Abstract: This application provides a polyimide fiber and a preparation method thereof. This method comprises first subjecting a dianhydride compound and a diamine compound to a polymerization reaction in a solvent to obtain a polyamic acid solution, wherein said diamine compound comprises a diamine having a structure of Formula 12 or Formula 13, wherein A is S or O; said dianhydride compound comprises one or more of dianhydrides having structures of Formula 14 and Formula 15; and t is 0 or 1; then subjecting said polyamic acid solution to spinning to obtain a polyamic acid fiber; and sequentially subjecting said polyamic acid fiber to imidization and thermal drawing to obtain a polyimide fiber. The polyimide fiber having the above structure has a higher rigidity and can introduce a hydrogen bond to provide an interaction between molecular chains so as to influence the arrangement of the molecular chain in the polymer and the crystallinity, which imparts more excellent mechanical properties to the polyimide fiber.

Abstract: This disclosure provides a polyimide fiber prepared from a dianhydride compound and a diamine compound, wherein said diamine compound is selected from one or more of the compounds represented by the following formulae (I), (II), (III) and (IV). A polyimide fiber is prepared by using a polyimide polymer system having a specific hydroxyl heterocyclic diamine copolymerization structure, and the prepared polyimide fiber has relatively high strength and modulus and is resistant to high temperature. Furthermore, the polyimide fiber prepared by this disclosure is provided with an active group on its surface, thus being easily adhered to various resin matrices, and the composite material prepared has good mechanical properties.

Abstract: The present invention belongs to a method for preparing organic ligand-capped titanium dioxide nanocrystals, wherein the method comprises steps of using methyl titanate, ethyl titanate, n-propyl titanate, iso-propyl titanate, butyl titanate or titanium tetrachloride as a titanium source, and with capping by oleic acid or an organic capping agent, reacting the titanium source in an organic non-polar solvent with an aqueous alkaline substance solution in the interface at a temperature of 25 to 280° C. for 0.5 to 240 hrs, thus a transparent sol containing titanium dioxide nanocrystals is obtained, said the titanium dioxide nanocrystals have particle diameters of 1-20 nm. The preparing process has the features of mild reaction conditions and is a simpler and easier method with a shorter preparation period, thereby facilitating the industrialization.

Abstract: The present invention provides a process for producing a nanosemiconductor luminous material on a liquid-liquid interface, comprising the steps of: a) an oxide of a Group IIB metal and a carboxylic acid with 2-18 carbon atoms or an oleic acid reacting with each other in a solvent at 150-300° C. for 5-30 min, wherein the mol ratio of the oxide to the acid being 1˜5:5˜1; b) adding trioctylphosphine oxide and trioctylphosphine with a mol ratio of trioctylphosphine oxide to trioctylphosphine of 10˜1:1˜10 and a mol ratio of the total mol numbers of trioctylphosphine oxide to the oxide of 10˜1:1˜10; c) adding an aqueous solution of at least one alkaline/alkaline earth metal chalcogenide in a mol ratio of the chalcogenide to the oxide of 10˜1:1˜10; and d) reacting at 20-100° C. for 0.5˜10 h to obtain a sol containing a semiconductor nanoparticle. The produced semiconductor nanoparticle can emit a wavelength-adjustable visible light under a UV lamp.

Abstract: A two-phase thermal method for the preparation of cadmium sulfide quantum dots where a cadmium source, a sulfur source and a capping agent are heated in water and water-insoluble organic solvents forming a two-phase system. By means of varying reaction time, cadmium sulfide quantum dots of different sizes can be prepared. Quantum dots already obtained can be used as crystal seeds in the reaction of newly added reaction precursor to give larger sized quantum dots with a size distribution similar to that of the initial crystal seeds so as to realize the control of quantum dot size. The quantum dots obtained in the present invention have relatively narrow size distribution, and emit royal purple or blue light under ultraviolet lamp, with a photoluminescence quantum efficiency of from 3 to 60%.

Abstract: The present invention relates to a two-phase thermal method for the preparation of cadmium sulfide quantum dots. In the method, cadmium carboxylate containing 2 to 18 carbon atoms or cadmium oxide is selected as cadmium source; thiourea or thioacetamide is selected as sulfur source; oleic acid or trioctylphosphine oxide (TOPO) is selected as capping agent, and molar ratio of cadmium source to sulfur source is in a range of from 10:1 to 1:10, and molar ratio of cadmium source to capping agent is in a range of from 1:7 to 1:25. Water and water-insoluble organic compound in equal or similar volume are used as solvents forming a two-phase system. The mixture is heated at 120-180° C. in an autoclave for 0.5 to 24 hrs. By means of varying reaction time, cadmium sulfide quantum dots of different sizes could be prepared.

Abstract: The present invention belongs to a method for preparing organic ligand-capped titanium dioxide nanocrystals, wherein the method comprises steps of using methyl titanate, ethyl titanate, n-propyl titanate, iso-propyl titanate, butyl titanate or titanium tetrachloride as a titanium source, and with capping by oleic acid or an organic capping agent, reacting the titanium source in an organic non-polar solvent with an aqueous alkaline substance solution in the interface at a temperature of 25 to 280° C. for 0.5 to 240 hrs, thus a transparent sol containing titanium dioxide nanocrystals is obtained, said the titanium dioxide nanocrystals have particle diameters of 1-20 nm. The preparing process has the features of mild reaction conditions and is a simpler and easier method with a shorter preparation period, thereby facilitating the industrialization.

Abstract: The present invention provides a process for producing a nanosemiconductor luminous material on a liquid-liquid interface, comprising the steps of: a) an oxide of a Group IIB metal and a carboxylic acid with 2-18 carbon atoms or an oleic acid reacting with each other in a solvent at 150-300° C. for 5-30 min, wherein the mol ratio of the oxide to the acid being 1˜5:5˜1; b) adding trioctylphosphine oxide and trioctylphosphine with a mol ratio of trioctylphosphine oxide to trioctylphosphine of 10˜1:1˜10 and a mol ratio of the total mol numbers of trioctylphosphine oxide to the oxide of 10˜1:1˜10; c) adding an aqueous solution of at least one alkaline/alkaline earth metal chalcogenide in a mol ratio of the chalcogenide to the oxide of 10˜1:1˜10; and d) reacting at 20-100° C. for 0.5˜10 h to obtain a sol containing a semiconductor nanoparticle. The produced semiconductor nanoparticle can emit a wavelength-adjustable visible light under a UV lamp.