Initiator efficiency factor

Rj represents initiation rate (units of any rate expression), / is the initiator efficiency factor, is the initiator decomposition rate constant (per second), and [I] is the initiator concentration in moles per liter. 

Not all primary radicals that form attack the monomer. Some are lost to side reactions. An initiator efficiency factor, /, is therefore needed. It is a fraction of all the radicals that form and can be expressed as... 

Why is an initiator efficiency factor needed for the rate equation What is a kinetic chain length ... 

OiPr)3 cocatalyst, compound XLId was also shown effective for the ATRP of acrylates initiated by ethyl 2-iodopropionate (yielding PMA, PBA, and PMA-b-PS polymers), but the initiator efficiency factor was anomalously low (as low as 0.55), without apparent intervention of extensive terminations at the outset of the polymerization. On the other hand, complex XLId did not lead to any polymerization of MA under OMRP-RT conditions (initiation by AIBN), demonstrating that the primary radicals and the short PMA chains are trapped irreversibly by XLId. The reason for the low initiator efficiency in ATRP could, therefore, be explained by the occurrence of ATRP activation and irreversible OMRP trapping, leading to one-electron oxidative addition which, given the 1 1 Mo /initiator... 

---