engleski

Polyethylene/nanoclays/zeolite nanocomposites in food packaging application

Many food products can be subjected to contamination by undesirable microbes (fungi, yeast bacteria) and chemical and mechanical changes. In order to prevent or impede such contamination, novel packaging technologies are continually being developed to prolong the shelf- life and improve the safety and properties of fresh foods. Food packaging therefore plays a significant role in the food supply chain and is an integral part of both food processes and supply. Polymers such as low-density polyethylene (LDPE) constitute a majority of primary packages for foods and beverages and a great deal of research has been devoted to the development of active polymer packaging. Nanoparticles are nowadays used in the production of food packaging, which improves the barrier properties and/or reduces the contaminant concentration to assure safety of food. Polymer nanocomposites are mixtures of polymers with inorganic or organic nanofillers that are uniform dispersed at nanolevel. The very large matrix/filler interfacial area changes the molecular mobility, the relaxation behavior and the consequent thermal and mechanical properties of the material. In this work low density polyethylene (LDPE) containing zeolite(T-MAZ 7), nanoclay (Cloisite 20A)and calcium carbonate nanofiller was studied. Polyethylene nanocomposites were prepared by extrusion on twin screw extruder and the determination of mechanical properties (tensile strength and elongation at break) of films that were prepared by pressing at 190 °C has been done. Thermal properties were performed by thermogravimetric analysis (TGA) and measurement were carried out on a TA Instruments Q500 in a nitrogen flow rate of 100 ml/min at heating rate of 5°/min in temperature range from 25 to 550 °C. The results have revealed that the samples containing zeolite and nanoclay have increased thermal stability and mechanical properties of polyethylene nanocomposites in comparison to samples prepared only with zeolite.

low density polyethylene; mechanical properties; packaging materials; thermal properties

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