Polyfunctional initiator-transfer

New Telechelic Polymers and Sequential Copolymers by Polyfunctional Initiator-Transfer Agents (Inifers) End Reactive Polyisobutylenes by Semicontinuous Polymerization... 

J.P. Kennedy and R.A. Smith, New telechelic polymers and sequential copolymers by polyfunctional initiator-transfer agents (inifers). II. Synthesis and characterization of a, a>-di(ferf-chloro)polyisobutylenes,. Polym. Sci., Part A Polym. Chem., 18(5) 1523-1537,1980. 

The polymerisation of PO and EO, initiated by polyfunctional starters, to make short chain polyether polyols is a reaction that is strongly dependent on diffusion. The consumption rate of PO or EO is given by two simultaneous factors the rate of the chemical reaction in the liquid phase and the efficiency of the monomer mass transfer from the gaseous phase to liquid phase (see details in section 4.1.5). The PO (or EO) consumption rate, considering the mass transfer, is described by equation 13.27 [45-50] ... 

The impact of nucleophilic and electrophilic groups of the active center on the substrate at the contact area in the enzyme-substrate complex (the effect of synchronous intramolecular catalysis). The polyfunctional catalysis involves a great many processes push-pull mechanisms, processes involving a relay charge transfer, as well as a general acid-base catalysis. Presumably, the enzyme in the initial state of the enzymatic reaction already contains structural elements of the transition state and in this case the reaction must be thermodynamically more advantageous. 

Formation of a low concentration of polyfunctional macromolecules dissolved in the monomer is a special feature of the early stage of the chain polymerization mechanism. Because of the usually high degree of polymerization of the formed chains, the gel-point conversion is relatively low. Exceptions are cases in which a very low concentration of a polyfunctional monomer (i.e. a divinyl molecule) is copolymerized with a high concentration of a difunctional monomer (i.e. a vinyl molecule), or cases where transfer or termination rates are comparable with propagation rates (i.e. homopolymerization of epoxides initiated by tertiary amines or Lewis acids). 

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