Poly(ε-caprolactone)-grafted acetylated anhydroglucose oligomer by ring-opening polymerization: Synthesis and characterization

A novel acetylated anhydroglucose oligomer (AGU‐oligomer), prepared by acid catalyzed transglycosidation of potato starch triacetate and ethylene glycol, was used as a multifunctional coinitiator for the ring‐opening polymerization of ε‐caprolactone (ε-CL). The polymers were synthesized using different weight ratios of the starting materials and were characterized by NMR, SEC, and MALLS. The results confirmed the expected P(AGU/CL) polymer structure, namely a ‘comb‐like’ graft‐copolymer having the AGU oligomer as backbone with PCL grafts of variable chain lengths (LCL = 4–21). Thermal and mechanical properties of graft‐copolymers with different ε‐CL block lengths were examined. By changing the graft length, crystallinity was controlled and amorphous polymers were obtained with AGU‐oligomer contents higher than 50 wt %. The tensile properties varied with the composition and a copolymer having 40 wt % of AGU‐oligomer behaved like soft elastomer, showing high elongation at break.