STUDIES ON MECHANICAL, THERMAL AND PERMEATION PROPERTIES OF HDPE (BLOW GRADE) WITH MICROSILICA CLAY

Abstract

HDPE is widely used in container applications. The mechanical properties and barrier properties can be further improved by the addition of reinforcements like nanoclays. But, however the cost of nanoclays are higher about Rs.5000 – 6000/kg whereas micro silica cost is economical about Rs.450-1000/kg. Hence we used micro silica of 270nm particle size in this project with HDPE blow grade.

HDPE (High density polyethylene) was melt blended with micro silica at different proportions (1, 3 & 5 wt %) by using twin screw compounding extruder. Test specimens were prepared by an injection molding machine. The containers/bottles were produced using injection- blow molding machine. The test specimens and the product were tested as per ASTM standards. The effect of micro silica on the mechanical, thermal and permeation properties were evaluated.  Tensile strength and Tensile modulus increased as the clay concentration increases upto to 1% and then decreased. Elongation at break was decreased. Flexural strength and Modulus increased up to 1 or 3wt% and then decreased. Hardness was increased. Impact strength was decreased as the clay concentration increases. HDT and VSP were increased by 10 and 2deg C respectively. The Density was increased. Shrinkage was decreased. Water absorption was decreased. The intercalation properties were studied using X-ray diffraction technique for HDPE micro silica composites.

Key words: HDPE, micro silica, mechanical, thermal, barrier properties