Synthesis of thermoreactive polysiloxanes with cyclic fragments in the side chain

The synthesis of polysiloxanes with pendant unsaturated cyclic fragments have been successfully performed by hydrosilylation reactions of polymethylhydrosiloxane with 4‐vinyl‐1‐cyclohexene in the presence of platinum hydrochloric acid (0.1 M solution in THF), Karstedt's catalyst (Pt₂[(VinSiMe₂)₂O]₃) and platinum on the charcoal (5%). Reactions were carried out at various temperatures with different ratios of initial compounds. It was shown, that not all active ≡Si? H groups take part in the hydrosilylation reaction. Some kinetic parameters of reactions were studied. The synthesized oligomers were characterized by FTIR, ¹H, ¹³C, H,H‐COSY, and C,H‐correlation NMR spectroscopy. Calculations using the quantum‐chemical semi empirical AM1 method for modeling reactions between methyldimethoxysilane [Me(MeO)₂SiH] and 4‐vinyl‐1‐cyclohexene were performed to evaluate possible reaction paths. Synthesized oligomers were characterized by gel‐permeation chromatography, differential scanning calorimetric, thermogravimetric, and wide‐angle X‐ray analyses. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of polysiloxanes with pendant bicyclic fragments

Transparent poly vinyl alcohol (PVA) based coatings with antimicrobial activity against a wide range of microorganisms have been prepared. The films have been prepared by spincoating a mixture of PVA, ammonium dichromate and metal (zinc or silver) precursor from water solutions, and then rendered insoluble by crosslinking under UV illumination. Antimicrobial activity has been tested against different bacteria and fungi, such as Bacillus atrophaeus, Bacillus megaterium, Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, Salmonella enterica, Escherichia coli, Neurospora crassa, and Saccharomyces cerevisiae. It was found that combining the zinc and silver precursors resulted in films which had excellent antimicrobial activity and at the same time exhibited superior environmental stability compared to films containing prepared with single metal precursor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011