title: Crystallization, structural relaxation and thermal degradation in Poly(L-lactide)/cellulose nanocrystal renewable nanocomposites.
abstract: In this work, crystallization, structural relaxation and thermal degradation kinetics of neat Poly(L-lactide) (PLLA) and its nanocomposites with cellulose nanocrystals (CNC) and CNC-grafted-PLLA (CNC-g-PLLA) have been studied. Although crystallinity degree of nanocomposites remains similar to that of neat homopolymer, results reveal an increase on the crystallization rate by 1.7-5 times boosted by CNC, which act as nucleating agents during the crystallization process. In addition, structural relaxation kinetics of PLLA chains has been drastically reduced by 53% and 27% with the addition of neat and grafted CNC, respectively. The thermal degradation activation energy (E) has been determined from thermogravimetric analysis in the light of Kissinger's and Ozawa-Flynn-Wall theoretical models. Results reveal a reduction on the thermal stability when in presence of CNC-g-PLLA, while raw CNC slightly increases the thermal stability of PLLA. Fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy results confirm that the presence of residual catalyst in CNC-g-PLLA plays a pivotal role in the thermal degradation behavior of nanocomposites.
authors.affiliation: Macromolecular Chemistry Research Group (LABQUIMAC), Dept. of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Spain. Electronic address: erlantz.liizundia@ehu.es.
authors.forename: E
authors.initials: E
authors.lastname: Lizundia
authors.affiliation: Basque Center for Materials, Applications and Nanostructures (BCMaterials), Parque Tecnológico de Bizkaia, Ed. 500, Derio 48160, Spain. Electronic address: luismanuel.leon@ehu.es.
authors.forename: J L
authors.initials: JL
authors.lastname: Vilas
authors.affiliation: Macromolecular Chemistry Research Group (LABQUIMAC), Dept. of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Spain; Basque Center for Materials, Applications and Nanostructures (BCMaterials), Parque Tecnológico de Bizkaia, Ed. 500, Derio 48160, Spain. Electronic address: joseluis.vilas@bcmaterials.net.
authors.forename: L M
authors.initials: LM
authors.lastname: León
mesh_terms: D002152:Calorimetry, Differential Scanning; D002482:Cellulose / Q000737:chemistry*; D003460:Crystallization; D053761:Nanocomposites / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D011091:Polyesters / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry
chemical_list: D011091:Polyesters; C033616:poly(lactide); D002482:Cellulose
keywords: Acetone (PubChem CID: 180); Cellulose (PubChem CID: 14055602); Cellulose nanocrystals (CNC); Chloroform (PubChem CID: 6212); Methanol (PubChem CID: 887); Polylactide; Renewable nanocomposites; Sodium hydroxide (PubChem CID: 14798); Stannous octanoate (PubChem CID: 159632); Sulfuric acid (PubChem CID: 1118); Toluene (PubChem CID: 1140); l-Lactide (PubChem CID: 7272)