Modeling the Phase Behavior of Polymer/Clay Nanocomposites (original) (raw)

Materials Today, 2004

The nanocomposite approach has advantages over traditional fiber reinforced composites in the low filler loading range. Despite this, the market for highperformance fiber reinforced composites with high fiber volume fractions has not been affected by these developments.

Recent Advances in Clay/Polymer Nanocomposites

Advanced Materials, 2011

Composite materials represent one of the most active fields in the polymer industry. Many different types of fillers, carbon black, calcium carbonate, glass fibres and talc in the micrometer size range have been added to polymers to provide an improvement of the final product properties. However, this improvement is only achieved at high filler concentrations, which lead to an increase in the viscosity of the material and, hence, problems in processing.

In situ polymerization of polyester-based hybrid systems for the preparation of clay nanocomposites

Polymer, 2013

Polystyrene and poly(methyl methacrylate/styrene) were prepared by in situ polymerization in the presence of Cloisite 20A, and were then used to synthesize unsaturated polyester-based thermoplastic/ thermoset hybrids with improved properties. This approach allows for an increased degree of dispersion and delamination of the silicate layers as well as the presence of thermoplastic chains within the thermoset resin, which improve the physical properties of the system. During curing, methyl methacrylate promotes the conversion of styrene inside the clay galleries and also in the thermoplastic-rich phase. X-ray diffraction and transmission electron microscopy (TEM) revealed a fine intercalated/exfoliated structure in the nanocomposites. Fracture tests showed that a combination of clay and thermoplastic resulted in a synergistic improvement of the fracture toughness of the nanocomposite while stiffness was maintained at the level of the unmodified polyester. The hybrid systems exhibited spherical domains of thermoplastic-rich phase dispersed in the thermoset matrix. The clay was present only in the thermoplastic-rich phase with a portion congregated at the interface between the thermoset and thermoplastic domains. Interestingly, morphological studies showed that the clay layers surrounded microgels of thermoset contained within the thermoplastic domains. Such microgels of thermoset are thought to be fewer and smaller in the hybrid systems without clay, leading to smaller and more compliant dispersed phase domains at the same thermoplastic content and reduced fracture toughness.

Polymer/Clay Nanocomposites: An Emerging Material Class

Polymer/clay nanocomposites are materials composed of a polymer matrix and nanometer size clay particles. They exhibit significant improvements in tensile modulus and strength, reduced permeability to gases and liquids compared to the pure polymer. These property improvements can be realized while retaining clarity of the polymer without a significant increase in density. Polymeric nanocomposites hold the potential to replace conventional plastics and plastic composite materials in many applications such as automotive components, packaging, appliances, electrical/electronic parts, and building and construction products. This paper reviews the background and growth of nanocomposite technology, presents some of the data on property enhancement, and evaluates the future of this emerging class of polymer material.

Hybrid polymer–clay nanocomposites: A mechanical study on gels and multilayered films

Polymer, 2008

The present contribution describes the preparation and characterization of polymer-clay nanocomposite gels and films containing poly(ethylene oxide) and various ratios of Laponite and Montmorillonite. The aim is to understand how clays with different chemistry, sizes and surface areas interact with each other and affect the structure and characteristics of polymer based nanocomposites in the form of both gels and multilayered films. The rheological behavior of the gels is compared to the spreading process during sample preparation and the resulting film structures and properties are analyzed. While gradually replacing Laponite clay with equivalent amounts of Montmorillonite clay decreases the viscosity of the resulting gels, we observed that the progressive increase of the Montmorillonite percent in the samples leads to a gradual increase of the storage and loss moduli in the multilayered films. At the nano-scale, SAXS and XRD measurements on films indicated that the clay platelets orient parallel to the film plane and that the polymer chains intercalate between silicate galleries. Thermal analysis shows that the polymer crystallinity can be controlled by combination and variation of different clays.

Intercalation strategies in clay/polymer hybrids

Progress in Polymer Science, 2014

Layered silicate clays are natural crystallites and are well recognized for their structures and industrial applications, but there are very few reports on their structural confinement properties and on the mechanisms that underlie their polymer interactions. In this review, we summarize the recent progress on clay modification via conventional ion exchange reactions, sol-gel linking, atom transfer radical polymerization, and polymer intercalation. The organic interaction of ionic clays involves different noncovalent bonding forces, such as amido acid five-membered ring chelation, carboxylic acid chelation, intermolecular hydrogen bonding, and double-layer hydrophobic alignment in a layered clay confinement. Controlling the organic species, their amounts and their self-assembled conformation in a clay confinement could lead to the tailoring of the silicate platelet interlayer distance and of their organophilic properties.

Polymer-Clay Nanocomposite Materials: Solution and Bulk Properties

MRS Proceedings, 2000

ABSTRACTThe influence of shear on viscoelastic polymer-clay solutions was investigated by means of small-angle neutron scattering (SANS) under shear. SANS measured the shearinduced orientation of polymer and platelets. With increasing shear rate an anisotropic scattering pattern developed. At higher shear rates, the scattering anisotropy increases due to the increased orientation of the clay platelets in the shear field. Cessation of shear leads to fast recovery demonstrating the system to be highly elastic. As a result of drying, these solutions produce translucent nanocomposite films with a microporous membrane character. Depending on the preparation and degree of polymer-clay film dispersion, it is possible to modify the morphology and elastic properties of nanocomposite materials. Atomic Force Microscopy (AFM) reveals the network character and the development of morphology as a function of polymer concentration. Preliminary SANS experiments on the films will be correlated to mor...