Impact of Accelerated Weathering Conditions on Morphology and Degradation Kinetics of Polyethylene Carrying Bags

摘要

Though the importance of the production of polyethylene carrying bags could not be denied yet their abundant use, non-biodegradability and stability against light and heat have created environmental as well as waste management problems. One of the solutions to these challenges is the recycling of the polymers. Therefore, two samples of commercially available polyethylene carrying bags processed in Pakistan (Y) and Canada (E) were exposed to accelerated weathering conditions like UV light, heat and condensation processes by keeping the sample in QUV chamber for 20 days. The analyses were made before, during and after the exposure employing FT-IR, TGA. DSC and SEM techniques. The results concluded that after the exposure, the type of the polymer has been changed from HDPE to LLDPE and LLDPE to LDPE for sample Y and E, respectively. It was observed that the degradation took place due to the formation of oxygenated products and their rate was increased in term of carbonyl index with the exposure time. The per cent crystallinity was increased, whereas the activation energy, order of reaction, melting point and thermal stability were decreased with the exposure time in both the samples. SEM analyses revealed that the degradation was instigated only from the preferential sites in sample Y, while in sample E the degradation proceeded in all directions. The impact of accelerated weathering conditions was greater on sample E than sample Y which were discussed and compared in the light of variation in the concentration of additives, molecular weight and poly-dispersity in the samples.