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Deformation‐Induced Color Changes in Melt‐Processed Polyamide 12 Blends
Author(s) -
Lavrenova Anna,
Holtz Adrien,
Simon Yoan C.,
Weder Christoph
Publication year - 2016
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.201500403
Subject(s) - excimer , materials science , polyamide , monomer , fluorescence , chromophore , deformation (meteorology) , polymer , composite material , photochemistry , optics , chemistry , physics
Blends of polyamide 12 and small amounts (0.15–1 wt%) of the excimer‐forming fluorescent dye 1,4‐bis(α‐cyano‐4‐octadecyloxystyryl)‐2,5‐dimethoxybenzene (C18‐RG) are produced by melt‐processing. While green monomer fluorescence from well‐individualized chromophores is observed at low dye concentration (0.15%), higher dye concentrations lead to aggregation of the dye so that the emission characteristics are dominated by red excimer fluorescence. Upon mechanical deformation of samples with appropriately selected dye content (0.25 wt%), a pronounced mechanochromic effect can be observed, which manifests itself through a mechanically induced transformation from excimer‐dominated to monomer‐rich emission. The monomer to excimer emission ratio I M /I E is increased by a factor of up to 2 in a step‐wise manner when samples are uniaxially deformed past the yield point.