Thermal and thermooxidative degradation studies of electrolytes based on polyethylene oxide) (PEO) have been extended to include a range of inorganic salts to elucidate the role of the salt. In confirmation of earlier studies, inorganic salts generally reduce the thermal stability of PEO in an inert atmosphere but protect the polymer against thermal oxidation. These effects are explained, in part, by the strength of the interaction between the metal cation M+ and the oxygen atoms in the polymer backbone. The greater the charge density of M+, the greater its destabilizing influence during degradation under nitrogen and the greater its stabilizing effect in an oxidizing atmosphere. This arises because complexation tends to reduce the strength of backbone C-0 bonds but also retards peroxidation at adjacent C-H bonds. The anions also influence the decomposition reactions both by screening the cations and by direct chemical interaction. In the presence of oxygen, acetaldehyde, methanol, and C02 are the most abundant low-boiling products from both PEO and its complexes. Ethylene, which is abundant when PEO-salt complexes are pyrolyzed under N2, is absent. Methyl and ethyl formates are also formed in small amounts from complexes but not from pure PEO, though the latter does evolve small amounts of other esters and dioxane. Mechanisms of thermooxidative degradation accounting for these observations are proposed.

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The coupling of living polymer chains with reactive groups on a polymer backbone is an attractive method for synthesising well-defined graft copolymers l ) . Attempts to couple living polymers, such as polystyryllithium, with halogenated groups, however, have generally proved disappointing because of competing elimination or metalhalogen exchange reactions. Such competing processes lead to the formation of significant quantities of free polystyrene in grafting reactions between lightly brominated polybutadiene and living polystyrylanionsz). Coupling reactions between halogenosilane groups and living polyanions are much cleaner. Thus, polystyryllithium can yield star polymers on reaction with 1 ,2-bis(methyldichlorosilyl)ethane3).In the work reported here, the feasibility of this type of reaction for the preparation of poly(diene-g-styrene)s was tested. A liquid polybutadiene (PBD) was functionalised with chlorosilane groups which were then coupled with living anions of polystyrene and poly(a-methylstyrene):

The radical‐induced grafting of styrene onto polyisoprene (PIP) in benzene solution at, 60°C was studied in rubber concentration (up to 0.5 monomer mole liter‐1) in which the polymerization of styrene shows ideal kinetics with no retardation by PIP. The proportion of polystyrene incorporated as graft is independent of the initiator (benzoyl peroxide) concentration and was found to be consistent with the kinetic expression derived by Cameron et al. The graft fraction of polystyrene which is higher than in the corresponding styrene‐polybutadiene system reflects the higher reactivity of PIP toward radicals. Azobisisobutyronitrile produces no graft copolymer in this system.