Introduction
White glue or polyvinyl acetate can be converted into a rubber ball by the addition of a saturated borax solution. The saturated borax solution causes the polymer chains of polyvinyl acetate to cross-link. The polyvinyl acetate can be envisioned as long chains that move easily having contact to one another which gives us a material that is like liquid. When the saturated borax solution is added to the polyvinyl acetate the long chains become cross-linked, which can be envisioned as two chains joined by a bridge, the two chains can no longer slide against one another and so we are left with a solid material. Borax is sodium borate, Na3BO3. The borax actually dissolves to form boric acid, H3BO3. This boric acid-borate solution is a buffer with a pH of about 9 (basic). Boric acid will accept a hydroxide OH- from water as indicated below.