摘要:
Fluoroelastomers are combined with chemical agents in the presence of supercritical carbon dioxide by swelling the fluoroelastomer with the carbon dioxide, and impregnating the swollen fluorelastomer with the chemical agent. The process can be conducted at relatively low temperatures and pressures such that degradation of the fluoroelastomer or the chemical agent is avoided. The chemical agent is preferably a curing agent which includes functional groups that interact with functional groups on the fluoroelastomer to create an association therebetween. The process is enhanced by pre-dissolving the chemical agent in a solvent which does not solubilize the fluoroelastomer to a great extent, but which is itself soluble in supercritical carbon dioxide. In addition, during combining, mechanical mastication is performed to create a free flowing powder.
摘要:
Elastomeric polymers are combined with chemical agents in the presence of supercritical fluids such as supercritical carbon dioxide by swelling the polymer with the supercritical fluid, and impregnating the swollen polymer with the chemical agent. The process can be conducted at relatively low temperatures and pressures such that degradation of the polymer or the chemical agent is avoided. The chemical agent is preferably a curing agent which includes functional groups that interact with functional groups on the polymer to create an association therebetween. The process is enhanced by pre-dissolving the chemical agent in a solvent which does not solubilize the polymer to a great extent, but which is itself soluble in the supercritical fluid. In addition, during combining, mechanical mastication is performed to create a free flowing powder.
摘要:
A process of making fibers by electrostatic spinning includes the use of a mixing vessel (10), a piston (15) for pressurizing the polymer, carbon dioxide sources (20) for lowering the viscosity of the polymer or pressurizing the collection vessel (35), a pressure generator (25), view ports (30), a target (36), a spinning needle (40), a camera/TV recorder (45) and a voltage source (50).
摘要:
A process of making fibers by electrostatic spinning includes the use of a mixing vessel (10), a piston (15) for pressurizing the polymer, carbon dioxide sources (20) for lowering the viscosity of the polymer or pressurizing the collection vessel (35), a pressure generator (25), view ports (30), a target (36), a spinning needle (40), a camera/TV recorder (45) and a voltage source (50).
摘要:
Fibrous material suitable for incorporation into filter elements of smoking articles such as cigarettes are impregnated with additives and agents such as flavorants, flavorant-enhancers and/or free radical scavengers. The fibrous material is contacted with the additive dispersed in a high pressure gas or supercritical fluid (SCF) held at elevated pressures. The high pressure gas or SCF swells the fibrous matrix and enables the additive to be incorporated within the matrix. When pressure is reduced, the gas or SCF vaporizes and leaves the additive embedded in the fiber interstices. As a result, the additive is slowly released over a finite period of time. When incorporated into a cigarette filter, the additive is released at a desired rate from the interior of the fibrous filter into the cigarette smoke.