Three-dimensional printing with chemical functionalization agents

A three-dimensional printing kit, comprising:

• a powder bed material comprising polymer particles;
• a fusing agent to selectively apply to the powder bed material, the fusing agent comprising water and an electromagnetic radiation absorber, wherein the electromagnetic radiation absorber absorbs radiation energy and converts the radiation energy to heat;
• a chemical functionalization agent to selectively apply to the powder bed material, the chemical functionalization agent comprising water and an amine-containing polymer, wherein the amine-containing polymer is a branched or unbranched polymer comprising a polymer backbone having multiple pendant side chains, wherein individual side chains comprise —NH2, —NH—, or a combination thereof;
• and
• a coloring agent comprising an amine-reactive compound to react with the —NH2 or —NH— of the amine-containing polymer.

A method of making a three-dimensional printed object, the method comprising:

• iteratively applying individual build material layers of polymer particles to a powder bed;
• based on a three-dimensional object model, selectively applying a fusing agent onto the individual build material layers, wherein the fusing agent comprises water and an electromagnetic radiation absorber;
• based on the three-dimensional object model, selectively applying a chemical functionalization agent onto the individual build material layers, wherein the chemical functionalization agent comprises water and an amine-containing polymer, wherein the amine-containing polymer is a branched or unbranched polymer comprising a polymer backbone having multiple pendant side chains, wherein individual side chains comprise —NH2, —NH—, or a combination thereof;
• exposing the powder bed to energy to selectively fuse the polymer particles in contact with the electromagnetic radiation absorber to form fused polymer matrix layers from individual build material layers to thereby form the three-dimensional printed object, wherein the three-dimensional printed object includes a first surface portion comprising —NH2, —NH—, or a combination thereof and a second surface portion without the —NH2, —NH—, or the combination thereof;
• and
• applying a coloring agent comprising an amine-reactive compound to the three-dimensional printed object such that the amine-reactive compound attaches to the —NH2, —NH—, or the combination thereof in the first surface portion.