Summary of the technology
Researchers from the Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering of the University of Alcalá in collaboration with researchers from the Department of Chemistry and Physics of the University of Almería, presents a procedure for the manufacture of active membranes based on submicron fibers combining an antimicrobial action with the ability to retain apolar contaminants in aqueous solution. The membranes are produced by an electrospinning process in aqueous solution from mixtures of water soluble polyacids and polyols, which are subsequently stabilized by a thermal curing process and post-functionalized by the incorporation of amino-terminated dendrimers by a grafting process using a coupling agent. The material can be applied to the treatment of drinking water, to the regeneration of waste water, to the treatment of process waters and also to the controlled release of active substances, such as drugs, food preservatives, etc.
The group seeks companies from the pharmaceutical, food, material technology and environmental sectors to sign technical cooperation agreements, commercial agreement with technical assistance and patent licensing agreements.
Description of the technology
This invention relates to a process for the manufacture of active membranes for treatment of water based on submicron fibers which combine an antimicrobial action with the ability to retention nonpolar contaminants. The synthesis consists of an electrospinning process in which a non-spun matrix is prepared, a thermal curing process which stabilizes the fibers making them insoluble in water and a post-functionalization step of the fibers in which a dendrimer is grafted by covalent bonds.
In the first step, an aqueous solution of two water-soluble polymers, a polyacid and a polyalcohol with molecular weights higher than 80 kDa and in weight percentages not exceeding 10%, is prepared in such a way that the number of carboxyl groups of the polyacid is similar to that of the hydroxyl groups of the polyalcohol.The membranes are prepared by electrospinning. The potential difference applied is 20-25 kV and the separation between needle and collector is at least 20 cm. The result must be a nonwoven matrix of straight fibers, free of defects and with uniform fibre diameter not exceeding 350 nm.
In a second phase, the thermal curing of the fibers takes place, after drying at 50 ° C for 24 hours, by heating in an oven at 140 ° C for at least 30 min. In this process the formation of ester bridges takes place, which gives rise to a water insoluble membrane. The fibers are then thoroughly washed to remove material that has not been fully fixed and dried under vacuum (10 kPa) at 50 ° C for 24 hours. After this step, the membrane must retain the fibrous structure and must not release organic matter after water immersion above 10 mg of total carbon / g of membrane.
The third phase of the synthesis process is the grafting of dendrimers for which membranes with a free carboxyl group density of at least 5 mmol / g measured by acid-base titration are used. The dendrimers must have primary amines as surface groups and the bonding occurs by formation of amide covalent bonds with the carboxyl groups of the stabilized membrane. A coupling agent is used to carry out the reaction. The amount of dendrimer attached to the membrane is maximum in aqueous solution in the absence of hydroxylated solvents. The dendrimers can be of any generation of 3 or greater and are dosed at least with the equivalent of 0.2 mmol / mol COOH. The duration of the fixation process is at least 12 hours during which the membranes are maintained in contact with the dendrimer and the coupling agent under slight orbital agitation. The membranes are then carefully washed with the solvent used for the reaction and with plenty of water. Finally, they are dried under vacuum (10 kPa) at 100 °C for 24 h.
Intellectual property status
Patent already applied for
Patent application number : P201600852
Where : Spanish Patent and Trademark Office
Current development status
Desired business relationship
Commercial agreement with technical assistance
Universidad de Alcalá-OTRI
Research & Technology Organization