Atom Transfer Radical Polymerizations of Complexes Based on Ti and Zr Alkoxides Modified with β-Keto Ester Ligands and Transformation of the Resulting Polymers in Nanocomposites

Abstract

Well-defined complexes of Ti and Zr alkoxides and β-keto ester ligands carrying polymerizable double bonds were copolymerized with methyl methacrylate applying atom transfer radical polymerization. The structure and the morphology of the obtained hybrid polymers were investigated using NMR, FT-IR, and size exclusion chromatography. All methods revealed an incorporation of both comonomers in the polymer backbone. NMR and FT-IR analyses demonstrated that after polymerization the chemical linkage between the metal alkoxides and the organic macromolecules was preserved. The alkoxide-containing macromolecules were used as precursors in the formation of metal oxide-containing nanocomposites applying the sol−gel process. The decomposition temperature of the final nanocomposites increased depending on the chemical composition of the materials. Small-angle X-ray scattering investigations revealed a short-range order for the polymers containing Ti-alkoxides which disappeared after carrying out the sol−gel process due to the hydrolysis of the well-defined complexes. Transmission electron microscopy showed the formation of amorphous metal oxide nanoparticles inside the polymer network with diameters of a few nanometers. The particles were highly dispersed due to the low mobility of the alkoxides in the matrix during the sol−gel process.

Self‐healing nanocomposites from silica − polymer core − shell nanoparticles

“…Since the introduction of atom transfer radical polymerization (ATRP), considerable effort has been devoted to applying ‘living’ radical polymerization techniques to the design of nanostructured materials . One of the major applications of controlled radical polymerization is the preparation of polymer structures, such as brushes, on surfaces . ATRP is an effective strategy to build tailored interfaces between inorganic surfaces and polymeric materials, allowing the control of chain length, molecular weight distribution and surface coverage …”

Preparation of novel polymer-metal oxide nanocomposites with nanophase separated hierarchical structure

“…In general, nanocomposites with a phase separated structure in nanoscale can be prepared by four different methods: (i) embedding an inorganic moiety into the polymer, (ii) using interpenetrating polymer networks with chemical bonds, (iii) incorporating inorganic groups by bonding them to the polymer backbone and (iv) forming a dual inorganicorganic hybrid polymer (Kickelbick 2003). These structures can be created by a sol-gel process, core-shell composite, the electrodeposition of conductive polymers such as polyaniline, exfoliated claybased nanocomposite, and the self-assembly or assembly of nano building blocks for the formation of mesophase structures (Sudheendra and Raju 1999;Sanchez et al 2001;Kickelbick 2003;Lahav et al 2006;Angelomé et al 2005;Ivanovici et al 2008).…”

Synthesis of Monomeric and Dimeric Copper(II) Carboxylates Bearing Polymerizable Groups and Their Performance in the Copolymerization with MMA

“…The advantage of the incorporation of metal complexes into polymers is that they can introduce novel properties such as magnetism − and electronic or optical properties in the final material. The resulting inorganic−organic hybrid composites are thus promising materials for various applications, such as nonlinear optics or energy storage. , Such polymers can be obtained either using metal complexes with polymerizable groups , that are copolymerized with regular monomers or by polymers that include functional groups attached to their chain which allow a coordination of metal ions. − Cross-linked materials are usually obtained if the coordination sites are pending functionalities attached to the polymer chain and metal ions are added to these functionalized polymers. If metal complexes are used as monomers for such structures, they can contain both polymerizable groups and easy accessible coordination sites.…”

“…Hence, the produced monomers offer two different reaction sites for radicals: (i) the polymerizable bond of the methacrylate ligands and (ii) a redox reaction with the copper ion. That makes the polymerization process complex, and the behavior during copolymerization differs compared to other complexes that show only one stable oxidation number such as Ti− and Zr−alkoxides modified with β-keto esters carrying the polymerizable group 2-(methacryloyloxy)ethyl acetoacetate or Zr−carboxylates . In order to understand that behavior, the polymerization was carried out in different ratios of 1 , 2 , and MMA and also with varying amounts of the initiator.…”