Plastics Engineering - May 2014 - (Page 25)

Kingfa is in cooperation with Xinjiang Production and Construction Corps to promote fully biodegradable mulch film in Xinjiang. cultural industry sees the widespread applications of mulch films. statistics showed that there are 300 million mu (20 million hectares) of land in china where polyethylene (PE) film is used in cultivation. the annual consumption, growing by an annual average of 10%, now exceeds one million tons. although the use of mulch film in agriculture yields more crops and brings enormous economic benefits, it also severely pollutes the ecological environment. Addressing "White Pollution" as used plastic mulch accumulates in arable land, it gradually pollutes both the ecological environment and the landscape. it obstructs crops from absorbing water and nutrients, causing the yield of some crops to drop by as much as over 20%. Plastic mulch technology, once regarded as the "white revolution" in the agricultural industry, has turned completely into "white pollution." there are currently two ways to alleviate the pollution problems caused by mulch film: through recycling and the use of biodegradable alternatives. according to the analysis and comparison of researches conducted in china and abroad, "partially biodegradable plastic mulch" (e.g., photo- and oxo-biodegradable PE film and starch-based PE film) is an ineffective solution. Film residues in the soil are in excess of more than 30% of the film consumption and then accumulate year by year. traditional plastic mulch, like photo- and oxo-degradable films, degrade easily under ultraviolet (UV) light, but the fragmented films remain underground for many years. as for starch-based film, although the starch part is partially degradable, the PE is not, leaving even more PE fragments in the soil and making the pollution problem even worse. Other types of products in the market, such as water-soluble film and liquid film are easy to dissolve in water, which means they are incapable of meeting the requirements of plastic mulch in terms of service life, heat insulation, and hydration power. thanks to their special molecular structure, fully biodegradable plastic materials remain stable during use. after its service life, such a material can ultimately be decomposed in compost, soil, water, activated sludge, and so on. it is degraded into cO2 and water by microorganisms or by enzymes inside animals' or plants' bodies. With good biocompatibility and biodegradable properties, fully biodegradable plastic mulch is an eco-friendly option to tackle the problem of film residuals. Three Major Advantages of 100% Biodegradable Films Mulch films that are made of fully biodegradable plastics have a number of advantages. First of all, the film's covering time is controllable and therefore the product can be tailored according to the region where it will be used, the natural conditions there, and the target covering time limit. after finishing its duty, the film will be fully degraded automatically. secondly, labor costs to reclaim the film after use are avoided. last but not least, the possibility of secondary pollution is ruled out as the film can ultimately be metabolized into water and cO2. Utilizing 100% biodegradable plastics is a general trend in the West nowadays. central Europe and Japan have gradually turned to these products for growing cash crops. it www.plasticsengineering.org | www.4spe.org | MaY 2014 | Plastics EnginEEring | 25 http://www.plasticsengineering.org http://www.4spe.org

Plastics Engineering - May 2014

Table of Contents for the Digital Edition of Plastics Engineering - May 2014