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Upon crystallization from DMF/diethyl ether or CH2Cl2/pyridine of tetracoordinated Zn(II) complexes containing either 4-fluorophenyl or 4-anisyl substituted O,N,O-tridentate Schiff base ligands and pyridine as auxiliary ligand, three new doubly phenoxide-bridged dimeric Zn(II) complexes were isolated and their catalytic properties for the ring opening polymerization (ROP) of rac-lactide were explored. The single-crystal XRD analysis allowed to corroborate the molecular structures of the binuclear complexes, showing that the pentacoordinated Zn(II) metal ion adopts a slightly distorted square pyramidal geometry. The basal plane Is formed by the O,N,O-donor set of the tridentate Schiff base ligand and a phenoxo bridging oxygen, while a pyridine or a DMF molecule is located at the apex of the pyramid. The binuclear complexes were employed as catalysts in the ROP of rac-lactide for polylactide (PLA) synthesis. Polymerization conditions such as reaction time, catalyst concentration and use of benzyl alcohol as cocatalyst were studied, as well as their influence on the conversion rate, average molecular weight and polydispersity of the obtained PLA. The catalyst substituted with fluorine was more reactive, but with a lower control on the molecular weight compared to the methoxy-substituted catalyst. On the other hand, the presence of pyridine as an auxiliary ligand generates an improvement in the polydispersity of PLA.

Preparation of polypropylene‐based nanocomposites using nanosized MCM‐41 as support and in situ polymerization MCM‐41 nanoparticles used as support for metallocene in the polymerization of propylene were incorporated in the polypropylene matrix. This methodology allows to control the amounts of filler and catalyst concentration.

Homo and copolymers of metallocenic poly(propylene) with 1‐hexene and 1‐octadecene are used to prepare nanocomposites via melt mixing by using graphite nanosheets (GNSs) as filler. Different amounts of GNSs are used in order to study the influence of the filler on the thermal, mechanical, and electrical properties of nanocomposites. Significant changes have been observed in the crystallization temperature (Tc) of the nanocomposites. Thermogravimetric analysis shows improvement in thermal stability. Young's modulus and elongation at break of the nanocomposites are depended on the type of the matrix and the amount of GNSs. Materials with high flexibility are obtained in the cases of matrices based on copolymers even at high filler loading. Nanocomposites have become a semiconductor material reaching conductivity of 10−4 S cm−1. Two different thermal treatments have been applied in the preparation of the films by compression molding. X‐ray diffraction analysis shows the existence of polymorphism according to the thermal treatment applied.

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