526 Novel food packaging techniques of the nanocomposite material are improved and can be adjusted by varying the water content. Clay will decrease the water permeability to some extent (maximal with a factor 2). Clay will reinforce the starch blends only when it is fully exfoliated Hot pressed films made out from material indeed showed a great advantage compared to films made from pure thermoplastic starch. Ordinary TPS evaporates water very quickly upon ageing. Figure 24.2a shows a photograph of a hot pressed film of pure thermoplastic starch(after ageing the granulates for three hours at room temperature following the extrusion step). The apparent morphology indicates that it is not possible to form a true film any more. In contrast Fig. 24. 2b shows a hot pressed film of a starch/clay nano-composite Transparent and homogeneous films can be formed which show an increased mechanical stability and toughness as well 24.4 Legislative issues It is important to remark that biodegradability and compostability are different concepts. While biodegradation may take place as a result of the disposal of a material in landfills, composting usually requires a pre-treatment of municipal solid waste; it is necessary in fact to remove all bulky non-compostable items before beginning the composting process, separating organic from inorganic waste. Moreover, before composting other steps are necessary: particle size reduction. magnetic removal of metals, moisture addition and mixing. Under ideal conditions the decomposition of organic material can take 30 to 60 days International Standards Research(ISr) at the request of ASTM studied the performance of biodegradable plastics in full-sized composting facilities and under laboratory conditions. The ISR work determined that plastics needed to meet three criteria to be compostable. According to this standard ASTM D6400 they must be able to 1. demonstrate inherent biodegradability at a rate and degree similar to natural biodegradable polymers 2. disintegrate during active composting, so that there are no visible, distinguishable pieces found on the screens 3. have no ecotoxicity nor impact the ability of the resultant compost to support microbial and plant growth. 5 A standard world-wide definition for biodegradable plastics has not been established, nevertheless all the definitions already in place (ASTM, CEN, Iso) correlate the degradability of a material to a specific disposal environment and to a specific standard test method which simulates this environment in a time perio which determines its classification. The European Parliament on 20 December 1994 adopted a directive(94/62 EC) in order to harmonise national measures concerning the management of packaging and packaging waste, to provide a high level of environmental protection and to ensure the functioning of the internalof the nanocomposite material are improved and can be adjusted by varying the water content. Clay will decrease the water permeability to some extent (maximal with a factor 2). Clay will reinforce the starch blends only when it is fully exfoliated. Hot pressed films made out from material indeed showed a great advantage compared to films made from pure thermoplastic starch. Ordinary TPS evaporates water very quickly upon ageing. Figure 24.2a shows a photograph of a hot pressed film of pure thermoplastic starch (after ageing the granulates for three hours at room temperature following the extrusion step). The apparent morphology indicates that it is not possible to form a true film any more. In contrast Fig. 24.2b shows a hot pressed film of a starch/clay nano-composite. Transparent and homogeneous films can be formed which show an increased mechanical stability and toughness as well. 24.4 Legislative issues It is important to remark that biodegradability and compostability are different concepts.2 While biodegradation may take place as a result of the disposal of a material in landfills, composting usually requires a pre-treatment of municipal solid waste; it is necessary in fact to remove all bulky non-compostable items before beginning the composting process, separating organic from inorganic waste. Moreover, before composting other steps are necessary: particle size reduction, magnetic removal of metals, moisture addition and mixing. Under ideal conditions the decomposition of organic material can take 30 to 60 days. International Standards Research (ISR) at the request of ASTM studied the performance of biodegradable plastics in full-sized composting facilities and under laboratory conditions. The ISR work determined that plastics needed to meet three criteria to be compostable. According to this standard ASTM D6400 they must be able to: 1. demonstrate inherent biodegradability at a rate and degree similar to natural biodegradable polymers 2. disintegrate during active composting, so that there are no visible, distinguishable pieces found on the screens 3. have no ecotoxicity – nor impact the ability of the resultant compost to support microbial and plant growth. 15 A standard world-wide definition for biodegradable plastics has not been established, nevertheless all the definitions already in place (ASTM, CEN, ISO) correlate the degradability of a material to a specific disposal environment and to a specific standard test method which simulates this environment in a time period which determines its classification. The European Parliament on 20 December 1994 adopted a directive (94/62 EC) in order to harmonise national measures concerning the management of packaging and packaging waste, to provide a high level of environmental protection and to ensure the functioning of the internal 526 Novel food packaging techniques