Shin-etsu Chemical Co., Ltd.

Shin-estu Chemical Co., Ltd.

The Institute of Physical and Chemical Research

Hiroshi Miyoshi

Yasuyuki Takiguchi

Akira Hayashida

Ken Yahata

Yasuyoshi Komoto

Jun Watanabe

Isao Endo

Tohru Chiba

Okmi Park

The method for preparing a crosslinked polycarbodiimide according to the present invention comprises reacting a polydicarbodiimide compound with a compound, which has in a molecule thereof two or more hydroxy or mercapto groups, in the presence of an alcoholate of an alkali metal or of an alkaline earth metal. The crosslinked polycarbodiimide obtained according to the method is excellent in heat resistance and mechanical properties.

Method for preparing crosslinked polycarbodiimides

A hydroxy- or mercapto-bearing organic compound is caused to react with a polycarbodiimide compound in the presence of an alcoholate of an alkali metal or of an alkaline earth metal. The carbodiimide linkage in the polymer which results from the above-described reaction is crosslinked.

Polycarbodiimide derivatives and method for preparing the same

A polycarbodiimide compound is reacted with an organic compound having at least two amino groups in the molecule. A polycarbodiimide compound is reacted with an amine compound having a silicon atom in the molecule. The carbodiimide bonds remained in the crosslinked material are further crosslinked. The crosslinked material is further heated/calcined to obtain an inorganic material having high heat resistance and strong toughness.

Polycarbodiimide derivative and process for producing the same

According to the method for preparing chitosan of the present invention, chitosan is prepared by inoculating a filamentous fungi belonging to the family Mucoraceae into a culture medium for pre-cultivation containing yeast extract, malt extract, peptone, glucose and magnesium sulfate to perform pre-cultivation and then inoculating the pre-culture into a culture medium for main-cultivation having a composition essentially identical to that of the medium for pre-cultivation to perform the main-cultivation. Particularly preferred filamentous fungi belonging to the family Mucoraceae is Absidia coerulea. According to the method for preparing chitosan through the cultivation of microorganisms, chitosan exhibiting uniform quality can efficiently be produced and the method does not adversely affect the circumferential environment.

Method for preparing chitosan

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Kawasaki, Japan

Hiroshi Miyoshi