Thepristine air of Delhi coerces one to move away from the hustle and bustle ofthe city as soon as an opportunity strikes. However, this implies confrontingthe inevitable demon of packing up for the journey. As soon as that dreadedhour strikes my mother conjures up a wide array of poly bags. Meticulouslysaved for centuries, they are meant to keep the soiled clothes and footwearaway. Strict instructions are given to do the same however, seldom are theyfollowed. Armed with this huge cache of poly bags, nestled deep inside thetravelling bag I feel I am combat ready for the sojourn.
This importance ofplastics in our lives could be gauged from the fact that 15,342tonnes of plastic waste is generated by India, out of which, 9,205 tonnes werereported to be recycled and leaving 6,137 tonnes uncollected and littered. Easyto manufacture and being economical, plastics have a wide range of applicationsbeing used in simple products like pens to more sophisticated machineries like spacecrafts. Despite the concerted efforts of the government and the scientificfraternity to mitigate this problem there has been no significant reduction inthe volume of the plastic waste generated. Being highly durable they do notdegrade easily and thus have myriad environmental consequences. On one hand,both the manufacture and the destruction of plastic by incineration pollutesland, water and air producing many carcinogens in the process, while on theother, consumption of plastics by marine and land animals proves to be fatal.The images of venerable cow munching through the plastic waste or washed upwaste on the beach are ubiquitous.
Although recycling the waste helps to anextent yet it was imperative to find an alternative that amalgamates theproperties of plastics that make them versatile along with making thembiodegradable. This gave the birth to bioplastics.Bioplasticscomprise of a whole family of materials withdifferent properties and applications and can be defined as the plasticsderived from renewable sources. They can be divided into two broadcategories according to European bioplastics: · Bio based plastics- plastics derivedfrom biomass sources such as vegetable fats and oils, corn starch ormicrobiota. · Bio-degradable plastics- plastics which disintegrate into organic matter andgases like CO2, etc.
in a particular time.Commonly used bioplastics are based on cellulose, starch,glucose and oil. Specific techniques are then employed to convert thesefeedstocks into thermoplastic starch, polylactic acid(PLA),poly-3-hydroxybutyrate(PLH), polyamide 11 and biopolyethylene.§ Thermoplastic starch-This is the most significant and widely used bioplastic. Starch is derived fromcrops like potato and corn.
Thermoplastic starchgenerally represents just one component of which starch based bioplastics areformed. The second part of the blend consists of water repellent andbiologically degradable polymers like polyester, polyesteramids, polyesterurethanesor polyvinylalcohols. Starch based bioplastics find their application inproducts like bags, plant pots, cutlery etc.§ PLA(polylactic acid or polylactide)- This is by far the most promising bioplastic for the near future.
Itscharacteristics resemble conventional fossil fuel based plastics. PLA is mostlyproduced by the fermentation of starch from crops like corn, wheat, sugarcaneinto lactic acid followed by polymerization. Its blends have a wide range ofapplications including computer and mobile phone casings, biodegradable medicalimplants, foil, moulds, tins, cups, bottles and packaging devices. § PHB (poly-3-hydroxybutyrate)- This is produced by bacteria processing glucose or starchand resembles petroplastic polypropylene.
It is biodegradable and haveadvantages of being resistant to hydrolytic degradation. The application of PHBblends varies from the fabrication of glues to hard rubber.§ PA 11 (polyamide11)- Produced from natural oil;this bioplastic is not biodegradable but decreases production of greenhouseemissions and consumption of non-renewable sources during its production. It isused in high-performance applications such as automotive fuel lines, pneumaticairbrake tubing, sports shoes etc. § PHA (Polyhydroxyalkanoates)–Produced by bacterial fermentation of sugar and lipids. This find its utilitymajorly in the medical industry. It’s properties include more ductility andless elasticity than other plastics in addition to being biodegradable.
§ Cellulose based plastics-which includes cellulose esters like cellulose acetate, nitrocellulose, andtheir derivatives- celluloid. § Protein based plastics-most common sources include wheat gluten and casein for the production ofdifferent biodegradable polymers.Bio-derivedpolyethylene-This is chemically and physically identical to traditional polyethylene.Ethylene can be derived from ethanol which in turn can be procured fromfermentation of agricultural feedstocks such assugar cane or corn.ADVANTAGESBioplastics offer several advantages over traditionalplastics. Some of them such as bio-based PE and PETsave onto fossil fuels as they use renewable sources for their production andthus is carbon neutral.
They can also be recycled. Moreover, biodegradabilityis another add on and provides additional means of recovery at the end ofproduct’s life and hence helps in curbing pollution to an extent. Existing properties like durability,flexibility, heat resistance etc. have been also been significantly enhanced inbioplastics.OTHER SIDE OFTHE COINBioplastics cannot be classified as a panacea for dealing with thestatus quo. Hence, it is critical to deliberate the drawbacks of usingbioplastics as a substitute to make an informed decision. Manufacturing cost ofbioplastics is higher as compared to conventional petroleum based plastics.This fundamental and formidable barrier is responsible for a low percentageshare of bioplastics in the plastic market.
PLA costs about 20 percent more andPHA is nearly double the price of traditional petroleum-based plastics. Evendeveloped countries like United States lack facilities till date that couldsegregate bioplastics from normal plastics. This implies that these wouldcontaminate the recyclable plastic waste or could end up in a landfill whereit’s decomposition under anaerobic conditions produces a greenhouse gas,methane.CONCLUSIONIt is indispensable to surmount these challengeshowever simultaneously research should be focused on finding betteralternatives. The problem of segregating bioplastics from normal waste can beovercome by color coding these environment friendly plastics.
Public awarenessis essential to avert the disposal of bioplastics in landfills where they mightcontribute to the production of greenhouse gases. Sound infrastructure shouldbe developed so as to manage the bioplastics that end up at landfill andutilize the methane produced through them to meet the energy needs preventingwastage of resources at each step. One of the major contention with thewidespread use of bioplastics is how much environment friendly are itsmanufacturing processes. Hence it is essential that the bioplastics aresynthesized in a sustainable manner where there is limited carbon footprint. Itis time that we pay heed to this issue with utmost exigency and no room forlaxity. Let’s thus pledge to act now and reduce our plastic consumption thanregret when the damage is irreparable.