanic analysis (DMA) methods. XRD analysis showed the basal spacing of the O-MMT increased in nanocomposites and this indicated that the intercalation of the copolymer chain into the O-MMT interlayer performed and nanocomposites were obtained successfully. Additionally, copolymer/O-MMT nanocomposites exhibited improved thermal properties at higher temperatures than the pristine copolymer. DMA results enlightened the viscoelastic properties of synthesized materials. DMA results indicated that obtained nanocomposites have higher mechanical strength because of the interaction/compatibility in between copolymer chains and O-MMT. In the light of these results, this work has introduced new perspectives on design, fabrication and viscoelastic properties of certain organo-clay copolymer nanocomposites for the synthesis of new materials and potential industrial applications.     

Electrocatalysis property of CuZn electrode with Pt and Ru decoration

Electrocatalysis properties strongly depend on the interaction of metallic particles and this interaction enables to change the electronic structure of alloys which enhances the catalytic activity. This property is the key factor in the developing of cost-effective and efficient Hydrogen Evolution Reaction (HER) electrocatalysts for sustainable hydrogen production. In this study, novel electrocatalysts which are decorated with Pt and Ru have been developed for HER electrocatalysis. Microscopic analysis such as scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and atomic force microscopy (AFM) are performed to determine the morphological and compositional structures. Electrocatalysis properties are evaluated by cathodic current-potential curves, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) in 1.0 M KOH solution. Chronoamperometry (CA) and cycle tests are used for stability/durability of electrocatalysts. Results show that a small onset potential of the porous Cu/Ni/CuZn–Pt is obtained for HER. Exchange current density and polarization resistance are found to be 5.39 mA cm^?2 and 2.0 Ω cm² at overpotential of ?100 mV for porous Cu/Ni/CuZn–Pt, respectively, indicating that Cu/Ni/CuZn–Pt is higher electrocatalytic properties than the others. Moreover, very low overpotentials at 10 and 40 mA cm^?2 are obtained on porous Cu/Ni/CuZn–Pt compared with porous Cu/Ni/CuZn–Ru and Cu/Ni/CuZn. Porous Cu/Ni/CuZn–Pt also displays excellent stability/durability in test solution. The remarkable electrocatalysis properties of porous Cu/Ni/CuZn–Pt can be explained due to high porous structure, leaching of Zn from the deposit, intrinsic activity of Pt as well as changing in the electronic structure. It should be considered that porous Cu/Ni/CuZn–Pt is of high corrosion resistance in test solution for 120 h, which makes it good candidate for HER.     

Synthesis of new imidazole-based monomer and copolymerization studies with methyl methacrylate

In this study, copolymers were synthesized using methyl methacrylate (MMA) and 2-allyloxymethyl-1-methylimidazole (AOMMI) monomers at various ratios. For this purpose, hydroxyl end-functionalized imidazole was initially prepared with 1-methylimidazole and then it was used to prepare allyl-derived imidazole monomers. Finally, the synthesis of copolymers (poly(MMA-co-AOMMI)) was carried out using different proportions of commercial MMA and AOMMI monomers. Photopolymerization method was preferred as polymerization technique. The polymerization was carried out in solvent-free medium and benzophenone was used as the initiator. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR) and elemental analysis were used for the structural characterization of the obtained copolymers. Molecular weights and the thermal behaviour of the synthesized copolymers were analysed with gel permeation chromatography (GPC) and thermogravimetry (TG) techniques, respectively. The surface of the products was tried to be illuminated using scanning electron microscopy (SEM). According to the obtained FTIR, NMR and elemental analysis results, the copolymers were successfully synthesized. A number average molecular weights of poly(MMA-co-AOMMI) samples were found 13,500 (MMA:2/AOMMI:1), 16,600 (MMA:1/AOMMI:2) and 17,300 (MMA:1/AOMMI:1) according to the mixing ratios. When the thermal stabilities of the synthesized copolymers were observed, it has been seen that those containing imidazole had higher stability than the neat PMMA.