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Poly( ε ‐caprolactone)–Poly(oxyethylene) Multiblock Copolymers Bearing Along the Chain Regularly Spaced Pendant Amino Groups
Author(s) -
Canciello Mariarosaria,
Maglio Giovanni,
Nese Giuseppe,
Palumbo Rosario
Publication year - 2007
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/mabi.200600261
Subject(s) - polymer chemistry , copolymer , ring opening polymerization , polymerization , caprolactone , chemistry , ether , crystallinity , condensation polymer , telechelic polymer , molar mass distribution , end group , amphiphile , polymer , organic chemistry , crystallography
Poly( ε ‐caprolactone) (PCL) macromers ( $\overline M _{\rm n} $ = 1.7–3.8 kDa) which contain one Z‐protected NH 2 group per chain were synthesized by ring‐opening polymerization of ε ‐caprolactone in the presence of Sn(oct) 2 using as initiator a diamine prepared by condensation of N ‐Boc‐1,6‐hexanediamine and N α ‐Boc‐ N ε ‐Z‐ L ‐Lysine. The coupling of these macromers with COCl end‐capped poly(oxyethylene) (PEO), $\overline M _{\rm n} $ = 1.0 kDa, afforded amphiphilic multiblock poly(ether ester)s (PEEs) which have, along the chain, regularly spaced pendant protected amino groups. Deprotection, accomplished without chain degradation, yielded NH 2 groups available for further reactions. The molecular structure of macromers and PEEs was investigated by 1 H NMR and SEC. DSC and WAXS analyses showed that macromers and copolymers were semicrystalline and their T m increased with increase in the molecular weight of PCL segments. The inherent viscosity values (0.25–0.30 dL · g −1 ), together with SEC analysis results, indicated moderate polymerization degrees.