The Influence of Initiator Concentration on Selected Properties on Poly-N-Vinylcaprolactam Nanoparticles
| Autor: | Aleksandra Niżniowska, Agnieszka A. Gola, Witold Musiał |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
chemistry.chemical_classification
Thermogravimetric analysis Aqueous solution General Chemical Engineering Dispersity Cationic polymerization n-vinylcaprolactam 2-acrylamido-2-methyl-1-propanesulfonic acid Polymer N-vinylcaprolactam lower critical temperature solution Lower critical solution temperature Article lcsh:Chemistry cationic initiator chemistry Dynamic light scattering lcsh:QD1-999 Precipitation polymerization General Materials Science nanoparticles conductivity Nuclear chemistry |
| Zdroj: | Nanomaterials Nanomaterials, Vol 9, Iss 11, p 1577 (2019) Volume 9 Issue 11 |
| ISSN: | 2079-4991 |
| Popis: | The thermosensitive polymers of N-vinylcaprolactam P1, P2, P3, P4, and P5 were synthesized via the surfactant free precipitation polymerization (SFPP) at 70 ° C in the presence of cationic initiator 2,2&rsquo azobis[2-methylpropionamidine] dihydrochloride (AMPA). The influence of various concentrations of initiator AMPA on particle size, aggregation and lower critical temperature solution (LCST) was investigated by dynamic light scattering (DLS) measurement. The conductivity was measured in the course of the synthesis and during temperature decrease of the reaction mixtures. The polymers were characterized by Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), 1H NMR, and thermogravimetric analysis. Thermal parameters of the degradations process were investigated using thermogravimetric analysis (TGA/DTA) under non-isothermal conditions in N2 atmosphere. The samples were characterized by powder X-ray diffraction analysis (PXRD).The hydrodynamic diameter (HD), polydispersity index (PDI) and zeta potential (ZP) were measured in aqueous dispersions of the synthesized polymers in temperature 18&ndash 45 ° C. HD and PDI values at 18 ° C were 137.23 ± 67.65 nm (PDI = 0.53 ± 0.18), 83.40 ± 74.46 nm (PDI = 0.35 ± 0.08), 22.11 ± 0.29 nm (PDI = 0.45 ± 0.05), 29.27 ± 0.50 nm (PDI = 0.41 ± 0.04), 39.18 ± 0.57 nm (PDI = 0.38 ± 0.01) for P1, P2, P3, P4, and P5, respectively. The aqueous solutions of the obtained polymers at 18&ndash C had a positive charge. ZP&rsquo s for P1, P2, P3, P4, and P5 polymers at 18 ° C were 11.64 ± 4.27 mV, 12.71 ± 3.56 mV, 3.24 ± 0.10 mV, 0.77 ± 0.28 mV, 1.78 ± 0.56 mV respectively. The LCST range was between 32 and 38 ° C. We conclude that the concentration of initiator affects the size of obtained polymeric spheres and theirs LCST. |
| Databáze: | OpenAIRE |
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