LITHIUM ALKYLNICKELATE AND ALKYLPALLADATE BIMETALLIC ATE COMPLEXES ASINITIATORS FOR ANIONIC-POLYMERIZATION OF METHYL-METHACRYLATE

Anionic-coordinative polymerization of methyl methacrylate (MMA) was c arried out in the presence of new bimetallic initiators based on lithi um alkylnickelates and alkylpalladates in tetrahydrofuran, at -78 degr ees C. Well-defined poly(methyl methacrylate), PMMA, with molecular we ights increasing linearly with conversion and relatively narrow polydi spersities ((M) over bar(w)/(M) over bar(n) = 1,26 to 1,4) were prepar ed by initiation with some of the ''ate'' complexes. In the presence o f lithium ''ate'' Ni-based complexes, PMMA with enhanced syndiotactici ty [(rr) = 73 to 75%] was formed.