Abstract: The present invention relates to a process for hydrophilizing a porous material made of a fluorine resin comprising irradiating an ultraviolet laser beam on the porous material impregnated with an aqueous solution of hydrogen peroxide or water-soluble organic solvent. According to the process, the chemically and physically inactive surfaces including the inside of the micropores of the porous materials made of fluorine resins can be sufficiently hydrophilized without deteriorating the excellent heat resistance, chemical resistance and the like of the fluorine resins.

Abstract: The present invention relates to a process for modifying the surfaces of the molded materials made of fluorine resins comprising irradiating an ultraviolet laser beam on said surfaces in the presence of an ultraviolet-absorbing compound and a fluorosurfactant. According to the process, the adhesive and wetting properties and the like of the surfaces of the molded materials made of fluorine resins can be remarkably improved.

Abstract: The invention provides surface-modified hydrophilic fluororesin moldings. The surface of a fluororesin molding is at least partly hydrophilized by irradiating at least part of the fluororesin molding with ultraviolet laser light not longer than 400 nm in wavelength in a state such that the molding is in contact with gas-treated water prepared by introducing into water a gas such as hydrogen gas, nitrogen gas or a rare gas or with some other specific aqueous liquid. The thus-obtained fluororesin moldings are suited for use, for example, as materials of artificial blood vessels excellent in antithrombotic property, and contact lenses free of modification-due discoloration. Further, they are expected to find a wider range of application where their performance characteristics are to be utilized.

Abstract: A process for modifying surfaces of fluorine resins including irradiating an ultraviolet laser beam on the surfaces in the presence of an inorganic silicon compound. The inorganic silicon compound could be a silicate, silicon oxide, silicon nitride, or silicon carbide.

Abstract: A method for surface modification of a fluorine resin by irradiating the surface of the fluorine resin containing a heat-resistant light-absorbing polymeric material and/or a light-absorbing material is with laser light. Surface properties of the fluorine resin molded articles, particularly adhesion and wetting properties, can be greatly improved by a simple operation with high efficiency.

Abstract: A super heat-resistant silicon carbide fiber has an oxygen content of less than 0.1% by weight. In a process for producing the super heat-resistant silicon carbide fiber, a precursor fiber prepared by spinning a polycarbosilane having an oxygen content of less than 0.8% by weight is irradiated with a radiation in an oxygen-free atmosphere or in vacuo to make the precursor fiber infusible. The infusibilized fiber is fired in an oxygen-free atmosphere or in vacuo at a temperature of from 1000.degree. to 2200.degree. C. without exposure to an oxidizing atmosphere; or stabilized in the same atmosphere at a temperature of from 300.degree. to 600.degree. C. without exposure to an oxidizing atmosphere and fired in an oxygen-free atmosphere or in vacuo at a temperature of from 1000.degree. to 2200.degree. C.