Polyeondensation Reactions

A few of the polyeondensation reactions may be performed in a single liquid phase. Examples of this are the reaction of diisocyanates with diols (8) or diamines (7) and the formation of polycarbonates from bisphenols and phosgene in a solvent with pyridine as the acid acceptor 15, 22),... 

Low-temperature polyeondensation reactions are best carried out with highspeed stirring (I, 14), although there are examples of successful reactions performed with only moderate stirring. Home blenders are excellent reaction vessels. The processes may be scaled up easily by use of large cans or drums and overhead stirrers. Polymerization may be carried out continuously in T-tubes or other devices. Figure 1 illustrates a glass laboratory apparatus for continuous polymerization. 

In addition to the use of low-temperature polyeondensation reactions as a research tool leading to new polymers, several other applications have been described. 

Typical comonomers and coinitiators for the polyeondensation and ROP reactions are summarized in Figure 8.2. For polyeondensation, various hydroxycarboxylic acids or mixtures of diol and dicarboxylic acid are used as comonomers of lactic acid of these, glycolic acid is most frequently used. On the other hand, for ROP, various heterocyclic compounds including... 

The process of polyeondensation of terephthaloyl-bis (n-oxybenzoyl-chloride) witii decamethyleneglycol resulting in liquid-crystal polyester was studied in [131]. The monomers containing groups of complex esters entered into the reaction with diols at sufficiently high temperature (190 °C). 

Bo et al reported the synthesis of 21 by Suzuki polyeondensation of 2,7-carbazolediboronic acid pinacol ester and 5,6-bis(oetyloxy)benzothiadi-azole based dibromide using Pd(PPh3)4 as the eatalyst preeursor and a bipha-sic mixture of THF-toluene (5 l)/aqueous NaHCOj as the reaction medium. Pji based PSCs exhibit a PCE of 5.4% (Scheme 1.24). ... 

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