Synthesis of AB2 star-shaped miktoarms copolymers and their crystallization behavior

A small molecule (GMS-SA(2)) with one alkyl chain and two terminal carboxyl groups was synthesized successfully via the reaction of glyceryl monostearate with excessive succinic anhydride. Then, the small molecule was used as a coupling agent to condensate with polyethylene glycols ( PEG ) with different molecular weights or polyethylene glycol monomethyl ether ( PEGm ) in the presence of stannous octoate as the catalyst and diphenyl ether the as azeotropic agent to remove water. Thus, the AB, star-shaped miktoarms copolymers were obtained successfully, and were characterized via H-1 NMR, DSC, GPC, XRD, FTIR and micropolariscope, etc. DSC and XRD measurements indicate that the crystallizing temperature and the melting temperature of the AB(2) star-shaped miktoarms copolymers were different from those of the corresponding linear PEGs because the existing of GMS-SA2 altered its crystallizing velocity and the perfect degree of crystal. It is very important to control the crystal shape of the star-shaped copolymers through introducing the miktoarms into the copolymers and changing its content in copolymers.