Potassium Diperiodatocuprate Research Articles

Synthesis, Characterization, and Flocculation Properties of Branched Cationic Polyacrylamide

A water soluble branched cationic polyacrylamide (BCPAM) was synthesized using solution polymerization. The polymerization was initiated using potassium diperiodatocuprate, K5[Cu(HIO6)2](Cu(III)), initiating the self-condensing vinyl copolymerization of acrylamide and acryloxyethyltrimethyl ammonium chloride (DAC) monomer. The resulting copolymer was characterized by the use of Fourier-transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. Its flocculation properties were evaluated with standard jar tests of sewage. The effects of initiator concentration, monomer concentration, reaction temperature, and the mass ratio of monomers on intrinsic viscosity and flocculation properties of the product were determined using single-factor experiments and orthogonal experiment.

Synthesis, Characterization, and Flocculation Properties of Branched Polyacrylamide

A water soluble branched polyacrylamide has been synthesized through solution polymerization. The polymerization was initiated by potassium diperiodatocuprate, K5[Cu(HIO6)2](Cu(III)), in alkaline medium and capable of initiating the self condensation vinyl polymerization of acrylamide monomer. The polymer obtained was characterized using Fourier-transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. Its flocculation properties were evaluated with clay suspensions using standard jar tests. The concentration of monomers, concentration of initiators, reaction temperature and solution pH on the influence of intrinsic viscosity and flocculation properties of production were studied. The results demonstrate that the branched polymer can be used as a kind of novel flocculant in water and wastewater treatment.

Preparation and properties of chitosan‐graft‐poly(methyl methacrylate) nanoparticles using potassium diperiodatocuprate (III) as an initiator

AbstractGraft copolymer nanoparticles prepared from chitosan (CS) and methyl methacrylate (MMA) monomer were synthesized in aqueous solution by using potassium diperiodatocuprate [Cu(III)] as an initiator and characterized in terms of particle size, zeta potential, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, thermal stability, and X‐ray diffraction spectrometry. The results indicated that CS was covalently linked to poly(methyl methacrylate) (PMMA), and the resulting copolymers formed nanoparticles. These nanoparticles [prepared at 35°C, in a weight ratio of MMA/CS of 5 : 1 and with a Cu(III) concentration of 1.5 × 10−3 mol/L] were 54–350 nm in size, with a mean hydrodynamic diameter of 183 ± 3 nm and were highly uniform in particle‐size distribution, with a rather spherical shape and an obvious positive charge surface. The effect of reaction conditions such as Cu(III) concentration, reaction temperature, and the weight ratio of MMA/CS on the mean particle size was also investigated. Insulin‐loaded nanoparticles were prepared, and their maximal association efficiency was up to 85.41%. The experiment of release in vitro showed that the nanoparticles gave an initial burst release followed by a slowly sustained one. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Potassium diperiodatocuprate-mediated preparation of poly(methyl methacrylate)/organo-montmorillonite composites via in situ grafting copolymerization

In this study, potassium diperiodatocuprate (Cu3+) was selected as an initiator to prepare poly(methyl methacry- late)/organo-montmorillonite composites (OMMT-g-PMMA) by in situ graft copolymerization. Three synthetic parameters were systematically evaluated as a function of the temperature, the concentration of initiator, pH and the ratio of MMA to OMMT. It was found that Cu3+ was a highly efficient initiator for the preparation of OMMT-g-PMMA i.e., monomer con- version and grafting efficiency were as higher as 95%. The X-ray diffraction measurement showed the intercalation of PMMA chains into OMMT layers on base of an increasing basal spacing after polymerization. FTIR analysis also sug- gested that the PMMA chains were effectively grafted onto OMMT substrate. The enhanced thermal stabilities of OMMT- g-PMMA composites were confirmed by the thermal gravimetric analysis (TGA). Finally, a single-electron-transfer mechanism was proposed to illustrate the formation of radicals and the preparation process of OMMT-g-PMMA compos- ites. Cu3+ can be used as an effective and practical initiator in preparing the organic/inorganic composite due to its high

