Process for the recovery of ionomer
A process for the recovery of a perfluorosulphonic acid ionomer from a component comprising a perfluorosulphonic acid ionomer is disclosed, the process comprising immersing the component comprising the perfluorosulphonic acid ionomer in a solvent comprising an aliphatic diol and heating. Also disclosed is the use of the recovered perfluorosulphonic acid ionomer, for example in to prepared a proton conducting membrane or a catalyst ink.
1. A process for the recovery of perfluorosulphonic acid ionomer from a component comprising a perfluorosulphonic acid ionomer, wherein the component comprising a perfluorosulphonic acid ionomer is selected from the group consisting of
a perfluorosulphonic acid ionomer composite membrane wherein the composite membrane contains materials that confer mechanical strength,
a perfluorosulphonic acid ionomer membrane wherein the membrane comprises a recombination catalyst,
a perfluorosulphonic acid ionomer membrane wherein the membrane comprises a hydrogen peroxide decomposition catalyst,
a catalyst coated membrane,
a membrane electrode assembly,
and,
an electrode,
said process comprising the steps of:
(i) immersing the component comprising a perfluorosulphonic acid ionomer in a solvent consisting of a C 1-8 aliphatic diol compound and optionally a co-solvent that is miscible with the C 1-8 aliphatic diol compound, wherein said diol compound comprises at least one —CH 2 OH group;
and
(ii) heating the component/solvent mix to a temperature of 90° C. to 150° C., wherein the temperature is below the boiling point of the solvent, to obtain a dispersion comprising solvent and perfluorosulphonic acid ionomer.
2. The process according to claim 1 , wherein the component comprising a perfluorosulphonic acid ionomer is chopped or shredded prior to being immersed in the solvent.
3. The process according to claim 1 , wherein the solvent includes the co-solvent.
4. The process according to claim 3 , wherein the co-solvent is water.
5. The process according to claim 3 , wherein the co-solvent is a C 1-4 alcohol.
6. The process according to claim 3 , wherein the co-solvent is a mixture of water and propan-1-ol.
7. The process according to claim 1 , said process further comprises a step
(iii) immersion of additional component comprising perfluorosulphonic acid ionomer in the dispersion obtained in step (ii) and subjecting the membrane/solvent mix to a temperature of 90° C. to 150° C., wherein the temperature is below the boiling point of the solvent.
8. The process according to claim 7 , said process comprising heating the component/solvent mix to a temperature of 90° C. to 120° C.
9. The process according to claim 1 , said process comprising heating the component/solvent mix to a temperature of 90° C. to 120° C.