Hydroplasticization of latex films with varying methacrylic acid content
| Autor: | Olaf C. G. Adan, Loes van de Kamp Peeters, Bart Erich, Jurgen Scheerder, HP Henk Huinink, Benjamin Voogt, Paul Venema |
|---|---|
| Přispěvatelé: | Transport in Permeable Media, Thermo-Chemical Materials Lab |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Physics and Physical Chemistry of Foods
Polymers and Plastics Carboxylic acid 02 engineering and technology engineering.material 010402 general chemistry 01 natural sciences Hydroplasticization Coating chemistry.chemical_compound Coatings Materials Chemistry Copolymer Dimers Plasticizing effects VLAG chemistry.chemical_classification Chemistry Carboxylic acids Organic Chemistry Relaxation (NMR) Acrylic co-polymers Carboxylic acid groups Relaxation time Dynamic mechanical analysis Polymer Molecules 021001 nanoscience & nanotechnology 0104 chemical sciences Polymer mobility Chemical engineering Methacrylic acid engineering Proton NMR 0210 nano-technology Methacrylic acids Polymer domains Plastic coatings Proton mobility |
| Zdroj: | Polymer, 166, 206-214 Polymer, 166, 206-214. Elsevier Polymer 166 (2019) |
| ISSN: | 0032-3861 |
| Popis: | The hydroplasticization of coatings of acrylic copolymers with different amounts of methacrylic acid (MAA) was investigated to clarify the role of carboxylic acid functionalities on the change in polymer mobility due to water uptake. The coating T g as a function of water uptake was studied using dynamic mechanical analysis. The T g 's decreased with increasing water content, confirming the plasticizing effect of water on the coatings. At relative humidities RH between 0 and 60% the coating T g shows a sharper decrease than at higher RH, an effect that increases with increasing MAA content. This behavior is attributed to the presence of dimers of carboxylic acid in the coatings, which is also observed with FTIR-ATR analyses. Due to water uptake, the dimers are disrupted and form “open” dimers where carboxylic acid groups remain in close proximity and are connected through water molecules. With 1 H NMR relaxometry, two T 2 relaxation times are found, representing two hydrogen pools with different mobilities. Both mobilities increase with increasing water content, indicating the presence of polymer domains with different hardness. Correlating the T 2 relaxation times with the coating T g 's shows that at higher MAA content the proton mobility as a function of T g of the soft domains increases with increasing MAA content. Since the polymer proton mobility, and hence the polymer mobility, is expected to scale with the polymer T g , it is hypothesized that harder domains are present in the coatings, which are not visible in the Ostroff-Waugh decays due to the fast relaxation behavior of these protons. |
| Databáze: | OpenAIRE |
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