Assist Prof. Dr. Chakrit Sirisinha Thailand Young Scientist Award Year 2001   Dr. Chakrit Sirisinha has been working on polymer rheology, rubber mixing and rubber blends. For a study of mixing behaviour, it has been found that the filler dispersion (or the so-called state-of-mix) plays an important role in extrudate swell as well as extrudate surface quality. Thus, by controlling the degree of filler dispersion, not only good processability and extrudate quality, but also low mixing energy and short mixing time could be achieved. The addition of some additives such as processing oil or slipping agent could improve processability and extrudate quality via the state-of-mix. Recently, the investigation of the mixing behaviour and its role in properties of different-grade natural rubber (NR) and filler has been of interest.   As for a study of rubber blend, the results obtained reveal that filler distributes unevenly in each phase of the blend. Filler tends to reside more in the phase with lower viscosity and / or that with closer polarity to the filler, which affects significantly the mechanical properties of the blends. In addition, for the unfilled blends, the present research project aims to maximise the use of MR, and the results obtained show that phase morphology in blends influences remarkably the oil resistance in the blends between nitrile rubber (NBR) and natural rubber (NR), and those between chlorinated polyethylene (CPE) and NR. The smaller the phase size, the higher the resistance to oil of the blends.