Melamine-based crosslinked polymer Mannich product

A crosslinked polymer, in the form of a Mannich polycondensation product, comprising reacted units of

• a first monomer of formula (I)
• or a solvate thereof, a stereoisomer thereof, or a mixture thereof;
• melamine;
• and
• an aldehyde of formula (III)
• wherein:
• m is 2 or 3;
• and
• n is 2 or 3;
• wherein the crosslinked polymer has X number of repeating units of formula (IV);
• wherein X is 2 to 10,000;
• wherein * represents an amino site of an additional melamine ring;