PRESSURE SHEAR PULVERIZATION (PSP) PROCESS FOR THERMOPLASTIC AND THERMOSET WASTE

摘要

A novel process of pulverization known as Pressure Shear Pulverization (PSP) process has been developed for thermoplastics (PE, PP, PS, PVC, PA, PET and/or their mixtures), thermosets (polyurethanes and phenolics), composites, and various blends (thermoplastics and paper). PSP is a proprietary, non-extrusion process and is realized inside a specially designed pulverization head. It is very different from cryogenic grinding, various versions of solid state shear extrusion (SSSE), and other size reduction processes. PSP has several advantages, namely, high output, low specific energy consumption, and low cost of pulverization head. PSP process is capable of producing coarse to very fine particles by manipulating the processing parameters. This paper deals with the development of pulverization of pre-consumer cross-linked LDPE foam waste and LDPE/Paper mixture by PSP process. As a model system, the processibility and properties of virgin LDPE have been studied. Physical properties of LDPE foam waste and polymeric powder have been determined and compared to understand the behavior of polymer under the combined action of thermally and mechanically induced stresses. Lab-scale and pilot-scale PSP machines have been designed and constructed.