Non-Food has been very
Non-Food has been very much due to bioplastics based on PLA and used for packaging goods with a short lifetime (food packaging, waste bags, diaper backing sheets, mulch films, etc.). Here the biodegradability and the associated alternative disposal route are especially beneficial for the consumer. The demand for bioplastics for durable goods is continuously rising and will outstrip the demand for bioplastics for short life-time goods in the medium term. Since the importance of biodegradability takes a back seat in this context and sometimes is not even requested, research and development at FKuR focuses more and more on the exclusive use of renewable resources. Whereas bioplastics for packaging are indeed converted into films by means of different extrusion processes, injection moulding is the most commonly used process worldwide for the production of plastic components. Typical application fields are to be found in all industry branches. Merely as examples we can mention here automotive, construction, electronic and household articles, the furniture and toy industries as well as medical technology. Biograde ® - injection mouldable bioplastics with properties similar to polystyrene Injection mouldable bioplastics – similar to extrudable bioplastics for packaging – preferably have to be capable of being processed on conventional machinery. For injection moulding specific mechanical characteristics (demoulding) and temperature conditions (dwell time) have to be taken into consideration. Injection mouldable cellulose ester compounds from FKuR are marketed under the brand name “Biograde“. They offer the following advantages: • Up to 100 % natural resources (depending on grade) • Raw material: wood from European forests • Excellent heat distortion temperature up to 122 °C • Injection mouldable on conventional injection moulding machinery • Thermoformable on conventional equipment • Suitable for food contact • Biodegradability tested according to EN 13432 by independent organisations. The balanced properties profile is comparable to the mechanical characteristics of polystyrene (fig. 1). Biograde is extraordinarily rigid, scratch resistant and also transparent depending on the grade. Typical existing applications are shown in the photos. Moreover any kind of application made from polystyrene or any other rigid commodity plastic may be realised with Biograde. Cellulose based Bioplastics have already existed for a long time: let‘s call them Generation ZERO! www.fkur.com Elongation at break (%) 14,0 12,0 10,0 8,0 6,0 5,0 2,0 0,0 Biograde ® C 8500 CL Standard-PS 2000 2500 3000 3500 4000 4500 5000 Tensile Modules (MPa) Sources: Biograde ® C 9540 Fig. 1.: Selected mechanical properties of Biograde in comparison to standard polystyrene Biodegradable, disposable cutlery made from Biograde C 9540 [1] Tänzer, W.: Biologisch abbaubare Polymere. Deutscher Verlag für Grundstoffindustrie, (2000) [2] Eyerer, P.; Elsner, P.; Hirth, T.: Domininghaus – Die Kunststoffe und Ihre Eigenschaften. 6. Auflage. Springer-Verlag, Berlin-Heidelberg (2005) [3] Oberbach, K.: Saechtling – Kunststoff Taschenbuch. 28. Auflage, Carl Hanser Verlag (2001) bioplastics MAGAZINE [05/08] Vol. 3 29
Non-Food Proteinous Bioplastics from Bloodmeal Homogeneity Article contributed by Johan Verbeek, University of Waikato, Hamilton, New Zealand and Lisa van den Berg Granular appearance Heterogeneities Cohesive failure and increased homogeneity It is almost impossible to remember a world without plastics; however, environmental concerns over the origin, use and disposal of plastics have created a substantial effort into finding alternative solutions to these issues. Recycling is aimed at reducing the amount of virgin material required; biodegradable polymers are intended to solve the disposal and ultimate fate of polymers, while research into finding sustainable sources for polymer production is aimed at reducing the reliance on petrochemical sources. Although bioplastics sound like the perfect solution to these problems, bioplastics also have some drawbacks; most importantly the perceived competition with food production. As a result, attention is shifting to second generation bioplastics manufactured from non-potential food sources. However, one of the challenges for bioplastics is to be successfully integrated into common synthetic plastic processing routes, such as extrusion and injection moulding. Chain entanglements and secondary interactions are what differentiate synthetic polymers from other low molecular weight organic substances. Inter- and intra molecular bonds, as well as chain entanglements, prevent chain slippage leading to the superior properties of polymers. Proteins are natural biopolymers and exhibit the same behaviour. Various amino acid functional groups offer a wide range of possible inter- and intra-molecular interactions, leading to the complex structure found in proteins. This implies that successful processing hinges on the ability to manipulate protein structure. In this article thermoplastic bioplastics produced from proteins, obtained as a co-product in the meat industry, are discussed. Bloodmeal is mostly unfit for human consumption and is currently used as a low cost animal feed supplement. With more than 80% protein, it has the potential to be used as a thermoplastic biopolymer. However, during the production of bloodmeal, proteins are exposed to high temperatures, inducing aggregation and crosslinking. Cross-links are heat-stable, covalent bonds between either cysteine or lysine amino acid residues, resulting in an insoluble powder. Previous studies have claimed blood proteins not to be extrudable, failing to produce a homogenous plastic material. This offers a great challenge to its processability since the wrong conditions may lead to further cross-linking, not only leading to a non-homogenous material, but also potentially 30 bioplastics MAGAZINE [05/08] Vol. 3
