In the process, the particle structure of rigid PVC will change greatly, at lower processing temperatures, due to the role of heat and shear, the particles decompose into primary particles; as the temperature increases, the primary particles are partially crushed; when processing higher, the primary particles can be completely crushed, the crystal melts, the boundary disappears, forming a two-dimensional network, this process is called melting or gelation, generally known as plasticization.
The degree of plasticization is a reflection of the degree of crystallization of the product and the degree of melting of PVC primary particles, plasticization can be measured by the rheological method. The State Technical Supervision Bureau issued GB/T 10002.1-1996, with the addition of dichloromethane impregnation test to reflect the plasticization of the pipe.
The torque rheometer (plasticizer) is ideal for studying the flow, plasticization, thermal and shear stability of materials. The rheometer provides a dynamic measurement method that is closer to actual processing and allows for continuous, accurate and reliable determination of the rheological properties of materials under similar conditions to actual processing, such as the mixing of multi-component materials, cross-linking and curing of thermosetting resins, vulcanization of elastomers, dynamic stability of materials and the effect of screw speed on the processing performance of the system.