engleski

The effect of UV irradiation on LDPE/PCL blends for fruits packaging

Nondegradable polymers as a packaging materials has bad influence on the environment, cause damage to plants, animals and along with acid rains, global warming, disappearance of plant and animal species, fertility of the soil, ozone layer it's being consider as one of the greatest environmental problem today. Low-density polyethylene (LDPE) sheets are used in food packaging because of it's good mechanical properties, easy processing and flexibility. However, the lack of LDPE as nodegradable packaging material is huge environmental pollution. Contribution of this research would be development of new, biodegradable materials which can be use in packaging fruit in fruitgrowing. In this work, the effect of ultraviolet irradiation on the properties of LDPE/ PCL blends was studied. Blends of low- density polyethylene (LDPE) and poly (ε- caprolactone) (PCL), (LDPE/PCL blends) investigated were prepared with melt mixing (compounding) in Brabender mixer under different LDPE/ PCL content (90/10, 70/30, 50/50, 30/70, 10/90 wt%). The specimens of neat polymers and LDPE/PCL blends were molded in hydraulic press. The material was exposed to UV irradiation for 30 days. The photodegradation behaviour at the exposed surfaces of LDPE / PCL blends was studied using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The E'' curves confirmed the partiall miscibility of LDPE/PCL blends. The thermal stability of the composites was enhenced with the addition of PCL and increase of the PCL content. The experimental results after UV irradiation showed that LDPE/ PCL blends undergoes both chain scission and crosslinking reactions. Chain scission reactions occurred in LDPE and for PCL crosslinking reactions predominated. The DMA and DSC studies showed that the glass trasition and crystalinity of the LDPE in blends were increased after UV irradiation. While the thermal stability of LDPE decreased after UV irradiation.

Nondegradable polymers ; packaging materials ; ultraviolet irradiation ; low-density polyethylene ; poly (ε-caprolactone

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