Thiosulfate polymers
View Patent ↗A thiosulfate polymer includes both an electron-accepting photosensitizer component and thiosulfate groups in the same molecule, arranged in random order along the backbone. The thiosulfate polymer composition can be formulated into compositions and applied to various articles, or used to form a predetermined polymeric pattern after photothermal reaction to form crosslinked disulfide bonds, removing non-crosslinked polymer, and reaction with a disulfide-reactive material. Such thiosulfate polymer compositions can also be used to sequester metals in nanoparticulate form, and as a way for shaping human hair in hairdressing operations.
1. A non-crosslinked polymer comprising, in random order: (a) recurring units comprising pendant thiosulfate groups, and (b) recurring units comprising an electron-accepting photosensitizer component,
which electron-accepting photosensitizer component has a spectral absorption in the range of at least 200 nm and up to and including 725 nm sufficient to cause the formation of crosslinking disulfide bonds from the pendant thiosulfate groups, and the electron-accepting photosensitizer component in the (b) recurring units has an excitation energy (E PS* ) that is greater than or equal to the difference between the oxidation potential of the pendant thiosulfate group and the reduction potential of the electron-accepting photosensitizer component, and thus satisfies the following Equation 2:
E PS* ≧E R ox −E PS red Equation 2
wherein E R ox is the oxidation potential of the pendant thiosulfate group and E PS red is the reduction potential of the electron-accepting photosensitizer component.
2. The non-crosslinked polymer of claim 1 , wherein the (a) recurring units comprise at least 1 mol % and up to and including 99 mol %, and the (b) recurring units comprise at least 1 mol % and up to and including 99 mol %, based on the total recurring units in the non-crosslinked polymer.
3. The non-crosslinked polymer of claim 1 , wherein the (a) recurring units comprise at least 15 mol % and up to and including 90 mol %, and the (b) recurring units comprise at least 10 mol % and up to and including 85 mol %, based on the total recurring units in the non-crosslinked polymer.
4. The non-crosslinked polymer of claim 1 , further comprising, in random order, (c) recurring units other than the (a) and (b) recurring units, which (c) recurring units comprise a pendant ionic group, the (c) recurring units being present in an amount of at least 0.1 mol %, based on the total recurring units in the non-crosslinked polymer.
5. The non-crosslinked polymer of claim 1 , further comprising, in random order, (c) recurring units derived from one or more acrylates, methacrylates, acrylamides, methacrylamides, styrene monomers, or other vinyl monomers.
6. The non-crosslinked polymer of claim 4 , further comprising at least 1 mol % and up to and including 49 mol % of (d) recurring units that have a total neutral charge, the amount being based on the total recurring units in the non-crosslinked polymer.
7. The non-crosslinked polymer of claim 4 , wherein the (c) recurring units comprise a pendant carboxy, carboxylate, phospho, phosphonate, phosphate, sulfo, sulfonate, or sulfite group.
8. The non-crosslinked polymer of claim 1 , wherein the electron-accepting photosensitizer component is present in an amount of at least 0.1 mol % and up to and including 10 mol %, in relation to the molar amount of thiosulfate groups present in the non-crosslinked polymer.
9. The non-crosslinked polymer of claim 1 , wherein the electron-accepting photosensitizer component has been derived from an organic photosensitizer N-containing heterocyclic compound.
10. The non-crosslinked polymer of claim 1 , wherein the electron-accepting photosensitizer component has been derived from the group of compounds consisting of cyanoaromatic compounds, aromatic anhydrides, aromatic imides, condensed pyridinium salts, pyryllium salts, and quinones.
11. The non-crosslinked polymer of claim 1 that has a glass transition temperature of at least 20° C. and up to and including 250° C.
12. The non-crosslinked polymer of claim 1 comprising pendant sodium or potassium thiosulfate groups.
13. The non-crosslinked polymer of claim 1 , wherein the (b) recurring units comprising the electron-accepting photosensitizer component are derived from at least one of the following PS-22 through PS-24:
PS-22
PS-23
PS-24
14. A film, disk, slab, or particle comprising the non-crosslinked polymer of claim 1 .
15. A crosslinked thiosulfate polymer having crosslinking disulfide bonds, which polymer is derived from the non-crosslinked polymer of claim 1 by irradiation with radiation having a wavelength in the range of at least 200 nm and up to and including 725 nm, which crosslinked polymer further comprises a metal or metal ions reacted with the crosslinking disulfide bonds.