An experimental study of devolatilization of nonane, xylene and 1-hexanol from molten polyethylene in a modular co-rotating twin screw extruder is described. Various modular screw designs, as well as different feed rates, screw speeds, and barrel temperatures were used. It was found possible to correlate the extent of devolatilization in different modular screw designs with a mass transfer coefficient which depends on screw speed and LDPE feed rate. The mass transfer coefficient depended on the liquid being devolatilized, being highest with I-hexanol and lowest with nonane. In addition, the values of the mass transfer coefficient were obtained through experiments on the twin-screw extrusion of PE with nonane, xylene and hexanol. Interpretations of these results are described.