Polymer/layered silicate nanocomposites: a review from preparation to processing

https://pure.rug.nl/ws/files/6693298/2006ProgPolymSciNalawade.pdf

Supercritical carbon dioxide as a green solvent for processing polymer melts: Processing aspects and applications

Polymers are considered to be good hosting matrices for composite materials because they can easily be tailored to yield a variety of bulk physical properties. Moreover, organic polymers generally have long-term stability and good processability. Inorganic nanoparticles possess outstanding optical, catalytic, electronic and magnetic properties, which are significantly different their bulk states. By combining the attractive functionalities of both components, nanocomposites derived from organic polymers and inorganic nanoparticles are expected to display synergistically improved properties. The potential applications of the resultant nanocomposites are various, e.g. automotive, aerospace, opto-electronics, etc. Here, we review recent progress in polymer-based inorganic nanoparticle composites.

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Nanocomposites Derived from Polymers and Inorganic Nanoparticles

An overview of the progress in polymer nanocomposites is presented in this paper with an emphasis on the different methods used for preparing polymer-layered silicate (PLS) nanocomposites and the extent to which properties are enhanced. Other related areas that are also discussed include the types of polymers used in PLS nanocomposites preparation, the types of PLS nanocomposites morphologies that are most commonly achieved, the structure and properties of layered silicates, and the most common techniques used for characterizing these nanocomposites. © 2007 Wiley Periodicals, Inc. Adv Polym Techn 25:270–285, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20079

Preparation of polymer–clay nanocomposites and their properties

Supercritical carbon dioxide (scCO2) is a unique solvent with a wide range of interesting properties. This review focuses upon recent advances in the use of scCO2 in materials synthesis and materials processing. In particular, we consider the advances made in three major areas. First the design and application of new surfactants for use in scCO2, which enable the production of metal nanoparticles, porous polymers and polymers of high molecular weight with excellent morphology. Second the development of new polymer processing and polymer blend technologies in scCO2, which enable the synthesis of some very complex polymer composites and blends. Finally, the application of scCO2 in the preparation of novel biomedical materials, for example biodegradable polymer particles and scaffolds. The examples described here highlight that scCO2 allows facile synthesis and processing of materials, leading to new products with properties that would otherwise be very difficult to achieve.

Materials processing in supercritical carbon dioxide: surfactants, polymers and biomaterials

PMMA-layered silicate intercalated nanocomposites are synthesized using supercritical carbon dioxide (scCO2) to produce ordered materials with significant levels of reinforcement. The scCO2 is used to homogeneously distribute monomer as well as act as a low-viscosity solvent for MMA polymerization. This route allows for synthesis of nanocomposites containing significant levels of organically modified layered silicates (OMLS). Below 40 wt % OMLS, the intercalated nanocomposites exhibit a d spacing commensurate with dimensions of the fully extended surfactant chains. Above 40 wt % OMLS, the composite volume is saturated with inorganic material, and the d spacing decreases to homogeneously distribute the polymer volume. A model for estimating this transition concentration is presented. At concentrations approaching the homogeneously intercalated morphology, the basic mechanical and physical properties of the composite are investigated.

Highly concentrated, intercalated silicate nanocomposites: Synthesis and characterization

Supercritical Carbon Dioxide (SC CO2) is used as a reaction/processing medium in the fabrication of fiber-reinforced composite materials. SC CO2 allows resin (reactive monomer), to penetrate inside the fibers themselves, partitioning into the amorphous regions of the fiber. The crystal structure then templates polymerization of matrix within the fiber. This process produces a composite that exhibits ultralong-range order from the nanoscale reinforcement of crystals to the macroscale fiber reinforcement of matrix. In addition, SC CO2 lowers resin viscosity and aids in wetting out Nylon 6,6 fiber reinforcement in a process similar to reaction injection molding (RIM) or resin transfer molding (RTM). This article will discuss the fabrication technique in detail, including process parameters and the structure of resulting composites and morphology of modified fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1600–1607, 2003

In situ polymerization and nano‐templating phenomenon in nylon fiber/PMMA composite laminates

Supercritical carbon dioxide (SC CO 2 ) is used as a reversible plasticizing agent to promote solvent welding in highly oriented LLDPE films These films are laid up in a quasi-isotropic fashion to enhance material properties in all directions It is shown that, after processing, the oriented morphology and crystallinity are effectively unchanged These laminated films are investigated both physically and mechanically The mechanical strength of laminate interfaces is tested using a T-Peel test Tensile properties of the laminated film are evaluated and compared to the single oriented plies Tear resistance is measured using a single specimen J 1C 

Supercritical CO2 welding of laminated linear low density polyethylene films

Recent advancements in SC CO 2 mediated synthesis and material processing have led to polymer-polymer blends and composite materials with complex morphologies, exhibiting long-range order and orientation on multiple length-scales from the nanometer to the centimeter scale. The material under consideration in this work is a polyamide 6,6 (nylon)/poly (methyl methacrylate) (PMMA) fiber-reinforced composite that was fabricated in a unique SC CO 2 assisted process. The tensile and flexural properties of these unique composites are studied and the evolution of damage and energy dissipation are monitored through cyclic loading and microscopic analysis of post-stressed composite cross sections. It is shown that this morphology leads to improved flexural modulus and increased ultimate strength with only a small decrease in tensile modulus. These composites also exhibited significant improvements in stress distribution and load transfer without the use of fiber sizing agents for fiber/matrix compatibilization.

Terrence C. Caskey

Papers

Highly concentrated, intercalated silicate nanocomposites: Synthesis and characterization

In situ polymerization and nano‐templating phenomenon in nylon fiber/PMMA composite laminates

Supercritical CO2 welding of laminated linear low density polyethylene films

Evaluating the mechanical performance of supercritical CO2 fabricated polymide 6,6/PMMA, fiber reinforced composites