Poly classical catalyst system

Calderon classical catalyst system, 457 CAPA. See Poly(e-caprolactone) (CAPA, PCL)... 

ADMET depolymerization has been explored in a variety of ways [174]. In its simplest form, an unsaturated polymer subjected to metathesis conditions in the presence of ethylene will undergo a retro-ADMET reaction, resulting from CM with ethylene. This concept had been explored with classical catalyst systems [le]. Schrock s catalyst was used to depolymerize PBD, poly-tr s-isoprene, polynor-bornene, andKraton (a butadiene/styrene diblock copolymer) [175] in the presence of ethylene (ethenolysis), and a mixture of products comprising the monomer and some oligomers were produced. 

While classical catalysts usually result in ill-controlled polymerization systems, well-defined Schrock initiators cyclopolymerize 1,6-heptadiynes in a living manner - in most cases a class VI living manner (according to Matyjaszewski [84]). Polymers based on one single repetitive unit (poly(cyclopent-l-enylene-... 

Thus, until the last decade, three families of catalysts have been reported to catalyze the addition, or vinyl-type homopolymerization of norbornene resulting in poly(2,3-bicyclo[2.2.1]hept-2-ene). These three catalyst types are the classical TiC -based Ziegler systems (type 1), the zirconocene/aluminoxane systems (type 2) and certain electrophilic palladium(II) complexes (type 3). 

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