Monomer linkage with termination

An example of monomer linkage with termination is free-radical polymerization. 

An example of monomer linkage with termination is free radical polymerization. An example of monomer linkage without termination is ionic living polymerization or (in the ideal case) controlled radical polymerization. 

The polymers listed above, and all other linear polymers as well, are formed from monomers which enter into two, and only two, linkages with other structural units. This statement corresponds to the previous remark that the structural units of linear polymers necessarily are bivalent. The interlinking capacity of a monomer ordinarily is apparent from its structure it is clearly prescribed by the presence of two condensable functional groups in each monomer in the third and fourth examples above. The ability of the extra electron pair of the ethylenic linkage to enter into the formation of two bonds endows styrene with the same interlinking capacity. In accordance with the functionality concept introduced by Carothers, all monomers which when polymerized may join with two, and only two, other monomers are termed bifunctional. Similarly, a hifunctional unit is one which is attached to two other units. It follows that linear polymers are composed exclusively (aside from terminal units) of bifunctional units. ... 

Using the same method a block copolymer of polypeptides and vinyl monomers was also prepared. As mentioned in Section II, Bamford and Mullik [22] introduced an interesting method of photoinitiation of vinyl monomers by the Mn2(CO)io or the Re2(CO)io/C2F4 system. By these methods polymeric molecule with (CO)sMn—CF2CF2—terminals is produced (see Scheme [12]). If a polymer of this kind is heated to 100°C in the presence of vinyl monomer, a block copolymer AB or ABA with Cp2- F2 linkage is produced [ ] ... 

The monomers were composed of a hydrocarbon linkage that was functionalized on both ends by a hydrophilic, hydroxyl-terminated dendron. TEM revealed the presence of rodlike aggregates with diameters of 34-36 A and variable lengths in the range of 2000 A. Such rodlike assemblies are considered to be ideally suited for the immobilization of large quantities of solvent (Terech and Weiss 1997). 

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