Acrolein, polymerization

Polymerization. In the absence of inhibitors, acrolein polymerizes readily in the presence of anionic, cationic, or free-radical agents. The resulting polymer is an insoluble, highly cross-linked soHd with no known commercial use. 

Furthermore, by studying butadiene -acrolein block polymerizations, we have tried to understand the mechanism of the acrolein polymerization. 

Transfer reactions to polymer are easily observed. Indeed, for the very high yields of the acrolein polymerization, Insoluble gels are obtained. With IT - as counter Ion, the polymerization being very fast, this phenomenon cannot be avoided. On the other hand, with Li+ and Na, no gel Is obtained if the yields remain lower than 70%. 

With Na+, as a cation, the activation energies for the anionic polymerization of acrolein and propylene sulfide (11) are approximately the same. On the other hand, with Li+, it is impossible to compare the acrolein activation energy with the same monomer or another polar monomer because no result is found in the literature. Moreover, for the acrolein polymerization, (Raj u+) lower than ( > +). 

Figure 6. Acrolein initiation by an a-m di-Na oligobutadiene in THF at —40°C initiator M = 1600 (---------) PAB,0 after the acrolein polymerization (----).

Acrolein polymerization given (1,2), (3,4) and (1,4) units. To explain the formation of all these units, the propagation mechanism must Involves two different types of living ends the (3,4) oxanlon living end (Figure 10) and the (1,4) delocalized living end (Figure 11). 

Because acrolein polymerizes by free-radical and ionic mechanisms, all of the above reactions... 

Because acrolein polymerizes by free-radical and by ionic mechanisms, all of the above reactions are possible, and the products are quite complex. The structures of the materials include linkages from both vinyl and carbonyl groups. In addition, tetrahydropyran rings, as shown above, can also form [357]. 

Acrolein, a member of the family of the polymerizable 2-alkenales and 2-alkenones, is provided with an extraordinary tendency for polymerization. Therefore, it may only be stored in the presence of a stabilizer (e.g., hydrochinone) in the absence of light, air, and moisture because of spontaneous polymerization. Even small amounts of initiator have the ability to force acrolein polymerization radically, anionically, or cationically, partly in an explosive manner. According to the existing reaction conditions and the catalysts used, it is possible to attain polymers of completely different shapes with characteristic features [9,13,35]. 

To solubilize the products of radically induced acrolein polymerization, the following procedures are used. 

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