Analysis of Identification Methods of Polyether Tpu Film and Polyester Tpu Film

　　Here are two ways to implement the transaction from a practical perspective:1. Identification by density test method According to the method of laboratory density test.conclusion as below:Material density

　　Polyether 1.13-1.18g/cm3

　　Polyester 1.18-1.22g/cm 3

　　This operation is easier to carry out, and the steps are simple, which is the identification method that we realize in the daily life transaction. 2. Identification of polyurethane elastomers by color reaction

　　Method: (1) The TPU sample is dissolved in 5-10 ml of glacial acetic acid. If it is TPU which is insoluble in glacial acetic acid, it can be dissolved by a suitable solvent such as cold or hot. M-cresol, dimethyl hydrazine or dimethyl amide is an effective solvent for dissolving TPU. The solution of dissolved TPU is dropped into about 0.1 g of p-aminobenzyl reaction reagent, and it turns yellow after a few minutes. By hydrolyzing TPU, the ester group reacts with hydroxylamine to form hydroxamate, and then reacts with acid ferric chloride to form a deep red or purple complex salt to identify the TPU film as a polyester TPU film, and the ether compound does not exhibit characteristics. Color reaction.

　　Method: (2) About 5g of TPU was reacted with a few drops of 2mol/L potassium hydroxide in a phenolphthalein-added methanol solution, using phenolphthalein as an indicator to keep the mixture alkaline, and add a few drops of hydroxylamine hydrochloride to methanol. saturated solution. The mixture was heated (50 ° C) in a few seconds, acidified with 1 mol / L hydrochloric acid, and a ｄｒｏｐ of 3% aqueous solution of ferric chloride was added. The polyester TPU film immediately showed a characteristic purple color, which was prepared from castor oil or dimerized fatty acid. The polyester is brown or purple-brown, and the polyether TPU does not develop color.