Abstract: The interaction between components of crude and pour point depressant has been studied 6y the means of infrared spectra. From experiments , the following conclusions have been obtained that hydrogen bonds have been formed between polar groups of pour point depressant and those of asphalt. High molecular chain of pour point depressant would turn and distort so that plane molecular structures of asphalt decrease to overlap and the amount
、of asphalt polymers decreases. }On the other hand, hydrogen bonds have been formed between polar groups of pour point depressant and those of resin. High molecular chain of pour point depressant would turn and distort so that the amount of micelles of resin decreases. The pour point of crude is mainly determined by the content and component of wax, resin and pour point delitessant may take patt in the crystal course of wax so that the dimensions and shapes of wax crystals can be changed, and the pour point of crude is depressed.

Key words: pour point depressant, components of crude, mechanism of pour point depression