A process for the production of virtually full density polyolefin suitable for further processing by drawing to form a high tenacity, highly oriented polyolefin sheet comprising: a) feeding a metered amount of polyolefin powder into the nip between two heated calender rolls; b) rolling the powder through the nip under these conditions until a coherent sheet of polyolefin is produced. According to a highly preferred embodiment, initially, the nip is set at a gap smaller than the size of the smallest polyolefin powder particle and at a temperature above the melting point of the powder and once a coherent sheet of polyolefin exits the nip the temperature in the nip is lowered to a temperature below the melting point of the polyolefin powder and the gap increased to a desired level above the thickness of the largest powder particle.