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Issue 06/2015

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From Science & Research

From Science & Research Elasticity module, tensile strength and elongation at break of the sb-PLAs were in the same range compared with commercial PLLA. The low impact strength of PLA is usually improved by the addition of plasticisers or impact modifiers. It could be shown that polybutylene succinate (PBS), a likewise bio-based aliphatic polyester, enhanced the impact strength of both sb- and commercial PLA (Ingeo 3251D). While the values of the native polymers were comparable, the notched Charpy impact strength of the sb-PLA / PBS blend was approximately 30 % higher than that of the Ingeo 3251D / PBS blend (fig. 4). Properties of sb-PLA with non-equivalent D/L ratio Two different sb-PLAs with a D/L ratio of 80/20 (sb-PLA 3 and 4 in the table) were synthesised in the same way. The materials differ in molecular weights of the PLA diols used, as is shown in the table. Both materials crystallised slower than the sb-PLAs with a D/L-ratio of 50/50, which becomes obvious by an approximately 25 K lower crystallisation temperature in the cooling run of DSC. Moreover, the degree of crystallisation is lower but nonetheless reaches 32 %. Again, no lower melting hc crystals are detected. Elasticity module (3,200 MPa) and tensile strength (65 MPa) were in the same range compared with sb-PLA 50/50 having comparable molecular weight. Injection moulding of sb-PLA The processability of the native sb-PLA 2, as well as of the respective blend with PBS, was investigated at hesco Kunststoffverarbeitung GmbH, Luckenwalde and compared with Ingeo 3251D. Using a standard injection mould of a sulphur atom from the molecule construction kit produced by Cornelsen Experimenta (fig. 5), serial production process samples were moulded. The compact sphere body with six bonding arms is considered to be geometrically demanding, in terms of filling the injection cavity. The best results were achieved with sb-PLA 2 / PBS. Injection moulding of this material resulted in defect-free parts with a good surface which could be easily removed from the mould. Furthermore, sb-PLA 2 / PBS closely approached cooling and total cycle times of established ABS types. In contrast, the native Ingeo material, as well as the respective PBS blend, resulted in parts with air inclusions and incompletely moulded bonding arms. Additionally, the latter materials required significantly longer cycle times. Further research Having demonstrated the beneficial properties of sb- PLA, as well as the general principles of a technically implementable synthesis process, our future work will focus on the further development of the process and on the development of sb-PLA grades adopted to different processing techniques (injection moulding, film extrusion, blown film production etc.) and with different material properties. The decisive parameters to be varied include molecular weight, length and ratio of the isomeric blocks, additives and blending partners. Furthermore, alternative coupling agents will be investigated. Acknowledgement The project this publication is based on was funded by the Brandenburg Ministry of Economic and European Affairs and the EU. The responsibility for the content of the publication lies with the authors. The blending with PBS by Linotech, Forst and the determination of molecular weights by PSS, Mainz is gratefully acknowledged. References: [1] M. Hirata, Y. Kimura, Structure and properties of stereocomplex-type poly(lactic acid), in: Poly(lactic acid): Synthesis, structure, properties, processing and applications, 2010 John Wiley & Sons, Inc., 59 – 65 [2] L. Fambri, C. Migliaresi, Crystallization and thermal properties, in: ibid., 113 – 124 Fig. 5: Models of the sulphur atom made from the Molecule Construction Kit of Cornelsen Experimenta 44 bioplastics MAGAZINE [06/15] Vol. 10

Naturally Compost First 30 day days 60 days 120 180 days days Excellent Heat sealability Heat resistance up to 100 C Runs well with LDPE machine *This test was conducted under natural condition in Bangkok, Thailand. Dreaming of naturally compostable bioplastic ? Here is the answer. BioPBS is revolutionary in bioplastic technology by excelling 30°C compostable and being essentially bio-based in accordance with Vincotte for OK COMPOST (EN13432), OK COMPOST HOME marks, and DIN CERTCO for Biobased Products in European Union. It is compostable without requiring a composting facility and no adverse effects on the environment. BioPBS is available in various grades, which can be applied in a wide range of end use applications ranking from paper coated packaging, flexible packaging, agricultural film, and injection molding. It provides non-process changing solution to achieve better results in your manufacturing needs, retains the same material quality, and can be processed in existing machine as good as conventional material. In comparison with other bioplastics, BioPBS is excellent heat properties both heat sealability and heat resistance up to 100 °C. 8C084/8C085 8C083 BioPBS is available in various grades that conform to the following international standards for composting and biobased. For more information PTTMCC Biochem : +66 (2) 2 140 3555 / MCPP Germany GmbH : +49 (0) 152 018 920 51 / MCPP France SAS : +33 (0) 6 07 22 25 32 / 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

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