The plastics that are byproducts of the petroleum industry have been banned by many governments because of its harmful way of production and non-biodegradable nature. There are a few companies that have started thinking of producing bioplastics. Some of the manufacturers have tried making products made of materials that can be recycled. Most of them have made use of already used products but then very little have been recovered after degradation. One of the main motivations to look into bioplastics is the inability of the plastic made from petroleum to degrade at a reasonale pace. These plastics take more than a 100 years to degrade which causes many longterm harmful effects on our environment.
For the production of bioplatics starch based polymers which are polysaccharides having repeated glucose units are employed. These glucose units in turn have glucosidic linkages in the 1-4 positions of carbon. Usually it is found that the number of glucose units vary from 500 to 2000 for different types of plant species like corn, potatoes and wheat. The two major molecules of starch are amylopectin and amylase. The alpha linkage of amylase is responsible for the flexibility of the polymers. The starch content in starch based biodegradable plastics varies from 10% to 90%. The more the starch content in the plastic, the better the biodgradability. Hence bioplastics are more biodegradable. Aliphatic polyesters and polyvinyl alcohols are added with starch based polymers to make it suitable for different kinds of applications and improve its performance. The process of biodegradation can occur when there is an enzymatic reaction at the glucosidic linkages that are present in between the units. This makes the chain smaller and the sugar units are splitted into monosaccharides and disaccharides. These units can be used in the biochemical pathways. The polymers that have more than 60% of starch content are perfectly and completely biodegradable. If the content of starch is less than that, the starch units behave like weak links and then it becomes a possible site for a biological attack. The polymer matrix breaks into small fragments but complete bio degradation is not possible as a result of this breakage.
Petroleum based plastics use a lot of energy but bioplastic manufacturing involves 65% less energy than conventional plastic manufacturing and this makes the bioplastic much more energy efficient. The generation of greenhouse gases is also less by 68% than the petroleum based plastics. Naturally we can say that it is more environment friendly. Bioplastic degradation will not harm the environment because it will degrade completely in a short period of time and it has no chance of leaching into the soil or any danger of toxic chemicals going into the soil. Bioplastics can also be recycled for other uses and now the production process has also become cost effective thus reducing the expense of producing the bioplastics.
The corns that are planted for the production of bioplastics are usually genetically modified. In this way the soil can get contaminated for the purpose of growing such crops and can also lead to pollution. And bioplastics that are produced from such crops have low melting points. On a warm day we may find that the bioplastic bags have melted. For the proper degradation of bioplastic it should be kept under a temperature of 140 degree Fahrenheit continuously for 10 days. If we dump it in the dustbin along with other plastic it would take really long to break down. Research is ongoing in the field of bioplastics manufacturing to produce bioplastics which are durable and cost effective as well to suit various utility purposes.