Fully bio‐based poly(ɛ‐capolactone)/poly(lactide) alternating multiblock supramolecular polymers: Synthesis, crystallization behavior, and properties

Abstract

ABSTRACTSupramolecular poly(ɛ‐capolactone)/poly(lactide) alternating multiblock copolymers were prepared by UPy‐functionalized poly(lactide)‐b‐poly(ɛ‐capolactone)‐b‐poly(lactide) copolymers. The prepared supramolecular polymers (SMPs) exhibit the characteristic properties of thermoplastic elastomers. The stereo multiblock SMPs (sc‐SMPs) were formed by blending UPy‐functionalized poly(l‐lactide)‐b‐PCL‐b‐poly(l‐lactide) (l‐SMPs) and UPy‐functionalized poly(d‐lactide)‐b‐PCL‐b‐poly(d‐lactide) (d‐SMPs) due to stereocomplexation of the PLLA and PDLA blocks. Sc‐SMPs with low content of d‐SMPs (≤20%) are transparent, elastic solids, while those having high d‐SMPs content are opaque, brittle solids. The effects of l‐SMPs/d‐SMPs mixing ratios on thermal, crystallization behaviors, crystal structure, mechanical and hydrophilic properties of sc‐SMPs were deeply investigated. The incorporation of UPy groups depresses the crystallization of polymer, and the stereocomplex formation accelerates the crystallization rate. The used initiator functionalized polyhedral oligomeric silsesquioxanes causes a different effect on the crystallization of PLA and PCL blocks. The tensile strength and elongation at break of ld/dd‐SMPs (d represents the initiator diethylene glycol) are significantly larger than that of lp/dp‐SMPs (p represents the initiator polyhedral oligomeric silsesquioxanes), and their heat resistance and hydrophilicity can be also modulated by the l‐SMPs/d‐SMPs mixing ratios and the different initiators. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45575.