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Turunc O.,University of Potsdam | Turunc O.,Emden Leer University of Applied Sciences | Meier M.A.R.,University of Potsdam
Macromolecular Rapid Communications | Year: 2010

Thiol-ene additions of methyl 10-undecenoate, a castor oil derived renewable platform chemical, were studied with the goal of preparing a set of renewable monomers. Good to excellent yields were obtained for these solvent and initiator free thiol-ene additions. The resulting monomers were then polymerized using TBD as a catalyst, to linear as well as hyperbranched polyesters that also contain thio-ether linkages. All thus prepared polymers were fully characterized (NMR, GPC, DSC, and TGA) and the results of these investigations will be discussed within this contribution. The thermal analysis of these polymers revealed melting points in the range from 50 to 71°C. Moreover, no significant weight loss was observed below 300°C. Clicking renewable resources: The castor oil derived platform chemical methyl 10-undecenoate is a very suitable starting material for thiol-ene click reactions. Different functional groups can thus be introduced in an efficient manner to yield renewable monomers. Their polymerization leads to plant oil derived polyesters with good thermal properties, which could probably substitute existing fossil resource based materials. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Vinagre M.,Autonomous University of Madrid | Munoz B.,Emden Leer University of Applied Sciences
Language Learning and Technology | Year: 2011

Recent studies illustrate the potential that intercultural telecollaborative exchanges entail for language development through the use of corrective feedback from collaborating partners (Kessler, 2009; Lee, 2008; Sauro, 2009; Ware & O'Dowd, 2008). We build on this growing body of research by presenting the findings of a three-month-long research project that explored the impact of peer feedback on the development of learner accuracy. Our aim was to study participants' attention to form and the relative effectiveness of error correction strategies. In order to do so, we organised an e-mail exchange between seventeen post-secondary learners of Spanish and German. Data consist of exchanges between the five dyads who completed the full three-month project. As suggested by Vinagre and Lera (2008), analysis of these data indicate that despite frequent use of error correction, the use of remediation led to a higher percentage of errors recycled and was more conducive to error recycling in later language production. © 2011. Source

Mutlu H.,University of Potsdam | Mutlu H.,Emden Leer University of Applied Sciences | De Espinosa L.M.,University of Potsdam | De Espinosa L.M.,Max Planck Institute of Colloids and Interfaces | Meier M.A.R.,University of Potsdam
Chemical Society Reviews | Year: 2011

Two decades have passed since the metathesis polymerisation of α,ω-dienes was successfully demonstrated by the group of Wagener and the term acyclic diene metathesis (ADMET) polymerisation was coined. Since then, the advances of metathesis chemistry have allowed to expand the scope of this versatile polymerisation reaction that nowadays finds applications in different fields, such as polymer, material, or medicinal chemistry. This critical review provides an insight into the historical aspects of ADMET and a detailed overview of the work done to date applying this versatile polymerisation reaction (221 references). © 2011 The Royal Society of Chemistry. Source

Turun O.,Karlsruhe Institute of Technology | Turun O.,Emden Leer University of Applied Sciences | Meier M.A.R.,Karlsruhe Institute of Technology
Green Chemistry | Year: 2011

The increasing need for biodegradable polymers in medical applications, attempts to use renewable resources instead of fossil resources for material synthesis, and highly efficient polymerization methods that meet the requirements of green chemistry draw attention to fatty acid-based biodegradable polymers. In the present study, we have prepared a set of anhydride and ester functional biodegradable polymers from undec-10-enoic acid via ADMET polymerization reactions and/or thiol-ene click reactions. The efficiency of these polymerization methods and the thermal, as well as hydrolytic, stability properties of the polymers were evaluated and compared to each other. The results reveal that the polymers exhibit melting points in the range 44-58°C, which is higher than physiological temperature, and that polyanhydrides degrade considerably faster in solution than structurally similar polyesters. © 2011 The Royal Society of Chemistry. Source

Turuncc O.,Karlsruhe Institute of Technology | Turuncc O.,Emden Leer University of Applied Sciences | De Espinosa L.M.,Karlsruhe Institute of Technology | Meier M.A.R.,Karlsruhe Institute of Technology
Macromolecular Rapid Communications | Year: 2011

An increasing number of reports on the syntheses of carbohydrate- and plant oil-based polymers has been published in ongoing efforts to produce plastic materials from renewable resources. Although many of these polymers are biodegradable and this is a desirable property for certain applications, in some cases non-degradable polymers are needed for long-term use purposes. Polyolefins are one of the most important classes of materials that have already taken their places in our daily life. On the other hand, their production relies on fossil resources. Therefore, within this contribution, we discuss synthetic routes toward a number of polyethylene mimics derived from fatty acids via thiol-ene and ADMET polymerization reactions in order to establish more sustainable routes toward this important class of polymers. Two different diene monomers were thus prepared from castor oil derived platform chemicals, their polymerization via the two mentioned routes was optimized and compared to each other, and their thermal properties were investigated. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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