Optimization of the Solid-State Shear Extrusion Process for Natural Rubber

The pulverization mechanism of low-cross-link-density natural rubber in Sold State Shear Extrusion is the objective of this work. Although the results support the rotating speed of the screw has a great impact on the produced particle size, the process has to be applied in a certain range of the temperature and normal stress depended on the material. A non-monotonic behavior between the particle size and set temperature in different heating zones were observed. The results show carbon black causes a non-monotonic behavior. Based on this observation, it is concluded that the mechanical properties of material have a great impact in the pulverization process.We also developed a Gaussian slip-link model for non-filled polymer networks. The cross-link density is the only adjustable parameter. We compared our model with theexperimental data for three different polymers and a good agreement was observed. A new method was proposed to predict the cross-link and entanglement densities independently based on our model. This model is compared to three different models based on tube and slip-link models.