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Changes in hydrogen bonding in protein plasticized with triethylene glycol
Author(s) -
Hicks Talia Maree,
Verbeek Casparus Johannes Reinhard,
Lay Mark Christopher,
ManleyHarris Merilyn
Publication year - 2015
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.42166
Subject(s) - triethylene glycol , hydrogen bond , polymer chemistry , materials science , plasticizer , chemical engineering , chemistry , polymer science , organic chemistry , composite material , molecule , engineering
Bloodmeal decolored with 4 wt % peracetic acid can be extruded into a semi‐transparent bio‐plastic through the addition of sodium dodecyl sulfate (SDS), water, and triethylene glycol (TEG). TEG is often used to plasticize protein thermoplastic materials because of its ability to form both hydrophobic and hydrogen bonds. Synchrotron‐based FT‐IR was used to monitor changes in the types of hydrogen bonding occurring in TEG plasticized protein during heating. Heating was found to overcome a portion of the weaker hydrogen bonds found within and between proteins, observed as a blue‐shift in the N‐H and O‐H stretching vibrations occurring at ∼3280 cm −1 . TEG was shown to be involved in a larger array of hydrogen bonding environments after heating, evidenced by the broadening of the C‐OH stretch around 1076 cm −1 , suggesting improved plasticizer‐protein interactions. Additionally, these bonds were found to be as strong as the original interactions, observed as a shift in the C‐OH peak back to its original wavenumber (∼1076 cm −1 ) during cooling. Initially, TEG was spatially distributed into distinct plasticizer‐rich and plasticizer‐poor domains, giving rise to two glass transitions. Heating allowed the migration and uniform dispersion of TEG throughout the material, and merged the two glass transitions into one broader glass transition region. Heating during DSC removed the peak around 60°C corresponding to the enthalpy of relaxation, which is associated with physical aging of amorphous and semi‐crystalline polymers. While physical aging occurred during the storage of DBM, in the presence of TEG it occurred to a lesser extent. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42166.