Abstract there are several types of reactors and plastic processing machines defined upon their way of functioning. reactive extrusion is a process in which the polymerization, depolymerization reaction, and several different reactions can be carried out under controlled temperature, pressure and feed. in this type of extrusion, product is allowed to flow along a continuous channel within screw and barrel where feed is properly mixed under heat and pressure; this allows more quality of product after reaction. in depolymerization reaction the material is fed through the hopper and additives are added directly along with barrel or pumped through the vent holes. the temperature of the barrel is set on to ceiling temperature which enhances the depolymerization through the thermal and chemical degradation of the polymer. there are various possibilities to enhance depolymerization such as: 1. glycolysis 2. alkylysis 3. hydrolysis 4. aminolysis 5. acidolysis, etc. the reaction depends upon the properties of the polymer. advantages of process: product purity enclosed tubular reactor temperature control easy control of process continuous/ line process efficient mixing flexible design of reactor or extruder residence time and overall process time control.