Biodegradable loose fills

Foil bags for the collection of biological waste and biodegradable loose-fill packaging materials are already in use. 

Compared to the global market for PE film applications (approximately 30,000 kt in 2007), the market for biodegradable polymers (65 kt in 2007 excluding loose fill applications) represents a small niche segment, which has been established over the last decade. The competitive advantages and market drivers of biodegradable polymers in specific applications are based on ... 

One of the first applications of biodegradable materials is based on the cooked, extruded, and expanded starch known from the food and chemical sectors (Fig. 14.23). Starch is cooked with water in the extruder and chemically modified as necessary or mixed with plasticizers, then expanded to a starch foam and dried. The extrudate is ground so that the functional properties thus created can be used in the food/chemicals sector. The foamed, cut, and dried extrudate is the end product for loose-fill packaging applications. The degree of expansion is a measure of the foam texture. It increases strongly with product temperature at the die, helped by a higher specific mechanical energy input. However, both measures increase the water-solubility of the product. 

Excluding loose-fill packaging, which is a relatively more mature sector for starch-based biodegradable polymers, global market tonnage in 2005 is 71,700 tonnes and the compound annual growth rate for the period 2005-2010 is projected to be 20.3%. 

Starch-based materials represent the largest class of biodegradable polymer with 44,800 tonnes (including loose-fill foam packaging) consumed in 2005. Excluding loose-fill, starch-based materials amounted to 21,700 tonnes in 2005. Polylactic acid (PLA) is the second largest material class with 35,800 tonnes in 2005, followed by synthetic aliphatic-aromatic copolyesters with 14,000 tonnes. The embryonic PHA category amounts to around 250 tonnes. 

Packaging is the largest market for biodegradable polymers in Asia Pacific with 44% of market volume in 2005. Bags and sacks is the second largest market with 21% followed by loose-fill packaging with 15%. 

Table 5.2 shows global consumption of starch-based biodegradable polymers, excluding loose-fill, by major world region for the years 2000, 2005 and 2010. 

Loose-fill packaging was one of the first successful areas of application for starch-based biodegradable polymers. Loose-fill starch-based foam is used for packaging consumer products as an alternative to polystyrene and polyethylene. While, biodegradable plastics have made some inroads into these markets, the future prospects for their growth in loose-fill are not so exciting as they are in some other areas of packaging. 

If starch is modified by partially fermenting it, or esterifying or etherification, the resulting material can be extruded by adding plasticizers. Starch-based plastics are readily biodegraded. In most cases, the polymers are also water-soluble. Several suppliers now offer thermoplastic starch. Major markets include soluble films for industrial packaging, films for bags and sacks, and loose fill. 

The Role Of Life-Cycle-Assessment For Biodegradable Products Bags And Loose Fills... 

As the biodegradable Mater-Bi loose fills can be obtained by using a conventional extruder, Novamont SpA evaluated their LCA to find the most ecologically favourable way for their production. The production of loose fills from granules directly at the customer s site, turned out to be most convenient as it minimized the transportation costs. ... 

Green plastics comprise only a very small part (less than 1%) of today s plastics. They do, however, make up a significant part of some specialty, niche markets starch-based loose-fill packaging now constitutes 30% of the loose-fill packaging market. The plastics described here are those currently commercially available, and are limited mainly to those available in the United States. Manufacturers are named only for illustrative purposes the list is not intended to be comprehensive. The plastics materials are described generically, with respect to the major polymer constituent(s) for each generic type there are likely to be many specific formulations. Brief mention is made, at the end, of some materials that have been studied in the laboratory. Biomedical applications are described separately (see Biodegradable Polymers, Medical Applications). 

Application of food extruders gives much better results in processing of starch-based materials than conventional plastic extruders due to the plant origin of the biopolymer. Most of the experimental works which apply extmsion-cooking for the production of starchy loose-fill foams started in the Department of Food Process Eng., Lublin University of Life Sciences in 2012. Their objective is to achieve commercially acceptable biodegradable products based on locally produced potato, corn- and wheat starch, which can replace popular expanded polystyrene loose-fill foam products. Results of the first phase of this study are presented in their work (Mitrus and Moscicki 2014). 

The market of starch-based biodegradable plastics has the second largest share, in terms of volume, with the main applications being represented by compost bags, shopping bags, loose-fill packaging and mulch films. 

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