Rf. Storey et al., Synthesis of novel hydrophilic poly(ester-carbonates) containing pendent carboxylic acid groups, J MACR S PU, 38(9), 2001, pp. 897-917
Citations number
42
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
JOURNAL OF MACROMOLECULAR SCIENCE-PURE AND APPLIED CHEMISTRY
A functional cyclic carbonate, 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-on
e (MBC), was utilized in the synthesis of novel poly(ester-carbonates) cont
aining pendent carboxylic acid groups. Copolymers with epsilon -caprolacton
e (CL) and L-lactide (LLA) were synthesized by ring-opening polymerization
(ROP) using either an Al-alkoxide (solution) or Sn(Oct)(2)-alcohol (bulk) i
nitiating system. Analysis of the copolymers revealed a random distribution
of the comonomer units along the polymer chain. The copolymers exhibited a
morphous character at low MBC incorporations despite the crystalline nature
of homo-poly(epsilon -caprolactone) (PCL) and homo-poly(L-lactide) (PLLA).
Removal of the benzyl protecting group by hydrogenolysis yielded carboxyli
c acid-functional copolymers. It was observed that the benzyl ester group o
f MBC became susceptible to transesterification reactions at ROP temperatur
es greater than or equal to 1350 degreesC, and the corresponding copolymers
were insoluble in both organic and aqueous solvents. It is proposed that c
arboxylic acid functionality will allow an improvement in the biodegradabil
ity and physical properties of PCL and PLLA and possibly improve their util
ity for biomedical applications such as time-released drug delivery. Moreov
er, polymerization of comonomers at high temperature may present a pathway
toward the synthesis of new biodegradable hydrogels.