Photo-oxidation and biodegradation of Polyethylene nanocomposites

Polyethylene (PE) is widely used in packaging and agricultural industries because of its low cost and unique combination of properties such as high strength, light weight, water resistance, high stability and ease of fabrication. Each year a considerable amount of PE waste accumulates at landfill sites, and it takes a very long time to biodegrade. Since PE waste is not always retained in the upper level of a landfill for a long time, it can undergo very limited oxidation. In an attempt to solve the polymer degradation problem, researchers have identified a simple and inexpensive method that involves blending PE with pro-oxidants, which enhances oxidation significantly. The PE-pro-oxidant blend, known as oxo-biodegradable polyethylene, has been found to undergo oxidation rapidly but experiences very little biodegradation. This work aims to evaluate the suitability of polyethylene-layered silicate nanocomposites as a biodegradable polymer that can degrade through the oxo-biodegradation process. One of the main objectives of the thesis is to investigate the combined effect of nanoclay and a commercial pro-oxidant on the photo-degradation and biodegradation of PE. This study also investigates whether the roles of nanoclay and pro-oxidant in biodegradation can be achieved by using modified nanoclay that has been prepared by synthesising a pro-oxidant on the surface of unmodified MMT. In conclusion, nanoclay in oxo-biodegradable PE nanocomposites enhances both the photo-oxidation and biodegradation of polyethylene. However, the oxo-biodegradable PE nanocomposite that contains Co2+- PEG monolaurate pro-oxidant is the most efficient because it provides a low-cost solution to reduce PE wast