The immense popularity and durability of polycarbonate (PC), which has resulted in its large-scale production, has led to increasing concerns about waste management and its safe disposal. In addition, bisphenol-A (BPA), a monomer of PC, has faced a lot of flak in recent times from environmental activists due to the associated health risk for humans on exposure to the chemical. All these factors have fuelled the need to have a "green" solution to overcome this problem. Scientists from the Department of Biotechnology of the Indian Institute of Technology Madras have recently reported an eco-friendly way of decomposing polycarbonate. On pre-treating PC with UV light and heat and further exposing it to given types of fungi, substantial decomposition was observed post 12 months with no release of BPA. PC films supplied by Sabic Innovative Plastics, being the starting material were subdivided into 3 sets for use in the experiment. One of the sets was left untreated and used as it is and for the other two sets, the PC films were subjected to two separate types of pre-treatments. Soil sample, collected from a plastic dumpsite, was treated and its suspension was used as the inoculum. To study the actual bio-degradation process, the scientists set up the following experiment on each sample: measuring the total biomass weight, quantifying carbohydrates and measure the total quantity of proteins. Other analysis were conducted on these camples to detect and reveal the overal polymer properties evolution with and without pre-treatments as a function of time. Surface morphology, weight losses, DSC, ATR-FTIR were ran on each sample to accurately measure the effect of microorganisms attack on polycarbonate.
As per the ASTM and ISO standards, the process of Biodegradation is defined as when the polymer upon degrdation releases CO2 and H2O and becomes compostable. Simple breakdown of the polymer chains leading to lowering of MW may not be a correct representation of Biodegradation. Request to check this parameter.
posted by Amit kumar, R&D - Applied/ Formulation/ Product development at Alfanar engineering
A good study has been conducted on analyzing biodegradation mechanism of Polycarbonate, especially -- Bis phenol A ( BPA) a- carnigenic monomer for PC. Similar kind of work has also been conducted on Poly chlorinated Biphenyl (PCB's)- a known carnogenic chemical present in various paints obtained form Shipyard waste using gamma irradiation , by Sriram Institute for industrial Research , Delhi. Such study is really helpful in coping with environmental & health hazardous materials