Manipulation of crystallization nucleation and thermal degradation of PLA films by multi-morphologies CNC-ZnO nanoparticles.

Currently, the quest for more renewable and biodegradable materials is a scientific priority to address the problems of petroleum-based plastics are difficult to degrade. In this work, cellulose nanocrystals (CNC) have been used as a template and four morphologies of CNC-ZnO nanocomposites were prepared via a hydrothermal method, and CNC-ZnO/polylactic acid (PLA) composite films were obtained by solution casting. We find that CNC-ZnO nanocomposites as heterogeneous nucleating agents improved the crystallinity and the film with flower-like CNC-ZnO was improved by 2.4 %. Ea required for thermal degradation of the PLA films decreased to 66-81 % of that of neat PLA, calculated by the Kissinger method, the Friedman method, and the Flynn-Wall-Ozawa (FWO) method. The R2 model was the solid degradation mechanism of the PLA films, analyzed through the Coats-Redfern method and the Criado method. The H-bond content of the composite films was significantly reduced after thermal aging at 150 °C. We found that three-dimensional CNC-ZnO (ZnO-3) made more prominent contributions to the crystallization, thermal degradation, and thermal aging of PLA films than other dimensional. The thermal properties can be regulated by the dimension, size, and apparent morphology of CNC-ZnO nanoparticles.

Tetra-aqua-bis-(6-chloro-pyridine-3-carboxyl-ato-κO)cobalt(II) tetra-hydrate.

In the title compound, [Co(C(6)H(3)ClNO(2))(2)(H(2)O)(4)]·4H(2)O, the Co(II) cation is located on an inversion center and is coordinated by four water mol-ecules and two 6-chloro-pyridine-3-carboxyl-ate anions in a slightly distorted octa-hedral geometry. In the crystal, complex mol-ecules and lattice water mol-ecules are linked by O-H⋯O and O-H⋯N hydrogen bonds into a three-dimensional network.

[5-(Pyridin-2-yl)-1H-tetra-zole-κ(2) N (4),N (5)]bis(triphenyl-phosphane-κP)copper(I) tetra-fluoridoborate.

In the title Cu(I) compound, [Cu(C6H5N5)(C18H15P)2]BF4, the Cu(I) cation is N,N'-chelated by a 5-(pyridin-2-yl)-1H-tetra-zole ligand and coordinated by two triphenyl-phosphane ligands in a distorted tetra-hedral geometry. The tetra-zole and pyridine rings are essentially coplanar [dihedral angle = 4.1 (3)°]. The tetra-fluoridoborate anion links to the complex cation via an N-H⋯F hydrogen bond.

Bromidotricarbon-yl[2-phenyl-5-(pyridin-2-yl-κN)-1,3,4-oxadiazole-κN]rhenium(I) dichloro-methane monosolvate.

In the title rhenium(I) complex, [ReBr(C(13)H(9)N(3)O)(CO)(3)]·CH(2)Cl(2), the dichloro-methane solvent mol-ecule is disordered over two positions with an occupancy ratio of 0.81 (15):0.19 (15). The Re(I) atom is coordinated by two N atoms from a 2-phenyl-5-(pyridin-2-yl-κN)-1,3,4-oxadiazole (L) ligand, three C atoms from three carbonyl groups and a Br atom in a distorted octa-hedral geometry. The three rings in L are almost coplanar (a mean plane fitted through all non-H atoms of this ligand has an r.m.s. deviation of 0.063 Å), and the carbonyl ligands are coordinated in a fac arrangement.

Bromidotricarbon-yl[2-(pyridin-2-yl-κN)-5-p-tolyl-1,3,4-oxadiazole-κN]rhenium(I) dichloro-methane monosolvate.

In the title compound, [ReBr(C(14)H(11)N(3)O)(CO)(3)]·CH(2)Cl(2), the coordination geometry of the Re(I) atom is a distorted ReC(3)N(2)Br octa-hedron with the carbonyl C atoms in a fac arrangement. Within the 2-(pyridin-2-yl)-5-p-tolyl-1,3,4-oxadiazole ligand, the dihedral angles between the oxadiazole ring and the pyridine (py) and benzene (bz) rings are 1.7 (2) and 7.1 (2)°, respectively, and the dihedral angle between the py and bz rings is 5.5 (2)°. In the crystal, aromatic π-π stacking between the oxadiazole rings of adjacent mol-ecules [centroid-centroid separation = 3.465 (3) Å] is seen.