The effects of poly(ethylene glycol) grafting density on the extensional solution flows of high molecular weight polyacrylamide

The effects of poly(ethylene glycol) grafting density on the extensional solution flows of high molecular weight polyacrylamide

Controlling the extensional rheological properties of solutions is of great interest for a number of applications, such as printing and coatings, as polymeric additives can modify a fluid's droplet size, formation, and breakup. We have measured the extensional flows of polyacrylamide graft poly...

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Bibliographic Details
Published in:Journal of polymer science (2020) Vol. 62; no. 16; pp. 3848 - 3860
Main Authors: Linscott, Adam, Zhu, Rene, Hong, Lauren, Castellanos, Madison, Morozova, Svetlana
Format: Journal Article
Language:English
Published: Hoboken, USA John Wiley & Sons, Inc 15-08-2024
Wiley Subscription Services, Inc
Subjects:
Breakup
Density
drop‐on‐substrate rheology
extensional rheology
fluid dynamics
graft density
graft polymers
Grafting
Polyacrylamide
Polyethylene glycol
Polymers
Relaxation time
Rheological properties
Rheology
solution flows
Substrates
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Summary:Controlling the extensional rheological properties of solutions is of great interest for a number of applications, such as printing and coatings, as polymeric additives can modify a fluid's droplet size, formation, and breakup. We have measured the extensional flows of polyacrylamide graft poly(ethylene glycol) amine (PAM‐g‐PEGa) solutions as a function of grafting density. PAM‐g‐PEGa is synthesized with grafting densities of 2.5%, 5.5%, 8%, and 30% and extensional flow was analyzed with drop‐on‐substrate rheology. Flow time scales and profiles are then compared to understand the effects of backbone extension from the addition of side chains. At low grafting densities, the viscous friction from the added side chains is comparable to, and in some cases, counteracts the losses in extensibility to the graft polymer's backbone, leading to increases in the relaxation time of the polymer. At higher grafting densities, the extension of the backbone reduces the relaxation time. By characterizing the effects of the graft density architecture on extensional flows, we are able to fine‐tune and control the breakup dynamics of elastic solutions.
ISSN:2642-4150
2642-4169
DOI:10.1002/pol.20230449