Major roles of blend partner fragility and dye placement on component glass transition temperatures: Fluorescence study of near-infinitely dilute species in binary blends

Christopher M. Evans, John M. Torkelson*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

We measure the glass transition temperatures (T gs) of near-infinitely dilute (0.1 wt %), well-dispersed polystyrene (PS) components in seven blend partners using intrinsic and extrinsic fluorescence. The PS T gs span a 150 °C range when PS is dispersed in partners with T gs of -6 to 150 °C. We calculate self-concentrations for PS (β self PS) of ∼0 to 0.72 via the Lodge-McLeish model, the largest range ever reported for a blend component. Our study reveals that perturbations to PS T g, which may be quantified by β self PS calculations, correlate with partner fragility rather than partner T g, with higher fragility partners resulting in higher β self PS values. In particular, for 0.1 wt % PS in poly(vinyl chloride) (PVC), the partner with the highest reported fragility but an intermediate T g, the PS T g is only weakly perturbed with β self PS = 0.72. These results indicate that partner fragility plays a key role in determining the strength of T g perturbations to a blend component. Also noteworthy is 0.1 wt % PS in poly(4-vinylpyridine) (P4VP) where the PS T g is slaved to that of P4VP (β self PS ∼ 0). Fluorescent label location on the backbone does not significantly influence the measured T g. However, the distance separating a label from the backbone is crucial in determining T g and thereby β self PS. In PVC, β self PS decreases from 0.72 to ∼0 when a dye is attached to the PS backbone by a methyl ester or butyl ester group, respectively, indicating a highly heterogeneous environment within ∼0.45 nm of the backbone.

Original languageEnglish (US)
Pages (from-to)8319-8327
Number of pages9
JournalMacromolecules
Volume45
Issue number20
DOIs
StatePublished - Oct 23 2012

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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