A kneader can be used for mixing additives into a thermoplastic material or for characterizing the effects of processing additives. The equipment used is a ThermoElectron Rheomex OS – Haake RM600 with a variety of rotors, such as z-blade, Banbury and Roller. The kneading process is monitored by recording data such as temperature, torque and energy use. The kneader can be heated to a maximum temperature of 400°C. Unlike the compounder, which involves a continuous process, the kneader processes batches of approx. 50 grams. Once a good recipe has been developed, it can be subjected to optical, thermal or mechanical characterization.