Analysis of the Test Results of Glass Transition Pressure and Conductivity of Polypropylene Under Different Pressure Conditions

A self-made high pressure experimental setup, which is used to test the compressive strain and dielectric properties of polymer materials under different pressure conditions, is described in this paper. The glass transition pressure and resistivity of polypropylene insulation material were studied using this setup. By changing the testing temperature, it was found that the glass transition pressure showed a positive correlation with temperature. At the room temperature, when the pressure increases to about 230Mpa, the material shows a remarkable glass transition characteristic. The glass transition pressure of homo polypropylene and co polypropylene were tested separately, and it was found that the glass transition pressure of homo polypropylene was significantly lower than that of co polypropylene, which was opposite to the comparison of the glass transition temperature of the two. Testing the conductivity of polypropylene at different pressures revealed a significant downward trend with increasing pressure.