摘要:
A process for producing fine particles is provided including the steps of (1) preparing a solution having a viscosity of 20 mPa·s or less at 25° C. by using a polymer and a first solvent, (2) mixing the solution with a second solvent to prepare an emulsion and (3) removing the first solvent from the emulsion to obtain fine particles containing the polymer.
摘要:
Described is a process for preparing polymer-enrobed pigment particles, which comprises mixing in the presence of finely dispersed pigment particles a solution of a polymer in a first solvent with a second solvent in which the polymer is substantially insoluble. The pigment particle can be specifically modified by judicious selection of the polymer.
摘要:
An object of the present invention is to provide a method for precipitating polyphenylene ether which decreases the number of fine particles thereof and reduces periodic fluctuations in particle size, thereby being able to stably produce homogeneous polyphenylene ether particles. The invention relates to a method for precipitating polyphenylene ether by mixing a polyphenylene ether solution comprising polyphenylene ether and a good solvent therefor with a poor solvent for polyphenylene ether to precipitate polyphenylene ether particles, the method comprising: using a precipitation tank equipped with (a) a draft tube, (b) an at least one-stage stirring blade disposed in the draft tube and selected from an inclined paddle blade, a screw blade and a ribbon blade, (c) one or more baffles disposed on the outside of the draft tube, (d) a solution supply port, (e) a poor solvent supply port and (f) an exhaust port; adding, to a mixed solution comprising the good solvent, the poor solvent and polyphenylene ether particles and circularly flowing by rotation of the stirring blade (b), the polyphenylene ether solution from the solution supply port (d) and concurrently a poor solvent from the poor solvent supply port (e), thereby precipitating polyphenylene ether particles; and discharging and recovering the precipitated polyphenylene ether particles together with the mixed solution from the exhaust port (f).
摘要:
The invention refers to a method of controlling the porosity of porous spherical particles produced from a polysaccharide dissolved in a solvent, in which it can be gelled. The polysaccharide solution is finely divided by mechanical means into spherical droplets which are allowed to pass through a humid atmosphere and transferred to a capturing medium while controlling the temperature and humidity of humid atmosphere.
摘要:
In a method for recovering polymers in a substantially pure form from a solution containing the polymers, the solution is first treated with a reactant (e.g. an acid, a sequestrant or a mixture of both) to form the free polymers and salts of the reactant. Second, the solution is treated to remove the salts therefrom and in a final stage the polymer solution is concentrated and the polymers recovered. The second treatment step may consist of membrane-filtration, ion-exchange or electrodialysis.
摘要:
The invention relates to a process for the chlorosulfonation of polyarylene sulfide in which the polyarylene sulfide is completely dissolved in chlorosulfonic acid at a temperature of -10 to +20 C., then agitated at reaction temperatures in the +5 to +20 C. range for a reaction time of 180 min at the most, possibly with the addition of oleum or acetic anhydride and the precipitated in an aqueous medium. The polyarylene sulfide is preferably poly-p-phenylene sulfide. The invention also relates to chlorosulfonated polyarylene sulfide produced by this process, which dissolves in a quantity of 10 to 50 wt % in N-methyl pyrrolidone and has a mean molecular weight Mw of >50,000 g/mol. Finally, the invention also relates to the use of chlorosulfonated polyarylene sulfide for the production of molding, foils, fibres or diaphragms with a proton conductivity in the 2 to 200 mS/cm range.
摘要:
Copolymers designed for use as particulate carriers containing functionalizable amino subunits for coupling with targeting ligand are described. The copolymers are polyesters composed of .alpha.-hydroxy acid subunits such as D, L-lactide and .alpha.-amino acid subunits such as serine or in the preferred embodiment, terpolymers of D,L-lactide and glycolide and .alpha.-amino acid subunits such as serine. Stable vaccine preparations useful as delayed release formulations containing antigen(s) or antigen(s) and co-adjuvants encapsulated within or physically mixed with ploymeric microparticles are described. The particulate carriers are useful for delivering agents to the immune system of a subject by mucosal or parenteral routes to produce immune responses, including antibody responses.
摘要:
A highly productive process for preparing cured silicone powder having a uniform particle size, in which a platinum-alkenylsilozane complex catalyst is added to a water-based dispersion of a silicone composition. The silicone composition is (i) an organopolysiloxane having at least two silicon-bonded alkenyl groups in each molecule, and (ii) an organopolysiloxane having at least two silicon-bonded hydrogen atoms in each molecule. The catalyst is added and dispersed in the form of liquid particles with an average particle size in volumetric particle size distribution in water of no more than one micron.
摘要:
A process for recovering polyamide from composite articles that contain polyamide involves (a) subjecting at substantially nondepolymerizing conditions the composite article to a solvent for polyamide for a time sufficient to dissolve substantially all of the polyamide and leaving an insoluble fraction; (b) separating insoluble fraction of the composite article from the dissolved polyamide; and (c) precipitating the dissolved polyamide with appropriate precipitants.