Investigation of Biodegradation Speed and Biodegradability of Polyethylene and Manihot Esculenta Starch Blends

Over 350 million tons per year of conventional plastics is produced from petroleum currently and this amount is expected to rise exponentially in the near future. Proper disposal of these products has caused a great problem for the waste management industry and as a result, there is a significant negative impact on the environment. As a matter of fact, in order to reduce the environmental impact of plastics, some products obtained from agriculture (like starch) are used as polymer blend with synthetic plastics. This study shows that Manihot esculenta can be blended with polyethylene to form a partially degradable polymer. The processing conditions and sample formulations are shown to significantly affect the structure of the polymer which has a concomitant effect upon the degradation ratio as well as the degradation rate. Six samples in all were produced by varying composition of the blend between Low-density Polyethylene and Manihot esculenta using glycerol and water as plasticiser. These samples were buried in soil and the degradation ratios and rates were studied within a period of 28 days. Results showed that these produced biopolymers are environmentally compatible and bio-degradable. The rate of biodegradation in soil of these biopolymer samples varied largely. The polymer blend with 80% LDPE (20 CaS) by weight had the most regular weight loss over the period of the study. Under the conditions the study was carried out, polymer blend 20 CaS also had the steadiest rate of degradation. Hence 80% LDPE (wt.%) blended with Manihot esculenta starch is the optimal ratio with regard to the degradability of biopolymer in sandy-loam soil

Environmental Impact on Biodegradation Speed and Biodegradability of Polyethylene and Zea Mays Starch Blends

Several studies projected that by year 2025, 4.3 billion urban residents will be generating about 2.2 billion tonnes of municipal solid waste per year, over 10% of which will be plastics. The landfills in Nigeria are uncontrolled and do not conform to the international standards of similar operations elsewhere in the world; this makes the disposal of synthetic polymers in the soil even more hazardous. Due to the availability and relative inexpensiveness of Zea mays in Nigeria, this study explores the use of this natural polymer, blended with low density polyethylene (LDPE) as an alternative to synthetic plastics. Biodegradability of the biopolymer blend was observed while buried in loamy sand soil with properties similar to the soil found in the general area of the study. The results showed that a polymer blend with 50% LDPE (50 CoS) by weight had the most uniform weight loss over the period of the study. Under the soil conditions given in the study, 50 CoS also had the steadiest rate of degradation. Hence 50% LDPE (wt.%) blended with Zea mays starch is the optimal ratio with regard to the degradability of biopolymer in loamy sand soil Ota, Ogun State, Nigeria