Living polymers precursor

The living polymer precursor can be reacted stoichiometrically with a pluri-functional deactivator (an electrophilic compound if the sites are anionic), and chemical links are formed between the precursor chains and the deactivator. 

The second method is the most efficient way to synthesize well defined star polymers. It involves preparation of a living monocarbanionic precursor, which can be accurately characterized. In a second step, this polymer is reacted with a pluri-... 

The synthesis of well defined, ring shaped macromolecules has been independently achieved reacently in three different laboratories.U 13 A linear "living" dlcarbanlonlc precursor polymer is reacted with a stoichiometric amount of an efficient electrophilic coupling agent, such as dlbromo-p-xylene or dime thyldichlorosi lane. The reaction has to be carried out at... 

At this stage a sample of the living polymer is withdrawn and desactivated with methanol. The molecular weight of this "precursor PS" is determined by GPC. 

Diffiuex investigated a synthesis of cyclic poly(vinyl ether) using cationic polymerization [26,28]. The reaction process is depicted in Fig. 9. They studied on the living cationic polymerization of 2-chloroethyl vinyl ether (CEVE) initiated with the HI adduct of 4-(vinylbenzyloxy)butyl vinyl ether prepared by reacting chloromethyl styrene with sodium salt of 4-hydroxy-butyl vinyl ether in THF at 80 °C. By the cationic polymerization of CEVE, o /o-hetcrofunclional linear polymer precursor of cyclic poly(CEVE) was produced. The MWDs of the polymers were unimodal and very narrow (< 1.2),... 

A cyclic polymer of methyl methacrylate was also synthesized using a het-erotelechelic polymer precursor, although the formation of living polymer of methyl methacrylate is more difficult than that of styrene. Mizawa et al. described the synthesis of heterotelechelic poly(methyl methacrylate) containing a-maleimide-tw-dienyl end groups and its intramolecular cyclization... 

The counter radical method can also be used for graft copolymer synthesis. Solomon et al. propose two routes [51]. The first one involves copolymerization with a functional monomer such as methacrylate containing pendant al-koxyamine. In the second route, the alkoxyamine is grafted onto a polymer precursor used in a second step to initiate the living polymerization of a second monomer. PBd-g-PMA is prepared this way from PBd. 

When the C block is desired to be in the middle, an co-functionalized BC diblock copolymer has to be prepared in a first step. Two subroutes could be followed either to use the diblock precursor as maaoinitiator by a site transformation reaction to polymerize monomer A, or to use the end function for linking a living polymer A (Figure 4(c)). Again two different polymerization mechanisms can be involved. 

As in the case of anionic living polymerization, the ATRP polymerization allows the synthesis of polymer networks by the end linking process [303]. A difunctional initiator (bis(2-bromopropionyloxy)ethane) allowed the preparation of difunctional polymer precursors that can be used to prepare polymer networks with divinylbenzene-end linking. Divinylbenzene also gives access to a self condensing TEMPO functionalized AB monomer [304]. 

A modification of the Thom-Csanyi ROMP route to PPV makes use of a silyl-substituted paracyclophane derivative, which, under ROMP conditions, reacted to give a soluble precursor polymer. fransformation of the PPV could be achieved by treating the precursor polymer with acid or by hydrolysis of the silyl group followed by thermal treatment (Fig. 73). Because the pofymerization is living, polymers and block copolymers of well-defined molecular weight can be prepared [916]. 

Synthesis of Linear Polymer Precursors by Living Anionic Polymerization... 

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