Synthesis and electrospinning of polycaprolactone from an aluminium-based catalyst: influence of the ancillary ligand and initiators on catalytic efficiency and fibre structure

In the present study, we investigate the catalytic performance of a 2,2’-methylenebis(6- tert-butyl-4-methylphenol) (MDBP) - aluminium complex for the ring-opening polymerisation (ROP) of ε-caprolactone in combination with various alcohols as initiators. Three different alcohols are investigated, 1-adamantanemethanol (A), 1H,1H,2H,2H-perfluoro-1-octanol (F) and isopropanol (I). Samplings of polycaprolactone (PCL) at various reaction times show a linear increase of polymer molecular weight with time, with very narrow polydispersity, confirming the living nature of the catalytic system. Scanning electron microscope (SEM) images of electrospun PCL fibre mats produced from 30 wt% dichloromethane/dimethyl sulfoxide solutions show a high level of surface porosity with reasonable homogeneity of fibre diameters. Values of liquid absorption and water contact angle have been measured for the electrospun mats, with the F-capped PCL consistently showing absorption values up to three times higher than those of PCL samples capped with the other two alcohols, and increased hydrophobicity. The nature of the alcohol can influence the surface hydrophobicity and absorption ability of the electrospun fibres, demonstrating the possibility of tailoring material properties through controlled polymerisation.