Metalloporphyrazines – Catalysts of Vulcanization of Liquid Siloxane Rubbers

Polymerization of tetramethylcyclotetra- siloxane monomer by ion-exchanged montmorillonite catalysts

AB S TRACT: Montmorillonites ion-exchanged with Li +, Na +, K § Ca 2+, Mg 2+ and Ni 2+ and acidic clay were used as catalysts for the polymerization of a cyclic siloxane monomer, 2,4,6,8tetramethylcyclotetrasiloxane. Montmorillonites with Ni 2+ and Mg 2+ in the interlayer, and acidic clay exhibit a greater ability for siloxane polymerization in both yield and mean molecular weight of products t...

Liquid/liquid separation of polysiloxane-supported catalysts.

Liquid/liquid separation after monophasic reactions is a viable way to use and recover polysiloxane-supported catalysts.

Liquid chromatography/mass spectrometry identification of intermediates and vulcanization products by using squalene as vulcanization model compound.

RATIONALE Sulfur-vulcanized rubber is a three-dimensional polymer network, insoluble in all organic solvents. For this reason, vulcanization products are difficult to study and identify by conventional analytical techniques. To simplify this task, low molecular weight olefins have been used as model compounds (MCs) in place of rubber in vulcanization experiments. METHODS In this work, the vul...

Theory & Practice Of Vulcanization

Identification of monoacyl- and monoalkylglycerols by gas--liquid chromatography--mass spectrometry using polar siloxane liquid phases.

A comparative study was made of the spectra obtained after gas-liquid chromatography-mass spectrometry of the trimethylsilyl ethers of 1- and 2-monoacyl- and monoalkyl-glycerols. The glycerol derivatives were resolved on the basis of positional substitution and the degree of unsaturation on Silar-5CP (a cyanopropylphenylsiloxane) liquid phase, and the peaks were examined in a Varian MAT CH-5 si...