Influence of grafting conditions on the properties of polyacrylamide-based cation-exchange cryogels grafted with 2-acrylamido-2-methyl-1-propanesulfonic acid

The effects of grafting conditions on the properties of a novel cation-exchange cryogel by grafting of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) onto polyacrylamide-based cryogel (pAAm cryogel) using potassium diperiodatocuprate (Cu(III) solution) as initiator were investigated experimentally. The basic cryogels were saturated with the initiator solution followed by the solution of monomers to get the expected sulfo groups under various grafting conditions, such as concentrations of monomers and initiator, graft reaction time, graft temperature and the volume ratio of Cu(III) to NaOH. The results showed that these factors influenced the liquid dispersion behaviors and the flow resistance as well as the protein binding capacity of the grafted cryogels. Protein binding capacity increased with the increase of concentration of AMPSA and Cu(III), the graft temperature and the graft reaction time in a wide range under the present conditions. Compared with these factors, the volume ratio of Cu(III) to NaOH in the initiator solution in the considered situations had a relatively weaker influence on the cryogel microstructures and protein binding capacity. The maximum binding capacity of lysozyme reached 2.5 mg/mL cryogel in these grafted cryogels.

Kinetics of graft copolymerization of poly(hexanedioic acid ethylene glycol) and methyl acrylate initiated by potassium diperiodatocuprate(III)

AbstractA redox system, potassium diperiodatocuprate(III) [DPC]/poly(hexanedioic acid ethylene glycol) (PEA) system, was employed to initiate graft copolymers of methyl acrylate (MA) and PEA in alkaline medium. The results indicate that the equation of the polymerization rate (Rp) is as follows: Rp = k [MA]1.62[Cu(III)]0.69, and that the overall activation energy of graft polymerization is 42.5 kJ/mol. The total conversion at different conditions (concentration of reactants, temperature, concentration of the DPC, and reaction time) was also investigated. The infrared spectra proved that the graft copolymers were synthesized successfully. Some basic properties of the graft copolymer were studied by instrumental analyses, including thermogravimetry and scanning electron microscope. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2376–2381, 2007

Grafting of 4-vinyl pyridine onto poly(vinyl alcohol) initiated by potassium diperiodatocuprate(III)

In this article, the graft copolymerization of 4-vinyl pyridine onto poly(vinyl alcohol) via the potassium diperiodatocuprate(III)-poly(vinyl alcohol) redox system as an initiator was investigated in an alkaline medium. The graft copolymer was characterized with Fourier-transform infrared spectra analysis. A mechanism is proposed to explain the generation of radicals and the initiation. The effects of reaction variables, such as the initiator concentration, the ratio of monomer to poly(vinyl alcohol), pH, and reaction temperature and time, are investigated, and the grafting conditions are optimized. Graft copolymers with high grafting efficiency are obtained, thus indicating that potassium diperiodatocuprate(III)-PVA redox system is an efficient initiator for this graft copolymerization.

Grafting of Methyl Acrylate onto PET Initiated by Diperiodatocuprate(III)

A novel system, potassium diperiodatocuprate(III) (DPC)‐Poly(ethylene terephthalate) (PET), was employed to initiate the graft copolymerization of methyl acrylate (MA) onto PET in alkali medium. The effects of reaction conditions, such as the initiator concentratio, ratio of MA to PET, and temperature and time, were investigated. Graft copolymers with high grafting parameters were obtained (E%>80%), which indicated that the DPC‐PET system is an efficient initiator for this graft copolymerization. The structures and the thermal stability of PET‐g‐PMA were characterized by scanning electron microscope (SEM), infrared spectroscopy (IR) and thermogravimetric analysis (TGA). A mechanism is proposed to explain the generation of radicals and the initiation of graft copolymerization. The SEM photographs show that the graft copolymer greatly improved the compatibility of the PET/PMMA blends. The moisture regain (MR) of PET‐g‐PMA is found to increase comparde with PET.

