Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Poster: Crystallization, Nucleation and Self Assembly

CPP 19.3: Poster

Dienstag, 12. März 2013, 18:15–20:15, Poster C

Unusual crystallization kinetics in poly(1,1-dimethyl silacyclobutane) — •Junyu Li¹, Schönberger Astrid², Kuttich Björn¹, Johannes Elbert², Gallei Markus², Stühn Bernd¹, and Rehahn Matthias² — ¹Experimental Condensed Matter Physics, TU Darmstadt — ²Ernst-Berl-Institute for Technical and Macromolecular Chemistry, TU Darmstadt

The crystallization behavior of poly(1,1-dimethyl silacyclobutane) (PDMSB) with molecular weight ranging between 3.000 and 50.000 kilodalton has been studied through Small Angle X-ray Scattering (SAXS), X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). Well-defined PDMSB homopolymers with polydispersity index less than 1.2 have been prepared by living ring-opening anionic polymerization. It has been found that in the cooling process only one crystallization peak was observed by DSC, however, in subsequent heating process two obvious melting peaks appeared. SAXS results show that there is only one long range order. DSC measurements also show that when isothermal crystallization temperature T_c is low enough, there will be two melting peaks, but only one melting peak when T_c is high. The value of lower melting peak T_m1 increases with T_c, showing the increase of lamella thickness due to increase of T_c. However, the value of higher melting peak T_m2 stays constant with T_c. In addition,surface-attached PDMSB on polystyrene particle was studied. DSC results show that only one melting peak was observed independent of T_c. Based on these observations, re-crystallization is suggested to explain this interesting phenomenon.