What were LEGO® Modulex bricks made from? Were they made from the same kind of plastic that LEGO® bricks are made from?
Great question! Actually, the answer is “Yes” AND “No”!
When my source from the original Modulex® company was telling me about colors and pigments, he also said that they experimented with both ABS and PPO for the plastic. Apparently, these two plastics yielded slightly different colors with the pigments. He also felt that the range of colors for the PPO was larger than for the ABS.