A lack of degradability and the closing of landfill sites, as well as growing water and land pollution problems, have
led to concern about plastics. With the excessive use of plastics and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. Awareness of the waste problem and its impact on the environment has awakened new interest in the area of degradable polymers. The biodegradation of five different types of commercial bioplastics available on the market as agricultural mulch film (Bioflex, Ecoflex, Mater Bi, Chitosan and Bi-OPL foil) was evaluated under different soil
types (Sandy, Sandy Loam and Loamy soil) to study the material stability and life expectancy, and to establish which was better to be used in the production of biodegradable drip tubes for drip irrigation system. Weight loss, tensile strength (TS) loss and loss of percentage elongation (%E) were measured in 0, 1, 2, 3, 4, and 5 months. Bi-OPL appeared to possess a high resistance to soil types, as indicated by lower changes in tensile strength, weight losses and with maximum 26% decreased in
elongation at break. At the end of the experiments, Chitosan films were completely degraded in all soil types and both surface and subsurface positions. The starch contained in Mater Bi samples was degraded after 60 days with 4% weight losses and leads to 3% observed losses in tensile strength. Weight losses of Ecoflex and Bioflex were greater after three months (more than 30%) than that previously (5% to 10%). The tensile strength of both Ecoflex and Bioflex films decreased about 4% and 3% respectively in loamy soil and loamy sand soil by Week 12, More than 40% of the elongation capacity of the films were lost by Month 3 in both soil types. The decrease of %E in both films was slightly faster in loamy and loamy sand soil than in sandy soil. |
