Temperature dependence of crystalline transition of highly-oriented poly(l-lactide)/poly(d-lactide) blend: In-situ synchrotron X-ray scattering study

Zhang, Xiong; Liu, Guoming; Zhang, Xiuqin; Wen, Tao; Vos, Sicco de; Joziasse, Cornelis A.P.; Wang, Dujin

doi:10.1016/j.polymer.2012.11.076

Cited by 77 publications

(68 citation statements)

References 46 publications

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“…The onset crystallization temperature is 140 C. The subsequent heating curve shows two melting peaks at 175 C and 223 C corresponding to the melting of homo-crystals and SC, respectively. The melting temperatures are in agreement with those reported in the previous papers [36,38]. Under quiescent condition, no spherulites were observed at 170 C. However, when the supercooled melt was subjected to shear at 50 s À1 for 5 s, several crystallites were observed at the same temperature.…”

Section: In-situ Waxssupporting

confidence: 91%

Enhancement of stereocomplex formation in poly(l-lactide)/poly(d-lactide) mixture by shear

Song

Zhang

Yin

et al. 2015

Polymer

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Section: In-situ Waxssupporting

confidence: 91%

Enhancement of stereocomplex formation in poly(l-lactide)/poly(d-lactide) mixture by shear

Song

Zhang

Yin

et al. 2015

Polymer

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“…It thereby increases stiffness and strength related to a rise in crystallization . Several studies on mechanical properties during deformation have been performed on PLLA film, which was strained or deformed at a given degree of strain, rate and/or temperature, although little was revealed about the mechanical properties remaining after deformation . Because film fabrication is a common process in the industry, and is done to improve mechanical properties, groups have investigated both uniaxially and biaxially strained films .…”

Section: Introductionmentioning

confidence: 99%

Characterization of biaxial strain of poly(l‐lactide) tubes

Løvdal

Andreasen

Mikkelsen

et al. 2015

Polymer International

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Poly(L-lactide) (PLLA) in its L-form has promising mechanical properties. Being a semi-crystalline polymer, it can be subjected to strain-induced crystallization at temperatures above T g and can thereby become oriented. Following a simultaneous (SIM) biaxial strain process or a sequential (SEQ) biaxial strain process, the mechanical properties of biaxial strained tubes can be further improved. This study investigated these properties in relation to their morphology and crystal orientation. Both processes yield the same mechanical strength and modulus, yet exhibit different crystal orientation. Through further WAXS analysis it was found that the SEQ biaxial strain yields larger interplanar spacing and distorted crystals and looser packing of chains. However, this does not influence the mechanical properties negatively. A loss of orientation in SEQ biaxial strained samples at high degrees of strain was detected, but not seen for SIM biaxial strain, and did not correlate with mechanical performance in either case. However, post-annealing reduced the orientation to the same level in both cases, and the modulus and strength is decreased for both SIM and SEQ biaxial. It is therefore concluded that mechanical properties after biaxial strain are related to strain-induced amorphous orientation and the packing of crystals, rather than strain-induced crystallinity.

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“…While remarkable observations have been reported on the quiescent stereocomplexation of PLA, increasing attention was drawn to the favoring effect of flow existing in realistic polymer processing . Not only the amount but also the T m of sc ‐PLA was significantly increased in such cases, which was attributed to the flow enhanced mixing and disentanglement of molecular chains .…”

Section: Introductionmentioning

confidence: 99%

Nanostructures of Stereocomplex Polylactide in Poly(l-lactide) Doped with Poly(d-lactide)

Huang

Luo

Wang

et al. 2015

Macromol. Chem. Phys.

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Nanostructures of stereocomplex polylactide (sc‐PLA) are obtained and studied in poly(l‐lactide) (PLLA) doped with a low amount of poly(d‐lactide) (PDLA) during successive melt‐quenching, extrusion, spinning, and drawing processes corresponding to quiescent, shear flow, elongational flow, and tensioned annealing conditions, respectively. Nanogranules of predominantly sc‐PLA are initially formed with rapid quenching in quiescent and shear flow, which developed into microspheres with slow quenching and uniform nanofibrils in elongational flow. While only amorphous or the α′‐form PLLA is formed with the quenched melts and macroscopic fibers, the embedded nanogranules and nanofibrils are highly crystallized with the coexistence of sc‐PLA and the α‐crystals. A 1D coalescence of nascent sc‐nuclei into nanofibrils in elongational flow is preliminarily proposed to explain the structure evolution and the minor reinforcement of the nanofibrils on the macroscopic fibers.

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Temperature dependence of crystalline transition of highly-oriented poly(l-lactide)/poly(d-lactide) blend: In-situ synchrotron X-ray scattering study

Cited by 77 publications

References 46 publications

Enhancement of stereocomplex formation in poly(l-lactide)/poly(d-lactide) mixture by shear

Enhancement of stereocomplex formation in poly(l-lactide)/poly(d-lactide) mixture by shear

Characterization of biaxial strain of poly(l‐lactide) tubes

Nanostructures of Stereocomplex Polylactide in Poly(l-lactide) Doped with Poly(d-lactide)

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