Effect of n ‐Alkyl Side Chain Length on the Thermal and Rheological Properties of Poly N ‐(3‐(alkylamino)‐ N ‐(3‐(isopropylamino)‐3‐oxopropyl)acrylamide) Homopolymers

• Published in: Macromolecular chemistry and physics Vol. 222; no. 15
• Main Authors: Kumari, Archana, Vishwakarma, Sambhav, Mitra, Kheyanath, Chen, Chuangbi, Cui, Shuming, Maiti, Biswajit, Mondal, Sourov, Biswas, Chandra Sekhar, Maiti, Pralay, Stadler, Florian J., Ray, Biswajit
• Format: Journal Article
• Language: English
• Published: 01.08.2021
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.202100118

Abstract Four new N ‐isopropylacrylamide‐ and N ‐ n ‐alkyl amine‐based acrylamide monomers, N ‐(3‐(alkylamino)‐ N ‐(3‐(isopropylamino)‐3‐oxopropyl) acrylamide (Mn) ( n = 4, 8, 10, 12) are successfully synthesized and polymerized via reversible addition‐fragmentation chain‐transfer polymerization (polyMn, n = 4, 8, 10, and 12), which are characterized by gel permeation chromatography, 1 H NMR, Fourier transform infra red spectroscopy, thermo‐gravimetry‐differential thermal analysis, differential scanning calorimetry (DSC), and rheology. All polymers are thermally stable and undergo a two‐step degradation process at ≈280 and ≈375 °C. Glass transition temperature ( T g )s of these polymers decrease gradually from 99.6 to 52.5 °C with increasing n ‐alkyl side chain length. The rheology of these polymers in melt state agrees to a typical Rouse‐melt behavior and allows for confirming the T g determined from DSC. Benzyl alcohol solution rheology proves a weak structural build‐up, in particular for polyM12. Comparison of the quantum chemical calculations of polyMns with n = 4–8 reveals increase in backbone helicity with increasing n ‐alkyl side chain length.