Abstract
Polylactide (PLA) stereocomplexes (SCs) containing amorphous block copolymers have gained enormous interestdue to their unique properties and wide range of potentialapplications. In this work, we report the synthesis and properties ofnon-covalent triblock terpolymers: polystyrene-SCPLA-polyiso-prene (PS-SC-PI)viathe stereocomplexation of PS-b-PDLAwith PI-b-PLLA diblock copolymers through the solution-precipitation method. The diblock copolymers were prepared bycombining the anionic polymerization high-vacuum technique withring-opening polymerization (ROP). First, several well-defined omega-hydroxyl polystyrenes and polyisoprenes (PS-OH and PI-OH)with varied molecular weights were synthesized by anionic polymerization usingsec-BuLi as the initiator. PS-OH and PI-OH wereused as the macroinitiators for the ROP of DLA and LLA catalyzed by tin(II) 2-ethyl hexanoate to afford PS-b-PDLA and PI-b-PLLA. PS-SC-PIs were prepared by mixing PS-b-PDLA and PI-b-PLLA solutions (in dichloromethane) and precipitated intomethanol. The molecular characteristics of the block copolymers were determined by1H NMR spectroscopy and size exclusionchromatography. The formation of PS-SC-PIs was evidenced by differential scanning calorimetry, X-ray diffraction, and Fourier-transform infrared, and circular dichroism spectroscopies. A preliminary study by atomic force microscopy reveals the thin-film phasebehavior and the supramolecular organization of the PS-SC-PI