Plastics

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0.0004 millimeters Utilising waste material can be seen as fitting into the model of the circular economy, closing a loop in the resource, manufacture, use, waste stream. 2.4 Bio-based plastic Bio-based plastics are derived from biomass such as organic waste material or crops grown specifically for the purpose (Table 2.4). Utilising waste material can be 1.002 millimeters seen as fitting into the model of the circular economy, closing a loop in the resource-manufacture-use-waste stream. The latter source could be considered to be potentially more problematic as it may require land to be set aside from either growing food crops, at a time of growing food insecurity, or from protecting sensitive habitat, at a time of diminishing biodiversity. One current feature of biomass-based polymers is that they tend to be more expensive to produce than those based on fossil fuels (Sekiguchi et al. 2011, Pemba et al. 2014). Perhaps the two most common bio-based plastics are bio-polyethylene and poly(lactide). While most of the conventional polyethylenes are produced from fossil fuel feedstock, bio-polyethylene a leading bio-based plastic is produced entirely from biomass feedstock. Similarly, bio-polyamide11 is derived from vegetable oil and poly(lactide) is a polyester produced from lactic acid derived from agricultural crops such as maize and sugar cane. 2.5 Bio-plastics The term bio-plastic is a term used rather loosely. It has been often described as comprising both biodegradable plastics and bio-based plastics, which may or may not be biodegradable (Figure 2.3; Tokiwa et al, 2009). To avoid confusion it is suggested that the description ‘bio-plastic’ is qualified to indicate the precise source or properties on the polymer concerned. Table 2.4 Examples of common bio-based plastics Polymer Derivation Applications Cellophane Cellulose (e.g. wood, cotton, hemp) Sheets - packaging Base layer for adhesive tape Dialysis (Visking) tubing 1.0542 millimeters Chitosan Chiton Tissue engineering, wound healing, drug delivery 1.24 millimeters Rayon Cellulose (e.g. wood pulp) Threads - clothing 16 BIODEGRADABLE PLASTICS AND MARINE LITTER § most types of polyamide are derived from fossil fuels Misconceptions, concerns and impacts on marine environments 0.002 millimeters
1.002 millimeters Photo: Doug Beckers / Creative Commons 0.0004 millimeters 1.0542 millimeters Fig. 2.3 Bio-plastics comprised of biodegradable and bio-based plastics (taken from Tokiwa et al. 2009; available under the Creative Commons Attribution license). Bio-plastics 1.24 millimeters One current feature of biomass-based polymers is that they tend to be more expensive to produce than those based on fossil fuels PCL Biodegradebale plastics PBS PES PEA PHB Starch AcC PE Bio-based plastics NY11 0.002 millimeters 17 BIODEGRADABLE PLASTICS AND MARINE LITTER Misconceptions, concerns and impacts on marine environments
Page 1 and 2: Biodegradable Plastics & MARINE LIT
Page 3 and 4: Biodegradable Plastics & MARINE LIT
Page 5 and 6: Contents Abbreviations list 2 Execu
Page 7 and 8: Executive Summary The development a
Page 9 and 10: Background The objective of this br
Page 11 and 12: 1.002 millimeters Photo: Ludwig Tr
Page 13 and 14: Polymers and plastics - terminology
Page 15 and 16: Single-use plastic shopping bag mar
Page 17 and 18: Table 2.3 Common synthetic polymers
Page 19: Abbreviation Full name Common sourc
Page 23 and 24: Fragmentation, degradation and biod
Page 25 and 26: The biodegradability of polymers is
Page 27 and 28: 1.002 millimeters Fig. 3.3 Examples
Page 29 and 30: The behaviour of ‘biodegradable
Page 31 and 32: were collected from the stomach, th
Page 33 and 34: Public perceptions, attitudes and b
Page 35 and 36: CONclusions Plastic debris is ubiqu
Page 37 and 38: Moravek, S. J., M. K. Hassan, D. J.

Plastics

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