Supramolecular structure, phase behavior and thermo-rheological properties of a poly (L-lactide-co-ε-caprolactone) statistical copolymer.
PLAcoCL samples, both unaged, termed PLAcoCLu, and aged over time, PLAcoCLa, were prepared and analyzed to study the phase structure, morphology, and their evolution under non-quiescent conditions. X- ray diffraction, Differential Scanning Calorimetry and Atomic Force Microscopy were complemented with thermo-rheological measurements to reveal that PLAcoCL evolves over time from a single amorphous metastable state to a 3 phase system, made up of two compositionally different amorphous phases and a crystalline phase. The supramolecular arrangements developed during aging lead to a rheological complex behavior in the PLAcoCLa copolymer: Around Tt=131 °C thermo-rheological complexity and a peculiar chain mobility reduction were observed, but at T>Tt the thermo-rheological response of a homogeneous system was recorded. In comparison with the latter, the PLLA/PCL 70:30 physical blend counterpart showed double amorphous phase behavior at all temperatures, supporting the hypothesis that phase separation in the PLAcoCLa copolymer is caused by the crystallization of polylactide segment blocks during aging.
University of the Basque Country (UPV-EHU), Department of Mining-Metallurgy Engineering and Materials Science & POLYMAT, School of Engineering, Alameda Urquijo s/n, 48013 Bilbao, Spain.
Jone M
JM
Ugartemendia
University of the Basque Country (UPV-EHU), Polymer Science and Technology Department, POLYMAT, Faculty of Chemistry, PO Box 1072, E-20080 Donostia-San Sebastián, Spain.
M E
ME
Muñoz
University of the Basque Country (UPV-EHU), Polymer Science and Technology Department, POLYMAT, Faculty of Chemistry, PO Box 1072, E-20080 Donostia-San Sebastián, Spain.
A
A
Santamaria
University of the Basque Country (UPV-EHU), Department of Mining-Metallurgy Engineering and Materials Science & POLYMAT, School of Engineering, Alameda Urquijo s/n, 48013 Bilbao, Spain. Electronic address: jr.sarasua@ehu.es.
J R
JR
Sarasua
D001672:Biocompatible Materials / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002208:Caproates / Q000737:chemistry*; D006801:Humans; D007783:Lactones / Q000737:chemistry*; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012212:Rheology
D001672:Biocompatible Materials; D002208:Caproates; D007783:Lactones; D011091:Polyesters; D011108:Polymers; C033616:poly(lactide); C121056:caprolactone
Aging; Phase structure; Poly(l-lactide-co-ε-caprolactone); Polylactide; Thermo-rheology