Estimation of rheological percolation threshold and influence of fibre length on properties of polypropylene/sisal fibre composites having near critical fibre length

Abstract

In this paper, the rheological percolation threshold and the hardness of Polypropylene/Sisal fibre (PP/SF) composites were correlated. Power law fit was implemented for the estimation of rheological percolation threshold. Further, the performance properties of PP/SF composites having near-critical length fibre (NCLF) and short fibre were investigated in terms of thermomechanical, rheological, and dynamic mechanical parameters. The Shore D hardness data revealed that the rheological percolation threshold of the prepared composites remained in the range of 20–30 wt% of sisal fibre. Moreover, sisal fibre had an undeniable impact on the dynamic mechanical properties of the prepared composites. Further, the rise in the onset degradation temperature by 40 °C proved the improvement in thermal stability of the prepared composites. It was also found that PP/SF composite having 20 wt% of near critical length fibre had properties equivalent to that of PP/SF composite having 40 wt% of short fibre (fibre length less then critical fibre length). • Correlation between Rheological Percolation threshold and Shore D hardness. • PP/SF composites having near critical length fibres. • Effect of fibre length on performance properties of PP/SF composites.