Condensative chain polymerization

Note 3 Propagation in chain polymerization usually occurs without the formation of small molecules. However, cases exist where a low molar-mass by-product is formed, as in the polymerization of oxazolidine-2,5-diones derived from amino acids (commonly termed amino acid A-carboxy anhydrides). When a low-molar-mass by-product is formed, the adjective condensative is recommended to give the term condensative chain polymerization. 

Note 2 The earlier term polycondensation (namely, polymerization by a repeated condensation process, i.e., with elimination of simple molecules [1]) was synonymous with condensation polymerization . It should be noted that the current definitions of polycondensation and condensative chain polymerization were both embraced by the earlier term polycondensation . 

Note 2 The earlier term addition polymerization (as defined in [1]) embraced both the current concepts of polyaddition and chain polymerization , but did not include condensative chain polymerization . 

Yokozawa, T., and H. Shimura. 1999. Condensative chain polymerization. II. Preferential esterification of propagating end group in Pd-catalyzed CO-insertion polycondensation of 4-bromo-phenol derivatives. / Polym Sci A 37 (14) 2607-2618. 

Table 1.3 summarizes the different types of polymerizations [8]. Chain-growth polymerization involves chain growth by reaction of an active polymer chain with single monomer molecules. In step-growth polymerization, polymer growth involves reactions between macromolecules. In addition, non-polymeric byproducts may be formed in both types of polymerization. However, condensative chain polymerization is very rare. Table 1.4 summarizes the differences between chain-growth polymerization and step-growth polymerization. 

Ohshimizu, K., Shibasaki, Y, Komura,M. etal. (2007) Synthesis and characterization of aromatic block copolyamides by condensative chain polymerization. Chemistry Letters, 36,742-743. 

When a low-molar-mass by-producl is formed, the adjective condensative is recommended to give the term condensative chain polymerization . 

Chain polymerizations play an important role in the synthesis of industrial polymers polyolefins, vinyl polymers, and products of ring-opening polymerizations. Moreover, syntheses of biopolymers, both in nature and in laboratory, use certain kinds of chain polymerizations, known as condensative chain polymerizations. 

In summary, two conclusions may be drawn. First, non-stoichiometric polycondensations of class ni may give much higher molar masses than polycondensations of a-b monomers. Second, the kinetic course of the polymerizations deviate largely from that of a normal step-growth polymerization, and the term non-stoichiometric polycondensation is rather a formal label than a correct terminology. In the extreme case, when cyclization is totally suppressed, class III polymerization exactly obeys the definition of an aa + condensative chain polymerizaion . This term was proposed by lUPAC, and numerous condensative chain polymerizations are known from a-b monomers as discussed in Chap. 16. 

The temi condensative chain polymerization (CCP) was coined and approved by the lUPAC. It defines polymerizations which show all the typical kinetic features of a chain growth polymerization, whereas the individual growing steps involve an elimination (condensation) reaction quite analogous to a tme polycondensation. The typical features of a CCP are the following ones ... 

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