Polymer flocculants with improved dewatering characteristics
AssigneeEcole Polytechnique Federale De Lausanne (Epfl)
InventorsJose Hernandez Barajas, Christine Wandrey, David Hunkeler
Life of this patent
Estimating the term…
Abstract
A high molecular weight water soluble acrylamide based polymer having improved flocculating properties is provided. The polymer is prepared by a process, in which a small quantity of a chain branching agent is added to the polymerization reaction mixture continuously or semi-continuously while the monomers are polymerized. The polymer is useful in solid/liquid separations such as flocculants and coagulants in waste water treatment applications, and as thickening agents.
Claims19
A process for preparing a water soluble acrylic based polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable acrylic monomers;
- and
- polymerizing said acrylic monomers while adding to the reaction mixture a chain branching agent continuously or semi-continuously.
A process for preparing a water soluble acrylamide based polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable acrylamide monomers;
- and
- polymerizing said acrylamide monomers while adding to the reaction mixture a chain branching agent continuously or semi-continuously.
A process for preparing a water soluble acrylamide based polymer, comprising the steps of:
- providing a polymerization reaction mixture in an inverse-emulsion comprising acrylamide and dimethylaminoethylacrylate (as acid salt or quaternary salt) as polymerizable monomers, with at least 30% by weight of the monomers being said dimethylaminoethylacrylate (as acid salt or quaternary salt);
- and
- polymerizing said monomers while adding to the reaction mixture N, N-methylenebisacrylamide as a chain branching agent, in a constant manner, at a total amount of from about 1 ppm to about 100 ppm based on total monomers.
A process for preparing a water soluble acrylic based polymer, comprising the steps of:
- (a) providing a polymerization reaction mixture comprising one or more polymerizable acrylic monomers;
- and
- (b) polymerizing said acrylic monomers while adding to the reaction mixture a chain branching agent either continuously or stepwise as a function of reaction time,
- wherein said water soluble acrylic based polymer exhibits an intrinsic viscosity that is at least about 10% higher than the intrinsic viscosity achieved by performing the polymerization step (b) with batch addition of chain branching agent instead of continuous or stepwise addition.
A process for preparing a water soluble acrylic based polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable acrylic monomers;
- and
- polymerizing said acrylic monomers while adding to the reaction mixture a chain branching agent either continuously or stepwise as a function of reaction time,
- wherein said water soluble acrylic based polymer exhibits a an intrinsic viscosity of greater than about 4 dl/g in 1M NaCl at 25° C. and a sedimentation coefficient of the soluble portion of greater than or equal to 6.17 Svedberg in 0.05 M NaCl at 20° C.
A process for preparing a water soluble acrylic based polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable acrylic monomers;
- and
- polymerizing said acrylic monomers while adding to the reaction mixture a chain branching agent either continuously or stepwise as a function of reaction time,
- wherein said water soluble acrylic based polymer exhibits an intrinsic viscosity of greater than about 4 dl/g in 1M NaCl at 25° C. and an association to chain branching agent ratio of less than 2.5 as measured in 0.05 M NaCl at 20° C.
A process for preparing a water soluble acrylic based polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable acrylic monomers;
- and
- polymerizing said acrylic monomers while adding to the reaction mixture a chain branching agent either continuously or stepwise as a function of reaction time,
- wherein said adding further comprises adding said chain branching agent at a constant rate of between about 0.1 to about 20 weight % of the total amount of chain branching agent per hour during polymerization.
Dependencies are inferred from the claim text.