The synthesis of poly(dimethylsiloxane) (PDMS) by anionic polymerization of octamethylcyclotetrasiloxane (D4) in aqueous emulsion using an emulsifying agent acting also as initiator (benzyldimethyldodecylammonium hydroxide) is described. Stable emulsions of α,ω‐dihydroxy PDMS with an easily controlled molar mass (up to 15 000), a low polydispersity index and high yields were obtained. The amount of cyclics formed (essentially D4 to D7) is lower than that observed in bulk. Kinetics analysis and computerized simulations are in good agreement with a reaction scheme involving simultaneous polyaddition/polycondensation processes. At high monomer consumption, polycondensation predominates leading to a broadening of the molecular weight distribution (MWD). The apparent rate constants of initiation, propagation and condensation at various temperatures and the corresponding activation energies were determined.

Aliphatic ethers of cellulose are found to form stable monolayers when spread from dilute chloroform solution at the air−water interface. Monolayer pressure−area isotherms exhibit a liquid analogous phase followed by a transition region of relatively high compression at constant pressure. Limiting molecular areas are found to depend on side-chain length, indicating that the hydrocarbon substituents do not adopt an orientation strictly perpendicular to the water surface. Monolayers of mixed ethers containing, on average, a single long chain substituent per repeat unit, form liquid analogous phases at molecular areas equivalent to the area of the anhydroglucose ring. It is thus concluded that the cellulose backbone lies flat on the water surface. The transition region observed upon compression beyond the liquid analogous phase is attributed to the formation of bi- or multilayers, with molecules leaving the water surface. This interpretation is consistent with the observed decrease in plateau pressure with increasing temperature.

A kinetic study of the anionic polymerization of octamethylcyclotetrasiloxane (D4) in aqueous emulsion has been carried out in the presence of ionic additives. The rate of polymerization of several cyclosiloxanes has been compared, leading to additional evidence for an interfacial mechanism of polymerization. The emulsion process has been applied to the cationic polymerization of D4 and of tetramethylcyclotetrasiloxane (DH4) initiated by dodecylbenzenesulfonic acid. Very efficient for the synthesis of linear polymethylhydrogenosiloxanes (PMHS), these conditions did not seem suitable for the polymerization of D4. The extension of the process to other heterocyclic monomers is discussed through the anionic polymerization of phenylglycidylether.