Bioplastics are decomposable in natural aerobic (composting) and anaerobic (landfill) conditions. This biodegradation occurs by enabling microorganism in the environment to metabolize the molecular structure of plastic films in order to produce inert humus like material which is safe to environment. The application of bio-active compounds with swelling agents ensures that, when combined with heat and moisture, they will expand the molecular structure of plastic and the bio-active compounds will be metabolized as well as the plastic will be neutralized.
Bioplastics are of various types like starch based plastic which constitute about 50 percent of the bioplastic market and currently thermoplastic starch is considered as the most important and widely used bioplastic. Polylactic acid (PLA) plastics are produced from cane sugar or glucose. The biopolymer poly-3-hydroxybutyrate (PHB) is produced by certain bacteria processing glucose or starch. It is produced on industrial scale in South American sugar industry. Transparent film is produced by it at a melting point higher than 130 degree Celsius and it can be biodegraded without residue. Currently researches are going on to introduce genetically modified bioplastic which is a great challenge to bioplastic industry.
As biodegradable plastic relies less on fossil fuel as a carbon source and also produces less net-new greenhouse emissions during biodegradation so the production and use of bioplastic is regarded as a more sustainable activity in comparison to petro plastics. Bioplastics decreases hazardous waste produced by oil-derived plastics which remain unchanged for hundreds of years and open a new era in packing technology and industry. Many studies have shown that biodegradable plastics represent a 42% reduction in carbon footprint.
The degree to which biodegradable plastics are degrading varies with temperature, polymer stability and available oxygen content. They require tightly controlled conditions to be degraded. According to the Society of Plastics Engineers over 200 million tons of plastic is annually manufactured around the world among which only USA manufactures 26 tones alone. According to EPA report 5.8% of those 26 million tones of plastic waste is recycled. Certified biodegradable plastic serves the utility of plastic e.g. light weight, resistance, relative low cost etc. with full ability to biodegrade in a compost facility. Biodegradable plastics enable composting of a much large portion of non-recoverable solid waste as they can be readily commingled with other organic wastes. This makes commercial composting of all mixed organics commercially viable and economically sustainable. The use of biodegradable plastics is an enabler for complete recovery of large quantities of municipal solid waste via aerobic composting.
By introducing biodegradable plastics solution to a world of manufacturing we will be able to aid the environment in an effective way. If we consider their cost, except cellulose most of the biodegradable plastic technology is relatively new and is currently not cost competitive with traditional plastic. In some special applications bioplastics are unbeatable because of the reason of pure material costs form only a part of the entire product cost.