Synthesis, characterization and properties of low density polyethylene filled with reduced graphite oxide

Abstract

Graphite based materials have become promising candidates in polyolefin nanocomposites in widening the application such as a packaging material. However, the utilization of these combination exhibits a doubt on how was the effect once heat is applied onto the nanocomposites. Herein, a systematic study has been carried out to investigate the effect of reduced graphite oxide (rGO) towards low density polyethylene (LDPE). A simple solvent casting method was carried out in fabricating low density polyethylene / reduced graphite oxide (LDPE/rGO) nanocomposites with the filler contents of 0.05 – 1 wt%. Without any modification between LDPE and rGO, several characterizations have been implemented towards the nanocomposites. Optical properties through UV-visible spectroscopy were effectively identifying the transparency of the nanocomposites, where the transparency decreased with the increased of rGO. The tensile test was also carried out in order to determine the tensile properties of the fabricated film. Thin film with 0.3 wt% of rGO content has showed highest tensile strength compared to the rest of the nanocomposites film. Gas barrier together with the dielectrical properties of the nanocomposites were studied in depth. Transmission electron microscopy (TEM) was employed to observe the dispersion and morphology of the rGO in LDPE. Further, thermal decomposition of the nanocomposites was investigated through thermogravimetric analysis (TGA). Kinetic studies on the degradation nanocomposites had concluded that Flynn-Wall-Ozawa (FWO) model is one step higher compared to Kissinger (K) model. In order to identify the elements that decomposed, gas chromatography (GC) and mass spectroscopy (MS) coupled with TGA were used to separate the evolved compounds into alkane, alkene and aromatic groups, respectively. Where, toxic gaseous will only being released out when the nanocomposites was heated up to 460 °C. With the addition of rGO in the LDPE matrix, the degradation behaviour of the nanocomposites was identifying through UV radiation. There is only slight difference on the thin film’s properties after 360 hours of UV-B radiation. Based on the analysis, the studies clearly indicated that the feasibility of incorporating rGO into the LDPE matrix had improved the optical, mechanical, thermal and dielectric properties. This has widened the application of LDPE/rGO nanocomposites in serving as a packaging material.