Cationic polymerization livingness

PaMeSt chain end] >10) before the addition of IB. This is based on a recent finding that the living cationic polymerization of pClaMeSt can be accomplished under conditions identical to those used for the synthesis of poly (aMeSt-fc-IB) copolymer [22, 23]. Importantly, the living PpClaMeSt chain end is very stable and there is no loss of livingness even after 5 h under monomer starved conditions. This is attributed to the reduced tendency of intramolecular alkylation due to the particularly large deactivating effect of the p-chloro substituent on the 2,5-positions of the aromatic ring. 

Livingness of the Microflow System-controlled Cationic Polymerization... 

In Section 9.4.1 we discussed ideal living polymerization. Let us examine the livingness of the microflow system-controlled cationic polymerization here. 

Therefore, all requirements for living polymerization seem to be satisfied, at least in a practical sense, in the microflow system controlled cationic polymerization. The livingness strongly depends on the reaction time. In a very short period of time highly reactive intermediates, in this case reactive propagating polymer ends, can survive and they can be utilized for subsequent reactions when different monomers or a terminating reagent are added. This concept is quite similar to that discussed in Section 6.3. 

Since the discovery of living polymerizations by Swarc in 1956 [1], the area of synthesis and application of well-defined polymer structures has been developed. The livingness of a polymerization is defined as the absence of termination and transfer reactions during the course of the polymerization. If there is also fast initiation and chain-end fidelity, which are prerequisites for the so-called controlled polymerization, well-defined polymers are obtained that have a narrow molar mass distribution as well as defined end groups. Such well-defined polymers can be prepared by various types of living and controlled polymerization techniques, including anionic polymerization [2], controlled radical polymerization [3-5], and cationic polymerization [6, 7]. 

Cho CG, Feit BA, Webster OW (1990) Cationic polymerization of isobutyl vinyl ether livingness enhancement by dialkyl sulfide. Macromolecules 23 1918-1923... 

During the 1970s, when the field of Hving cationic ROP underwent extensive developmenf the absolute rate constants were determined only for THE [106]. Nonetheless, a number of kinetic investigations were conducted with the cationic polymerization of substituted aziridines [121] and 1,3-oxazoHnes [122-124], and this in turn led to the revelation of a variety of attributes of livingness associated with these processes. 

---