Morphology, micromechanical, and macromechanical properties of novel waterborne poly(urethane-urea)/silica nanocomposites

0568974 - ÚMCH 2024 RIV CH eng J - Journal Article
Gajdošová, Veronika - Špírková, Milena - Aguilar Costumbre, Yareni - Krejčíková, Sabina - Strachota, Beata - Šlouf, Miroslav - Strachota, Adam
Morphology, micromechanical, and macromechanical properties of novel waterborne poly(urethane-urea)/silica nanocomposites.
Materials. Roč. 16, č. 5 (2023), č. článku 1767. E-ISSN 1996-1944
R&D Projects: GA MZd(CZ) NU21-06-00084
Grant - others:AV ČR(CZ) ASRT-22-01
Program: Bilaterální spolupráce
Institutional support: RVO:61389013
Keywords : mechanical properties * microindentation * polyurethanes
OECD category: Polymer science
Impact factor: 3.4, year: 2022
Method of publishing: Open access
https://www.mdpi.com/1996-1944/16/5/1767

Morphology, macro-, and micromechanical properties of novel poly(urethane-urea)/silica nanocomposites were analyzed by electron microscopy, dynamic mechanical thermal analysis, and microindentation. The studied nanocomposites were based on a poly(urethane-urea) (PUU) matrix filled by nanosilica, and were prepared from waterborne dispersions of PUU (latex) and SiO2. The loading of nano-SiO2 was varied between 0 (neat matrix) and 40 wt% in the dry nanocomposite. The prepared materials were all formally in the rubbery state at room temperature, but they displayed complex elastoviscoplastic behavior, spanning from stiffer elastomeric type to semi-glassy. Because of the employed rigid and highly uniform spherical nanofiller, the materials are of great interest for model microindentation studies. Additionally, because of the polycarbonate-type elastic chains of the PUU matrix, hydrogen bonding in the studied nanocomposites was expected to be rich and diverse, ranging from very strong to weak. In micro- and macromechanical tests, all the elasticity-related properties correlated very strongly. The relations among the properties that related to energy dissipation were complex, and were highly affected by the existence of hydrogen bonding of broadly varied strength, by the distribution patterns of the fine nanofiller, as well as by the eventual locally endured larger deformations during the tests, and the tendency of the materials to cold flow.
Permanent Link: https://hdl.handle.net/11104/0341942