Structural engineering of polyurethane coatings for high performance applications

Concepts for the incorporation of inorganic building blocks into organic polymers on a nanoscale

Organic-inorganic hybrids appear as a creative alternative for obtaining new materials with unusual features. This is related to their diphasic structures, leading to multifunctional materials. The low-temperature processes which are used to synthesize such structures provide a wide versatility in the design of the compounds. The potentiality of the chemistry is to play on the structure of these mixtures and dissociate the various contributions in tailoring both phases and controlling the interfaces. In this paper, a review of some chemistry pathways to hybrid materials is presented. The nature of the bonds between organic and inorganic phases is used to divide them in two major families: class I corresponds to materials with weak interphase bonding, while class II corresponds to materials where both phases are chemically grafted. Applications of these materials in the fields of optics, iono-electronics, mechanics, biology and others are expected. Some applications are reviewed, with respect to the versatility of the synthetic procedure. Most of the properties of these new high-technology materials are dependent on their structural and chemical composition as well as on the dynamical properties inside the blends.

Hybrid organic–inorganic materials: a land of multidisciplinarity

The present paper describes the synthesis and characterization of nanocomposite materials built from the assembly of organic polymers and two-dimensional host materials, particularly reviewing those composed of layered double hydroxide (LDH) inorganic frameworks. When the meaning commonly adopted for nanocomposites is narrowed, the system is constituted of sheets lying on top of each other in which covalent forces maintain the chemical integrity and define an interlamellar gap filled up with the polymer guest. The situation is different from an inorganic filler dispersed into a polymeric matrix. The incorporation of polymer between the galleries proceeds via different pathways such as coprecipitation, exchange, in situ polymerization, surfactant-mediated incorporation, hydrothermal treatment, reconstruction, or restacking. The latter method, recently effective via the exfoliation of the LDH layers, appears to be more favorable, in terms of crystallinity, to capture monomer entities than the whole polymer....

Polymer Interleaved Layered Double Hydroxide: A New Emerging Class of Nanocomposites

Homogeneously dispersed organic–inorganic hybrid nanocomposites can be obtained by increasing the interfacial interactions between both components via the formation of hydrogen bonds or covalent bonds, by mixing various polymers or via the adequate choice of the inorganic precursors The mechanical response of these advanced functional materials is an issue of paramount importance when industrial applications are targeted Large progress in the understanding of the mechanical properties of O–I hybrids has been gained by testing these materials under different conditions (static and dynamic, low and large deformations up to fracture) and using specific techniques developed for the mechanical characterization of conventional materials such as polymers, glasses or ceramics However, the mechanical properties of hybrid O–I materials are dependent on their micro- and nanostructures and on the nature and extent of the O–I interfaces Consequently, predictable mechanical properties for hybrids still represent a major challenge for hybrid materials science Industrial attraction for hybrid materials has been emphasized by the development of new functional coatings An important issue is the interface between the film and the substrate since strong adhesion can be tailored and ensures that delamination of the film will be limited

Mechanical properties of hybrid organic–inorganic materials

Thermoporometry by differential scanning calorimetry: experimental considerations and applications

Composites of poly(vinylacetate) (PVAc) and silica were prepered from the in situ polymerization of acid-catalyzed tetraethoxysilane. The physical properties of these composites were compared with those of PVAc/fumed silica (of 7-nm nominal perticle size) composites prepered by both melt-milling and solution-casting from THF or CCl 4 . Their morphologies were examined by TEM and SAXS revealing that, although all the materials were optically transparent, differences in the primery perticle size and interfacial regions exist. IR data showed that substantially more hydrogen bonding occurs in the in situ prepared composites.

Poly(vinyl acetate)/silica-filled materials: material properties of in situ vs fumed silica particles

Role of trialkoxysilane functionalization in the preparation of organic-inorganic composites

The effect of polymer structure on blend miscibility with polyvinylphenol (PVPh) has been studied for at least one polymer from a variety of polymer classes with potential hydrogen-bond accepting groups: polyesters (aliphatic and aromatic), polycarbonates, polyimides, polyamides, polysulfones, polyurethanes, polyethers, polysiloxanes, poly(amideimides), and cellulose esters. Many of the polyesters, polyamides, and cellulose esters showed evidence of interaction and miscibility with PVPh. In most of the other cases, there was no sign of miscibility. Generally good correlation exists between thermal behavior and infrared spectral data. Where there is significant interaction seen between the polymers by FTIR, substantial miscibility is seen by DSC analysis. In some cases, the phase behavior depended on the blend preparation scheme. © 1994 John Wiley & Sons, Inc.

A survey of polyvinylphenol blend miscibility

The effect of polymer structure on blend miscibility with poly(vinylphenol) (PVPh) has been studied for a variety of polyesters that contain aromatic moieties in their backbone. In general, polyesters derived from aliphatic diols showed evidence of interaction and miscibility with PVPh. However, immiscibility was observed if the aromatic content of the polyester was very high. Polyesters derived from aromatic-containing diols generally showed little interaction and no miscibility with PVPh. Both solution-blending and melt-blending methods were utilized to prepare the blends. Good correlation between the thermal behavior and infrared results was observed

Michael R. Landry

Papers

Thermoporometry by differential scanning calorimetry: experimental considerations and applications

Poly(vinyl acetate)/silica-filled materials: material properties of in situ vs fumed silica particles

Role of trialkoxysilane functionalization in the preparation of organic-inorganic composites

A survey of polyvinylphenol blend miscibility

Miscibility in binary blends of poly(vinylphenol) and aromatic polyesters