Octa-armed star-shaped poly(ε-caprolactone)s with a phthalocyanine core by ring-opening polymerization: Synthesis and characterization

Abstract A series of hydroxyl-terminated octa-armed star-shaped poly( e -caprolactone)s (8SPCL 1–3 , represented as 5 , 6 and 7 , respectively) with an initiator core of 2,3,9,10,16,17,23,24-octakis(3-hydroxypropylmercapto)phthalocyaninatozinc(II) ( 4 ) was synthesized by the ring-opening polymerization of e -caprolactone using tin(II) 2-ethylhexanoate as the catalyst. The obtained star-shaped polymers were characterized by FT-IR, 1 H NMR, GPC and UV–vis spectroscopy. The measured intrinsic viscosities of all polymers were used to calculate the number-average molecular weight. The fluorescence of polymers 5–7 was studied. The changes in the visible spectra of 7 were investigated by increasing the concentration and adding methanol and cations such as Ag + , Hg 2+ , or Pb 2+ . The electrical conductivities of the polymers measured in vacuum and in air were between ∼10 −9 and 10 −6  S m −1 . DSC and polarized optical microscopy techniques were used to evaluate the crystalline behavior of 5–7 . The thermal stability of 5–7 was investigated by TGA.