Study of the grafting of bromoacetylated α-hydroxy-ω-methoxypoly(ethyleneglycol) onto anionically activated poly(ε-caprolactone)

Bromoacetylated alpha-hydroxy-omega-methoxy-poly(ethyleneglycol) ((M-n) over bar = 2000 g mol(-1)) was allowed to react with a poly(epsilon-caprolactone) ((M-n) over bar = 53,700, (M-w) over bar/(M-n) over bar = 1.50) that was first activated by removing some of the proton atoms borne by the carbon atoms located in alpha-position of carbonyl groups using lithium N-N-diisopropylamide as basic reagent in tetrahydrofurane at -78degreesC under argon flow. The reaction resulted in the grafting of methoxy poly(ethylene glycol) segments to some of the poly(epsilon-caprolactone) chains. The resulting polymeric compounds were characterized by various analytical techniques including NMR, SEC, DSC, X-ray diffraction and contact angle. Various characteristics of the recovered compounds, namely degree of substitution degree of crystallinity, glass transition and melting temperatures, hydrophilicity, were evaluated. It was concluded that grafting was effective but sometimes not all poly(epsilon-caprolactone) chains were modified, depending on experimental conditions. Moreover, 150 nm nanoparticles were obtained without any additional surfactant for a 0.74% substitution degree copolymer.