Synthesis of high molecular weight poly (β-pinene)

Abstract

In the course of attempts to develop conditions for the living polymerization of β-pinene (β-PIN) we discovered that the conventional “H₂O”/EtAlCl₂ system produces poly(β-PIN)s of heretofore unattained high molecular weights (at least up to ∼40,000) and that the molecular weight can be controlled by the polymerization temperature in the −23 to −100°C range. The log $\bar M_n$versus 1/T plot is linear and yields ΔH_DP=−0.83 kcal/mol. The repeat unit of the high molecular weight polymer is which reflects isomerization polymerization. The T_g of poly(β-PIN) is 65°C by DSC. Melt drawn fibers are amorphous by X-ray analysis.