Monomers with Two Different Polymerizable Groups

Most monomers contain only one polymerizable group. There are some monomers with two polymerizable groups per molecule. Polymerization of such monomers can lead to more than one polymer structure. The polymerization of 1,3-dienes, of large industrial importance, is discussed in Sec. 8-6. 1-Substituted-l,2-dienes (allenes) undergo polymerization through both the substituted and unsubstituted double bonds 

Various types of initiators have been studied, including ionic, radical, and coordination (Chap. 8) [Ghalamkar-Moazzam and Jacobs, 1978 Leland et al., 1977]. Polymerization through the unsubstituted double bond is the predominant reaction. 

Some monomers such as acrolein and ketene contain two different types of polymerizable group (C—O and C—C). The polymerization of acrolein has been studied with radical, cationic, and anionic initiators [Calvaryrac et al., 1973 Gulino et al., 1981 Schulz, 1967 Yama-shita et al., 1979]. Radical polymerization proceeds exclusively through the vinyl group 

Anionic polymerization yields a polymer containing two types of repeating units corresponding to reaction through both the alkene and carbonyl double bonds. 

However, polymerization through the alkene group is the dominant reaction. 1,4-Polymerization also occurs  

Cationic polymerization of acrolein has been reported to yield polymers containing both types of repeating units, although one would not expect the alkene group to be reactive toward cationic initiation. 

Dimethylketene has been polymerized by anionic initiators. Three different repeat units are formed (XLVII, XLVni, XLIX) corresponding to polymerization through the alkene 

---