Viscosity Variation During Addition of Ester and Ether Macrodiols to Isocyanates
| Main Authors: | Paulina Nemaniutė, Marijus Jurkūnas, Dalia Bražinskienė, Svajus Joseph Asadauskas |
|---|---|
| Format: | Proceeding poster Journal |
| Bahasa: | eng |
| Terbitan: |
, 2021
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/6359427 |
Daftar Isi:
- Polyurethane blends usually thicken up during the polymerization, but unexpected drop in viscosity could be occasionally observed [1]. In this study, an oligomeric ether-ester macro diol (EEMD of 2700 g/mol) [2] was diluted with polyethylene glycols (PEG of 200 g/mol or 400 g/mol). The polyols were mixed with a trifunctional adduct of hexamethylene -1,6- diisocyanate (HDI3, CAS 3779-63-3) at 1.4 mol excess to initiate addition reactions and assure eventual gelation. Within 1 min of mixing dynamic viscosity η was measured using Anton Paar MCR 302 rheometer and a concentric cylinder system. The spindle was lowered leaving 1 mm gap between cylinders and assuring the absence of air bubbles. Viscosity was measured at 3 different shear rates: 1 s-1, 10 s-1, 100 s-1, see fig 1. The theoretically predicted viscosities are somewhat higher than measured. During early stages of polymerization the viscosity is highly dependent on shear, but later the trends become Newtonian-like [3]. Despite ongoing polymerization, viscosity seems to drop initially, or at least stagnate. It remains unclear what causes such unusual tendencies of viscosity dependence on polymerization
- Abstract and poster from the conference. The same abstract can also be found on pg 175 within the proceedings website https://www.ebooks.ktu.lt/eb/1561/advanced-materials-and-technologies-book-of-abstracts-of-23rd-international-conference-school/