Showing papers on "Polymer nanocomposite published in 1990"

Flow induced polymer-filler interactions: Bound polymer properties and bound polymer-free polymer phase separation and subsequent phase inversion during mixing†

Abstract: The irreversible absorption of macromolecules on to solid filler particles during mixing in the melt is investigated. The molecular weight and concentration dependence of the absorbed layer thickness are evaluated and the chemical and morphological nature of the irreversibly absorbed polymer (bound polymer) are determined. It is found that the thickness of the bound polymer is not only dependent on the filler concentration but also dependent on polymer molecular weight. Bound polymer in high density polyethylene/colloidal silica systems is more amorphous and contains higher concentration of oxidation products (which are induced by a mechanochemical reaction during mixing) when compared with free polymer. As a result of bound polymer formation, flow induced crystallization and polymer entrapment during mixing, a phase separation between bound polymer and free polymer takes place which eventually leads to a liquid to solid phase inversion when the phase volume of the solids exceed a critical value under isothermal conditions. If the mixing is continued after phase inversion, the particle size of the newly formed powder is reduced and particle size distribution, is narrowed. This process of phase inversion and subsequent size reductions are termed as crumbling which can take place at filler concentrations well below the expected maximum packing fraction of solids, if the filler particle size is small and/or the molecular weight of the polymer is high. Crumbling phenomena are utilized in the agglomeration of fine powders and microencapsulation of solids and/or liquids.

Electrocodeposition of polymer blends for photoreceptor substrates

Abstract: Polymer films are formed by electrocodeposition of solutions containing a dispersion of charged particles of a first polymer and charged particles of a second polymer. Microheterogeneous films are obtained having micro-domains of a minor component polymer dispersed in the major component polymer. Processes for preparing dispersions for electrocodeposition are also provided In a first process, two polymers are dissolved in a common solvent and then dispersed as small charged particles in another solvent which is a precipitant for both polymers. In another process, a dispersion of a first polymer is prepared by adding a solution of the first polymer to a dispersant solvent, and then a solution of a second polymer is dispersed in the dispersion of the first polymer. In another process, a solution of the second polymer is added to a dispersion of the first polymer which contains only a single non-solvent for the second polymer. In yet another process, a dispersion of the first polymer in a first solvent system is mixed directly with a dispersion of a second polymer in a second solvent system, resulting in a dispersion of the first and second polymers in a resulting solvent system of the first and second solvent systems. In yet another process, a block copolymer composed of two blocks is dissolved in a solvent, and then dispersed in a non-solvent to form the dispersion.

Optical Field Induced Scattering in Polymer Dispersed Liquid Crystal Films

Abstract: Polymer dispersed liquid crystals are composite materials consisting of inclusions of liquid crystalline materials dispersed in a polymer binder. If the refractive indices of the constituent liquid crystal and polymer are appropriately matched, then films of these materials may be switched between an optically scattering state and a non–scattering transparent state1−2 by the application of electric fields which reorient the liquid crystal in the inclusions. In this paper we discuss the response of these materials to intense laser radiation, and examine the mechanisms associated with optical field induced reorientation.

Polymer composite with dispersed fine grains and a method for manufacturing the same

Abstract: A polymer composite includes a thermoplastic plastic polymer having a fine grain metal or metal oxide dispersed therein. Preferably, the fine grains has a size of about 1,000 nm or less. A method of making the polymer composite by adhering a metal layer to a thermoplastic polymer layer in a thermodynamically nonequilibrated condition followed by relaxation of the polymer layer to obtain thermodynamic equilibrium which causes the metal layer to be absorbed by the polymer layer as fine grains is also disclosed.

Polymer material having shape memory characteristics

Abstract: The present invention provides a polymer material having shape memory characteristics and characterized in that the material is prepared from a polymer substance obtained by dissolving an amorphous fluorine-containing polymer in an acrylic monomer, and polymerizing the monomer with or without permitting the resulting polymer to form an interpenetrating polymer network, and a polymer material having shape memory characteristics and characterized in that the material is prepared from a blend of (a) and (b), (a) being an amorphous fluorine-containing polymer or crystalline polymer containing vinylidene fluoride, and (b) being an acrylic polymer.

Vibration-proof damping polymer material

Abstract: A vibration-proof damping polymer material characterized in that the material is prepared from a polymer substance obtained by dissolving an amorphous fluorine-containing polymer in an acrylic monomer and polymerizing the monomer with or without permitting the resulting polymer to form an interpenetrating polymer network, and a vibration-proof damping polymer material characterized in that the material is prepared from a blend of (a) and (b), (a) being an amorphous fluorine-containing polymer or crystalline polymer containing vinylidene fluoride, and (b) being an acrylic polymer.

Nonlinear optical polymer composition and method for producing the same

Abstract: A nonlinear optical polymer composition which comprises a polymer matrix comprising a thermosetting resin and a nonlinear optical compound molecules of which are poled in the polymer matrix in a dispersed state or in a solid solution state, which has improved stability and durability.

Hydrophilic-hydrophobic polymer composites and membranes

Abstract: A polymer composite, a method of making a polymer composite and a polymer composite membrane. The polymer composite comprises a uniform dispersion of hydrophobic polymeric particles in a continuous phase of a hydrophilic polymer. The new method of forming a polymer composite includes the formation of a concentrated emulsion of a hydrophilic monomer and a hydrophobic monomer and heating the concentrated emulsion at a predetermined temperature. The polymer composites of this invention may be useful as permselective membranes.

Liquid-crystalline polymer composition

Abstract: The invention relates to a polymer composition containing at least 60% (wt) of a liquid-crystalline polymer and at most 40% (wt) of a polyhydroxy ether. The polymer composition allows itself to be easily processed above 250 ¤& C without thermal degradation of the polyhydroxy ether and has excellent mechanical properties perpendicular to the direction of orientation of the liquid-crystalline polymer.