| 摘要 |
PURPOSE: A method for measuring the pH values of a solvent for carbon fiber is provided to confirm the existence of byproducts from the collecting distillation of the solvent for the carbon fiber, dimethyl sulfoxide. CONSTITUTION: A method for measuring the pH values of a solvent for carbon fiber includes a process which contacts a pH reactive dye with the solvent for the carbon fiber. The color of the dye is changed by contacting the dye with the solvent according to the pH value of the solvent. The dye is one or more selected from phenolphthalein, methyl red, and thymol blue. A piece of paper dyed with the dye is used for the method. The solvent for the carbon fiber is dimethyl sulfoxide. The dimethyl sulfoxide is capable of being re-used by refining the waste liquid of the dimethyl sulfoxide based on a vacuum distilling process. The existence of byproducts from the dimethyl sulfoxide is confirmed based on the pH value of the solvent. |
