Traditionally single-screw extruders are operated in flood-fed mode, i.e.,the screw is fully filled under the hopper and takes in as much material as it can process. In addition, single-screw extruders can also be operated in starve-fed mode. By applying this mode, the screw under the hopper is partially filled. This results in a throughput, which is independent of the screw speed and is determined by the dosing rate. The starve-fed mode shows completely different processing characteristics (e.g. pressure build-up behavior, residence time, melting performance) compared to the flood-fed mode. Starve-fed mode is rarely used for single screw extrusion and experimental studies are very limited. However different studies showed significant advantages like improved mixing and melting performance. In this work we present extensive experimental research on operating starve-fed extrusion processes, down to 25% feeding rate. We compare different operating parameters like residence time, pressure build-up behavior ,and melting performance at different feeding rates and screw speeds. Additionally, and most notably we explored new developments of application for starve-fed extrusion of polyethylene materials containing a Very High Molecular Weight Polyethylene fraction (VHMWPE). VHMWPE offers several advantageous considering mechanical properties including very high impact strength and crack resistance, compared to conventional polyolefin. Pure VHMWPE has a very high viscosity, which makes it ineffective for common continuous melt processes, like compression molding, ram extrusion and sintering. The work shows that operating single-screw extruders in highly starve-fed mode significantly increases residence time and melt temperature. A combination of high residence time, high melt temperature and a very low feeding rate, results in significant elongation of VHMWPE-particles, which was not observed in literature before.