How the Complex Interplay between Different Blocks Determines the Isothermal Crystallization Kinetics of Triple-Crystalline PEO-b-PCL-b-PLLA Triblock Terpolymers
KAUST DepartmentKAUST Catalysis Center (KCC)
Permanent link to this recordhttp://hdl.handle.net/10754/626301
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AbstractPEO-b-PCL-b-PLLA triblock terpolymers are fascinating triple-crystalline materials. In this work, the isothermal crystallization kinetics of these terpolymers evaluated by differential scanning calorimetry (DSC) is presented for the first time and compared to analogous PCL-b-PLLA diblock copolymers and to PLLA, PCL, and PEO homopolymers. The results are complemented by in situ SAXS/WAXS synchrotron experiments. One-, two-, and three-step crystallization protocols were employed to study the crystallization kinetics of the blocks. At PLLA block crystallization temperatures, both PCL and PEO molten chains caused a strong plasticizing effect on the PLLA block crystallization, and the overall crystallization rate of the PLLA block in the terpolymers was higher than that in the PLLA-b-PCL diblock copolymers. In the case of the PCL block, the crystallization was followed after PLLA was fully crystallized (two-step crystallization). A nucleating effect induced by the previously formed PLLA crystals was observed. However, an antiplasticizing effect on PCL crystallization was detected if the sample is quenched directly from the melt to the PCL crystallization temperature (one-step crystallization). Finally, the crystallization of the PEO block was followed after PLLA and PCL had fully crystallized (three-step crystallization). The PEO crystallization rate highly decreased due to the confinement imposed by the previously formed PLLA and PCL crystals. Complex competitive effects such as plasticization, nucleation, antiplasticization, and confinement occurred during the isothermal crystallization of tricrystalline PEO-b-PCL-b-PLLA triblock terpolymers.
CitationPalacios JK, Zhao J, Hadjichristidis N, Müller AJ (2017) How the Complex Interplay between Different Blocks Determines the Isothermal Crystallization Kinetics of Triple-Crystalline PEO-b-PCL-b-PLLA Triblock Terpolymers. Macromolecules. Available: http://dx.doi.org/10.1021/acs.macromol.7b02148.
SponsorsThe authors would like to acknowledge funding by ALBA project 2016091863 (2017). We also acknowledge staff from the BL11 beamline at ALBA synchrotron, as well as travel funding by “Ministerio de Economía y Competitividad” and “Generalidad de Cataluña″ (Grant Number 2016091863). We gratefully acknowledge funds received by “Mineco MAT2014-53437-C2-P”. We are also grateful to Dr. Eva Crosas at ALBA Synchrotron, Cerdanyola del Vallès, Barcelona, Spain and Dr. Daniel Fulla at Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany, for their collaboration with the SAXS data treatment. Dr. Eva Crosas was supported by the Spanish Nuclear Safety Council (CSN).
PublisherAmerican Chemical Society (ACS)