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05 | 2010

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40 30 Normalized Equivalent CO 2 emissions Stress (MPa) 20 10 0 0 50 100 150 200 250 300 Strain (%) PEBAX ® Rnew 70R53 PEBAX ® 7033 Figure 4 Tensile test at 23°C of 70 Shore D hardness Pebax, based on PA12 (7033, blue) and PA11 (70R53, green) Resiliency (kJ/m²) 140 120 100 80 60 40 20 0 Temperature (°C) PEBAX ® Rnew 70R53 PEBAX ® 7033 Figure 5 Impact strength (notched Charpy) depending on temperature for 70 Shore D Pebax grades based on PA12 (blue) and PA11 (green). Normalized fossil Energy 120 100 80 60 40 20 0 120.0 100.0 80.0 60.0 40.0 20.0 Comparison of Normalized Fossil Energy Requirement 97 74 69 7033 70R53 7033 70R53 Industrial Scenario 1 Equivalent CO 2 emision -32% 50 -29% 100 100 71 Industrial Scenario 2 -25% 75 Having an amide / methylene ratio very close to PA12, and thus very similar solubility parameter, allowed the polymerisation of PA11 based Pebax copolymers to run as smoothly as with PA12 based ones. Moreover, the substitution of PA12 blocks by PA11 blocks in the Pebax formula did lead to significant improvement of the mechanical properties. Indeed, as can be seen during a tensile test, PA11 based Pebax show greater elasticity, with no observation of yield. Creep resistance is also improved. When cold properties were assessed, a major differential in the ductile – fragile transition could be noted for one of the most rigid grade, having a Shore D hardness of 70, with a shift by almost 10°C. All these results mean that the cristallinity of PA11 blocks in Pebax is the same as that of the homopolymer and the gain in mechanical strength was validated successfully in very demanding ski boot applications, hence the development of a new eco-designed range. An Eco-designed product On top of its mechanical advantages, PA11 has also the particularity to lean on the chemistry of Amino-11, which is a unique monomer produced from natural vegetal oil. This natural vegetal oil comes from a non-edible crop, castor oil, and thus does not compete with food production. The use of a PA of renewable origin indeed allows a significant improvement in the environmental balance of Pebax, as shown below. The graph on the left quantify the environmental gain from the synthesis of the Pebax Rnew 70R53 grade, containing about 89% carbon from renewable origin. Calculated ‘from cradle to granules’ according to ISO 14040-14043, the two calculations (scenario 1 and scenario 2) correspond to two industrial production lines. It can be seen that using this innovation helps reduce the amount of fossil energy required for the synthesis by 29% (compared to the same product but made from fossil materials), and the amount of CO 2 equivalent released by 25 to 32%. What about subsequent developments ? It should be noted that, although the polyamide rigid block has been successfully replaced by a block of renewable origin, the same does not apply to the flexible block. For the latter, there was no renewable alternative to PTMG when the project was launched. To gain the few remaining percents, studies are now looking into the substitution of PTMG by a bio-sourced grade. 0.0 7033 70R53 7033 70R53 www.arkema.com Industrial Scenario 1 Industrial Scenario 2 Figure 6 Eco-profile of 70 Shore D hardness Pebax based on PA12 (7033) or PA11 (70R53). 48 bioplastics MAGAZINE [05/10] Vol. 5

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