Effect of dicyclopentadiene-and diindenezirconocene dichlorides on free-radical polymerization of methyl methacrylate

The effect of zirconocene dichloride and its indene-containing derivative on the radical polymerization of methyl methacrylate initiated by benzoyl peroxide has been studied. The influence of the metallocenes on the kinetic parameters of the process and the average degree of polymerization has been established. Concentration and temperature dependences have been measured for the initial rate of reaction and the average degree of polymerization in relation to the content of the components in the systems. The microstructure of poly(methylmethacrylate) prepared in the presence of the used initiation systems has been determined.     

Cyclic peroxides and related initiating systems for radical polymerization of methyl methacrylate

Cyclic peroxides as initiators for the radical polymerization of methyl methacrylate were proposed. The initial rates, initiation rates, and effective activation energies of polymerization initiated by cyclic peroxides and cyclic peroxide-1-pyridyl-2-ferrocene systems were determined. The radical yields to the volume upon the thermal decomposition of cyclic peroxides and their catalytic decomposition in the presence of 1-pyridyl-2-ferrocene were determined. In combination with 1-pyridyl-2-ferrocene cyclic peroxides form efficient initiating systems favoring an increase in the polymerization rate, a decrease in the molecular weights, and an increase in syndiotacticity of the synthesized poly(methyl methacrylate).     

Photochromic copolymers containing 3-indolylfulgides/indolylfulgimides: Synthesis and photochemical properties in toluene and as films

Photochromic indolylfulgimides covalently attached to polymers have beneficial properties for optical switching. A 3-indolylfulgide and two 3-indolylfulgimides with one or two polymerizable styrene groups attached on the nitrogen atom(s) were synthesized. Copolymerization with methyl methacrylate (MMA) provided linear copolymers (one styrene group) or a cross-linked copolymer (two styrene groups). The properties of the monomers and copolymers in toluene or as thin films were characterized. The new copolymers were photochromic (reversible Z-to-C isomerization), absorbed visible light, and revealed good thermal and photochemical stability. At room temperature, all copolymer films showed no loss of absorbance after 5 weeks. At 80 °C in either toluene or as films, the Z-forms copolymers were less stable than the C-form copolymers, which showed little or no degradation after 400 h. The degradation rate due to repeated ring-closing – ring opening cycles was less than 3% per 100 cycles. The cross-linked copolymer showed photochemical stability comparable to monomeric fulgides in toluene, <1% per 100 cycles. In general, the properties of the linear and cross-linked copolymers were similar to the corresponding monomers in toluene. In films, the conformations of the Z-form were restricted due to the matrix indicating that the preparation of films from the C-form is advantageous.     

Chromophores with quinoxaline core in π-bridge and aniline or carbazole donor moiety: synthesis and comparison of their linear and nonlinear optical properties

Russian Chemical Bulletin - Two new D—π—A chromophores with the tricyanofuranyl acceptor (A), an amphi-divinyl quinoxaline π-electron conjugated bridge, and the carbazole or...     

Photoelectron spectrum and quantum-chemical analysis of structure of bis(N-methoxydiazene-N-oxido)methane

A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 2, pp. 74–79, March–April, 1989.     

Polymeric eye films based on polyvinyl alcohol and arabinogalactan with levofloxacin

Physicochemical methods were used to study the interaction of arabinogalactan from Siberian larch with the antibacterial preparation levofloxacin. Polymeric eye films with controllable output of the medicinal preparation were produced on the basis of an arabinogalactan-polyvinyl alcohol formulation. A high pharmaceutical activity of the new eye films was demonstrated.