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Synthesis, Thermal Properties, and Thermoresponsive Behaviors of Cyclic Poly(2‐(dimethylamino)ethyl Methacrylate)s
Author(s) -
An Xiaonan,
Tang Qingquan,
Zhu Wen,
Zhang Ke,
Zhao Youliang
Publication year - 2016
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201600152
Subject(s) - methacrylate , materials science , thermal , polymer chemistry , chemical engineering , polymer , composite material , thermodynamics , copolymer , physics , engineering
This study aims at physicochemical properties of thermo‐ and pH/CO 2 ‐responsive cyclic homopolymers. Three examples of cyclic poly(2‐(dimethylamino)ethyl methacrylate)s (PDMAs) are synthesized by combining the reversible addition–fragmentation chain transfer process and the Diels–Alder ring‐closure reaction. After cyclization, the glass transition temperature significantly increases (Δ T g = 51.8–59.7 °C) due to the different configurational entropy and end groups, and the maximum decomposition temperature to lose the pendent groups is drastically decreased from 309 to 278 °C. Effects of polymerization degree, polymer concentration, additive of NaCl, and pH/CO 2 on lower critical solution temperature behaviors of PDMA aqueous solutions are investigated. The cloud points ( T c ) of ring PDMAs are usually higher than their linear precursors, and the Δ T c values obtained under a fixed condition can reach up to 20.7 °C, revealing the crucial role of the topology effect. This study paves the way for unique properties and applications of smart cyclic polymers and their derivatives.