Abstract: In order to provide a scientific basis for improving paraffin properties and its application, the digital instrument of melting point and universal material machine are used to study the melting point and strength of the paraffin-stearic acid system. The mechanism is also discussed with infrared spectroscopy. The result of experiment indicates stearic acid has some effect on paraffin melting point. When the content of stearic acid is lower than 40 wt %, the melting point of paraffin decreases with the increase of stearic acid addition, however, when the content of stearic acid is in the range of 40 wt% to 100wt%, the melting point increases, stearic acid has positive effect on strength of paraffin, especially, when the content of stearic acid is in the range of 0 to 10wt%, the strength of paraffin increases rapidly, and the strength growth rate reaches 32.56%, the reason is that the stearic acid wipes out the bubble in paraffin and the paraffin becomes more uniform. According to infrared spectroscopy, there is a lot of resemblance between paraffin and stearic acid, so they can fuse together at any proportion; in industrial application, less than 20 wt% stearic acid should be reasonable in order to increase the strength but not decrease the melting point too much.

Key words: paraffin, stearic acid, strength, melting point, infrared spectroscopy