Optimisation of silane grafting in single screw extruder

Reactive extrusion is an attractive means of polymer processing since the shaping and reaction takes place in a single operation. Silane grafting of low density polyethylene has been achieved in a single screw extruder. The optimum conditions for silane grafting, i.e. temperature, shear rate, and silane and dicumyl peroxide concentrations, were determined on a torque rheometer and extrusion was then performed under optimum conditions. The study shows that an optimum low level of grafting/crosslinking can be introduced into polyethylene during extrusion for better mechanical behaviour and/or thermal stability without affecting the processability.