The effect of laboratory synthesized and modified layered double hydroxides on recycled and neat high density polyethylene matrix properties using stearic acid as an interface modifier

Abstract

In this research, the effect of layered double hydroxides (LDHs) as nanofillers on recycled and neat high density polyethylene (HDPE) properties was investigated. The synthesis of unmodified and modified LDHs was achieved via one-pot hydrothermal co-precipitation method at a constant pH. The nanofillers were organically modified by using sodium dodecyl sulphate (SDS) as surfactant and stearic acid (SA) as an interface modifier in order to overcome the incompatibility problems with HDPE Matrix. The nanocomposites were prepared by melt blending and compression molding with 3 and 5 wt% filler loading rate. Thermal, structural, and morphological tests were conducted to analyze the performance of the LDHs and the compatibilizing agent on the dispersion, and on the properties of the studied composites. Results revealed that 3 wt% of unmodified LDHs filler reinforced all physical and mechanical properties of the obtained nanocomposites based on recycled and neat HDPE matrix. When the weight of LDHs was increased to 5 wt%, morphological observations showed that SA has prevented the aggregation of LDHs particles and improved their dispersion into the recycled HDPE matrix. The physical and mechanical properties of the composite materials were enhanced dramatically with the addition of stearic acid as interface modifier into the recycled polymeric matrix compared to SDS intercalating which improved only the izod impact strength. The formulations of r-HDPE/3%LDH and r-HDPE/5%LDH-1%SA were found to be the ideal combinations which could provide novel mechanical applications to meet industrial requirements at higher scale.