Abstract
When only tightly bound poly (vinyl acetate) (PVAc) was adsorbed on silica, the plasticizer, di(propylene glycol) dibenzoate (DPGDB), was not effective in lowering its glass transition. To determine why the plasticizer was not effective, we probed the behavior of the deuterated plasticizer di (propylene glycol) dibenzoate (DPGDB-d10)/PVAc/silica system using deuterium (2H) solid state NMR and temperature-modulated differential scanning calorimetry (TMDSC). PVAc with 37% (w/w) of plasticizer/polymer was adsorbed on silica in adsorbed amounts of 2.60 and 0.76 mg PVAc/m2 silica. The dynamics of the plasticizer in the adsorbed PVAc was found to be more motionally heterogeneous than that observed in bulk samples. The NMR results provided firm evidence that when there is only a small amount of adsorbed polymer (e.g., only tightly bound polymer at less than 0.8 mg/m2), the plasticizer was effectively excluded from the polymer chains at the silica-polymer-air interface. When excluded from the tightly bound polymer, the plasticizer existed in an environment that was similar to that of pure plasticizer. At larger adsorbed amounts, the plasticizer was effective at lowering the Tg of the adsorbed polymer.
Recommended Citation
B. Hetayothin et al., "Does Plasticizer Penetrate Tightly Bound Polymer in Adsorbed Poly(vinyl Acetate) on Silica?," Macromolecules, vol. 50, no. 5, pp. 2092 - 2102, American Chemical Society, Mar 2017.
The definitive version is available at https://doi.org/10.1021/acs.macromol.7b00022
Department(s)
Chemistry
International Standard Serial Number (ISSN)
1520-5835; 0024-9297
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2024 American Chemical Society, All rights reserved.
Publication Date
14 Mar 2017
Comments
National Science Foundation, Grant DMR-1005606