Ion‐exchange macroporous hydrophilic gel monolith with grafted polymer brushes

The grafting of functional polymers to the pore surface of macroporous monolithic polyacrylamide cryogels was found to be an efficient and convenient method for the preparation of macroporous polyacrylamide gels, so-called cryogels (pAAm cryogels), with both controlled extent of functional group incorporated and with tailored surface chemistries. Anion-exchange polymer chains of poly(2-(dimethylamino)ethyl methacrylate) (pDMAEMA) and poly([2-(methacryloyloxy)ethyl]-trimethylammonium chloride) (pMETA), and cation-exchange polymer chains of polyacrylate have been grafted onto pAAm cryogels using potassium diperiodatocuprate as initiator. It was possible to achieve the ion-exchange capacity up to 0.2-0.5 mmol/ml. The graft polymerization did not alter the macroporous structure of the pAAm cryogel, however the flow rate of solutes through the cryogel matrix decreased with increase in the density of polymer grafted. The sorption of low-molecular-weight (metal ion, dye) and high-molecular-weight (protein) substances on the grafted monolithic pAAm column has been studied. The results indicate that a 'tentacle'-type binding of protein to grafted polymer depended on the architecture of the grafted polymer layer and took place after a certain degree of grafting has been reached. The binding of proteins by tentacle-like polymer chains allowed for increasing the binding capacity for proteins on the grafted pAAm cryogels up to 6-12 mg/ml.

Anion-exchange supermacroporous monolithic matrices with grafted polymer brushes of N, N-dimethylaminoethyl-methacrylate

Graft polymerization using potassium diperiodatocuprate as initiator was found to be an effective and convenient method for grafting functional polymer of N, N-dimethylaminoethyl methacrylate (DMAEMA) onto superporous polyacrylamide gels, so-called cryogels (pAAm cryogels). It was possible to achieve grafting degrees up to 110% (w/w). The two-step graft polymerization i.e. first activation of the matrix followed by displacement of initiator solution with the monomer solution, decreased pronouncedly the soluble homopolymer formation. The efficiency of graft polymerization using a two-step technique increased up to 50% (w/w) at a monomer conversion of 10%, compared to 10% graft efficiency with 60–70% monomer conversion for one-step direct graft polymerization. The pAAm cryogels grafted in one-step and two-step procedures, respectively, behaved similarly when binding low-molecular weight ligand but showed very different behavior for sorption of a high-molecular-weight ligand, bovine serum albumin (BSA). The differences in behavior were rationalized assuming different structure of the graft polymer layers and tentacle-type BSA binding to the grafted polymer.

Block copolymerization of poly(ethylene glycol) and methyl acrylate using potassium diperiodatocuprate(III)

AbstractBlock copolymers of methyl acrylate (MA) and poly(ethylene glycol) (PEG) have been obtained using a novel redox system—potassium diperiodatocuprate(III)[DPC]/PEG system in alkaline aqueous medium. Block copolymers with a high percentage of blocking were obtained, which indicated that the DPC/PEG redox system was an efficient initiator for this blocking. Effects of different conditions (concentration of reactants, temperature, concentration of the DPC, and reaction time) on the total conversion, percentage of blocking, and intrinsic viscosity were examined. The effects of different monomers and various PEGs with different molecular weight on the total conversion were also examined. A mechanism is proposed to explain the generation of radicals and the initiation of block compolymerization. Some basic properties of the block copolymers were also studied by thermogravimetry and scanning electron microscope. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2139–2145, 2005

Graft copolymerization of methyl acrylate onto sodium alginate initiated by potassium diperiodatocuprate(III)

A novel redox system, potassium diperiodatocuprate(III) (DPC) - sodium alginate (SA), was employed to initiate the graft copolymerization of methyl acrylate (MA) onto SA in alkali medium. The effects of reaction variables, such as the initiator concentration, the ratio of monomer and SA, SA backbone concentration, as well as temperature and time, were investigated, and the grafting conditions were optimized. Graft copolymers with both high grafting efficiency and high part of grafting were obtained, which indicated that DPC-SA redox system is an efficient initiator for this graft copolymerization. The structures and the thermal stability of SA and SA-g-PMA were characterized by scanning electron microscope (SEM), infrared spectroscopy (IR) and thermogravimetric analysis (TGA). A mechanism is proposed to explain the generation of radicals and the initiation.

