Production of low density polyethylene (LDPE) antibacterial master batch using Ag⁺/Cu²⁺ loaded zeolite

Abstract

In this thesis the ability of ion exchange of Cu2+ and Na+ ion on zeolite was studied. The ion exchange equilibrium isotherm was plotted and showed the low capacity of Cu2+ that exchange into the zeolite (7200 ppm of Cu2+). Furthermore, the antibacterial master batch produced from the low-density polyethylene (LDPE) and an inorganic filler, zeolite-A was successfully produced by using twin screw extruder technique. The zeolite-A was impregnated with Ag+ and Cu2+ at various ratios to study the effect of antibacterial activity of zeolite-A from those formulas. Color of the master batch is blue-green for LDPE compounded Ag/Cu zeolite-A and dark brown for LDPE compounded Ag zeolite. The addition of Ag+ and Cu2+ into the zeolite-A is due to overcome the color instability of product in Ag zeolite. The scanning electron microscope (SEM) micrograph showed the well dispersion of zeolite-A in master batch. X-ray fluorescence spectroscopy (XRF) showed the better exchange ability of Ag+ compared with Cu2+ observed from the reduction of Cu2+ in the zeolite-A at the certain ratio of Ag+/Cu2+ The X-ray diffraction (XRD) graph and differential scanning colorimetry thermogram showed the reduction of crystallinity of plastic when compound with filler. The zeolite-A content in master batch was investigated by thermo gravimetric analysis (TGA) and it showed that filler was in the master batch in the vary range from 14.46% to 34.41%. The antibacterial activity test showed the negative result due to the low concentration of metal released from the master batch. However, there are one formula of master batch that can inhibit the growth of bacteria which is the master batch from LDPE compounded with Ag: Cu = 2:1 zeolite.