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Title: The synthesis and properties of novel cyanosilicone polymers
Author: Adams, P. N.
ISNI:       0000 0001 3397 0060
Awarding Body: Polytechnic of the South Bank
Current Institution: London South Bank University
Date of Award: 1986
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The objective of this work has been to prepare a cyanosilicone polymer which shows both thermal stability and solvent resistance comparable to the commercially available fluorosilicones. A novel method of synthesising the polymers, involving the addition of allyl nitrile to a polymethylhydrogensiloxane, was studied. Reviews are presented of the chemistry of organosiloxanes with particular reference to the hydrosilation reaction. A survey of the different methods for preparing both the cyanosilicone and fluorosilicone polymers has been made, and their respective physical properties compared. A study has been carried out on the platinum-catalysed hydrosilation reaction between allyl nitrile and a model polymethylhydrogensiloxane polymer, (CH3)3Si-f-OSiMeH-TT40Si(CH3), and copolymers of this with dimethylsiloxane. The platinum catalysts investigated were chloroplatinic acid, platinum on carbon, Pta [(Me2ViSi)20J3' (PPh3)4Pt and (PPh3)2PtClz' where PPh3 = triphenylphosphine. The conditions which gave optimum reaction results, methods for deactivating the catalyst after the reaction and the phenomena of gelling during and after the course of the reaction were studied. The catalysts were also compared in their effectiveness towards crosslinking the cyanosilicone polymers. The viscosities of the cyanopropyl-substituted polymers were measured. Swelling measurements on the crosslinked polymers with a range of cyanopropyl substitutions were made in solvents with a range of solubility parameters. The percent Volume Swell and the solubility parameters of the cyanopropylsiloxane polymers were determined. The thermal stability of both the liquid and crosslinked polymers with a range of cyanopropyl substitutions were determined in air and under a nitrogen atmosphere using thermogravimetric (T.G.A.) techniques. Mechanisms are proposed for the degradation processes. Kinetic data including the activation energies for the degradation process and the order of reaction were determined from the weight loss curves •
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Organic chemistry