Comparison of cationic polymerization of α and β pinenes and limonene

The cationic polymerizations of α and β pinenes and limonene were compared, and the possibility of living polymerization of the three monomers was also examined. With Lewis acid AlCl 3 catalyst, the polymerization rate decreased in the following order: β pinenelimonene α pinene. The addition of SbCl 3 accelerated the polymerizations of α pinene and limonene, and retarded the polymerization of β pinene. In contrast to the polymerizations with AlCl 3, the polymerization of α pinene was faster than that of limonene when catalyzed with AlCl 3/SbCl 3.As compared with the AlCl 3 catalyst, AlCl 3/SbCl 3 binary system gave polymers of α pinene with higher molecular weight, polymers of limonene with similar molecular weight, and polymers of β pinene with lower molecular weight. In contrast to the structure of α pinene polymer, the structures of β pinene and limonene polymers were not affected by the addition of SbCl 3. The living polymerization of reactive β pinene monomer could be achieved with Styrene HCl adduct/TiCl 3(OiPr) initiating system, however, attempts of the living polymerizations of α pinene and limonene with a series initiating systems failed because of the low monomer reactivity.