|1- Tabebordbar, H., Mohamadnia, Z., Ahmadi, E., "Atom transfer radical polymerization of methyl methacrylate using copper-based homogeneous and heterogeneous catalysts", Chemical Papers, 71: (11), 2117-2127, (2017).|
This study aimed at polymerization of methyl methacrylate with novel catalysts in the atom transfer radical polymerization (ATRP) condition at 90 °C. This was accomplished using CuBr/N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (CuBr–AEAPTMS) as a homogeneous catalyst and one time with CuBr@AEAPTMS/SBA-15 as a heterogeneous catalyst. Catalysts were characterized using TGA, FT-IR, and UV–Vis spectroscopy. The structural analysis of the polymer was carried out by 13C NMR spectroscopy and GPC. Three characteristic parts of polymer produced by ATRP method including the initiator, monomer units, and end group was shown in 13C NMR spectra. In addition, the presence of C–Br unit showed that the polymerization process is alive. The 1H NMR analysis was used for kinetic investigation of methyl methacrylate polymerization with homogeneous and heterogeneous catalysts that showed high monomer conversion (98 and 90% after 35 min, respectively) and good control of molecular weight with a dispersity (Ð = 1.5–1.7). In addition, the plot of ln ([monomer]0/[monomer]t) versus time gave linear relationships indicating a constant concentration of the propagating species throughout the polymerization. Finally, the results of the polymerization using heterogeneous catalyst compared with homogeneous catalyst revealed that it was according to ATRP method.
|2- Fallahi, M., Ahmadi, E., Ramazani, A., Mohamadnia, Z., "Trimerization of ethylene catalyzed by Cr-based catalyst immobilized on the supported ionic liquid phase", Journal of Organometallic Chemistry, 848, 149-158, (2017).|
Two types of heterogeneous catalysts based on bis(2-dodecylsulfanyl-ethyl)-amine.CrCl3 complex immobilized into the modified SBA-15 channels has been synthesized. For the first catalyst [Cr-SNS@SBA-15(700)], the pristine mesoporous silica was subjected to dehydroxylation at 700 °C while another catalyst [Cr-SNS-IL(BF4)@SBA-15] was prepared using supported ionic liquid phase (SILP) with tetrafluouroborate (BF4) as a counter ion. The materials were characterized by transmission electron microscopy (TEM), nitrogen adsorption–desorption analysis, thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, elemental analysis (CHNS), X-ray diffraction (XRD) and UV-Visible spectroscopy. The catalytic activity of both catalysts was then investigated for ethylene trimerization reaction under various reaction conditions by emphasizing the use of low catalyst loading and Al:Cr molar ratio. The studies indicated that Cr-SNS-IL(BF4)@SBA-15 catalyst showed higher activity than either Cr-SNS@SBA-15(700) or homogeneous Cr-SNS under exactly the same reaction conditions. It was found that supported BF4− ions play a crucial role in the improvement of catalytic activity and selectivity to 51079 and > 99%, respectively. This study would open a new window in the design of types of supported catalysts for ethylene oligomerization mediated by more appropriate catalytic activity and selectivity.
|3- Kazemi, F., Mohamadnia, Z., Kaboudin, B., Allahyari, E., "Synthesis and characterization of maleylated cellulose-g-polyacrylamide hydrogel using TiO2 nanoparticles under sunlight", Iranian Polymer Journal
, 26: (9), 663-672, (2017).|
Graft polymerization onto the cellulose is one way to produce semisynthetic copolymers and semiconductors were hardly used as initiators. Maleylated cellulose (MC) with different degree of carboxyl groups was synthesized and degree of carboxyl groups was determined using titration method. Then the graft copolymers of acrylamide (AM) on MC were synthesized by titanium dioxide semiconductor photoinitiator in aqueous suspension under sunlight. The effect of different parameters, such as the degree of carboxyl groups, degassing of atmosphere, reactor type, light source, MC/AM ratio, and initiator concentration, was evaluated in the synthesis of graft copolymers. MC with a high degree of carboxyl groups about 2.8 mmol g−1 was selected for graft photopolymerization. Maximum monomer conversion (55%) for Maleylated cellulose-g-polyacrylamide (MC-g-PAM) was achieved with 0.5 mg TiO2, MC/AM = 0.056, argon atmosphere, sunlight source, and double quartz tube reactor. The maximum amount of equilibrium swelling (41 g g−1) was achieved for MC-g-PAM with 34% monomer conversion. The resulting graft copolymers were characterized by FT-IR, SEM, and TGA. Synthesis of MC-g-PAM using TiO2 nanoparticles (NPs) as the initiator was done successfully that shows the TiO2 NPs are useable in graft polymerization of acrylamide monomers onto the MC under sunlight.
|4- Kazemi, F., Mohammadnia, Z., Kaboudin, B., Gharibi, H., Ahmadinejad, E., Taran, Z., "Synthesis, characterization and swelling behavior investigation of hydrogel based on AAm and AA using CdS nanorods as photocatalyst initiator under different irradiations", JPPA, 330, 102-109, (2016).|
Hydrogels are three-dimensional hydrophilic polymer networks which are able to swell in the aqueous environment. Acryl Amide (AAm) was photopolymerized using cadmium sulfide (CdS) nanorod semiconductor as a photocatalyst initiator without additive under sunlight, blue and green LED irradiations. The effect of different synthesis conditions such as initiator kind and concentration, cross-linking agent concentration, light intensity, copolymerization with acrylic acid (AAc) and dilution (amount of water) were investigated toward the goal of maximum swelling for hydrogel. The results showed that the effect of cross-linker on the swelling is reverse but the swelling of hydrogel increases by increasing the amount of solvent and light intensity. The swelling of the hydrogels reached from 66 to the maximum amount of 650 g water/g hydrogel with the copolymerization of AAm with AAc. Swelling of the hydrogel after optimization was measured in ionic solution and under load. Synthesized superabsorbent hydrogel was characterized by Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and transmission electron microscopy)TEM). Results showed that the lower cost, high speed reaction and high efficiency of photopolymerization lead to hydrogel and superabsorbent with high swelling property.
|5- Ahmadi, E., Gatabi, J., Mohamadnia, Z., "Preparation and characterization of Zn(II) ion-imprinted polymer based on salicylic acrylate for recovery of Zn(II) ions", Polímeros, 26: (3), 1-7, (2016).|
This work describes the synthesis of new ion-imprinted polymers (IIPs) for selective solid phase extraction of Zn(II) ions from aqueous samples. IIPs were synthesized by copolymerization of salicylic acrylate (SA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a crosslinker in the presence of 2,2’-azobisisobutyronitrile (AIBN) as an initiator. The template ions were removed from IIPs particles by leaching with 0.1 M Ethylenediaminetetraacetic acid (EDTA) which leaves cavities in the particles with the capability of selective extraction of the Zn(II) ions. The monomer and the polymer after synthesis have been characterized by 1H NMR, 13C NMR and FT-IR studies. The effect of the pH on the extraction efficiency of Zn(II) ions was studied and optimized in pH around 6. The selectivity of the synthesized IIPs was studied in the presence of Co(II), Cd(II) and Ni(II) ions, and the IIPs showed higher affinity for Zn(II) in the presence of other interfering ions