Graft copolymerizaztion of methyl acrylate onto chitosan initiated by potassium diperiodatocuprate (III)

AbstractA novel redox system, potassium diperiodatocuprate [Cu (III)–chitosan], was employed to initiate the graft copolymerization of methyl acrylate (MA) onto chitosan in alkali aqueous solution. The effects of reaction variables such as monomer concentration, initiator concentration, pH and temperature were investigated. By means of a series of copolymerization reactions, the grafting conditions were optimized. Cu (III)–chitosan system was found to be an efficient redox initiator for this graft copolymerization. The structures and the thermal stability of chitosan and chitosan‐g‐poly(methyl acrylate) (PMA) were characterized by infrared spectroscopy (IR) and thermogravimetric analysis (TGA). In this article, a mechanism is proposed to explain the formation of radicals and the initiation. Finally, the graft copolymer was used as the compatibilizer in blends of poly(vinyl chloride) (PVC) and chitosan. The scanning electron microscope (SEM) photographs and differential scanning calorimetry (DSC) thermograms indicate that the graft copolymer improved the compatibility of the blend. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2283–2289, 2003

Graft Copolymerization of Methyl Acrylate onto Poly(Vinyl Alcohol) Initiated by Potassium Diperiodatocuprate(III)

A novel redox system, potassium diperiodatocuprate(III) [Cu (III)]-poly(vinyl alcohol) (PVA) redox system, was employed to initiate the graft copolymerization of methyl acrylate (MA) onto PVA in alkaline medium. The grafting parameters varied with concentrations of monomer, initiator, macromolecular backbone (DP=1750, M=80 000) and temperature. The formation of the graft copolymer was confirmed by Fourier transfer infrared spectroscopy (IR), scanning electron microscope (SEM), X-ray diffraction and thermogravimetric analysis (TGA). It was found that [Cu (III)]-PVA system is an efficient redox initiator for this graft copolymerization. A mechanism is introduced to explain the formation of radicals and the initiation. At the same time, the other acrylate monomers, such as methyl methacrylate, ethyl acrylate and n-butyl acrylate, were used as reductant to produce graft copolymerization. It was definitely observed that these reactions could occur in some degree. Thermal stabilities were checked by TGA and this indicated that graft copolymer was resistant to moisture absorption.

Self-condensing vinyl polymerization of acrylamide

A novel approach to branched polyacrylamide was described. The branched structure resulted from the amidyl radicals which were formed by the reaction of amide groups with Cu(III) of potassium diperiodatocuprate, K5[Cu(HIO6)2], in alkaline medium and capable of initiating the vinyl polymerization of acrylamide monomer. The obtained polymer was characterized by 1H NMR, FT-IR and intrinsic viscosity measurements.

The use of copper(III) complex compounds for the thermochemical analysis (DIE) of different organic substances

Potassium diperiodatocuprate(III), K7[Cu(IO6)2], was tested as a reagent for the determination of mono- and disaccharides by means of direct injection enthalpimetry. The reagent reacted readily with acyclic polyhydroxy compounds, the reaction proceeding the better, the more hydroxy groups there were in the substance and the closer the hydroxy groups were one to the other. It also reacted readily with phenols, the polyhydric ones in particular. Carbonyl and amino compounds mostly didn't react or did so slowly, but reacted readily in the presence of some other reactive group such as hydroxy, sulphhydryl or thioxo group. Semicarbazide reacted readily, presumably due to the presence of the reactive-CO-NH-group. It is concluded that carboxy groups in the proximity of hydroxy groups exercise a positive effect on the reaction. The presence of a nitro or sulphonic acid group has a negative effect on the course of the reaction with the copper(III) compound.