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Shear and extensional viscosity of thermally aggregated thermoplastic protein
Author(s) -
Uitto Jussi M.,
Verbeek Casparus J. R.,
Bengoechea Carlos
Publication year - 2020
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.49393
Subject(s) - plasticizer , rheometry , materials science , thermoplastic , polyol , rheology , triethylene glycol , pressure drop , composite material , extrusion , extensional viscosity , ethylene glycol , drop (telecommunication) , shear (geology) , capillary action , chemical engineering , polymer chemistry , shear viscosity , thermodynamics , polyurethane , telecommunications , physics , computer science , engineering
Novatein is a thermoplastic produced from blood meal and is used in different agricultural applications. Novatein has some unique processing challenges and its rheology was studied using screw‐driven capillary rheometry, with a particular focus on sheet extrusion using ethylene glycol, glycerol, propylene glycol (PG), or triethylene glycol (TEG) as plasticizers. The entrance pressure drop contributed up to 44% of the total pressure drop (entrance and capillary pressure drop), but this was significantly reduced by plasticization or increased temperature. Polyol addition led to higher shear viscosities in comparison to no polyol plasticization, most likely due to improved chain mobility resulting in orientation effects. Elongational flow was dominated by primary plasticization of the protein‐rich phase and changes in secondary structure, whereas secondary plasticization (phase separation into a polyol‐rich phase) played a significant role in the reduction of the shear viscosity. Of the selected plasticizers, PG showed the most efficient plasticization in both shear and elongational flow. When combined with the beneficial secondary structural changes brought about by TEG, the sheet forming ability of Novatein was drastically improved.