PA66 engineering plastic is a kind of high polymer with appropriately high molecular weight. The molecular weight directly affects its physical and chemical properties such as mechanical strength and heat resistance. The method of estimating molecular weight is to determine the relative viscosity of high polymers. Therefore, in the production and manufacture of PA66 engineering plastics, relative viscosity is a very important production indicator. Viscosity measurement is very important for guiding production, stabilizing production, and ensuring product quality. Significance, how to measure the viscosity of nylon 66 in the actual production process?

The method commonly used by plastic manufacturers to determine the relative viscosity of PA66 engineering plastics is the capillary viscometer method. This method is mainly divided into three steps: sample preparation, dissolution and measurement. At 25°C, a Ubbelohde viscometer is used to measure the solvent flow The ratio between the time of passing and the passing time of the solution is the relative viscosity of the PA66 engineering plastic. In the process of measurement, the required equipment includes analytical balance, dispenser, constant temperature bath, Ubbelohde viscometer with capillary inner diameter of 1.03mm; in order to ensure the accuracy and reliability of the measurement results, it is necessary to ensure the measurement equipment and The solvent meets the measurement requirements.

In the process of melting PA66 engineering plastics with concentrated sulfuric acid, temperature control is very important. If the temperature is too low, the dissolution speed of the sample will become slow; if the temperature is too high, the sample will undergo degradation reactions during the dissolution process, resulting in a relatively low sample relative viscosity; it can be seen that the dissolution temperature will affect the relative viscosity measurement results of PA66 engineering plastics Accuracy and repeatability.