by ropya
Perhaps get a edge sealer often used for decals, or in a pinch use elmers glue.Run a thin film of it all the way around the edge of the board.
Not on the faces, only the edges.
I recently ordered some extra Super Dungeon Explore tile which came in smashed in the corners due to poor packing. Bad enough to fray the plies of the material.
Put a but of glue in the frayed area and clamped it down for a couple days with a C-clamp and some wood.
After dry, trimmed the excess and did the edge sealer around the border.
Worked like a charm.