scispace - formally typeset
Search or ask a question
Author

Jeffrey W. Gilman

Bio: Jeffrey W. Gilman is an academic researcher from National Institute of Standards and Technology. The author has contributed to research in topics: Montmorillonite & Nanocomposite. The author has an hindex of 50, co-authored 140 publications receiving 11923 citations. Previous affiliations of Jeffrey W. Gilman include University of California & Philips.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, an overview of the research to date on the use of clays, dispersed at the nanometer level, in polymers for improving thermal stability and flammability is presented.

1,623 citations

Journal ArticleDOI
TL;DR: In this paper, the mechanism of flammability reduction of polypropylene-graft-maleic anhydride and polystyrene−layered-silicate nanocomposites using montmorillonite and fluorohectorite was investigated.
Abstract: Our continuing study of the mechanism of flammability reduction of polymer−layered-silicate nanocomposites has yielded results for polypropylene-graft-maleic anhydride and polystyrene−layered-silicate nanocomposites using montmorillonite and fluorohectorite. Cone calorimetry was used to measure the heat release rate and other flammability properties of the nanocomposites, under well-controlled combustion conditions. Both the polymer−layered-silicate nanocomposites and the combustion residues were studied by transmission electron microscopy and X-ray diffraction. We have found evidence for a common mechanism of flammability reduction. We also found that the type of layered silicate, nanodispersion, and processing degradation have an influence on the flammability reduction.

1,466 citations

Journal ArticleDOI
TL;DR: In this article, transmission electron microscopy (TEM) and wide-angle X-ray diffraction (XRD) were used to characterize the nanoscale dispersion of the layered silicate.
Abstract: Several polymer-layered silicate (clay) nano- composites (PLSNs) were analyzed by transmission electron microscopy (TEM) and wide-angle X-ray diffraction (XRD) in an effort to characterize the nanoscale dispersion of the layered silicate. The PLSNs investigated included thermoset (cyanate esters) and thermoplastic polymers (polystyrene, nylon 6, and polypropylene-g-maleic anhydride). The re- sults of this study reveal that the overall nanoscale disper- sion of the clay in the polymer is best described by TEM, especially when mixed morphologies are present. XRD is useful for the measurement of d-spacings in intercalated systems but cannot always observe low clay loadings (5%) or be used as a method to identify an exfoliated nanocom- posite where no XRD peaks are present (constituting a neg- ative result). Most importantly, the study showed that XRD is not a stand-alone technique, and it should be used in conjunction with TEM. Our studies suggest that new defi- nitions, or a clarification of existing definitions, are needed to properly describe the diversity of PLSN nanostructures seen in various materials. © 2002 Wiley Periodicals, Inc.* J Appl Polym Sci 87: 1329 -1338, 2003

596 citations

Journal ArticleDOI
TL;DR: In this paper, a series of alkyl-imidazolium-treated montmorillonite clays were prepared and characterized by elemental analysis, thermogravimetry (TGA) and thermal desorption mass spectroscopy (TDMS).

437 citations


Cited by
More filters
01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal ArticleDOI
TL;DR: A review of the academic and industrial aspects of the preparation, characterization, materials properties, crystallization behavior, melt rheology, and processing of polymer/layered silicate nanocomposites is given in this article.

6,343 citations

Journal ArticleDOI
TL;DR: In this article, a review of polymer-layered silicate nanocomposites is presented, where the polymer chains are sandwiched in between silicate layers and exfoliated layers are more or less uniformly dispersed in the polymer matrix.
Abstract: This review aims at reporting on very recent developments in syntheses, properties and (future) applications of polymer-layered silicate nanocomposites. This new type of materials, based on smectite clays usually rendered hydrophobic through ionic exchange of the sodium interlayer cation with an onium cation, may be prepared via various synthetic routes comprising exfoliation adsorption, in situ intercalative polymerization and melt intercalation. The whole range of polymer matrices is covered, i.e. thermoplastics, thermosets and elastomers. Two types of structure may be obtained, namely intercalated nanocomposites where the polymer chains are sandwiched in between silicate layers and exfoliated nanocomposites where the separated, individual silicate layers are more or less uniformly dispersed in the polymer matrix. This new family of materials exhibits enhanced properties at very low filler level, usually inferior to 5 wt.%, such as increased Young’s modulus and storage modulus, increase in thermal stability and gas barrier properties and good flame retardancy.

5,901 citations

Journal ArticleDOI
TL;DR: In this article, a review of polymer nanocomposites with single-wall or multi-wall carbon nanotubes is presented, and the current challenges to and opportunities for efficiently translating the extraordinary properties of carbon-nanotubes to polymer matrices are summarized.
Abstract: We review the present state of polymer nanocomposites research in which the fillers are single-wall or multiwall carbon nanotubes. By way of background we provide a brief synopsis about carbon nanotube materials and their suspensions. We summarize and critique various nanotube/polymer composite fabrication methods including solution mixing, melt mixing, and in situ polymerization with a particular emphasis on evaluating the dispersion state of the nanotubes. We discuss mechanical, electrical, rheological, thermal, and flammability properties separately and how these physical properties depend on the size, aspect ratio, loading, dispersion state, and alignment of nanotubes within polymer nanocomposites. Finally, we summarize the current challenges to and opportunities for efficiently translating the extraordinary properties of carbon nanotubes to polymer matrices in hopes of facilitating progress in this emerging area.

3,239 citations

Journal ArticleDOI
TL;DR: In this paper, the structure, preparation and properties of polymer/graphene nanocomposites are discussed in general along with detailed examples drawn from the scientific literature, and the percolation threshold can be achieved at a very lower filler loading.

2,999 citations