Synthesis and crystallization behaviors of poly(styrene- b-isoprene- b- ε-caprolactone) triblock copolymers

Abstract

The triblock copolymers, poly(styrene- b-isoprene- b- ε-caprolactone)s (PS- b-PI- b-PCL) have been synthesized successfully by combination of anionic polymerization and ring-opening polymerization. Diblock copolymer capped with hydroxyl group, PS- b-PI-OH was synthesized by sequential anionic polymerization of styrene and isoprene and following end-capping reaction of EO, and then it was used as macro initiator in the ring-opening polymerization of CL. The results of DSC and WAXD show big effect of amorphous PS- b-PI on the thermal behaviors of PCL block in the triblock copolymers and the lower degree of crystalline in the triblock copolymer with higher molecular weight of PS- b-PI was observed. The real-time observation on the polarized optical microscopy shows the spherulite growth rates of PCL 27, PCL 328 and PS- b-PI- b-PCL 344 are 0.71, 0.46 and 0.07 μm s −1, respectively. The atomic force microscopy (AFM) images of the PS 90- b-PI 66- b-PCL 28 show the columns morphology formed by it’s self-assembling.