Biodegradable Plastics - A Synergy of Nature and Good Sense

Introduction

The large scale use of plastics which are petroleum based and are non-biodegradable has threatened natural environment the world-over. Discarded plastic carry bags thrown all over the places has become a common sight specially in cities and rural areas. They choke drains, sewers etc. Conversion of municipal garbage wastes to useful manure through disposal by land filling has also become difficult due to presence of non-biodegradable plastic bags mixed in the garbage due to lack of proper sorting facilities at source. Thus the need of the hour is to find alternative eco-friendly bio degradable plastic materials with comparable physico-chemical properties.

According to the recent study, consumption of virgin plastics inIndia is expected to be in the range of 3 to 5 million tonnes by the year 2001 and the waste generated will vary from 1 to 2 million tonnes annually. While the consumption of plastic bags has increased manifold, of late, plastic waste management is emerging as a parallel industry with material worth crores recycled annually. But the technologies used for recycling are not environment friendly. Biodegradable polymers can be divided into two broad groupings, polymers that are designed to be directly susceptible to natural biological systems and secondly, additives designed to cause both macro fracturing of the resin with which they are blended as well as accelerated oxidative break down that breaks the molecular chain and permits direct metabolization by microbes when disposed in those environments. One approach in designing a degradable polymer has been to use in destructured or gelatinized starch. However, to make products that are not excessively moisture sensitive and can be processed into functional products, modification is necessary.

Polyster based materials, such as polylactic acid (PLA) and the microbiologically produced combination of polyhydroxy-butyrate and polyhydroxy-valerate (PHB/ PHV) are biodegradable polymers but they have processing limitations and production costs are likely to remain very high. For these reasons the most widely used system for degradable plastics is based on the second approach of designing a product which can be combined with a thermoplastic polymer to make a processible and functional plastic article that will degrade in appropriate environment. However no standard specifications or test protocol for the biodegradable plastics have been formulated. The technology for the manufacture of biodegradable plastics, which has since been commercially proven has been transferred to five different companies inIndia. It is for the first time that biodegradable plastic based on indigenous technology will hit theIndian market very shortly. The technology can be easily adopted by the existing plastic manufacturers using conventional machines.

The film possesses adequate mechanical strength and flexibility and can be processed just like normal plastics i.e. heat-sealed, printed, coloured etc. The granules and finished products can be stored almost like synthetic plastics and biodegrades under soil-burial conditions. Outdoor weathering and soil burial tests were carried out, the biodegradation time has been reported to vary from 6 months to 2 years depending on its composition and soil conditions. Tests conducted so far for toxic residue prove that the new plastic leaves no poisonous element in the soil. The biodegradable polymer developed has many end uses. The successful applications include, agricultural materials e.g. Mulchfilms, seedling pot and nursery bags for transplanting etc. everyday itemslike trash bags, carry bags for shopping etc., disposable gloves, apron and caps for use in pharmaceutical and electronic industry and also as a packaging material in numberof applications. In most part of the world, the packaging material which is not biodegradableis not permitted, thus the product is expected to benefit our exporters.

Plant & Machinery: a) Granule making - Pelletizing line, dispersion kneader, skip conveyor,dump extruder, pelletizerb) Film making - Blown film extruder Areas of Application Mulch bags or nursery bags (demand is around 6000 tonnes for Govt. afforestation programme). Disposable carry bags or garbage bags etc. Disposable aprons, gloves, caps etc. (used specially in pharmaceutical and electronic industry). Moulded articles can also be manufactured packaging in different industries and in exports.

Advantages: Plastic polybags have been banned in a number of states and cities inIndia e.g. Haryana, Himachal Pradesh, Jammu & Kashmir, Ghaziabad & Noida in UP, Chandigarh. The other states are also contemplated in doing so. In view of the above the indigenously developed bio-degradable plastic technology and the product made thereof has a great potential in near future.

Transfer Forms:The holder of the license will be provided with the process know-how document and process demonstration to manufacture biodegradable plastics. Terms and Conditions for Technology Transfer: Premium - Rs. 10 Lakhs, Royalty - 2.5% on ex-factory sales, Period - 10 years, Nature - non-exclusive, Demonstration Charges: Rs. 50.000

Main Application: Plastics Industry, Rubber Industry

Contact:

Technology Bureau for Small Enterprises
APCTT Building, Qutub Institutional Area
P.O. Box - 4575
New Delhi - 110016, India