“…They were mainly based on vinyl lactam polymers, such as PVP, polyvinyl caprolactam (PVCap), VC-713, etc. − In recent years, new kinds of KHIs have also been investigated. They are ionic liquids, − hyperbranched polymers, amino acid, − protein, ,, modified starch, compounds with synergism, , etc. However, these chemicals have some serious drawbacks, such as high price, low availability, low solubility, low cloud point, low efficiency, low biodegradability, no inhibition effect at high subcoolings (about 10 K), etc .…”