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Kinetics of Temperature‐induced and Reaction‐induced Phase Separation Studied by Modulated Temperature DSC
Author(s) -
Pieters Ronny,
Miltner Hans E.,
Van Assche Guy,
Van Mele Bruno
Publication year - 2006
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200690026
Subject(s) - lower critical solution temperature , vitrification , phase (matter) , materials science , differential scanning calorimetry , phase diagram , isothermal process , kinetics , chemical engineering , analytical chemistry (journal) , chemistry , thermodynamics , chromatography , polymer , organic chemistry , copolymer , composite material , medicine , physics , engineering , andrology , quantum mechanics
Temperature‐induced phase separation of P(EO75‐ ran ‐PO25)/PES and reaction‐induced phase separation of DGEBA/MDA modified with PVME are studied using MTDSC as an in‐situ tool. Phase separation can be probed by the onset of an ‘excess’ contribution in the MTDSC heat capacity signal, in good correspondence with the cloud point temperature. This feature enables the complete construction of the state diagram of P(EO75‐ ran ‐PO25)/PES. The detection of phase separation‐induced partial vitrification of the high‐ T g phase (PES‐rich phase) enables to sub‐divide the LCST‐type heterogeneous region in a zone 1 (no interference of partial vitrification) and a zone 2 (interference of partial vitrification of the PES‐rich phase). This sub‐division of the heterogeneous region has drastic implications on the remixing behavior of demixed blends. In DGEBA/MDA modified with PVME, reaction‐induced phase separation accompanied by an increase in reaction rate, followed by a vitrification step of the epoxy‐amine phase can be detected in‐situ. In non‐isothermal conditions, a diffusion‐controlled reaction after vitrification and a final devitrification of the system is also observed.