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Showing papers on "Polymer nanocomposite published in 1994"



Journal ArticleDOI
TL;DR: In this article, the role of supramolecular structure and morphology on solid-state luminescence of polymers is explored in rod-coil copolymers containing conjugated rods.
Abstract: Solid-state luminescence of polymers is currently of theoretical interest as well as for application in electroluminescent diodes. The role of supramolecular structure and morphology on solid-state luminescence of polymers is explored in rod-coil copolymers containing conjugated rods. The photoluminescence quantum efficiency of the rigid-rod homopolymer poly(p-phenylene benzobishthiazole) (PBZT) and the flexible-coil homopolymer poly(benzobisthiazoledecamethylene) (PBTC10) films is observed to be dramatically enhanced in the nanocomposite region. Results are given for the optical absorption spectra, the spectrum of the conjugated homopolymer PBZT, and the photoluminescence quantum efficiency.

72 citations


Journal ArticleDOI
TL;DR: In this article, a new type of clay-polyether nanocomposite has been prepared by self-polymerization of diglycidyl ether of bisphenol A in the galleries of acidic alkylammonium ion exchanged forms of montmorillonite.
Abstract: A new type of clay-polyether nanocomposite has been prepared by the self-polymerization of diglycidyl ether of bisphenol A in the galleries of acidic alkylammonium ion exchanged forms of montmorillonite. The acid catalyzed intragallery polymerization process leads to the spontaneous exfoliation to the 10A-thick clay layers. Intra- and extragallery polymerization processes are distinguishable by DSC. Clay-polyimide hybrid composites have also been prepared by the intercalation of polyamic acid in montmorillonites and subsequent thermal conversion to polyimide. In contrast to the completely exfoliated clay-polyether system, the polyimide system contain regularly intercalated clay aggregates in the polymer matrix. Although regular face-face clay layer aggregation is extensive, the clay-polyimide hybrid composite films exhibit greatly improved CO2 barrier properties.

25 citations


Patent
Patrick Guerin1
07 Nov 1994
TL;DR: An aqueous polymer particle dispersion including at least one first polymer and at least two second polymers, which polymers are mutually incompatible, is useful for preparing environmentally friendly paints.
Abstract: An aqueous polymer particle dispersion including at least one first polymer and at least one second polymer, which polymers are mutually incompatible. The first polymer is not cross-linked, it has a glass transition temperature of -25 to +0 °C, and it represents 40-65 wt % of the particles. The second polymer is neither alkali-soluble nor cross-linked, it has a glass transition temperature of 5 to 40 °C, and it represents 60-35 wt % of the particles. The second polymer has a glass transition temperature no more than 40 °C higher than that of the first polymer, and the average particle size is 100-300 nm. Said dispersion is useful for preparing environmentally friendly paints.

16 citations


Journal ArticleDOI
TL;DR: In this paper, a light-harvesting thin film supramolecular assemblies, consisting of rod-coil polymer nanocomposites as the light-absorbtion energy donors and a randomly dispersed conjugated rigid-rod polymer as the energy acceptor, have been prepared and shown to exhibit efficiency for singlet electronic energy transfer as high as 93%.

16 citations


Journal ArticleDOI
Antal Jakli1
TL;DR: In this article, it was shown that small (< 100 A size) fuzzes on the surface of the polymer fibers may play the essential role in the alignment of the liquid crystal molecules.
Abstract: Liquid crystal polymer composite systems can be divided into two main subgroups. The first consists of the polymer dispersed liquid crystals (PDLC), where the liquid crystal is dispersed in the continuous polymer matrix. The second contains the liquid crystal dispersed polymer (LCDP) systems (sometimes called as liquid crystal/gel dispersions), where only a small amount of polymer is dispersed in a continuous liquid crystal matrix. Neutron scattering and optical studies on various LCDP systems were made to investigate the structure of polymers dispersed in nematic and smectic liquid crystals. The results indicate that small (< 100 A size) fuzzes on the surface of the polymer fibers may play the essential role in the alignment of the liquid crystal molecules. These fuzzes can be realigned by the combination of external fields and heat treatments yielding a fading memory effect. This implies various application possibilities. Among them we describe a novel, electrically driven optical storage effect.

11 citations


Patent
07 Feb 1994
TL;DR: In this paper, the authors proposed a method for using two different polymer components having LCST behavior for use in industrial processes which require temperature-controlled light transparency, where the polymer mixtures P are built up from poly- alpha -methylstyrene as polymer component P1 and polyvinyl methyl ether as polymer components P2 in a weight ratio of from 98 : 2 to 2 : 98.
Abstract: The invention relates to polymer mixtures of two different polymer components having LCST behaviour for use in industrial processes which require temperature-controlled light transparency, where the polymer mixtures P are built up from poly- alpha -methylstyrene as polymer component P1 and polyvinyl methyl ether as polymer component P2 in a weight ratio of from 98 : 2 to 2 : 98.

2 citations


Patent
Takahiro Tochioka1
15 Jul 1994
TL;DR: The non-solvent polymer composite material is produced using no solvent and includes a rigid polymer (B) dispersed uniformly into a matrix (A) at the molecular level in a state of a copolymer (A/B and/or A'/B) as discussed by the authors.
Abstract: The polymer composite material is produced using no solvent and includes a rigid polymer (B) dispersed uniformly into a matrix (A) at the molecular level in a state of a copolymer (A/B and/or A'/B) thereby enhancing the interface bonding of the rigid polymer (B) to the matrix (A). The non-solvent method includes a step of polymerizing a thermoplastic polymer (A) and a monomer to form a rigid polymer (B) with no solvent in the molten and kneaded state to provide a copolymer (A/B and/or A'/B) in which the flexible molecular chains (A and/or A') are made up of the thermoplastic polymer to the rigid polymer (B) to reduce the stress concentrating sources of the rigid polymer dispersed microscopically at the molecular level in the thermoplastic polymer matrix and enhance the interface bonding between the rigid polymer (B) and the matrix (A).

2 citations


Patent
07 Dec 1994
TL;DR: In this article, a positive temperature coefficient material has a polymeric matrix (M) and a distribution of conducting or semiconducting particles to provide electrical conduction, the polymer matrix may be crystalline or amorphous.
Abstract: The positive temperature coefficient material has a polymeric matrix (M) and a distribution of conducting or semiconducting particles to provide electrical conduction. The polymer matrix may be crystalline or amorphous. A second crystalline polymer (S) is embedded in the first polymer matrix, with the two polymers not mixing. The fusion temperature of the second polymer is less than the fusion temperature of the first polymer. The first charged polymer is constituted by polyfluorovinylidene (PVDF) and the second polymer is constituted by high density polyethylene.

1 citations