A new tricrystalline triblock terpolymer by combining polyhomologation and ring-opening polymerization. synthesis and thermal properties

Abstract

New tricrystalline triblock terpolymers, polyethylene-block-poly(ε-caprolactone)-block-poly(L-lactide) (PE-b-PCL-b-PLLA), were synthesized by ROP of ε-caprolactone (CL) and L-lactide (LLA) from linear ω-hydroxyl polyethylene (PE-OH) macroinitiators. The linear PE-OH macroinitiators were prepared by C1 polymerization of methylsulfoxonium methylide (polyhomologation). Tin(II) 2-ethylhexanoate was used as the catalyst for the sequential ROP of CL and LLA in one-pot polymerization at 85 °C in toluene (PE-OH macroinitiators are soluble in toluene at 80 °C). 1H NMR spectra confirmed the formation of PE-b-PCL-b-PLLA triblock terpolymers through the appearance of the characteristic proton peaks of each block. GPC traces showed the increase in the number average molecular weight from PE-OH macroinitiator to PE-b-PCL, and PE-b-PCL-b-PLLA corroborating the successful synthesis. The existence of three crystalline blocks was proved by DSC and XRD spectroscopy. © 2019 The Authors. Journal of Polymer Science Part A: Polymer Chemistry published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2450–2456.