Starch–Organo Layer Silicate Masterbatch Formulation in LLDPE–Starch–Clay Nanocomposite Processing: Changes in Transparency, Barrier, and Biodegradability

The demand for plastic packaging, including polyethylene (PE), is significantly increasing in the present time. However, the natural degradation of fossil-based conventional plastics by microorganisms is challenging due to the chemical structure, high molecular weight, and the absence of a specific chemical group. Therefore, this research aimed to develop a starch-based biodegradable material using Linear Low-Density Polyethylene (LLDPE) and Organo Layer Silicate (OLS) nanocomposite. The aim was to increase the biodegradability of PE as well as improve the transparency and barrier properties. The process was achieved using an internal mixer to combine the masterbatch of Starch and OLS, followed by the extrusion of the masterbatch and LLDPE with a starch content of 10 and 20% wt, respectively. The OLS dispersed in the nanocomposite matrix functioned as a nucleation agent. The results showed that the transparency of the 10% starch nanocomposite sample was better than the value for the LLDPE while 20% was lower. The Water Vapor Transmission (WVT) of 10% starch was also close to the value for the LLDPE; meanwhile, the addition of starch as a hydrophilic material should be able to increase the WVT value. The trend was further confirmed by the increase in the size of the starch blocklets after the burial test, both at 10% and 20% starch nanocomposite samples. Meanwhile, the biodegradation process caused by the burial tests was higher at 20% due to the experience of more weight loss by the starch. The morphology of the LLDPE–Starch–OLS nanocomposite presented through SEM images also verified that the starch experienced initial biodegradation, leading to the formation of holes. Furthermore, the FTIR results showed that the decrease in the C=O bond peak was evidence of the biodegradation associated with the starch plasticizer.