Polymer nanocomposites: structure, interaction, and functionality

Abstract

This feature article discusses the main factors determining the properties of polymer nanocomposites with special attention paid to structure and interactions. Usually more complicated structure develops in nanocomposites than in traditional particulate filled polymers, and that is especially valid for composites prepared from plate-like nanofillers. Besides the usually assumed exfoliated/intercalated morphology, i.e. individual platelets and tactoids, such nanocomposites often contain large particles, and a network structure developing at large extent of exfoliation. Aggregation and orientation are the most important structural phenomena in nanotube or nanofiber reinforced composites, and ag-gregation is a major problem also in composites prepared with spherical particles. The surface characteristics of nanofillers and interactions are rarely determined or known; the related problems are discussed in the paper in detail. The surface of these reinforcements is modified practically always. The goal of the modification is to improve dispersion and/or adhesion in nanotube and spherical particle reinforced composites, and to help exfoliation in nanocomposites containing platelets. However, modification decreases surface energy often leading to decreased interaction with the matrix. Very limited information exists about interphase formation and the properties of the interphase in nanocomposites, although they must influence properties considerably. The properties of nanocomposites are usually far from the expectations, the main reason being insufficient homogeneity, undefined structure and improper adhesion. In spite of considerable difficulties nanocomposites have great potentials especially in functional applications. Several nanocomposite products are already used in industrial practice demonstrated by a few examples in the article.

Thermal, electrical, and mechanical properties of polyethylene–graphene nanocomposites obtained by in situ polymerization

“…Among PEs, high-density polyethylene (HDPE) stands out for its high tensile strength, which results from its crystalline structure, high molecular weight, and low branch content. 3 Recent studies in nanocomposites have involved fillers such as clays, 4,5 carbon nanotubes, 6 carbon nanofibers, 7 silica, 8 and graphite. The improvement of these properties could be achieved with the addition of fillers to the PE matrix.…”

Mechanical, thermal and accelerated weathering studies of bio‐based polyurethane/clay nanocomposites coatings

“…[6,7] The clay based polymer nanocomposites have received great attention due to the unique properties which are difficult to be obtained by micro sized fillers or by other nanofillers. Recently polymer nanocomposites have taken important role in the domain of material science due to the substantial improvement of many important properties like stiffness, thermal stability, gas barrier, weather resistance, flame resistance, biodegradability, etc.…”

Polyhedral Oligosilsesquioxane (POSS) Nanoparticle Localization in Ordered Structures Formed by Solvated Block Copolymers

“…Superior functional properties of POSS‐containing polymer nanocomposites offer opportunities for developing hybrid materials for a wider range of applications such as drug delivery, polymer electrolytes, thermoplastic and thermosetting polymers . Considering their potential, POSS‐containing polymer nanocomposites have been widely investigated …”