Initial Concentrations Of Components Research Articles

Kinetic features of phenylglycidyl ether polymerization under the action of tertiary amines

A study has been made of kinetic features of phenylglycidyl ether polymerization under the action of dimethylbenzylamine in the presence of alcohol additions. The temperature dependence of the rate constant of the side isomerization reaction has been determined. The rate constant of transfer of the growing active centre to propargyl, allyl and isopropyl alcohols have been determined, as well as the ratio of the active centre decay rate constant and the initiation rate constant, and the dependence of this ratio on the initial concentrations of components of the system.

Synthesis of New Thermally Stable Halopolyamides

Abstract Several new thermally stable halopolyamides were prepared by low temperature solution polycondensation from some new diacid chlorides and a number of diamines, namely p-phenylenediamine (I), m-phenylenediamine (II), benzidine (III), 4,4′-diamino-diphenylmethane (IV), 4,4′-diaminodiphenyl sulfone (V), ethylene-diamine (VI), hexamethylenediamine (VII), and 4,4′-diamino-dicyclohexylmethane (VIII). The diacid chlorides were derived from two series of some new dicarboxylic acids: (A) 2-halo-(chloro-, bromo-, and iodo-)-4-carboxyphenoxyacetic acid (K-XI); and (B) 2-halo-(chloro- and iodo-)hydroquinone-l,4-diacetic acid (XII and XIII). Dimethyl esters and diamide derivatives were prepared to confirm the structures of the diacid chlorides (Ka-XIIIa)i Nylon salts of the new dicarboxylic acids (DC-XIII) were also prepared. Some of the factors affecting the reduced viscosity of the polymers such as the effect of the concentration of initial components, temperature, and duration time were studied. In the cas...

Preparation and properties of spin-labeled lecithin-cholesterol liposomes.

Lecithin-cholesterol vesicles of various compositions containing membrane-bound spin-labeled cholestane can be prepared by appropriate choice of initial concentrations of components during sonication. Increasing incorporation of spin label increases incorporation of cholesterol and decreases incorporation of lecithin, with the result that liposomes with cholesterol-lecithin molar ratios larger than 2 can be obtained. Besides associating with cholesterol-lecithin complexes in the liposome, the spin label seems to associate with cholesterol. Changes of the paramagnetic resonance spectrum of the liposome-bound spin label due to changes in liposomal cholesterol and spin label mole fractions - assessed by three parameters - can be used in cell-liposome interaction studies.

Synthesis and study of polymers prepared from dianhydrides of 3,4,9,10-perylene-1,4,5,8-naphthalene tetracarboxylic acids and aromatic tetra-amines

Low molecular weight products of the condensation of dianhydride of perylene tetracarboxylic acid (DAPTA) with tetra-aminodiphenyl ester (TADPE) and high molecular weight soluble polyaminoamido acids containing alternating naphthalene and perylene units, were obtained in an aprotonic solvent-inorganic salt system. The effect of various factors (LiCl concentration, concentrations of initial components, reaction temperature and dianhydride ratio) on the rate of polycondensation and the molecular weight of polyaminoamido acids was examined. Conditions of cyclization were determined for copolymers. Poly-(aroylene-bis-benzimidazoles) containing alternating perylene and naphthalene units were prepared by high temperature polycondensation in polyphosphoric acid.