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Haraguchi K.,Kawamura Institute of Chemical Research
Polymer Journal | Year: 2011

We have fabricated new types of polymer hydrogels and polymer nanocomposites, that is, nanocomposite gels (NC gels) and soft polymer nanocomposites (M-NCs), with novel organic/inorganic network structures. Both NC gels and M-NCs were synthesized by in situ free-radical polymerization in the presence of exfoliated clay platelets in aqueous systems and were obtained in various forms and sizes with a wide range of clay contents. Here, disk-like inorganic clay nanoparticles function as multifunctional crosslinkers to form new types of network systems. NC gels have extraordinary optical, mechanical and swelling/deswelling properties, as well as a number of new characteristics relating to optical anisotropy, polymer/clay morphology, biocompatibility, stimuli-sensitive surfaces, micropatterning and so on. The M-NCs also exhibit dramatic improvements in optical and mechanical properties including ultrahigh reversible extensibility and well-defined yielding behavior, despite their high clay contents. Thus, the serious disadvantages (intractability, mechanical fragility, optical turbidity, poor processing ability, low stimulus sensitivity and so on) associated with the conventional, chemically crosslinked polymeric materials were overcome in NC gels and M-NCs. © The Society of Polymer Science, Japan (SPSJ) All rights reserved. Source

Kawamura Institute Of Chemical Research, Dainippon Ink and Chemicals | Date: 2013-06-19

The problem to be solved is to provide a nondrying polymer hydrogel, which is not dried under atmospheric conditions and has excellent mechanical properties, and a method for producing the nondrying polymer hydrogel. A nondrying polymer hydrogel having both excellent nondrying properties and mechanical properties (e.g., excellent elongation properties, compression properties, and surface adhesiveness) can be produced by using a nondrying polymer hydrogel including a deliquescent substance in such a manner that the water vapor pressure shown by the polymer hydrogel is equal to or lower than the water vapor partial pressure in the atmosphere, in particular, by allowing a deliquescent substance to be contained at a high concentration in a polymer hydrogel having a network structure formed by a polymer of a water-soluble radically-polymerizable organic monomer having a specific chemical composition and a delaminated water-swellable clay mineral.

Dainippon Ink, Chemicals and Kawamura Institute Of Chemical Research | Date: 2012-08-10

The object of the present invention is achieved by providing a copolymer, in particular, a block copolymer which has excellent coating formation ability, adhesive properties to a substrate, and does not adsorb protein; an antithrombotic coating agent which has superior antithrombotic properties and adhesive properties to a substrate to those of the conventional antithrombotic coating agent; and a medical instrument which is obtained by coating the antithrombotic coating agent, and the block copolymer includes a polymer (A) containing a (meth)acrylic ester monomer and a polymer (B) containing a (meth)acrylamide monomer and has excellent coating formation ability and high adhesive properties to a substrate.

Kawamura Institute Of Chemical Research, Dainippon Ink and Chemicals | Date: 2011-03-31

There are provided an infrared absorbing thin film that efficiently absorbs infrared rays and has good versatility by controlling the absorption intensity of titanium oxide in an infrared region and a method for producing the infrared absorbing thin film. The infrared absorbing thin film containing a rutile-type titanium oxide crystal can be produced through a step of dispersing or dissolving a complex of an amino group-containing basic polymer and a transition metal ion in an aqueous medium; a step of obtaining a composite having a polymer/titania layered structure in which the complex of the amino group-containing basic polymer and the transition metal ion is sandwiched between layers of titania, by mixing the aqueous dispersion with a water-soluble titanium compound in the aqueous medium; a step of calcining the composite in an air atmosphere at a temperature of 650 C. or higher and pulverizing the obtained crystal into a powder; and a step of mixing the obtained powder with a sol of a metal alkoxide to prepare a fluid liquid composition, coating a surface of a substrate with the obtained fluid liquid composition, and aging the coating film.

Dainippon Ink, Chemicals and Kawamura Institute Of Chemical Research | Date: 2010-11-29

A silica nanofiber/metal oxide nanocrystal composite is produced by a method including associating a polymer having a linear polyethyleneimine skeleton in a water-based medium in the presence of ice, adding alkoxysilane to the water-based medium obtained in the above step to form a composite nanofiber including the associate and silica that covers the associate, while the fiber spontaneously forms a disc-shaped network structure, a step of depositing a metal oxide on a surface of the fiber by mixing the disc-shaped structure obtained in the above step with a hydrolyzable metal compound, and a step of calcining the disc-shaped. structure obtained in the step above to form a silica nanofiber through removal of the polymer in the fiber, to convert the metal oxide into a nanocrystal, and to bond the nanocrystal to the fiber. When zinc oxide is used as the metal oxide, the composite functions as a luminous body.

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