Synthesis and Characterization of Double Crystalline Cyclic Diblock Copolymers of Poly(ε‐caprolactone) and Poly(l(d)‐lactide) (c(PCL‐b‐ PL(D)LA))

Abstract

The synthesis of symmetric cyclo poly(ε-caprolactone)-block-poly(l(d)-lactide) (c(PCL-b-PL(D)LA)) by combining ring-opening polymerization of ε-caprolactone and lactides and subsequent click chemistry reaction of the linear precursors containing antagonist functionalities is presented. The two blocks can sequentially crystallize and self-assemble into double crystalline spherulitic superstructures. The cyclic chain topology significantly affects both the nucleation and the crystallization of each constituent, as gathered from a comparison of the behavior of linear precursors and cyclic block copolymers. The stereochemistry of the PLA block does not have a significant effect on the nonisothermal crystallization of both linear and cyclo PCL-b-PDLA and PCL-b-PLLA copolymers.

Generating Triple Crystalline Superstructures in Melt Miscible PEO‐b‐PCL‐b‐PLLA Triblock Terpolymers by Controlling Thermal History and Sequential Crystallization

“…[5,12] Different crystallization phenomena that include nucleating effects, fractionated and confined crystallization, reduced crys tallinity, plasticization, and retarded or first order crystallization kinetics, have been extensively investigated in miscible diblock and triblock copolymers and terpolymers with more than one crystallizable block. [5,11,[16][17][18][19][22][23][24] Particularly, biodegradable and biocompatible diblock copolymers such as poly(ethylene oxide) bpoly(εcaprolactone) (PEObPCL), [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] poly(ethylene oxide) bpoly(llactide) (PEObPLLA), [44][45][46][47][48][49][50][51][52][53][54][55][56][57] and poly(εcaprolactone)b poly(lactide)s (PCLbPLA) [58][59]…”

Recent progress in block copolymer crystallization

“…Confinement of the BCP material influences both the microphase separation behavior and the crystallization. Using a common confinement environment, anodic aluminum oxide (AAO) was used to template BCP confinement in both PS‐ b ‐PE and PEO‐ b ‐PCL . For gAC PS‐ b ‐PE, T c PE was depressed for all confined samples; however, an extraordinary decrease was measured for w PE = 0.26.…”

“…The a P3HB's presence decreased T m PLLA and the crystallinity while also distorting the PLLA spherulites. 2‐Arm (triblock) and 4‐arm star PEO‐ b ‐PLLA, where PEO was the interior block, showed two trends with increased number of arms . First, T m PLLA and crystallinity decreased with an increase in the number of arms.…”

“…As discussed in previous sections, star copolymers are an important area that has been central to recent work . Some work has compared these copolymer architectures to their linear counterparts and has found decreases in crystallinity and even different morphologies.…”

Effect of block copolymer containing ionic liquid moiety on interfacial polarization in PLA/PCL blends

“…Thus, to design and prepare polymer alloy with reasonable structures and controllable performances, polymer scientists have tried to seek and design suitable compatibilizer, not only to design advanced materials but also to explore the underlying compatibilization mechanisms . Different compatibilizing agents such as PLA‐PCL and PLA‐poly(ethylene glycol) (PLA‐PEG) and PLA‐PCL‐PLA copolymers can improve the phase morphology and enhance miscibility of the two components . The study of morphological, mechanical, and crystallization behavior of the PCL/PLA blends compatibilized by various block copolymers (BC) has received great interest aiming at further evaluating the effect of compatibilization on the improvement of the interfacial tension and adhesion …”