Synthesis and characterization of a novel water-soluble mid-chain macrophotoinitiator of polyacrylamide by Ce(IV)/HNO3 redox system

A new water-soluble mid-chain macrophotoinitiator of polyacrylamide (PAAm) has been synthesized by redox polymerization. The polymerization of acrylamide (AAm) initiated by dihydroxy functional photoinitiator namely, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl propan-1-one (HE-HMPP), Irgacure 2959, in combination with cerium(IV) ammonium nitrate has been investigated in aqueous nitric acid. The effects of HE-HMPP, AAm, and Ce(IV) concentrations on the polymerization rate were investigated. The photodegradation and IR, ¹H NMR, UV, and fluorescence spectroscopic studies revealed that polyacrylamide with desired photoinitiator functionality in the middle of the chain were obtained. This prepolymer was used in photoinduced free radical polymerization of methyl methacrylate (MMA) to produce PAAm-PMMA block copolymer.     

On ramification in the compositum of function fields

The aim of this paper is twofold: Firstly, we generalize well-known formulas for ramification and different exponents in cyclic extensions of function fields over a field K (due to H. Hasse) to extensions E = F(y), where y satisfies an equation of the form f(y) = u · g(y) with polynomials f(y), g(y) ∈ K[y] and u ∈ F. This result depends essentially on Abhyankar’s Lemma which gives information about ramification in a compositum E = E ₁ E ₂ of finite extensions E ₁, E ₂ over a function field F. Abhyankar’s Lemma does not hold if both extensions E ₁/F and E ₂/F are wildly ramified. Our second objective is a generalization of Abhyankar’s Lemma if E ₁/F and E ₂/F are cyclic extensions of degree p = char(K). This result may be useful for the study of wild towers of function fields over finite fields.     

Preparation of PCM microcapsules by complex coacervation of silk fibroin and chitosan

Phase change material microcapsules were prepared by complex coacervation of silk fibroin (SF) and chitosan (CHI). n-Eicosane was used as the core material. The effects of SF/CHI ratio, and percentage of cross-linking agent and n-Eicosane content on the properties of microcapsules were studied. The size distribution and the surface morphology of microcapsules were characterized by optical and scanning electron microscopy. The encapsulation of core material was determined by energy dispersive spectrometer analysis. The results indicated that SF/CHI microcapsules were prepared successfully. Microcapsules had smooth outer surface when the ratio of SF to CHI was close to 5. On the other hand, at high SF/CHI ratios (≥14), microcapsules showed a two-layer structure, an inner compact layer, and an outer, more porous, sponge-like layer. The highest microencapsulation efficiency was obtained at a SF/CHI ratio of 20 in the presence of 0.9% cross-linking agent and of 1.5% n-Eicosane content.     

A novel (E,E)-dioxime and its mono-, di- and trinuclear complexes bearing tetradentate octyl sulfanyl phenylamino substituents. Synthesis,characterization and electrochemical properties of its transition metal complexes

A new vic-dioxime, 13,14-bis-(hydroxyimino)-9,12,15,18-diazadithiaoctacosane, has been synthesized from 2-octylsulfanylaminobenzene and (E,E)-dichloroglyoxime. Mononuclear transition metal complexes of Ni^II, Cu^II, Co^II and Fe^II have been prepared and were found to have a metal–ligand ratio of 1:2. The synthesis of di- and trinuclear complexes was achieved with U^IVO₂ and Cu^II depending on the stoichiometry of the reactants. The complexes were characterized by elemental analysis, ¹H-n.m.r., u.v.–vis, i.r., f.a.b.-m.s. and by cyclic voltammetry.     

A novel blue fluorescent chemosensor for metal cations and protons,based on 1,8‐naphthalimide and its copolymer with styrene

A new blue emitting 2‐allyl‐6‐(2‐dimethylaminoethyloxy)‐benzo[de]isoquinoline‐1,3‐dione, bearing an allylic group has been designed and synthesized. Bulk radical copolymerization has been carried out in order to prepare a fluorescent copolymer, based on styrene. The main photophysical characteristics of the monomeric and polymeric fluorophores have been investigated both in the absence and presence of metal cations and protons. It has been found that the monomeric naphthalimide can be used as a sensor for protons and Zn²⁺, Ni²⁺, Ce³⁺, Cu²⁺, Co²⁺, Ag⁺ cations. The polymeric fluorophore has been shown to be a selective chemosensor for Cu²⁺ cations. Copyright © 2006 John Wiley & Sons, Ltd.     

Synthesis,Molecular Structure and Spectroscopic Studies of 6,6'-(1E,1'E)-(Ethane-1,2-Diylbis(azan-1-yl-1-ylidene))bis(Phenylmethan-1-yl-1-ylidene)bis(3-(Octyloxy)phenol)

Crystallography Reports - 6,6'-(1E,1'E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(phenylmethan-1-yl-1-ylidene)bis(3-(octyloxy)phenol) has been synthesized and characterized by FTIR, 1H,...