Siemens Water Technologies Pte. Ltd.

Siemens Industry, Inc.

U.S. Filter Wastewater Group, Inc.

Heinz-Joachim Muller

Daniel Edward Mullette

Dongliang Wang

Nina Elbaz

A method of coating a polymer comprising the step of treating the polymer with an activating agent to produce a reactive polymer, for example treating a polymer bearing at least one X (halogen) group and at least one H with base to eliminate HX. The reactive polymer is then reacted with a reactive coating, for example PVP, preferably in the presence of an initiator like persulfate anions, to produce a coated polymer, which may be hydrophilic in nature.

Hydrophilic membranes

A method of improving the water permeability and/or cleaning a porous polymeric microfiltration or ultrafiltration membrane, preferably a hydrophobic/hydrophilic blended membrane, eg P VdF/PVP comprising the step of contacting the porous polymeric membrane with a source of monopersulfate, preferably an aqueous solution of 2KHSO.KHSO.K2SO.

Monopersulfate treatment of membranes

Porous polymeric membranes formed from a hydrophobic polymer, such as halar having membrane pores of a size sufficient to permit gas and/or vapor permeation 0.05 &#x3bc;m to 5 &#x3bc;m without permitting the flow of a hydrophilic fluid across the membrane. Pore distribution is uniform and porosity is high, in some cases up to 80%. Membranes may be in the form of a flay sheet or hollow fibre for example and can be used in a variety of applications such as stripping HF gas, degassing of caustic solution, chlorine gas/alkaline filtration, degassing tap water to remove dissolved chlorine. Processes used to make such membranes can be carried out using relatively non toxic solvents such as citric acid ethyl ester or glycerol triacetate.

Gas transfer membrane

Porous polymeric membranes including HALAR&#xae; (poly(ethylene chlorotrifluoroethylene)) and related compounds and the methods of production thereof which avoid the use of toxic solvents. Preferred solvents, coating agents and pore forming agents are citric acid ethyl ester or glycerol triacetate. The membranes may be in the form of a hollow fiber or flat sheet, and may include other agents to modify the properties of the membranes, such as the hydrophilic/hydrophilic balance. Leachable agents may also be incorporated into the membranes.

Poly(ethylene chlorotrifluoroethylene) membranes

A porous polymeric membrane formed from a blend of a polymeric membrane forming material, such as polyvinylidene fluoride or polysulfone and a polymeric reactivity modifying agent adapted to modify the surface active properties of the porous polymeric membrane. The reactivity modifying agent is preferably a linear polymeric anhydride, such as poly(alkyl vinyl ether/maleic anhydride). The surface activity modifications include modification of the hydrophilicity/hydrophobicity balance of the membrane, or hydrolysis followed by reaction with a polyamine to form a crosslinked polyamide layer. Such modified membranes have use as reverse osmosis membranes.

Modified membranes

Porous polymeric membranes including Halar (poly (ethylene chlorotrifluoroethylene)) and related compounds and the methods of production thereof which avoid the use of toxic solvents. Preferred solvents, coating agents and pore forming agents are citric acid ethyl ester or glycerol triacetate. The membranes may be in the form of a hollow fiber or flat sheet, and may include other agents to modify the properties of the membrane, such as the hydrophilic/hydrophobic balance. Leachable agents may also be incorporated into the membranes.

The invention relates to a terpolymer of tetrafluoroethylene (TFE) monomer, polyvinylidene fluoride (PVDF) monomer and hexafluoropropylene (HFP) monomer for forming an ultrafiltration or microfiltration membrane, method of forming said membranes, and to the ultrafiltration or microfiltration membranes themselves. The invention also relates to a method of forming a polymeric ultrafiltration or microfiltration membrane including preparing a leachant resistant membrane dope which incorporates a leachable pore forming agent, casting a membrane from the dope and leaching the pore forming agent from the membrane. The invention also relates to a method of preparing a polymeric ultrafiltration or microfiltration membrane of improved structure including the step of adding a nucleating agent to the membrane dope before casting.

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Thornleigh, Australia

Heinz-Joachim Muller