Mixing a high-viscosity or high-molecular weight polymer melt leads to shear-induced overheating due to the large torque induced, required to unleash the polymer chain entanglements. Therefore, it is worth investigating the synergetic relationship, if any, between various physical fields in order to maximize the efficiency of the plasticization effect.

The properties of composites in the plasticization process also depend on the control of the velocity, temperature, shear, and pressure fields. Understanding the mass and heat transfer processes in a plasticization system as a function of screw configurations is essential to further develop a more effective screw design to overcome some of the existing challenges. In the past, researchers paid little attention to understand heat transfer in viscous fluid. However, heat transfer also plays a significant role in plasticizing. These studies may focus on mixing and rheology. Their results showed that mixing performance improved and extrusion pressure reduced. introduced a vibrational force field in the screw plasticization system. Besides, Jiang introduced ultrasonic plasticizing in the extruder to achieve energy saving. Diekmann analyzed the direct-drive single-screw extruders without gearing and results indicated that plasticization capacity increased in the direct-drive system. Their results showed that the plasticizing capacity improved with the decrease of power consumption in the vane extruder. proposed a novel vane plasticization system in place of screw one to create extensional stress. Based on the elongational flow and volume transportation, Qu et al. Also, the melt temperatures and pressure fluctuation reduce in the flow channel. In this way, the mixing ability improves under the condition of lower power consumption and viscous dissipation than shear flow. Rauwendaal noted a CRD mixing screw with wedge-shaped barrier region to generate elongational flow. Rydzkowski developed an autothermal screw-disc extruder to induce autothermal effect. indicated that the shearing sections like axial and spiral Maddock elements and Z-elements are often used to improve the melt homogeneity by enhancing dispersive mixing. disclosed a mixture system by combining Pin and Dulmage type screws and also reported their beneficial effect in kneading, homogenization, and ensuring stability of gas/polymer solution. Spalding introduced a distributive melt-mixing type screw equipped with an Eagle mixer in injection molding process and obtained better melting capacity and higher mixing than a conventional screw. developed a barrier-flighted screw with Maddock mixer to achieve good melting performance and low temperature and pressure fluctuations. These reconfigured screws are stated to be better than a standard one. Different from conventional screw, the new types of screw can be roughly divided into four categories: distribution screws, barrier screws, separator screws, and channel screws with variable sections. The effect of barrel configurations and screw designs on heat and mass transfer has been investigated in the past and proved unquestionably important attributes for determining temperature uniformity and mixing effectiveness in extrusion and injection molding processes. It is very important to optimize the structural parameters and working characteristics of the screw in order to enhance plasticization of polymers. In general, the temperature distribution is not uniform in the process of plasticization this is due to significant friction heating and the low thermal conductivity of polymers. In polymer processing, plasticization screw is an added unit operation that facilitates melting and homogenization of an initially heterogeneous physical system. The thermal homogeneity and stability of polymer melts in this plasticization process is the key to determine the quality of products, especially for biodegradable nanocomposites or microcellular foam materials. The nonlinear effect of polymer plasticization is a multidisciplinary engineering science problem that includes heat transfer, rheology, and flow dynamics among others. Polymer plasticization is a complex process with many uncertain variables, which involves phase transfer and viscoelastic behavior.

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