Synthesis Of Functional Block Copolymer Of Polyphosphoester And Their Functionlization

Polyphosphoesters are a series of biodegradable polyesters with repeating phosphoester units in the backbone. Owing to their good biocompatibility in vitro and in vivo and biodegradability through hydrolysis or enzyme catalytic degradation, polyphosphoester raised a lot of attention recently in biomedical applications as drug and gene carriers.The purposes of this dissertation are develop a new method to syntheses block cpolymer of polyphosphoesters by using organic catalyst instead of metallic catalyst to overcome the potential toxicity problem of metallic catalyst and studied the potential functionlization of polyphosphoester. We used poly(ε-caprolatone) as the macroinitiator and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as the organic catalyst for the polymerization of ally functional phosphoester monomer 2-allyl-2-oxo-1,3,2-dioxaphospholane (AEP) in THF solution. We used gel permeation chromatography method to study the reaction kinetic of the polymerization and found that the polymerization fit a linear first-order time-conversion plot, therefore we can easily control the molecule weight, molecule weight distribution, composition and structure of the resulting polymer.By using the polymer we obtained above, we applied the"thiol-ene"click reaction to functionalize the polyphosphoester block. A series of amphiphilic block copolymer with various chemical and physical properties can be easily obtained. Micelles with nano-meter sized and special properties are formed by self-assembly of these polymers which may have potential application as carriers in drug and gene delivery.