Foam This involves a
Foam This involves a faster and more homogeneous heating that is reflected in low energy consumption, low cycle times and in more homogeneous cellular structures. Moreover, shapedfoams can be produced (fig. 4), which means a high potential to be applied for the packaging of household-appliances (for instance). There were previous attempts to produce these kinds of foams, using pellets as solid precursors (trying to simulate the production of EPS or EPP foams) instead of a solid-sheet as in the process developed by CellMat technologies. Pellets expand isotropically during exposure to microwaves and are finally fused together forming a foamed block, which is very similar to the ones produced from EPS [5]. However, the union between the expanded pellets is weaker than in the case of these synthetic foams, hence their mechanical properties are very poor. The employment of a single solid sheet as a solid precursor constituted a step forward because the foams obtained are continuous blocks with superior mechanical performances in terms of stiffness, strength and energy absorption. Another interesting aspect of this technology is the possibility of using lignocellulosic fibres as fillers because of their good chemical compatibility with starch (both polymers are constituted by the same repeating unit: glucose). These natural fillers represent waste from the agricultural industry, which can acquire an added value when used in this application. Moreover, they are easily incorporated into the polymer matrix during the plasticization process of starch (two different processes in one single step) and induce not only an improvement of the mechanical properties but also positive cellular structure modifications such as reduction in the cell size. This microwave foaming process, in spite of its numerous advantages, requires high investments so as to be scaled-up to industry. There are industrial microwaves ovens with high potential to be employed as foaming ovens but so far, they are only used for drying purposes. For this reason, CellMat Technologies is also focused on the development of foamable compounds based on TPS and blends with other biodegradable polymers such as PLA, with similar properties to that of polyolefin-based polymers and polystyrene (polymers usually employed in the foam industry). For instance, a TPS-based compound has recently been developed, which is foamable by chemical and physical blowing agents in an extrusion foaming process. Hence, this biodegradable compound allows the use of the same industrial machinery currently employed for the production of fossil-based foams without further significant investment. www.cellmattechnologies.com References [1] A resource-efficient Europe–Flagship initiative of the Europe 2020 Strategy. http://ec.europa.eu/resource-efficient-europe/ [2] http://en.european-bioplastics.org/market/ [3] Alavi, S. H.; Gogoi, B. K.; Khan, M.; Bowman, B. J. and Rizvi. S. S. H. Structural properties of protein-stabilized starch-based supercritical fuid extrudates. Food Research International. 32, 107 – 118. (1999). [4] Moraru, C. I. and Kokini, J. L. Nucleation and expansion during extrusion and microwave heating of cereal foods. Comprehensive Reviews in Food Science and Food Safety. 2, 147 – 165. (2003). [5] Zhou, J.; Song, J. and Parker, R. Microwave-assisted moulding using expandable extruded pellets from wheat flours and starch. Carbohydrate Polymers. 69, 445 – 454. (2007). Figure 3: Heat transfer in conventional and microwave ovens. Microwave radiation Sample surface T o_ gradient Hot spots Conventional oven Microwave oven Figure 4: From EPS foams and starch foams constituted by expanded pellets to starch foamed blocks produced from solid sheets. CellMat technologies Height Diameter 34 bioplastics MAGAZINE [04/15] Vol. 10
Foam Tomorrow is NOW! First 30 day days 60 days 120 180 days days Bioplastic for Paper Coating Naturally Compost . Recycle Excellent Heat sealability Heat resistance up to 100 C Runs well with LDPE machine *This test was conducted under natural condition in Bangkok, Thailand. Paper packaging coated with BioPBS can be disposed of along with organic waste. It is compostable without requiring a composting facility, and it has no adverse effects on the environment. PBS from MCC technology (GS Pla) is certified by Biodegradable Product Institute (BPI) for ASTM D6400 in North America, by Vincotte for OK COMPOST (EN13432) and OK COMPOST HOME marks in European Union, and by Japan Bioplastics Association (JBPA) for GreenPla Mark in Japan. PBS coated paper is recyclable and repulpable at 96% yield certified by Western Michigan University. For more information info@pttmcc.com www.pttmcc.com PTT MCC Biochem Co., Ltd. A Joint Venture Company of PTT and Mitsubishi Chemical Corporation 555/2 Energy Complex Tower, Building B, 14th Floor, Vibhavadi Rangsit Road, Chatuchak, Bangkok 10900, Thailand T: +66 (0) 2 140 3555 I F: +66(0) 2 140 3556 I www.pttmcc.com
