Synthesis of Poly(methylene-b-ε-caprolactone) and Poly(ε-caprolactone) with Linear Alkyl End Groups: Synthesis, Characterization, Phase Behavior, and Compatibilization Efficacy

Diblock copolymers of poly(methylene- b -ε-caprolactone) (PM- b -PCL) were synthesized in two steps: (a) polyhomologation, to obtain, following oxidative cleavage of the carbon–boron (PM, block 1 ), an α-hydroxyl-ω-methyl polymethylene (PMOH, CH 3 –[CH 2 ] m –OH) and, following the transfer reaction to the ring-opening polymerization catalyst, (b) ring-opening polymerization (ROP) of ε-caprolactone (CL) (PCL, block 2 ). In addition, a series of homopolymers derived from poly(ε-caprolactone) (PCL) oligoesters containing an end group of docosyl (CH 3 –[CH 2 ] 21 – or C 22; C 22 –PCL) were obtained as a model to compare their physical properties by DSC with those of PM- b -PCL. The oligomers derived from PM- b -PCL and C 22 –PCL were characterized by 1 H and 13 C NMR, AFM, DSC, GPC, and MALDI-TOF. PM- b -PCL and C 22 –PCL were evaluated as compatibilizers for PE/PCL polymer blends. Identification and analysis of optimized blocks of PM- b -PCL by POM and SEM showed improved mixing of PE/PCL blends.