Chemical resistance of TPU

The chemical resistance of TPU includes inorganic acid-base salts and organic solvents, the latter has the influence of chemical cross-linking and soaking time, and the comparison of polyester and polyether TPU.

Acid, alkali and salt resistance

The results show that the hardness, tensile stress, tensile strength, elongation at break, mass and volume changes of TPU, whether it is high or low, after being immersed in acid and alkali salts. At 82 (Shore A), a TPU of 2% to 18% is considered to have a small effect or little effect, while at 96 (Shore A), a TPU of 2% to 8% is considered to have no effect or little effect. It can be seen that there is no problem in using these acid-base salts.

Influence of chemical cross-linking

The TPU structure is MDI/BDO/PBA-1000, the hard segment content is 26%, and r0=1.0; the TPU is mixed with 2% organic peroxide to prepare the chemically cross-linked TPU, and the immersion condition is 25℃×7d. The data shows that physically and chemically crosslinked TPU has severe volume and mass swelling in aromatic ring solvents and perchloroethylene, and the swelling range is 27% to 237%. However, the swelling of chemical crosslinking is lower than that of physical crosslinking. TPU; moderate swelling in methanol, swelling range of 15% to 25%, swelling in ethylene glycol is very small; in dichloromethane, nitromethane, methyl ethyl ketone, cyclohexanone, ethyl acetate and tetrahydrofuran , Physically cross-linked TPU is dissolved, while chemically cross-linked TPU has serious swelling phenomenon. It can be seen that the solvent resistance of chemically cross-linked TPU is better than that of physically cross-linked TPU.