| 摘要 |
A method for the production of oxymethylene homopolymers involves (i) homogeneous polymerisation of an oxymethylene unit-forming monomer in presence of a formaldehyde acetal and a cationic polymerisation initiator, and (ii) stopping polymerisation before thermodynamic equilibrium and at less than 90% of maximum conversion, by (iii) deactivating the active polymer chain with an organic or inorganic base. A method for the production of oxymethylene homopolymers of formula R1>-(OCH2)n-O-R2> (I) containing up to 0.5 wt% oxyethylene groups and/or up to 1 wt% branching units, in which R1>, R2>alkyl; n : 500 or more . This method involves (i) polymerisation of a -CH2O- unit-forming monomer (M) in a homogeneous phase in presence of a formaldehyde acetal (II) and an initiator (IV) for cationic polymerisation, and (ii) stopping polymerisation before reaching thermodynamic equilibrium and at less than 90% of maximum conversion, by (iii) deactivation of the active polymer chain in the homogeneous phase by treatment with a dissolved or dispersed organic or inorganic base. |
