Berlin 2015 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 46: Flow-Induced Structures in Complex Fluids - Part II (joint session CPP/ DRG, Deutsche Rheologische Gesellschaft/ DY)

DY 46.5: Talk

Thursday, March 19, 2015, 10:30–10:45, C 264

Flow-induced crystallisation of polylactides — •Dietmar Auhl, Nils Leone, Yogesh Deshmukh, and Sanjay Rastogi — Maastricht University, Maastricht, The Netherlands

Polylactides (PLA) obey like many biopolymers a relatively poor crystallisation behaviour and are therefore difficult to process. In addition, PLA grades may vary in D,L-enantiomer distribution and form a stereocomplex, which significantly affects the crystallisation as well as final properties or product performance. Therefore, various routes are employed to control and improve the formation of crystal domains further to optimisation of processing conditions, e.g. chain modifications, addition of plasticisers or nucleating agents [1]. In this study, the crystallisation behaviour and morphology of such different PLA grades has been investigated in detail by rheo-microscopy with polarised light imaging as well as rheo-scattering for a broad range of thermo-mechanical histories and superposed to calorimetric data from thermal analysis. The comparison of experiments and molecular theory both highlight the flow-induced effects on polymer chains of initially equilibrated Gaussian conformation that enhance the crystallisation process, for which the total deformation and rate in relation to the time scales of molecular motions are decisive. [1] Saeidlou, S.; Huneault, M. A.; Li, H.; Park, C. B. Prog. Polym. Sci. (2012) 1657.