Relative quality test method

In the case of a general polymer, the relative molecular mass affects its performance, and the properties of the same polymer differ depending on the molecular mass. In order to understand the relative molecular mass of the polymer to be measured, the relative molecular mass is generally measured in solution. There are many methods for determination, such as end group analysis, boiling point elevation method, gas phase infiltration method, and different types of high polymers. Different test methods are used for different polymers. Different light scattering methods and ultracentrifugation sedimentation balance methods are used. And viscosity method, etc. Depending on the relative molecular mass, the viscosity method tests the relative molecular mass, the instrument is simple, the operation is convenient, and the accuracy is good. This method has been widely used in production and scientific research.

The relative molecular mass of ultra-high molecular weight polyethylene is tested by the viscosity method. The principle of testing the relative molecular mass by the viscosity method is simple: the high polymer is dissolved at high temperature in the solvent, and the viscosity is measured by an Ubbelohde viscometer. The greater the viscosity, the relative molecular mass. The higher the height. The specific method is as follows: 11-15 mg of ultrahigh molecular weight polyethylene is slowly dissolved at about (135 ± 0.5) °C with about 50 ml of a mixture of decalin and p-xylene (about 60 min), and the viscosity is measured in an Ubbelohde viscometer. The volume of the Ubbelohde viscometer is 2 ml, and the diameter of the capillary is 0.55 mm. After the viscosity is measured, the relative molecular mass is determined by a certain conversion, and the measurement method is carried out in accordance with GB1841-80. The relative molecular mass of the test article can reflect whether the selection of each parameter in the ultra-high molecular weight polyethylene molding process is reasonable. The main verified process parameters are: the rationality of the choice of antioxidant type, the temperature of the sintering temperature, the length of the sintering time, The size of the pressure and the cooling rate, etc. Antioxidants help prevent oxidation of ultra high molecular weight polyethylene
Solution; high sintering temperature, fast sintering rate, can save heating time, but the temperature can not be too high, if the temperature is too high, there will be obvious degradation, reducing the performance of ultra-high molecular weight polyethylene; likewise, the sintering time is short, there will be products in the middle Raw material, but if the sintering time is too long, the ultra-high molecular weight polyethylene will be degraded; although the cooling rate of the product will not degrade the ultra-high molecular weight polyethylene, if the cooling rate is too fast, the crystallinity of the product will be lowered, affecting the machinery. Performance and wear resistance, etc.