Functional Poly(Ester-Phosphoester)S:Synthesis,Characterization And Antibacterial Properties

Polycaprolactone(PCL) has attracted considerable interest in biomedicine, pharmacy, and tissue engineering because of its good drug permeability, biocompatibility, nontoxicity, and low cost. However, hydrolytic degradation rate of PCL is rather low because of its high crystallinity and hydrophobicity, and the lack of functional groups on PCL chain prevents it from further modification, which restrains its potential applications. Polyp hosphoesters are another kind of biomedical material with good biodegradability and hydrophilicity, which has attracted interesting all over the world. The copolymer of ε-caprolcatone and phosphoester has higher hydrophilicity and faster degradation rate than PCL homopolymer. In addition, the copolymers could be facilely modified on the phosphoester unit due to the pentavalent phosphorus atom. This work reports the synthesis and characterization of copolymer based on cyclic phosphoesters and ε-caprolcatone via rare earth phenolates catalysted ring-opening copolymerization under mild conditions. Utilizing2-(2-chloroethoxy)-2-oxo-1,3,2-di-oxaphospholane and2-(2-propynyloxy)-2-oxo-1,3,2-dioxaphospholane as functional cyclic phosphoester comonomer, poly(ester-phosphoester)s bearing chloro and alkyne functional groups were prepared respectively. Ammonium groups were introduced into these copolymers by direct quaternization or "click" chemistry, resulting in biodegradable poly(ester-phosphoester)s with antibacterial properties. The composition and chain structure of copolymer were characterized by NMR, FT-IR and GPC. The crystallinity and hydrophilicity of the copolymers were studied by XRD, DSC, SWCA in detail. The antibacterial abilities of the copolymers with ammonium groups were characterized by SEM, OD600and inhibition zone methods. The copolymers with dodecyl groups on the ammonium moieties exhibit higher antibacterial ability than those with shorter alkyl chains.