Development and characterization of green polyethylene/clay/antimicrobial additive nanocomposites

Abstract

In this work, nanocomposites were developed and evaluated using high-density bio polyethylene (BPEAD)/Cloisite 20A (3 and 6%)/commercial antimicrobial additive (0,5 and 1%) containing 1% of zinc pyrithione dispersed in vinyl acetate (EVA). The samples were prepared in a single screw extruder using the melt intercalation technique and then by flat extrusion to obtain the films. X-ray diffraction (XRD) showed an increase in basal spacing and exfoliation of the structure of some films. The Fourier Transform Infrared Spectroscopy (FTIR) analysis illustrated the main functional groups for BHDPE and EVA. Thermal analysis indicated that BHDPE degradation did not change with organoclay addition, but crystallinity increased. The mechanical properties showed an increase in the elastic modulus and a decrease in maximum tensile strength. This work contributes to the development and improvement of the natural properties of BHDPE in order to enlarge its applications.

Bio-high density polyethylene films embedded with organoclay and zinc pyrithione

“…Thus, the clay decreased the degradation temperature, while the antimicrobial additive did not compromise the thermal stability, according to the percentage of residue at 550ºC (Table 2). The residue values at 550ºC were consistent with previously reported works using LDPE/EVA [25,42] and HDPE/clay [21,23] .…”

“…Three crystalline peaks on BHDPE can be verified (Figure 1-a), the most intense in the angular range at 2θ = 21.5º corresponding to the (110) plane, the other two less intense at 2θ = 23.9º and 2θ = 36.4º corresponding to the (200) and (020) plans, respectively. These data corroborate the semicrystalline of BHDPE [25] , and the peaks match the specific crystallographic planes. Cloisite 20A® has characteristic peak at 2θ = 3.40º corresponding to (001) plane associated with the galleries that are expanded by the presence of organic salt, as well as the peaks at 2θ equal to 7.06º corresponding to the (002) plane, corroborating the data reported in the literature [32] .…”

“…The T 10 of BHDPE starts around 400ºC [25,43] , and there was no variation for PB1, PB2, PC3, and PC6 systems, as shown in Figure 3 and Table 2. The clay and antimicrobial additive did not affect the film degradation temperatures (T 10 and T 50 ).…”

“…Samples of BHDPE/Cloisite 20A® and BHDPE/ Sanitized® MB E 22-70 (Table 1) were extruded in a single screw extruder AX Plásticos AX-16 (Diadema, Brazil), operating with temperature zones (200, 205, and 210 °C) and screw speed at 50 rpm, as previously reported [25] . The films were prepared in the same single-screw extruder with the same temperature profile and screw speed of 60 rpm using a flat die of 220 mm width and cylindrical cooling rollers.…”

“…The essential parameters for studying thermal properties were Tm and Xc. BHDPE had a Tm around 130°C [25,44,45] . Compositions with clay reduced of approximately 5°C for PC3 and 18°C for PC6 relative to BHDPE.…”