The shear and extensional rheology of the three grades of HPC
was studied using twin bore (RH10) precision advanced capillary
rheometer (Malvern Instruments, UK) using Flowmaster version
8.3.10 control software. A schematic representation of the instrument
is shown in Fig. 1. A common crosshead is used to drive twin
pistons at a range of speeds causing melt to flowat known flowrate
through capillary dies. Pressure drop at the entrance of each capillary
diewasmonitored by the control software. The inner diameter
and length of the barrel used were 15 and 240mm, respectivel