Effects of rice husk filler on the mechanical and thermal properties of liquid natural rubber compatibilized high-density polyethylene/natural rubber blends

Natural rubber/high-density polyethylene (NR/HDPE) blend with rice husk (RH) filler and liquid natural rubber (LNR) as the compatibilizer was prepared using an internal mixer at 140 degrees C and 50 rpm. The reinforcing effect and compatibilizing performance of the added reagents in the composites were evaluated from the mechanical and thermal properties, and blend homogeneity. The tensile and impact strength decreased with RH loadings in the matrix, while the tensile modulus and hardness showed an opposite trend. The weak filler-matrix interaction, resulting in poor filler dispersion and large agglomerated particle size, caused those properties to decrease. However, the mechanical properties of the composites improved with the addition of NR or LNR into the matrix. The dissolution effect caused interactions between the phases, leading to an improvement in the compatibility in the blend. Changes in morphology resulted in the shift of T-g of the amorphous part of NR to higher temperatures, as observed in differential mechanical analysis (DMA) thermograms. Scanning electron microscopy (SEM) micrographs of the fractured surface had also revealed the good RH-matrix interaction and, thus, the dispersion of particles in samples with added LNR.